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Exhaust headers, good upgrade?

29K views 68 replies 11 participants last post by  AutoBravado  
#1 ·
Hi Frontier Enthusiats!

I've been seeing a lot of stainless steel exhaust headers for about $150 on eBay. I spotted one for about $20 less, but I can't find it anymore. They all appear to be the same despite the price differences.

Much to my surprise I spotted what I believe to be an identical product on Amazon for only $100.

Has anyone tried these? Any fitment issues?

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And finally a link to see it on Amazon:


I plan to replace the original catalytic converters with an upgrade from Eastern as they are bad while I'm in there. I have some cutting and fitting skills so I believe I'll be able to put a less restrictive converter in (made in the U.S.A.) by fitting it into the old bracket ends. It's not a high flow, it just has a bigger in and out to make it less restrictive. I don't know if anyone has tried it yet.

I look forward to the feedback.
 
#2 ·
Actually, I found a review under one of the other listings for these identical headers.

Rated at 2 stars between a 1 and 3 star review being averaged.

For the issues, these stars are generous.

Holes were too small. Gaskets didn't fit. EGR had to be heated and bent to move over 2" to fit.

I did find a better rated reviewed item for only $36 more dollars.
Images:
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There are a few more pictures on the link on Amazon. I couldn't seem to get those image locations to make it easier to see on the thread.
 
#3 ·
you usually get what you pay for with those cheaply made ebay headers... they're usually all the same factory out of china. it'd be a miracle if it fit w/o issues. i also just read that our trucks benefit almost nothing from headers because apparently the factory manifolds are very good already, not sure about the cats though. no idea if you'd have enough room for bigger ones but i would shy away from 'high flo' cats because they don't burn up the exhaust enough and really stink out anyone behind you, and depending on the state you live in might not pass emissions.
definitely let us know all about the install if you go for it... the more pics the better! i'd love to find some good power adders for this rig...
 
#4 ·
I have to agree. Headers is one thing I would not cut cost.
 
#5 · (Edited)
Some history, roadblocks, and a phew, I'll pass!



This all got started in my minds eye 2 years ago when I saw that my catalytic converters were starting to get weak on live data. I knew they were going to go.

I wasn't certain, but I thought I was trying to add a thread in the 1998-2004 Nissan Frontier forum if that makes any difference. It's just an iron bar, which immediately goes into a catalytic converter. By putting these headers, or something like it on, the 1st set of catalytic converters are deleted. Replace the next set with quality ones and I should stop having my check engine light turn on.

I was very surprised. In the last week the o2 sensor pattern downstream looked like the cats were behaving themselves so I am going to get inspected a few months ahead. Maybe they like the winter?

Yes, I agree, headers is not something you can't cheap out on without issues, but while these are cheap, they are also the only ones I've found for sale at all...excepting some $400ish ones which deleted both sets of cats, and I don't want cats that far back and then you have to run extra wires on your oxygen sensors...cats that far back aren't as effective...it might be an emissions nightmare.

you usually get what you pay for with those cheaply made ebay headers... they're usually all the same factory out of china. it'd be a miracle if it fit w/o issues. i also just read that our trucks benefit almost nothing from headers because apparently the factory manifolds are very good already, not sure about the cats though. no idea if you'd have enough room for bigger ones but i would shy away from 'high flo' cats because they don't burn up the exhaust enough and really stink out anyone behind you, and depending on the state you live in might not pass emissions.
definitely let us know all about the install if you go for it... the more pics the better! i'd love to find some good power adders for this rig...
Don't worry, I didn't plan on high-flow cats. I know they just mean you won't pass your emissions. I don't know how all the guys on the YouTube shows get away with them...or if they really are.

I was just planning on a bigger bodied catalytic converter, same high number of cells, just a bigger space to allow the engine to breathe through them a little easier.
 
#6 ·
IIRC, longtube headers return more on your investment. I think these are shorties, which aren't as effective. Thoughts?
 
#13 · (Edited)
The competition



I've been looking around, and I found on CARiD a number of manifold systems, as you can check out here:
Nissan Frontier Short, Long, and OEM style headers.

It turns out that the Amazon and eBay headers, which are all most likely made in the same factory in China, are all considered long tube headers. The Short Tube headers, which come stock on these vehicles are absolutely horrible from what I know of exhaust headers. So I'm not sure how people have said they don't help much...if they don't either Nissan did a better job at what's normally a lousy concept, or even the longer tubed headers still aren't tuned for pressure waves.
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And Flowmaster looks like Dormans's copy of "OEM":

Still Trying to get images to stick.

As you can see, the moment the the exhaust is out, they're all sharing the same pipe. I'm sure this is causing all kinds of chaos in the pulse waves. I could be wrong, somehow in these tiny spaces, perhaps Nissan pulled off the math to strike a good balance, but usually these aren't any good.

As you may know a good exhaust improves intake. It's the exhaust leaving the cylinders and the slight overlap between exhaust and intake which actually pulls the intake charge. In fact, the exhaust creating momentum for the intake is 8 times the force of the cylinder going down to create draw or pull. With these mess of headers, I'd think that a lot of the wave forms out of one exhaust would be inharmoniously interrupting their brother cylinder wave forms. Exhaust doesn't just flow out and intake doesn't just flow in, the pressure waves in a bad design can actually lose a lot of this momentum and energy. (every exhaust and intake includes flow in the opposite direction, you don't have to take my word for it, buy some books from David Vizard on Amazon. Flow can simultaneously be in opposite directions depending what part you're at, the edge, the center, etc.)

