Perrin Equal Length Header discussion

I agree with pretty much everything you said. There are a few guys around here that have been pushing the limits since the beginning. I know we had an 18g from the very first batch made for a Subaru. Jeremy's car made 300hp on pump with the 18g when nobody was making that kind of power. We had a Link from Possum Bourne before they were selling them in the U.S. I had to wait on it to come through customs. Another BG customer Mike who lives in FL now was the first person I know of in the southeast to have a 2.5 in a bugeye. Liquid Force has always pushed his cars. Coolrex is the only person I know of to go faster than me with an 18G. There are lots of leaders, but a lot of guys are willing to settle on whats proven and what is known to work. I know thats what Siegel likes to sell his customers ....proven packages. Personally thats not my thing, I like being an innovator, I like pushing stuff and I know there are some other guys on here that do as well. Those guys make the community better for all of us. I've gotten lots of good info from guys on Nasioc that broke stuff.


Which reminds me we need to start a thread dedicated to broken motors, I would love to inspect failures.

Matt

 

:eek3::eek3:knocking cosworth is sacrilege in the subaru community!:eek4:

on another note, relating to headers, anyone have any experience with these or know anyone with them?


how do you think the 4-1 design compares to the $1200 cusco 4-2-1 below?

 

I personally don't like either design. I'm really interested to see how the header comparo turns out. I suspect that the DC Sports will make more power than stock but will probally sacrafice some spool, the thing is most headers on sacrafice spool for the first pull, if you do a short pull and then the long pull it will usually spool like a stock header. The tubular manifolds don't hold heat as well as cast iron. I personally have no problem losing the boxer rumble for more power.

 

then tell me why they make less power or the same as stock. i have had two cars with cosworth make dissapointing power. both were built by sog. im sure they can vouch

 

I'm not going to get into the cosworth thing, I followed the instructions TO THE LETTER on one, the second I did it the SUBARU way. Cosworth's way resulted in a noisy valve train. The SUBARU way resulted in a MUCH more quite valve train.

The absolute first set of cosworth heads I setup are completely WRONG and they made pretty nice power...high 500's w/an FP-Red. Go figure.

I've never seen any heads and cams, Cosworth, Cobb, TWE, make more power over stock units with a large turbo. If it made power, it was either stock, or NOT something you can buy off the shelf and make ti a streetable engine.

As for...I guess thats Mike's...rant up there, when I post things, it is ALWAYS SUBARU specific. I do not have an experience with other makes other than US EVO 7~8, even then I've forgotten most of the EVO stuff. I dont think the header is worth the money per the gain, eventually someone's going to go to 35R and be down on power compared to stock...

Now if someone comes out with something that actually WORKS...thats different.

$2000 or more? Not may people will buy it.

$1000 might attract lots more customers.

$500 thats better.

$150~$300 ebay bitches!!!!!! Everyone would buy it.

 

Stock motors make 500hp with an FP Red.

There are plenty of guys that have 2Gs to drop on a header.

 

I was in no way insinuating that you did something wrong to the Cozzie heads, i was just saying i was not impressed with the power numbers.

As far as header discussion goes, if you have an STI an you want to make 300-350whp, absolutely, the FULL-RACE Manifold is NOT FOR YOU

for the guys looking for 400-600whp, they may want it if it proves to make the power Geoff claims.

What if we have a car that makes 450whp on MEthanol@25PSI with a stock header, or a DC sport header.

Now this guy buys the full race manny an it makes 450whp at 18psi.

what does this mean?

Guys dont have to run Meth kits anymore, your putting less boost through yur motor which increases longevity or life of the engine, etc etc

I think i know what you are trying to say Will you just said it the wrong way.

HEader design, exhaust pulse, cylinder and collector pairing is a BIG DEAL when it comes to making POWER. A properly matched exhaust will ALWAYS beat a stock unit.

So if you want 300-350whp, stick with stock.

Big Power guys, call me, you get 10% off

 

This is similar to the K series honda guys.

You see a guy with a stock internals motor and stock block(11:1) bolt in Skunk2 Stage 1s, a SSR header, Intake manifold, and KPRO make 249whp.

Chunky builds a 12.5:1 , Skunk2 Stage 2s, baller header, ported head, KPRO, etc etc and he makes 235whp.

Same in the Scooby world, you got guys making 450whp on STOCK MOTORS then you have guys that go with $6000 heads and cams, 35R, BUILT block, an they max out at 480whp

either everyones dynoes are WAY off from each other, motors are wildly inconsistent or.......................

 

Mike, we are agreeing.

 

Will a header void my warranty?

 

Yes

 

It'll void parts of your warranty...

 

STIG.....lol..LMAO

 

Thats a good question, the full-race is a pretty beefy design so I bet its pretty close.

Ill try and remember to weigh it when it comes in.

Matt

 

Thats the second...or for some people, the first...reason to switch to a non stock manifold-header. They weigh less.

 

doesnt chunky have the si version of the k and not the rsx version? aka the lesser of the two?

 

Chunky has a K20A2 RSX Type S

 

Chunky HAD a k20A3, but that was 3 years ago, he now runs a K20A2 with rods an pistons, cams he got from me

we did some cam testing for skunk2 and IPS and hes running the Skunk2 cams for now. Chunky is one of the guys always breaking boundaries in the K world. Much respect for him.

 

hell yeah, good for him. I met him at Steele dragway many moons ago when his Si was pretty much bone stock except for a homemade intake..I think he ran 15.3:wiggle:

 

Is the sound of these more like a "brrrrrrrr...." or a "braaaaaaa....."?

