I can get a sweet deal on a used comptech header........BUT its got a 2 1/4' collector.........was this the same header used in the great header test?

Thanx in advance

Jason

 

The Comptech header used in the "Great Header Test" was a stock USDM size, not 2.5"

HTH

 

I believe that all Comptech 4-2-1 b-series headers have a 2" collector.

I know for sure for the 94-99 GSR one because I just measured it.

 

so basically (sorry, but I'm kinda slow ), it was a 2 1/4' collector?

if this is the case, why did it produce power similar to headers with 2 1/2' collectors?

Thanx guys

Jason

 

Good question, they must have stole the design from somebody!

[e]I had the Comptech and it was a nice upgrade from stock.


[Modified by sackdz, 11:11 PM 4/3/2003]

 

No no, it's called years of racing experience that must have developed the header
*Rollseyes*


[Modified by kungfuSiR, 12:21 AM 4/4/2003]

 

B/C the car was lightly modded. You will see a larger difference as you get cams etc.

Comptech's own R&D

 

Sweet! so I can use a header with a 2 1/4 inch collector and get the same gains as a 2 1/2 inch collector (on a relatively stock engine)?

Which cat would work well with the comptech header? Would i see gains with a highflow cat as opposed to the stock usdm one?

Thanx.

Jason - who is brak'n em tonight!

 

ttt

wanna know about the cat!

 

Yes

 

On the great header test the Comptech header used had the 2" collector with a 2.5 full exhaust. The larger exhaust really help out the comptechs numbers.

 

headers a lone would not give much whp gain but add a full cat back exhaust with it and you'll see a lot better gains.

 

No, the header they used in the Great Header Test was the standard Type R street header with 2" collector. All of Comptech's street headers use a 2" collector. The only exception is their long tube race header which uses a 2.5" collector and retails for $1000+ versus the $400-$500 for the "street" applications.

If you want maximum gains you should definitely ditch the oem cat and get a high flow cat.


[Modified by BlueTeg, 1:13 PM 4/7/2003]

 

So, let me see if I have this right. The USDM ITR header and the Comptech header both use a 2" OD collector?

<----who thought all the exhaust piping was 2 1/4" OD

 

usdm ITR header collector = 2"
All comptech street headers have collectors that = 2"
They both have the same the exit diameters. Performance gains are found in the primary and secondary tube size differences and the fact that Comptech uses a stepped design in their headers.

The oem exhaust piping on the usdm ITR is in fact 2.25"


[Modified by BlueTeg, 6:10 PM 4/7/2003]

 

Like BlueTeg said, the comptech header has a 2 inch collector, as well as the stock USDM type R header. Along with comptech's 2.25od tubing exhaust, which is the same diamater as the Type R exhaust, only straight through instead of chambered, is the reason only minimal gains are found with this system.

A hiflow car sound cat will eliminate the bottleneck of the stock cat with an upgraded exhaust system. Dyno's have also shown that the carsound cats have produced the same numbers if not better than a testpipe.

 

2.25" OD translates to 2.14" ID
But keep in mind that like most aftermarket exhaust manufacturers there is a bottleneck at the b-pipe flange. Comptech's cat-back narrows to 2" ID at the b-pipe flange and then flares out to the advertised 2.14"ID/2.25"OD.

I found this information out the hardway

 

So, the cat steps from a 2" inlet to a 2.25" outlet??