According to the labels of the exhaust headers on CARiD, like the eBay and Amazon headers, they are considered long tube headers.

What's interesting, is the original exhaust headers are hard to even call headers, the way they immediately go into one pipe, then hook up to the cats. Also interesting, the Magnaflow catalytic converters I was originally looking at at $260 per bank bolt in, while there are several options to replace the manifolds along with the 1st set of catalytic converters with it all in one piece. I'd think forcing the header and catalytic converters to be replaced at the same time would be a way to make the job even harder.

Above are actually the short tube headers available. Magnaflow include would could be called medium tube headers in a way, as they give separate tubes for each runner unlike the original, then they collect together at the catalytic converter as seen below:

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CorrectedDoug Thorley headers at about $459 on CARiD and on Amazon are ceramic coated inside
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#7 ·
high flo cats passing emissions depend on where you live. some states don't even have emissions testing, lucky folks. some are brutal and not only do OBD2 check for O2 but also a visual check, and sniffing the pipe. in those cases what those guys do is mod anyway and just 'stock out' when it's emissions testing time, then when that's done they swap their performance parts back on. where i live they only do the obd2 check, so there are lots of folks here that are catless and pass, as long as they can trick the computer to not throw a cel, which is super easy, any tune will disable O2 CEL upon request. I hate when i get stuck behind some modded car that obviously has no cats (or a high flo cat) because I can't breathe...! nowadays i wouldnt want to have such a stinky vehicle. what i REALLY want is a supercharger for this truck, but it seems like no one makes them any more. but considering how much they cost, i wouldn't be getting one any time soon anyways...
 
#9 ·
Yep agree with everyone's comments. Check out Car ID (one of our sponsors) for your '04 and can PM them for the best price.

You are looking at 4-10 bills plus labor, depending on what you go with for stainless steel.

Good luck in your search.
 
owns 2012 Nissan Frontier PRO-4X CC LUXURY
#10 ·
I've run on a street car a set of cheap headers (Thorleys) and a set of nice headers (TTI). In an attempt to make the cheap headers better I took 'em to the ceramic coating place and had them ceramic coated inside and out. By the time I had them good enough I'd spent enough that it was a waste of money and I should have just bought good headers to start with. Had to go to the more expensive headers when the newer, bigger transmission didn't clear at the collectors, those were much better products with thicker flanges and they sealed better.

Personally I would not put merely chromed headers on. Ceramic coated headers help reduce engine-bay heat, and quality headers will have at least 1/4" thick flanges, if not 3/8". Cheap headers won't seal well against the block and will heat up the engine bay, causing problems for all those lines, hoses, and wire looms.
 
#15 · (Edited)
HAHA! The ceramic coated ones are Thorleys, like you were mentioning! ~$465



So you'd like then the latest higher quality pipes I found. I mentioned them, but the picture didn't stick. I guess Amazon is protecting links to their pictures. Hey, I may be helping them sell some just by talking about it, the least they could do is let me use the picture, lol.

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Before I started this thread, I planned on headers which would eliminate 2 cats, and replace the secondary catalytic converters with aftermarket wide mouthed ones, since that made so much power on my Chevy Prizm (though this car originally had just 1). When I started this, I thought the first catalytic converters were "secondary", but it turns out having inspected the actual truck, that to do my plan, I'd need to extend all 8 wires for the downstream oxygen sensors. I truly think this is a pain in the neck, and is very difficult to achieve unless you are good at soldering, AND finding a way to secure the wiring safely away from the exhausts (I'm good at wiring, but even being good, it'd have to be perfect to keep the PCM happy). I think to make this wire placement possible would require drilling or welding up hooks so it was even possible to secure wiring this much father down stream. I'd highly recommend not even doing this exhaust mod if you ever want to offroad. The original downstream O2 sensor positions are pretty deep and safe, the new positions would be much more vulnerable to what you're driving over if you're offroading.

Maybe I'm worrying too much, the secondary catalytic converters are actually pretty close to the wheels. You'd really have to drive over something big and awful and not put your tires over the obstacle to make this a problem.

I've never drilled into pipe to install more O2 sensor bungs, in general, I hate drilling metal. It gets expensive quickly...so the original thought I had for aftermarket, but very strong 400 cell catalytic converters (high flow would be about 200 cells, so this should be emissions friendly) won't be as easy unless I switch to a catalytic converter which includes an O2 sensor bung in the body of the catalytic converter.

Has anyone ever run an O2 sensor in the body of the catalytic converter when it wasn't originally designed that way? I really don't see that design often...likely almost not at all...and when I do it's usually an aftermarket catalytic converter where we just weld the bung seal so it can't fall off and leave the O2 sensor in the pipe's bung a little behind the catalytic converter. My best guess on how this would effect things is that it'd make the sensor more sensitive to issues with the catalytic converter. I like the environment, but I don't want making passing emissions too difficult either.
 
#11 ·
Perhaps obvious, but unless headers are plug'n'play...it will require custom work to attach rest of exhaust system. Do it once, do it right. Cheap headers don't last very long...I know this from my wrenching days.
 
#12 · (Edited)
I've done several exhaust installs. I wouldn't say I'm good at it from the perspective of doing it quickly to get paid well at it at work, but from a DIY perspective, I'll end with a good result even if it takes me a little longer to get there.

Exhaust manifolds, I've found, to be the most frustrating even with things easily come off with a little penetrating spray. Even when they come off easily enough, the fact that none of the bolts ever seem to be tapered to make them start easily is my nemesis. In fact, when dealing with them, I'm usually being about 50% productive in comparison to flag rates.

