Sub 300whp & Aftermarket Headers

[covertrussian]

Is anyone running aftermarket EL or UEL headers/manifolds in Stage 2 or mild stage 3 setups on here? What's your experience with them and how do you like them?

 

I've been thinking about some aftermarket EL (Tomei or Perrin, Full Race and Killer be are just too much for this) or UEL (Tomei) headers ever since I removed the rusted headshields of my factory header. At which point I was reminded with how inefficiently designed the factory headers are, mainly with cylinder pairing and how soon the two adjacent cylinders merge.

 

Looking for better low end city driving response, better EGT control and reliability, overall efficiency, and better fuel economy (lots of people claim 2-3mpg+ on EL headers). Equal Length headers seem to deliver all those, but at a price, loss of the boxer rumble. Aftermarket Unequal Length headers seem to be much better then stockers (merges are further down the line and are usually 4-1 design) but power gains and fuel economy gains over stock is not talked about much at all.

 

 

EL vs UEL

Interestingly enough BRZ's have a really bad torque dip on factory EL headers. Aftermarket EL headers seem to help it a little, but UEL headers just about eliminate that torque dip. Another interesting bit is, in header world 4-1 headers are usually known for max power while 4-2-1 headers are known for med ranges, this defies all of that.

 

The difference between EL and UEL doesn't seem to be as great according to Tomei. Sadly it doesn't seem like that many people run aftermarket UEL's thus it's hard to find good feedback/info/graphs (perhaps it's once you make the jump from stock you go to the better peak header?)

Sorry to use Tomei's dynos again, but there are no other good vs graphs (especially from same manufacturer headers)

http://legacygt.com/forums/attachment.php?attachmentid=240750&stc=1&d=1479186884

 

I'm leaning towards the EL's, because they seem to be better for the health of the engine (more consistent EGT's and AFR's). But if the car becomes a dog in low end, it would defeat the purpose of this mod. UEL having two shorter runners would in theory help with low end spool (main reason why stock header is so good at spool, very short runners), and well of course the rumble is kept, but is it worth the $700+ just to stay with UEL's?

[xtea]

I run them because comparing dyno charts showed me that having 4-2-1 EL headers would increase spool and mid range torque. I also wanted the safety factor for cylinder 4 egts. I found a set of used full race 1.5 scroll on nasioc for $800 shipped without up pipe. I decided on full race over tomei because of the steel strength and didn't want to risk headers cracking. I would've gone tomei if I could not find full race used.

 

I have seen NO evidence to suggest 4-1 i.e. killer b headers improve mid range torque. They seem to definitely help in upper range with bigger turbos, but with stage 2 to small turbo stage 3 I've seen nothing to suggest it gives much benefit. There are many who will tell you otherwise but they won't have any dyno sheets to show you.

 

Caveat. I do miss the rumble. But not enough to go back to less power and safety.

[utc_pyro]

I have the Tomei's, but put them on as part of a larger build. Thus no 1:1 comparison.

 

That said, spool is NOT an issue so far. The BNR Evo3 16G is fully spooling by 3100rpm and response feels close to what my VF40 was. Not the doom and gloom that internet hearsay was about the header volume making things really slow.

[covertrussian]

I run them because comparing dyno charts showed me that having 4-2-1 EL headers would increase spool and mid range torque. I also wanted the safety factor for cylinder 4 egts. I found a set of used full race 1.5 scroll on nasioc for $800 shipped without up pipe. I decided on full race over tomei because of the steel strength and didn't want to risk headers cracking. I would've gone tomei if I could not find full race used.

 

Most of the header comparison dynos are gone sadly. I plan on doing my own if and when I get a set.

 

I would get a full race setup for $800 in a heartbeat myself, sch10 piping ftw! Watching full race build their headers is what turned me onto wanting one too, just can't justify that much for daily.

 

I have seen NO evidence to suggest 4-1 i.e. killer b headers improve mid range torque. They seem to definitely help in upper range with bigger turbos, but with stage 2 to small turbo stage 3 I've seen nothing to suggest it gives much benefit. There are many who will tell you otherwise but they won't have any dyno sheets to show you.

 

Caveat. I do miss the rumble. But not enough to go back to less power and safety.

