Current KA24E exhaust thinking?

[turboICE]

The ITA car I purchased came with one of those bundle of snake headers and a three inch exhaust. The exhaust currently looks like it very well could have been on the car when Bob Stretch last owned it in 1997. I am not sure the bundle of snakes is worth all the hassle (steering linkage wore through a primary and HAVE to heat shield the master cylinder due to primary proximity) getting the dang thing in and out of the car.

Before I bought the built car, I was going to build my own and had picked up an S&S 4-1 (with emissions bungs) and a 2 1/2" 'tuner' exhaust with 'test' pipe (cat cutout).

3" just always sounded big to me for ~175 hp four banger that was not meant to wring the last rpm out of anyway. I do see that in the more distant past 3" was bantered about more than others, but more recent posting seem to indicate 2 1/2" has gained in popularity.

I guess my question for discussion comes down to is should I build another 3" exhaust or maybe go with the S&S header - 2 1/2" exhaust I already have.

Also tired of having to get the trailer in just the right geometry not to rip the exhaust or the trailer floor when loading.

Thoughts?

[ITA240]

Ed,
IIRC, that is the exhaust with a "step" design. (primary tubing starts at 1 1/2 inches, and steps up to 1 3/4 several inches away from the head). If so, I know that there was a lot of development and dyno time in the design of that header. I know the S&S header as well, but I think it will cost you power over the above mentioned design. If possible/practical, have a local fab shop replicate that header and tuck it up closer to the chassis. It will be more expensive than the S&S, but probably worthwhile.

I had more midrange power with the S&S set up (parallel merge collector--a short section of 2 inch and a smooth transition up to 2 1/2) than I did with the bigger headers and the 3 inch. It sacrificed some upper rpm strength though. (5500+)

If you still opt for the S&S for price or practicality, call and talk to Lauren. He has been building these things for a long time and is pretty helpful.

Joe H. probably still has more knowledge in his big toe than I do about these cars though.

Jim

p.s. pm or email me if you need more..

[turboICE]

Thanks here are some pictures of what I am considering:

Current header - Speciatly Products Design collecter (have been told too many times "best collector ever"), also the biggest royal PITA bundle of snakes and steering wear through the collector "repaired", worst transition to 3" ever:





The S&S header:



Old pipe next to 2 1/2" 'tuner' exhaust:

[stevel]

Thanks here are some pictures of what I am considering:

Current header - Speciatly Products Design collecter (have been told too many times "best collector ever"), also the biggest royal PITA bundle of snakes and steering wear through the collector "repaired", worst transition to 3" ever:
[/b]

Looks like that custom header is based off of the S&S. The flange and the pipes off of it look the same but then the they step up to bigger tubing. I wouldn't be surprised if they used the S&S and just modded it to there liking.

steve

[DavidM]

I'm by no means an expert, but when I talked to Bob he said that they had gone through a few different designs of header on the car I bought. That tells me he wasn't buying prefabed units, but was having somebody build them. I don't think you'll get the same power if you go to a different header. I'll have to look at mine more closely to see if it is as snakey as yours. I also believe I have 3" pipes, but will have to double check.

The shiney new one looks good though. I may have somebody fab me some new pipes out of stainless steel to add "ballast".

David

[stevel]

That tells me he wasn't buying prefabed units, but was having somebody build them. I don't think you'll get the same power if you go to a different header.
[/b]

I doubt it. I would bet that they start out with an off the shelf header and mod it from there, especially if they know they're not going to go into production with it. It's pretty damn expensive just to make a flange. That flange on the custom looks eerily similar to the S&S and I would bet money that's how that header started.


And to the poster. I wouldn't use that axle back piece. I bet that muffler will be more restrictive than it needs to be and will cost you some power. We've had good luck with the S&S, but I think the collector needs to be bigger myself. It looks to me like they compromised on it to mate up to the stock exhaust. If it were me I would open the collector up to 2.5" inches or maybe a little bigger.

s

[turboICE]

It may well have started from the S&S steve, but other than the flange similarity which would seem like an easily arrived at solution by any fabricator they don't have a lot in common. Collector location is far different (before bend vs after). I need to figure out how much longer those snake primaries really are.

The collectors are quite different with regards to merge length and cone design where they meet. I have been told by a few exhaust fabricators from turbo tuning shops to hot rod shops that SPD makes the probably the best 4-1 collectors around.

I need to get the new engine in and the car ready for an event coming up pretty quickly, so probably go with what I have for now. That will give me time for two things - consider responses on here and to see exactly how it behaves with the S&S and 2 1/2" exhaust.

This is an immediate short term solution - still interested in commentary on current thoughts on the 12V exhaust for the longer term.

[stevel]

It may well have started from the S&S steve, but other than the flange similarity which would seem like an easily arrived at solution by any fabricator they don't have a lot in common. Collector location is far different (before bend vs after). I need to figure out how much longer those snake primaries really are.

[/b]

agreed.

I'm waiting for Joe H. to chime in. He's got more experience with this than I.

s

[Tristan Smith]

Keep the custom header (replicate it if you have to). Bob Stretch didn't do anything without some serious thinking about it. My header is also a custom design, and that was done by Sunbelt. I have heard that the SS header is one of the best off the shelf headers, so if you go that route at least you are getting as good as it gets, but that tuner exhaust looks inadequate to me. I run a three inch exhaust and keeping these motors breathing seems to yield the best set up, in my case.

[turboICE]

Thanks for the responses. BTW, I don't even know that the header was selected or used by Bob Stretch. There was 6~7 years between Bob's last use and my purchase. Though you have probably seen the car Tristan since it was picked up from your neck of the woods - it is Geoff Churchill's old car.

[Tristan Smith]

Yes I know Geoff well. I believe that the car was in fact very close to the way that Bob built it. I think Geoff went through it all, and freshened things. I am assuming that that header cost a few dimes to make, and Bob has deeeeeeep pockets, so I would assume that it was with the car when purchased.

On a second review, the SS header doesn't look terribly different than the one I had built. Mine is a two piece header (two primary tubes each) that go to both sides of the steering shaft and slip fit into the collector. But the lengths and layout look very close. Heck, you have it, I would try both and see which respondes better with the car.

[BB Racer]

Ed, i am really interested in talking to you about the header that was on your car and your exhaust decisions. Can you send me an email offline to discuss. THX, Brandon from BB Racing. bbogart at bbracingusa . com.

[turboICE]

Not sure why since the header, tuner exhaust and its cat replacement test pipe are all supposed to be OEM replacement but I couldn't get any of it to line up stock.

I do know now that the header pipes after the collector are 2", which again would make no sense to me to install a 3" exhaust pipe to it. I am probably going to try to build a 2 1/2" pipe to run with it for now and then decide if I want to try to rework the other header.

[turboICE]

I have reached several conclusions in what has turned out recreating the wheel.

1. No matter what the math says the engine is strongest where it is needed with 3".

2. The difference between the super duper custom and the S&S is largely in the collector.

3. Even without the stepped design of the custom, the S&S works nearly as well when you get rid of their collector - replacing it is the hard part.

This is not a criticism of S&S because I belive the design along with the collector is fine for the purpose it was designed for - the street. The collector is for 2 1/4" to 2 1/2" exhaust. It isn't a race header, I am sure designed for race they would have selected a different collector and maybe even different primaries with steps.

My goal now is to have stepped header made along the lines of the S&S with a collector meant to go from those primaries to 3".

I'm waiting for Joe H. to chime in. He's got more experience with this than I.
[/b]

I don't think I have seen him around in a bit - but there are several things I would actually like to talk to him about.