As far as cheap, and not lasting, phew, thanks! I didn't know!

Now when it comes to shaping pipes before being welded, I'm not that great, so if I can purchase things which don't need a lot of modification, I'll be overjoyed. When it comes to welding while I'm not picture perfect, I get good penetration, and generally a few pin holes which I'll miss repeatedly on the reweld, lol, especially when welding in blind spots.

However, as far as flag rates go, while I'm not 200% efficient like a mentor of mine, I'm sometimes 133% for the welding portion of exhausts. ::smile::
 
#14 ·
Not sure true long tubes are made for the 3.3? There are stock manifolds, shorties and long tubes for 4.0, IIRC.

My experiences w/ cheap headers was a l-o-n-g time ago w/ a Ford small block. I recall them lasting maybe 1-1.5 yrs before there was a hole(s) due to rust. I always painted/treated them prior to installing, but it didn't matter. This was before China existed. LOL
 
#16 · (Edited)
Just looking at those headers, they neck-down too much at the collectors, or else the primary tubes are bigger than they need to be. Granted, exhaust condenses/contracts as it cools (in the 50s and 60s it wasn't uncommon for exhaust pipes to narrow 1/4" to 1/2" after the mufflers) but at this point in the exhaust system the products are still in active combustion and expansion rather than cooling down and condensing.

Extending the wiring for the various sensors doesn't have to be too horrible if you can find both the same and the opposite-gender connectors for the one on the end of the harness, to build what basically amount to extension cables. Additionally you don't necessarily have to use the bosses welded to the new headers, you can plug those and have new bosses welded just past the collectors on the headpipes.

I had installed a long-tube header on a '97 Stratus with a 2.4L DOHC I4. The header was actually for a Dodge Neon 2.0L DOHC but the exhaust ports and studs were the same. I did have to plug the O2 sensor hole on the collector (actually used a bolt with some exhaust-rated threadlocker and ground the head off so it would clear a structural member) and had the exhaust shop weld-on a new boss just past, worked well enough.

I suppose I should point out that good headers have equal-length primaries. If they don't then you may not really be getting much over the stock manifolds. The old Thorleys I had were so old they were still marketed as "Doug Thorley #52", which I assume is the 52nd model of header that his company had designed and sold. I really couldn't say if current ones are better, worse, or the same.
 
#17 ·
Due to how close the original headers are to the frame, I think on the 2004 Nissan Frontier there will never be a tuned header with equal length tubes to the collector.

The Thorleys have a much bigger collector than most available coming in at 1.75" instead of 1.5". The only one with a larger diameter for the collector is the magnaflow at 2.5", which I actually think is too large. All headers I've seen have primaries at 1.5", identical to stock.

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This would be the simplest of installs, but Magnaflow is well known for catalytic converters which don't last or don't work well enough to pass emissions at first install and coming in at over $700 it's very hard to swallow something which won't last. (Looking deeper into it, unlike other listings, they're selling each side separetly. They appear to be about $1,200!)

I'd have to hear a lot of first hand experiences of it making power and passing emissions to go for it AND that it lasted. (I said this when I thought $700 was for the set and not just 1 side! I'll do all kinds of custom fabrication before I spend this kind of money.)

And of course, the Magnaflows would mean if I were to delete catalytic converters they'd be the 2nd ones down the line instead of the first ones down the line...the worst part in all this is these catalytic converters are one with the headers unlike stock, where if there's an issue with any other plan, replacing the catalytic converters again would be a problem by itself.

Someone mentioned always painting their headers. I assume if it's ceramic coated this is unnecessary? Since only the Thorleys come ceramic coated, if I select anything else, I could use paint suggestions. These headers do get splashed on when ever you go through puddles. Sure there is a rubber skirt mostly covering them in the wheel wheel, but I'm sure some misting at least gets to them regularly as it's not a sealed space - probably to help with cooling.

I'm inclined to go with a paint, which is the same color as the intake I select. I'm more interested in knowing what paint is good...actually, mild steel paints easily enough, but what about stainless steel?
 
#18 ·
If they're ceramic they don't need to be painted. If you get ones that are full-polish they'll almost look chromed, slightly duller but still shiny.

I suppose that since I'm used to the V8 world when it comes to headers I'm biased, but I was accustomed to 2.25" or 2.5" collectors for smallblocks, and 2.5" to 3" collectors for mild-mannered bigblocks. I guess I would have expected 2" collectors on a large V6. After all, can always neck-down to 1.5" or 1.75" for a smaller factory exhaust system where the headpipe flanges meet the collectors.

As for equal-length primaries, you would be surprised what they manage to design in small spaces. I've seen Chrysler A-bodies with bigblocks with tuned headers. It's certainly not easy but the longer the headers the easier it is to achieve as that extra length means more room for the rearmost primary to stuff the slack needed for equal length.
 
#20 ·
Half a night of internet searches later...(tired, be forewarned)

If they're ceramic they don't need to be painted. If you get ones that are full-polish they'll almost look chromed, slightly duller but still shiny.
Note from AutoBravado, I didn't quite understand this second sentence, but can you confirm that the Thorleys have that "look"?
I suppose that since I'm used to the V8 world when it comes to headers I'm biased, but I was accustomed to 2.25" or 2.5" collectors for smallblocks, and 2.5" to 3" collectors for mild-mannered bigblocks. I guess I would have expected 2" collectors on a large V6. After all, can always neck-down to 1.5" or 1.75" for a smaller factory exhaust system where the headpipe flanges meet the collectors.

