E30 Zone

Well i approached BTB to see if they would consider developing an exhaust manifold and full system for the iS,and they came back with a price of £1800 +vat. T304 stainless.Bit too expensive so putting the feelers out see if there would be much interest on here to offlay the cost with a group buy..

For £1800 pound you could got ITB'ed plus the iS exhaust is great from factory anyway I am led to believe.

maxfield wrote:For £1800 pound you could got ITB'ed plus the iS exhaust is great from factory anyway I am led to believe.

ITB'ed? whats this throttle bodies. Dont know if standard exhaust is any good or if improvements can be made as no-one has tried to develope a new one,seeing as BTB are getting an extra 18 hp from the 325 sport manifold its worth a go.

Individual throttle bodies. You could go standalone alpha-n and loose the AFM too.

The iS is suppose to be a great exhaust as standard and not many power gains are to be had from it.

maxfield wrote: The iS is suppose to be a great exhaust as standard and not many power gains are to be had from it.

Thats what im asking how does anyone know its a great exhaust system if no-one has tried to develope it? there surely has to be gains got out of an 18 year old system development wise.

Because people have tried to develop it with very little gains.

It came with a tubular manifold from factory.

I'm sure someone will back me up on this...

If it was my money I would go with ITB's and a standalone managment.

maxfield wrote:Because people have tried to develop it with very little gains.

Id be very interested to know who and what results they came up with,couldnt find anything on the web about anyone developing it. As regard throttle boddies already looking into a tapered set.

y dont ask some of the guys on here that have a 318is and have/ are tuning theres for sum info on whether this i sworth wile or not?

I looked into this in the past only to be told by people who knew the iS far more than I did that there is little to be gained from changing the OE manifold.

Evo-S

a pukka 4 branch from the factory.... you don't see E36 M3,E30 M3,e34 M5 owners changing their stock 6 branches do ya!

i recon there is room for improvement in the system, but the manifold is up to scratch imo.

a decent remap gets you good gains on the IS, more than any manifold any sytem can. if you are racing and you could get an extra 5/10 bhp you could find from reworking manifold will give the "edge" then maybe its an option.

if you are improving the the gass flow in the engine, ie using ITB, cams etc then an improved manifold designed to work with these mods is the best option if you realy want to go for it.

if its on stock engine, with standard breathing its not worth it. on the m20's you have an avridge cast item so prety much any 6 branch is an improvement even with a standard head and breathing

speaking to demlot yesterday and we came to the conclution of just stick an s14 in there