 

Jerk. that was a legitimate question. I don't want my STi to sound like a Honda.

 

If its equal length its going to sound like a 4 cylinder. Not like a 3 cylinder.

 

so is that more of a "brrrrrrr" or a "braaaaaa"?

 

An interesting point is mentioned above...the ability to make an engine produce more hp with less boost. There was a test done a while back on a mustang that actually produced MORE hp with less boost by bolting on heads, exhaust and intake that all flowed better. I would have to look up the article as the exact numbers escape me, but it was a significant amount of power. The engine was not having to work as hard to get air through the engine. In that case any restrictions that you might have with the factory parts will result in improved power. Fact of the matter is that I have never seen a header ($600 crap or $2600 super duty race header) that has resulted in less power than the stock exhaust manifolds. I am sure there are some cheap ebay ones out there that might, but I have yet to see a test showing a loss of HP. This also applies to porting of the exhaust, intake tract, etc. Very cool stuff.

 

Nah dude, just do the stage 4 turbo kit. That makes the car really fast on GT-3.

 

Alex is behind.

again, in GT3 it works.

And yes, I do want to make blindfold cry. :rofl:

 

Hrmmmm. Good stuff going on in here

~Tracy

P.S. I have an STI now. Booyaka!

 

So was that more like a "brrrrrrvvvvv"??? or more like a "brrrrrrrrrrRRRRR"?

 

Dude, you are cracking me up! Stop it!

FYI, I was really pissed that my Evo sounded like a Honda...but it was fast as fuck. That's the price you pay for fast...so I hear.

~Tracy

 

This just in.....

 

HEY HEY! Don't you start dammit! I will have you baned for sponsor bashing *asks if I can really do that*



~Tracy

 

You motorboating son of a bitch.

 

Hmmm... good point. But if you really think about it that's more of a "pfhtpfhtpfhtpfht" sound. I would think that's close to stock. As long as its not a "brrrrrrrRRRRRR" (note the caps lock when Vtech kicks in) sound I'm interested. HP gains would be nice too.

 

*ahem* It's Vee-Tak

 

Lets try to keep this on topic guys and gals

 

This thread actually has a topic?



FWIW I ran a XX-Tuning header for a while. I believe it was a GT Spec clone. Either way it worked well when it was heated up but it didn't retain the heat as well as the stock manifold. On the dyno between reflashes it would cool off so much that the first run after would be down about 20+hp and it would spool alot slower. At the strip the header probably didn't get up to optimal temp until 3rd or 4th gear.

If I ever get another one I would look for something with thicker walled primaries that could be wrapped without worry of cracking.

 

Were you using launch control at the dragstrip. I know with the AEM launch control you can build a lot of heat in the header. I would imagine its pretty similar with most launch control.

I plan on having my Full-Race manifold coated.

Matt

 

I have ASIC's Gel 1120 launch control. It doesn't do much in terms of building heat in the manifold.


Aren't you at Roebling?

 

Negative I was supposed to be but the taillights aren't working on Beths Subaru, thats what I was supposed to drive down there.

Matt

 

I remember that the Full Race rep said something on nasioc, when asked whether their manifolds were equal length, that the actual runner length is of secondary importance to matching the pressure drop across all four runners. He said theirs actually is not exactly equal length.

Crashtke, I agree with you, I dont see why a better flowing header would ever be worse performing then a stock one. I guess the stocker just creates more intermittent exhaust pulses than the equal length so it keeps the turbo spooled up a little bit more. The worst part about these flat-4s is how far exhaust gases must travel from each cylinder to get to the turbo, especially when you compare them to Evo or SRT-4 manifolds.

 

Correct the runner length is secondary, they actually set the runner length so that the exhaust gas pulses are timed correctly. The exhaust ports on a subaru head are diffrent lengths so making a manifold equal length isn't really the answer.

 

Taken from the Garret Site on their Turbo FAQ 102:

Manifold design on turbocharged applications is deceptively complex as there many factors to take into account and trade off
General design tips for best overall performance are to:

* Maximize the radius of the bends that make up the exhaust primaries to maintain pulse energy
* Make the exhaust primaries equal length to balance exhaust reversion across all cylinders
* Avoid rapid area changes to maintain pulse energy to the turbine
* At the collector, introduce flow from all runners at a narrow angle to minimize "turning" of the flow in the collector
* For better boost response, minimize the exhaust volume between the exhaust ports and the turbine inlet
* For best power, tuned primary lengths can be used

Cast manifolds are commonly found on OEM applications, whereas welded tubular manifolds are found almost exclusively on aftermarket and race applications. Both manifold types have their advantages and disadvantages. Cast manifolds are generally very durable and are usually dedicated to one application. They require special tooling for the casting and machining of specific features on the manifold. This tooling can be expensive.

On the other hand, welded tubular manifolds can be custom-made for a specific application without special tooling requirements. The manufacturer typically cuts pre-bent steel U-bends into the desired geometry and then welds all of the components together. Welded tubular manifolds are a very effective solution. One item of note is durability of this design. Because of the welded joints, thinner wall sections, and reduced stiffness, these types of manifolds are often susceptible to cracking due to thermal expansion/contraction and vibration. Properly constructed tubular manifolds can last a long time, however. In addition, tubular manifolds can offer a substantial performance advantage over a log-type manifold.

A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds (see Figure 5. and Figure 6.).