As for equal-length primaries, you would be surprised what they manage to design in small spaces. I've seen Chrysler A-bodies with bigblocks with tuned headers. It's certainly not easy but the longer the headers the easier it is to achieve as that extra length means more room for the rearmost primary to stuff the slack needed for equal length.
I appreciate the comment. :) That would be way too big in this case, lol. With 1.5" for stock primaries, this Frontier would really lose lower end torque, maybe even upper RPM HP! LOL Just a mild comparison of size looking farther downstream at catback systems even the V6 4.0 engine in the next generation of Frontier do poorly with any bigger than 2.25"...the start of an exhaust needs to be smaller pipes. You don't want to sacrifice velocity for scavenging.

With the stock exhaust essentially not having primaries and it just being one pipe for a collector, barely with 2 primaries going up to at at right angles (depending on how you look at it), this may be the time, which even untuned headers would be an improvement. Your comment was still of inspiration and it caused me to do some more internet searches. No luck yet for a tuned header or even a truly long header.

(Literally, getting excited and staying up halfway through my usual sleep cycle later)
(I may have to give up editing this anymore and post it; I'll find out how well tired brain edited tomorrow, LOL!)

I'm completely mistaken. Cheap claimed as stock and OEM replacements may be an improvement on the original as I described them:

Aftermarket but possibly very similar to stock:
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The original stock appear to be even worse than the above example, which I described.
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Further note on a stock design image; this was an attempt to get a stock image, but even a "Nissan parts website" sends me to eBay to find "official" parts. Possible, but unlikely. More likely aftermarket. These parts being on eBay for $63, the air quotes indicate doubt they were official parts.

The closest to tuned I ever saw, so deep in the internet, I can't find a brand, or even a familiar website which sales it...pretty iffy, but they're the only "long" tube header like websites try to claim, which don't have the 1st primary super long running above while 2 shorter ones go underneath. Diamond in the rough, or too risky?
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#19 ·
Header paint is likely nearly worthless...at least it was for my Ford small block aftermarket headers back in the day. I went w/ black. Though the smell of it burning off over the first few miles was pretty cool. lol Temps at the headers FAR exceeds temps at the muffler >>> where some paint 'might' be more useful if aluminized steel material. Go SS or ceramic FTW...if there is a win here.
:nerd:
 
#21 ·
The headers pictured in Post 15 look to me like ceramic-coated. They're bright but just that little bit duller than chromed would be.

I would also personally avoid chromed headers, the chrome will discolor due to heat and look bad very quickly, plus won't help the thermal characteristics of the engine bay at all.

I'm not an expert on exhaust systems by any means, but it's probably best to not try to think of stock/stockish manifolds in the same way as headers. Manifolds are probably best thought of as a pressure chamber common across all of the cylinders feeding it; hot gases from each cylinder push into the pressure chamber as it's bleeding-out into the rest of the exhaust system, so that backpressure as a whole is relatively consistent across all cylinders. By contrast, at least in a tuned header each primary is its own pressure chamber of roughly equal volume, so they pressurize in pulses and bleed-down in-sequence. By being equal length they pulse in-series and in-time at the collector so that the pressure has dropped from the previous cylinder to roughly the same for the next cylinder. When the primaries are not equal, this pulse and pressure drop is not as consistent, hence the disadvantage in not using equal-length primaries.

Unequal length headers probably would be a performance improvement over manifolds, but remember, back in the heyday of the late sixties the American automakers used manifolds even on the performance engines, and they sized their manifolds throughout to give some pretty impressive performance. I suppose the question really is if the headers will offer enough performance improvement to put up with the problems (cracking, leaking, heat, emissions) that will result from using them. If you're not going to redesign and replace the entire exhaust system in addition to the headers then I would think no, it wouldn't be worth putting them on. If you do replace everything past the heads, then perhaps it might. Obviously this is one man's opinion though, I'm sure that there are competing views with their own strong arguments.
 
#22 · (Edited)
What's driving me bat-"*)&" crazy is that the Magnaflow ones I showed you all are claiming a 15 hp increase and they're even using the original space for the primary catalytic converters - maybe it's the huge collector? I've found on my Chevy Prizm that a huge catalytic converter brought it form 59 wHP to 90 wHP. The magnaflow would be the simplest of installs of them all...but it's just too pricey. At about $1,200 I could be $900 into having my Chevy Prizm back onto the street which has a long list of mods. Then my truck could stop being used for commuting except maybe once a week to keep it up, bring some tools home for the weekend, stuff like that.

I tried after my half of a night of studying on what other people have done to find some dyno proof of any of my ideas (I was honestly very sick last night and these wonderful header studies kept me sane, thank you to EVERYONE for their comments and those who are listening in!). The closest I could get was on the next generation of Frontier from 2005 and up to some year. Now their engine bay is kinder to them (I guess based on what's available to them), and whenever I see the available headers for them I'm jealous - tuned headers are available, but yet, 1 dyno chart shows mid range to upper range power increases on headers which weren't tuned. Once the 4.0 saw a tuner as well, they got the power back on the low end (there was some O2 sensor confusion) and increased power again on the rest of the curve.

While extremely impressive I'm comparing maybe a gaila apple to a golden yellow. They're quite similar, but different engine, easily different results. They're both delicious but one is stronger. Gaila's are firmer so they're the 4.0 and the Golden Yellow is my 3.3L Frontier, lol.

I almost forgot the most important part! On the Frontier with the 4.0, the headers was the single most important power and efficiency gaining mod. Yes, full systems help, and intakes and all that, but they're all frosting on the cake of those headers.

