MK1 8v and MK1 16v converion exhaust questions

Hi,

While not as big a choice as is available where suspensions are concerned, what are the recommended exhaust systems for a

1) MK1 8v with a gas flowed head and Kent GS1 cam?

2) MK1 16v conversion with Scirocco exhaust manifold?

I was thinking of Jetex from TSR in both cases although I'm sure the 16v may need more flow.

Any comments on exhaust manifolds would be helpful although as I am not going wild in terms of tuning I wonder whether the cost v gain on a 4 branch is really worth it.

I also don't want to sound like a Civic but deep toned burble would be nice  8)  

Advice and supplier info appreciated.

Personally, can't see the point of fitting a performance exhaust, or head work, without a performance exhaust manifold too. Having said that, the stock ones actually flow quite well, so you don't see huge gains.

you seem to be contradicting yourself?  :dontknow:

as you said, the standard manifolds ain't that bad and I've seen on rollers that the claims of most manufactures, note most, don't deliver as big an increase as claimed.

My core questions were relating to exhaust systems so any other takers?

You're right - let me explain it a little clearer. The exhaust manifold which comes on a Golf Mk2 16V, or Corrado 16V, or Passat 16V, is a very good design, and guys who have replaced it with a 4 branch one don't see a noticeable gain - there is probably a tiny gain to be seen.

HOWEVER - for a Mk1, you MUST swap the manifold because the space restriction doesn't allow the stock 16V one to be fitted. So there's no comparison to be made…..

As far as the exhaust system goes, 2?" is said to give most power, but because its so wide its not optimal for driveability or middle revs, only at WOT and the high end of the rev range. 2 1/4" (like the Ashley system) is ideal. Also matching the manifold to the exhaust system prevents any problems with mismatch during fitting and avoids improvised connections which might provide a flow restriction and reduce power.

I never really researched 8V manifolds, so I guess someone else will have to tell you about those…

Makes sense, however (not sure you picked this up in original post) but I'm using the 16v Rocco exhaust manifold to get around a number of problems with a 16v conversion ie as you say the MK2 16v manifold will not fit in the MK1. This should be camparable to what you mention about MK2 16v etc in terms of performance. I'm also using a Rocco inlet manifold so that fuel lines and the airhead don't have to be moved.

The jetex is 2 1/4 as far as I know so maybe I should just go for that as it is tried and tested for several years?

Can't really comment on the Scirocco 16V manifolds - do you have them yet? They are very rare, they offer good shortcuts to installing the engine, but I don't know if they perform as well as the other options. Have you measured the size of the downpipe connection, and if so is it going to be easy to join it to another exhaust system? Also does it have a flexi section, etc?

It's a manifold only so a down pipe etc will need to be attached. Don't have a pic unfortunately but research said they actually perform quite well - I believe a 16v system via downpipe will bolt on.