LSx engine 180 degree headers?

[boodlefoof]

Hey guys,

I've been looking around here and on LS1tech and I was unable to find any information about whether 180 degree headers would be of any benefit on an LSx engine. I realize they use a different firing order than the Gen I engines, but would there be any benefit to be had by using some sort of crossover headers?

Clearance/space considerations aside...

[chicane67]

You could alleviate any firing order issue by changing the individual tube location in the collector. So in effect, all the 180* header theory would still there.

[Damn True]

So do we have anyone savvy in the ways of header building and the space constraints of an LSx/1st Gen Camaro that can tell us if this is doable or cost/difficulty prohibitive.

[parsonsj]

First, does anybody know what the expected benefit is? How much hp gain are we talking about?

jp

[Damn True]

Even if it was a wash (which it isn't) I'd still be interested, depending on price, based on the sound alone.

[Chad-1stGen]

Ok I'm a nub. Care to explain the 180* theory?

[Damn True]

This explains it for an FE. I think on a bow-tie you swap the two center cylinders from each bank.

[parsonsj]

Care to explain the 180* theory?

180 theory is that if you get the 4 primary tubes to a collector at 180 degree intervals then you make collector as efficient as possible.

Take the LS1 firing order: 18726543. So one collector needs 1, 7, 6, and 4; and the other gets 8, 2, 5, and 3.

As you can imagine, the fabrication/packaging difficulty of such an arrangement in a normal passenger car is substantial.

jp

[Damn True]

Forgot the link:
http://home.alltel.net/bsprowl/Exhaust/180FEHeaders.htm

[Jimmy Sean]

Here is a Corvette with 180 deg headers.

[Yelcamino]

Here is a Corvette with 180 deg headers.

That sounded awesome! I need a set for mine! Any chance of knowing the brand of header?

[Damn True]

I've seen that video before and ATI comes to mind. Could be wrong.

[Mike Norris]

Come on John, we can build a set, I ain't scared. Be a hell of a project.

Packaging is always a bear with any front mounted engine in a stock style chassis. We used them a lot in late model stock cars and modifieds where the chassis is svery wide open.

I can not imagine that Corvette has tubes shorter then 40-45" to make it work.

Mike Norris

[Jimmy Sean]

That sounded awesome! I need a set for mine! Any chance of knowing the brand of header?

I believe this thread is speaking of the car in the video.
http://forums.corvetteforum.com/show...232&forum_id=1

[parsonsj]

Come on John, we can build a set, I ain't scared. Be a hell of a project.

You know with your facilities, I'm sure we can. All we need is a willing victim (err... customer).

We'd have to get 4 tubes across the bottom of the engine, and keep those tube lengths less than 40" I'd guess.

jp

[Bow Tie 67]

That sounds wicked!!

[Jimmy Sean]

I'm thinking outloud here. Do a two into one for each of the middle cylinders and then run a single tube to the other bank Sort of a Tri-Y, then at least you only have two tubes that crossing under the engine. Though each collector would be a three tube. Unless you pair up the out side cylinders for a tri-y also, then it would be a two tube collector.

How would that effect the sound compared to a conventional 180 degree header I wonder?

[Damn True]

You know with your facilities, I'm sure we can. All we need is a willing victim (err... customer).

We'd have to get 4 tubes across the bottom of the engine, and keep those tube lengths less than 40" I'd guess.

jp

If only I was at that stage in the build John.

....another benefit...or so I've read...is that you don't need as much duration in the cam to get good scavenging.

Just the same...if you guys show up with an LS and a bunch of tube you are more than welcome to use my Camaro as template.

[wendell]

I believe the ASA cars ran 180 degree crossover headers. Howe builds headers and built the ASA chassis. amybe give them a call. For the life of me I can't see how they're going to work in a street car butthe do sound good.

[Damn True]

I'm thinking you'd have to run the crossover just aft of the bellhousing and use a slip-joint and band-clamp.


"This one time.....at band clamp......"