Yes, plans are in play for other mods, but to me those are less complicated and confusing. And thank you. I have studied about pulse wave tuning and what not, but you're explanation of why equal length primaries just works really made it finally make sense to me.

In brief, since you're curious, I plan a cheap short ram intake for winter driving because the cold air is murdering my gas mileage. Hey, if it improves flow great, but the stock cold air intake would go back on when things warm up if funds aren't available for a cold air intake. I know how much hot air doesn't help with power, but I also have proof on my extensive testing on my Chevy Prizm that you can have too cold of air for efficiency to the point of it being power robbing. In fact, you can check it out on YouTube. ::wink::

https://youtu.be/SfTcm3J92E4

I also have a Flowmaster muffler if anyone knows if they're any good. I think it's a delta 40 if I recall correctly. I originally bought it for my Chevy Prizm, but Flowmaster said that it helped cars most if they had at least 24 more inches of piping after the muffler. That was impossible on my Chevy, and I was already pretty happy with the Magnaflow muffler (It looked to about rust through being aluminized steel, but apparently it's life time warranty so...) This Magnaflow muffler is mid sized SUV rated muffler may just belong on my Frontier to spice things up, without getting crazy noisy. >:D

My Chevy Prizm by the way for its first year or 2 after the cat back exhaust was so loud all my friends knew I was coming a couple blocks before they could see me. It calmed down, but it was way outside of my comfort zone. I wore ear plugs for the first year before carbon quieted things up...I'm not going through that again, lol. I'm sure I lost some down low torque and power before other mods woke that part of the car back up, but I got 55 MPG on the freeway in September and October on a monthly 313 mile trip. 44 MPG uphill and 55 overall down. Stock that car should do about 27, lol. Also, maybe I got lucky, but when I was done with her the torque app calculated based on OBD II data, that I had taken a 45 wHP car up to 117 wHP at it's hey day. :) I'm expecting less results form the Frontier, lol. The Prizm supposedly had 126 hp at the crank, but if so the factory really de-tuned the poor girl.

Sorry that was short story long. Can't help it. Loved the success of it.

@shift_RUSH, thank you! Now I know that Magnaflow could last longer with some paint. I thought it being aluminized would help it from rusting, and I suppose it did, but it really didn't fare any better than the mild steel piping going up to it . . . maybe it did worse.

For some reason when you say back in the day, it makes me think 80's trucks because those were the vehicles, which I first learned to change oil on, but not much more. If so, at least by their labels, header paint can take about 900 degrees more F than what I saw possible in the 90's (based on me just perusing at AutoZone's paint)...which basically made them barely good enough for a muffler if you ask me. 1,400 degree paint would have to be more than good enough since catalytic converters start bronzing at 1,000 degrees. They're not supposed to get that hot either. It's how they know they won't be honoring your catalytic converter warranty because you burned it up with misfires or something. And Catalytic Converters get way hotter than headers...at least on the cars I've shot my touchless thermometer at.
 
#23 ·
The closest to tuned I've seen yet...

Well of course, in my search, I've now accidentally seen that Frontiers with the 3.0 in the 80's also had long tube headers. It seems that the best exhaust manifolds always seem to be available on the next or previous generation for any vehicle I feel like upgrading, lol.

My Chevy Prizm or 8th generation Toyota Corolla doesn't have cool turbo and tuned header options and yet the 7th and 9th generation do.

Seems the only way around this is to go full custom...I'm afraid of what one off local quality can produce. Maybe I should, but I don't think I'm going this route.

Despite these setbacks, I have found a header, which I called risky in that I've seen this sellers website only a couple of times over the years. I believe I shared a picture of it, but here's a link to the website and product. I hope someone has had experience with them?

https://www.4x4parts.com/i-18916314-frontier-header.html
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Their flange is 13/32" thick instead of the usual 3/8" I was guided on this thread to at least get, so it's even a tad more sturdy than all the carid options.

The collector output is 1 3/4". Most are 1.5" just like the standard cylinder head openings are. So this is good...only the Magnaflow short tube header combined with catalytic converters is larger, and as I said before I worry that's actually too large. I don't mind bigger, but I feel that this close to the engine a huge increase in size will just cool the exhaust more with the expansion and slow it down, which I think could reduce scavenging. Maybe the Magnaflow's collector is better for peak HP and Torque, but while I like peak power, don't we all want increases down low which will help power and efficiency? Or at least less loss down low. Plus, the Magnaflow other than that collector, isn't much different than a simple Dorman product.
 
#24 ·
I found one more header to round out the list.

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This is a very different variant by Doug Thorley. As usual, I find Doug Thorley everywhere. They're the most beautiful that's for sure.

The variant above isn't ceramic coated - unfortunate, but I think I finally know why so many of the designs have the longest tube even longer...it's to get the EGR hooked up more easily. All the other designs require bending the EGR tube. Oh wait! By the description it IS ceramic coated! It's silver ceramic coated. Anyone know how that performs versus other ceramic coatings? Looking more at the stats it has a largest collector! 2.250 in. I know I knocked down the Magnaflow's must larger collector, but I can't help but be excited about this!

I think some of you were thinking that EGR hole was actually for an O2 sensor. No, commonly the O2 sensor is at the base next to the collector. An uniformed installer might try putting the downstream sensor there...since it normally is there right after the catalytic converter.

I don't like it when the upstream sensor is going into just one of the exhausts. All things being equal from injector to injector, spark plug and coil on plug to each combustion chamber, it may not matter, but I'm sure no engine is ever all that equal.