 

Killer B is basically right next door to me (25miles away), I like their header but the price is way out there. Maybe they have blemished sales .

 

No surprise at all on killer b not improving mid range torque, in NA world 4-1 headers shift the power band way right. It has to do with scavenging and runner length. 4-2-1 headers are considered a good mid-range header with less peak power, of course this is assuming both headers are equal length.

 

That's NA world though, most turbo manifolds end up being being 4-1's since it's hard to package 4-2-1 on an inline motor. We are the oddballs out with NA like header designs in this game .

 

I would be interested to see a 4-1 vs 4-2-1 equal length header dyno and 4-1 vs 4-2-1 unequal length dyno's. Mainly because I'm curious if NA "rules of thumb" apply to turbos

 

 

I have the Tomei's, but put them on as part of a larger build. Thus no 1:1 comparison.

 

That said, spool is NOT an issue so far. The BNR Evo3 16G is fully spooling by 3100rpm and response feels close to what my VF40 was. Not the doom and gloom that internet hearsay was about the header volume making things really slow.

 

That's awesome fairly similar setup to me then. You went with Tomei EL's right?

 

I wish Tomei's graph started at a sooner RPM, you can actually see UEL having a good amount more torque then EL at 2700rpm.

[covertrussian]

Sorry for another NA data post, but it's so much easier to find controlled tests for the FT-86 platform, luckily they are boxers and luckily they have the same firing order as us. Which means cylinder pairing guidelines runner length differences apply to us too.

 

This guy did an awesome Tomei UEL header (4-1) vs Skunk2 EL header (4-1) comparison test. He did it right too, he fully tuned each header on the same car, this shows the max potential of the header. This is the most correct way of testing any part, especially if your fine tuned to MBT already. Any efficiency adding part will usually require less timing to reach MBT, once your on the other side of the hill loosing power and detonating. Thus I wouldn't be surprised if a header addition to a fine tuned car would make it loose power.

 

What's even better is both headers have the 4-1 merge collector. To my and his surprise the Tomei UEL got more peak power too. If I had a BRZ UEL header would be sitting on my doorstep already.

http://blog.vittuned.com/wp-content/uploads/2015/08/skunk2_vs_tomei.png

[xtea]

On the BRZ header design has nothing to do with how much air gets crammed into the engine. You can't really compare what headers do on a NA car to how differently designed headers will affect turbo performance and power output on a forced induction engine.

[utc_pyro]

I agree with xtea. With a turbo setup, a lot of NA things go out the window exhaust wise. EGBP is so much higher, and you get more performance by making to turbo happier.

 

Though in reality both EL and UEL probably do just fine on our cars. Both will flow better than the stock contraption.

[covertrussian]

While they are different, they are not as different as a lot of people make out to be, they both have to abide by the same fluid dynamics. The real difference is being able to utilize exhaust scavenging; smaller turbos have too much back pressure thus result in major reversion, while bigger turbos are a lot less restrictive thus can finally start utilizing scavanging. Bigger turbo setups can utilize high overlap cams just like NA motors.

 

With that said, that test tells me that for NA world UEL vs EL, as long as they are both 4-1, doesn't matter (I really wonder if that torque dip is tune induced, probably AVCS). Looking around for 4-2-1 headers found the Nameless dyno which seems to not have the awful torque dip either (granted there are other factors at play too like tube diameters and primary length.)

http://i1260.photobucket.com/albums/ii566/namelessperformance/FRSStockvsBigHeader_zpsd3872ef9.png

 

In the next post, I'm gonna dissect the most common turbo EJ headers against header design basics.

[covertrussian]

While working on the big comparison post found this and this is really cool! A guy on Nasioc, used compressed air and a lighter to check an ebay UEL header (similar to Tomei UEL) to check scavanging and reversion.

 

https://www.youtube.com/watch?v=RwwL7XbW1Ng

 

This shows that even though it's a 4-1 design, there is a lot of crosstalk still!

[utc_pyro]

That video is actually what convinced me to do ELH.

 

That said, when I was re-coating my Old Grimmspeed PNP headers I noticed a similar effect. When you put a torch down one port to heat things up, air was sucked into the others.

