4 replies to this topic

[REDICE]

Im about to have a 1275 built for supercharging (mercedes m45 blow through intercooled) and was wondering what the best exhaust size is.

My LCB manifold is 30mm o/d. Is this a bit small? 2 inch for main pipe? What mufflers will give the best balance between noise control and performance?

 

Is it advisable to get rid of the heart shape in the combustion chamber - im using 18cc forged omega pistons? Aiming for high 8s c/r

Is it worth dry decking? I want to do it right do it once.

 

I know I should trawl on here for hours cause its already here "somewhere" but Im hoping a couple of minutes from you smart people will put me on the right track quickly.

Cheers 

[mini13]

a generic large bore LCB will be fine for your use, also 2" systemis about right (and also the largest you can get off the shelf anyway),  I would go for a twin box system to keep noise down, with turbo's a  single box is fine as the turbo acts as a silencer.

 

I would try to keep the heart shape, its a good design, and you shoud be able to get the CR down wtithout taking it out. for an SC high *'s might be a bit high, i would be looking at low 8's due to the lower ( than a turbo) compressor efficency.

 

I lke dry decking, but its certainly not 100% needed, comes down to cost really.

[Turbo Phil]

I'd pretty much echo what Joe has said. The reason the open chamber design is often used is purely as a means to drop the compression. As you've got 18cc pistons you should be able to retain a more efficient chamber shape. I'd also say high 8's for a roots type blower is to high.

Phil.

[REDICE]

Thanks heaps guys. Im assuming I keep the header tube size the same as the port?   

[mini13]

yep, i think you'll find tyhe LCB's follow what a decet ported head size will be.