The only apparent better design than the Doug Thorleys is this no name brand on the 4x4 website. I'm sure in all honesty that the Magnaflow shorty and combined catalytic converter has it's place, but for my prejudice....my prejudice against Magnaflow Catalytic converters is from a parts store guy who said they were always returned unlike U.S. made Eastern's.
 
#25 ·
Of course the other thing I have against the Magnaflow is it's basically a shorty design and extreme cost, but it seems I've been duped again. These Doug Thorleys are the same, which I've just seen at yet another camera angle! LOL

But...the collector is reported so much bigger....hmmm...typo or a variant product?
 
#26 ·
Just an FYI, if you get bare headers you can have them ceramic-coated. That's what I had done with my old Doug Thorleys, took 'em to a local coatings shop and spent the bucks to have them ceramic coated inside and out. Granted mine didn't have any sensor holes (there are no exhaust sensors on a carbureted vehicle) so they didn't have to figure out coating thickness and oversize-tap the hole in advance to let anything screw down.
 
#28 · (Edited)
Doug Thorleys being steel and Ceramic Coated



That's awesome!

There's a chart for what exhaust material looks like what in how many years.

Mild steel did the worst. 2-3 years, very rusty.

Aluminized steel 3-5 years to look good in some places and very rusty in others.

409 stainless steel 8-10 years. Mottled appearance but not horrible.

304 stainless steel 10+ years, only minor changes in color with no rust. This is the only one, which a magnet doesn't stick to, except at bends and welds.

I got this on the Summit Racing website under the Doug Thorley Header pictures for my/our truck:
Image


Back to your comment. These Doug Thorleys aren't a special metal, but because they are ceramic coated they are doing very well. I was thinking about wrapping the headers to keep engine compartment temperatures down (stock these are VERY hot engine bays in especially in comparison to other trucks), but it turns out, that voids the warranty and assures destruction of Doug Thorley headers.

Also, I've read that ceramic coatings keeps more of the heat in the hot gases rather than soaking the heat into the headers. The cooling of the gases slows the gases down, and reduces scavenging.

How'd you modify the truck to not have a check engine light or "service engine soon" with this modification? Or, are you not in an emissions checked area?
 
#29 ·
ceramic coating is a much better long term solution compared to wraps. Wraps can (do) soak up water which causes the tubing to rust faster. Wraps also overheat the steel. I also remember reading that they (tubing) "wear out" from the inside-out due to the extreme heat.
ceramic coating is sprayed inside & out. The inside spray rejects alot of the heat and keep it "in" the exhaust gas.

As to how you prevent CEL, you can use an O2 spacer/de-fouler or you can have your ECM tuned (should do that anyway if you are doing headers so hte fuel maps can take advantage of free-er flowing) and the tuner can deactivate the error output (because it doesn't see a difference between sensor 1 & sensor 2). the spacers can be found on-line or in your local NAPA
 
#30 ·
ceramic coating is a much better long term solution compared to wraps. Wraps can (do) soak up water which causes the tubing to rust faster. Wraps also overheat the steel. I also remember reading that they (tubing) "wear out" from the inside-out due to the extreme heat.
ceramic coating is sprayed inside & out. The inside spray rejects alot of the heat and keep it "in" the exhaust gas.
Which is also why it's important to have them ceramic-coated prior to ever fitting them. If they've had exhaust through them then they cannot ceramic-coat the inside. The inside is arguably more important than the outside.
 
#34 ·
Moving forward...approximate wHP numbers

Hi guys (or gals, usually not many),

I really appreciate everyone's comments and support. I had no idea how much I didn't know before I started all this.

To me, it's down to the 4x4 website one, which is closer to tuned, and the Doug Thorley for greater ease of installation. (The 4x4 websites header is like some headers which need more alteration of the EGR for it to fit up.)

Further note: the 4x4 website is a sponsor of clubfrontier so somebody should be able to tell me if they have good, trustworthy service

It was easy when this thread started to think I could easily spend $100 for the header, another 2x$89 on 400 cell catalytic converters (assuming prices haven't changed there) and a bit more for extra supplies to help move O2 sensors and what not.

At $450 plus just for the headers I apologize I won't be moving forward quite as quickly as I first started but as I learn more or make a purchase, I'll let you know.

If I knew how to add to the thread a vote for keeping this thread purer to the task at hand or not, I'd ask for it.

But here's a little tangent.

I bought a short ram air intake about a week ago and it's predicted to be here in the next few days. I don't like hot air intakes when it's hot, but it's super cold out so I thought it could at least be my winter intake, lol.

I did a baseline run using OBD II data and the torque app to calculate peak wHP. I was in shock that I have about 50 more wHP at about 3,300 RPM then my last test! The last test had another 1,300 to 1,800 RPM to get a much lower wHP number. What's changed? Fixed my knock sensor the hack way like is mentioned here:
http://www.clubfrontier.org/forums/f46/knock-sensor-relocation-how-41704/index45.html#post2569266

The other change is it was 8 degrees F...now everyone says cold air makes more power, but in the past, I've usually seen artic temperatures hurt power because you can have too much of a good thing.

I hate changing two variables at once...but if it's wanted, I may just unplug the knock sensor and test if it was the cold or the knock sensor which changed power so much.

After all, we do need a good baseline before the header goes in right?

Note: I've taken screenshots of wHP quite a few times, these numbers are approximate. I need to sort through my emails to find the hard numbers.
 
#38 ·
I bought a short ram air intake about a week ago and it's predicted to be here in the next few days. I don't like hot air intakes when it's hot, but it's super cold out so I thought it could at least be my winter intake, lol.