[covertrussian]

I wonder if anyone has some similar tests with a nice EQL header.

 

I really wanna buy a used Tomei EL and UEL header and do some proper logs/dynos/MPG tests. Anyone want to lend me one for science?

[utc_pyro]

I'll lend you an entire Grimmspeed PNP setup (up, cross, collectors) to add to the testing. Changed too much at the same time for A B testing.

[covertrussian]

Oh man that's tempting! I was planning on porting and polishing my stock headers and not bothering with aftermarket headers, but seeing how bad stock is makes me want to just get a better setup

 

I really need to get my clutch replaced soon so that I could break it in and do the tests. Gaskets are going to be fun... All of this started with me wanting to replace my invidia up pipe, now I want headers, RIP wallet.

[Max Capacity]

Having had one of Geoff's, Full Race manifolds on the race Civic, I can say they are a quality piece. He was very good with sending us updates as he was building our manifold, great guy to work with.

 

I have also been told to be careful when it comes to porting these manifolds. You want to keep the velocity of the exhaust gasses.

[cBax]

Tuned a friend's FRS with an UEL header and was able to get rid of most of the dip with some AVCS changes but not all of it. There is definitely some odd AVCS mapping in the 4k range on those cars and you do not fully "correct" it.

 

At the time of the last N/A tuning session, he had UEL headers, cat back, intake mani extenders, inlet and air intake.

 

We put a supercharger on it a few months ago. Attached is a VD comparison of N/A to S/C (I'm pretty sure dashed line is ign timing), some local dyno pulls after the S/C street tune (still needs a little work), and a screen capture of the stock In and Ex AVCS mapping. Putting a bigger pulley on it over the winter and a wastegated BPV to maintain 10psi.

[rapture]

Ive run perrin el headers from day one

Couldnt wait to get those cast stock heavy ass headers off! Lol

Def agree w above statments

Never had to worry about tanking cyl 4

I love them , first i had the normal size but recently upgraded to the big tube

As im heading towards 400+

I say do it

Just dont wrap them

[covertrussian]

NA that thing is filthy rich up till 5k rpm, still that's some really good power, not that much less then what a stock WRX would do.

 

I'm still working on a header analysis post, where I'm trying to analyze header design rules to the headers we have on the market, and how each would act in theory.

 

Ive run perrin el headers from day one

Couldnt wait to get those cast stock heavy ass headers off! Lol

Def agree w above statments

Never had to worry about tanking cyl 4

I love them , first i had the normal size but recently upgraded to the big tube

As im heading towards 400+

I say do it

Just dont wrap them

 

Did you loose a lot of low end torque with the big tubes? Also how thick is the piping on Perrin's, last I checked they were on the thinner (~16g) side for my liking.

[rapture]

Ive always ran catless up dwn , headers & catback

I say let them breathe

More air, more fuel, more power

U kno the equation lol

Honestly the first i ever noticed lag that was substantial was after going fmic

First i went perrin tmic

Then mishi fmic ( thing is huge)

But even then cars still quick

Im currently on the big tube up pipe as well

I love my setup

[rapture]

I wouldnt over think it

Yea its nice to be quick from stop to stop or light to light

But i got tired of that and wanted to be faster on the highway

Got tired of cars like g35 sedans w minor work having more topend

I think your on the rite path tho , go equal length , my cars still sounds nasty without the

Unequal length grumble

[cBax]

NA that thing is filthy rich...

 

haha yeah. I'm pretty sure that's not where it was left. Just the only comparison I had on the same test road. The s/c wasn't final either, it's also a little leaner down low now.

[covertrussian]

Ordered Tomei EL header since FRSport is having an awesome blackfriday sale on them.

 

Once I find some time I'll finishing typing up the reason for why I went with these vs UEL's (not sound related at all ) or vs other brands.

[rapture]

Dont forget new subi gaskets and i prefer copper spray..

[covertrussian]

It looks like Tomei's gaskets are pretty good quality multi-layer metal ones, are they garbage?

[rapture]

Oh idk

Never used them...

Im sure theyre fine

[xtea]

If you compare similarly speced cars on efi logics database the tomei's give the most low end torque consistently fairly close to invidia and fullrace/batlground knockoff.