I did a baseline run using OBD II data and the torque app to calculate peak wHP. I was in shock that I have about 50 more wHP at about 3,300 RPM then my last test! The last test had another 1,300 to 1,800 RPM to get a much lower wHP number. What's changed? Fixed my knock sensor the hack way like is mentioned here:
http://www.clubfrontier.org/forums/f46/knock-sensor-relocation-how-41704/index45.html#post2569266

The other change is it was 8 degrees F...now everyone says cold air makes more power, but in the past, I've usually seen artic temperatures hurt power because you can have too much of a good thing.

I hate changing two variables at once...but if it's wanted, I may just unplug the knock sensor and test if it was the cold or the knock sensor which changed power so much.

After all, we do need a good baseline before the header goes in right?

Note: I've taken screenshots of wHP quite a few times, these numbers are approximate. I need to sort through my emails to find the hard numbers.
If you're getting 50 wHP from an intake, you found the best intake ever.

But no, it's the Torque app. A couple of my friends use the Torque app all the time on their German cars for everything except HP, because they never found it remotely accurate. Because it only calculates HP/Torque based on set input values (and not external variances), the Torque app was always way off from actual dyno pulls (which is the accurate way to measure wHP). Aside from HP though, all the other features of the Torque app work great.

Expanding on this more, when it comes to OBD-type apps and devices, they usually suck when it comes to calculating accurate HP/Torque, and here's why - All the OBD-type apps and devices all pretty much use the same method to calculate horsepower: it uses a combination of your phone's GPS location accuracy and the weight of the vehicle (some use wheel diameter too), plugs it into a calculation, and spits out a "horsepower/torque" number. Calculating HP/Torque isn't the same as actually measuring HP/Torque, because there's so many variables the calculation doesn't take into account.

For example, your phone's GPS isn't accurate enough to calculate precise distance travelled since it depends on your signal strength. As for vehicle weight, if you input the vehicle weight listed on the door label, it's already wrong. Vehicle weight can vary widely by occupant weight, any cargo weight, amount of liquids in the engine bay (not just the amount of fuel in the tank), any variation in vehicle equipment such as different tires or wheels, etc. And, wheel diameter can be measured - but that can change just by temperature. As far as I know (and if I'm wrong, someone tell me) there's no way to calculate HP/Torque - it must be measured, meaning an actual dyno which does take into account everything I listed above + ambient temperature, tire rolling resistance, etc. So I wouldn't take the horsepower/torque numbers an OBD-type app or device as accurate.

But wait - don't delete your Torque app just because of what I said. The popular OBD-type apps/devices usually do great when reading hard numbers (actual data taken from the ECU) and they are consistent when it comes to seeing changes. So if you're using the app for monitoring everything else from the ECU, keep doing it. I've been using my UltraGauge to monitor ECU readouts (temperatures, O2 sensor resistance, etc.) but I never believe the horsepower/torque numbers it's calculating ::smile::
 
#35 ·
On my old Sentra, spacing the downstream o2 sensor was all you needed to do to avoid a CEL. We would get a 2 pack of Non Foulers at autozone, drill one out to 1/2", and then leave the other as is. The drilled one would leave just enough clearance for the o2 sensor to fit through, the second would go first into the exhaust. This would avoid the P0420 code you get from having no cats/bad cats.

I also had a friend weld in a fake catalytic converter on the mid pipe. It looked like a cat, but it was a straight pipe through. In my county we have an OBD plug in, and visual inspection. I passed every year.

I will say, because my Sentra was an 06, the o2 sensor also calculated AFR's, it was the only year that did this. I would occasionally throw a different code that seamed to be popular on newer nissan (Newer at the time), I assume that had the same technology. Not sure if the Frontiers have this.
 
#36 ·
O2 sensors vs AFR's and working on power baselines



My Generation 1 Nissan Frontier (2004) has just plain O2 sensors.

I'm curious as to what popular codes you'd sometimes get?

Harder wHP numbers:

1/2/2018
On one recent run at a weather reported 17 degrees F I got 127 .5 wHP at 4875 RPM and 149.7 Torque at 3762 RPM. MAF maxed at 149 g/s - if I remember right my intake air was at 30 F.

12/30/2017
Another screen shot shows that on a warm winter day, maybe 50's outside? That my intake air was a surprising 102.2 degrees F...usually I found stock these Frontiers were close to ambient temperatures, thus my comments in the signature, why a cold air intake? (CAI)

12/29/2017
Prior to my knock sensor fix I got 77.8 wHP at 4325 and 94.5 torque at 4325 RPM. Not a good run. 20 more wHP is easy.

12/28/2017
I have a screen shot noting that on a 6 degrees F weather reported day my intake was 30 degrees F.
 
#39 ·
More power numbers - except for the MAF, there's no consistency

:( I was pretty excited about 50 wHP or 50% more real world power, but looking at the screen shots I must have remembered a g/s instead of a wHP.

Hey, that's why you have to work off of science and not just memory, right?

Against my best run 8 months ago I only had 7 more wHP, but recently vs. 8 months ago my worst run I got 37 more wHP. It sure is important to look at those screen shots before I run my mouth.

5%-41 more wHP at 4k-ish RPM is still a big difference :)

Looking at the numbers more, I have to say they're all over the place and not that clear of a picture. Just between the numbers below on different runs you could claim as much as a 26% difference, where the two kinds of air filters never clearly do better or worse - they both do both.

Now recent testing showing a big jump at the MAF is encouraging. That the recent best test did have ~14 g/s more of air moving than this summer. I gotta rule out of that was the cold air or the knock sensor hack fix.

I was really focused on g/s at WOT this summer as I was testing how a dirty K&N air filter did vs a clean new paper air filter. (They did the same.) Cleaned my K&N air filter and guess what. STILL basically the same g/s of air through the engine.

The power numbers are all over the place, but the MAF for airflow through the engine is pretty tight.

More hard wHP numbers wrote torque a lot instead of lb ft of torque at the wheels:
4/18/17
91.7 wHP @ 4275 RPM
113.6 torque @ 3775 RPM
120 MAF max, dirty K&N filter

4/18
126.7 wHP @ 3650 RPM (I threw out the torque below, but this should probably thrown out too as aberhent data)
threw out the torque (184 ft lbs) - impossible high, must have down shifted 2 gears instead of 1 (automatic)
121 MAF WOT with paper filter
Coolant 82C

4/18
90.4 wHP @ 4275 RPM
140.5 torque @ 3362 RPM
MAF 112 Coolant 84 C

4/18
97.4 wHP @ 3612 RPM
141.6 torque @ 3612 RPM
MAF 121.9 dirty K&N

4/18
96.9 wHP @ 4550 RPM
126.4 torque @ 3350 RPM
MAF 121 K&N

The last few runs I focused on waiting for the coolant temps to be with 2 degrees C and I waited for the intake temp to get back to 27 degrees C. After only 1 pull intake temps would go up to 41 degrees C and I'd have to cruise until it came back down.

4/23/17
34C intake after a pull and 84 coolant
110.2 wHP @ 4675 RPM
123.8 torque @ 4675 RPM
Back to the paper filter and MAF was 113 - or one hundred and low teens.

5/11/17
107.5 wHP @ 4488 RPM
137.3 torque @ 3612 RPM
114 MAF run with 34C intake
 
#40 ·
A few more power runs, finally showing something of interest

6/15/17

Humidity 73%
5920 lbs (Nissan Frontier, heavily burdened, two motorcycles and tons of household goods and all my tools)

Finally with a clean K&N air filter (well, mostly, drove across the country with it west to east coast, but while that's a lot of driving, that won't get any air filter dirty unless it was really dusty, and it wasn't):
95.5 wHP @ 4750 RPM
131.4 torque @ 3625 RPM
128 MAF
Air intake at 35C after run

6/15/17
101.3 wHP @4550 RPM
132 torque @ 3575 RPM
132 MAF paper

6/16/17
117.7 wHP @3962 RPM
156 torque @3962 RPM
128 MAF paper filter

Conclusion: unless you drive a LOT of miles, a K&N Air Filter isn't helping you with air flow or power on these trucks; however the gas mileage did look better on an uphill instant MPG test (same identical speed and MAF values - only variable changed was the air filter)

7/1/17
117 wHP @3962 RPM
156.1 torque @3962 RPM

One of the top engine builders (David Vizard, I own a couple of his books) in the country says running K&N air filters he helps engines make more power. I've seen the real dyno charts proving this, but maybe a necessary truth is that a K&N air filter really doesn't do anything for a stock truck. Without some serious racing modifications, your truck gets enough flow out of a paper air filter.

Well, I can't say any of my numbers are consistent enough to be ready for a truth about before and after exhaust headers, but what I can say is that I have tons of MAF data on K&N vs. paper filters and I'll know if the short ram helps with more air flow.


I hope the last two posts are appreciated...I've been avoiding typing up all that collected data for a long time. Took a couple hours minus social media distractions, lol.
 
#42 ·
I know, I know, Below is probably WAY too much justification for the Torque App, lol



The worst lag on any OBD II is O2 sensor data. We call it live data, but you can only get live data on something like that with a lab scope.

Also, it's limitation is more based on how fast the manufacturer communicates through the OBD II port more than the ability of the program.

A mid 2000's to current mustang will have the little green lights, which light up every update pretty much stay lit with barely a visible pause. Lighting fast. It's barely blinking out.

My 1999 Chevy Prizm, even on a dealer level scan tool? Severe lag. Every 1/2 second it could update, or 3. Kinda painful to diagnose issues with that data lag.

A 2004 Nissan Frontier? Somewhere in between.

Trying to describe it, I'd say there are about 8 updates in 3 seconds on the hp/torque curves. Since GPS speed lags too much Ian Hawkings, the Torque Pro creator actually has the speed calculated with OBD II speed information which is much quicker.

The biggest thing you can mess up for it is give the wrong weight for the truck.

In April my truck weight was what I could figure off of public data plus what I weighed and stuff that was normally in my truck and what it weighed.

After April, I had to have my truck weighed to prove I was moving enough weight for a move compensation. After that the hp/torque numbers tended to report a little higher. (My truck's weight had been underestimated)

The biggest thing that I was wracking my brains over as to why the information seemed to change too much. I think I figured it out. It is because this truck is an automatic and I need to hold it in a gear to get a better test.

IF that gets more consistent data, then Pro Torque to Pro Torque app, control and modification test run, given the same temperatures and the same piece of road, and not a windy day, the information should be good enough compared to itself.

At least on my Chevy Prizm, the numbers were very consistent and that was with abysmal update speed.
 
#46 ·
I emailed the 4x4 Club Frontier sponsor

I want to know about these better tuned headers. Who makes them?

Image


I didn't open with this, but my biggest worry is that it feels like there's so little information, that it's just some guy who builds it after it's ordered. Is he/she good? Orders, which may be "custom" in this sense have very little out if the product doesn't work out. They expect you to simply own it, even if there's a severe issue...exceptions being that you tried to install it immediately and at your own expense send it back.

Honestly the 4x4 rules and regulations of dealing with customers makes me very nervous to buy from them.