pics of the $100 will be good to, especially of me holding it ;)

small tubes will keep the velocity higher and heat in the gas to the exhaust turbine. as for the inlet manifold, i would have though bigger would be better, from my readings but a series will need low down and midrange for fun.

Thanks for the pics Benny,

Ive gone with tube slightly smaller than the port. I am a little restricted with design because im using the same post turbo exhaust that i`d already made for the twin cam engine to save some fabrication. The runners are fairly even in length and merge smoothly into the turbo flange, shouldnt be too bad. With the smaller diam tube it might cost me a little at the top end but if it helps the bottom end as much as it hurts the top i think it will be a better package.

I`ll have to get some pics up.

Quote:

I know that Stepped headers have positive effects on NA engines, i.e the dia of the pipes increase at a given length to maintain gas velocities and reduce issues with harmonics and reverse flow. [from memory, I will double check my reference book], but I'm not sure what the effects will be on a boosted engine.

Simon, if you are looking for design inspiration, I think you could draw some inspiration from the Fred Gibson Motorsport Group C EXA. It has rather long runners before entering the turbo. Apparently this was to compensate for the poor performance down low, as you could imagine it was built to run at the higher rev range. I will attach some pics I took of it several years ago
cheers
Benny

104rwhp

169 the 69 is the important part hehehe

is this just on the exhaust flange or inlet manifold too?

if its on the exhaust flange/manifold- to big causes the air to cool too quickly on the way out, a smaller tube will keep the air temp up, and there for flowing at a higher speed and less dense out the tail pipe.

Im not making 100% sense as usual- its my interpretation of stuff i have read various places.

Sorry Mik, im a bit confused by your post.

I was thinking the small diameter tube would help pick up a little HP lower in the revs but maybe at the cost of HP at the top end.

Im guessing the larger diameter tube/bends would probably have the opposite effect.

samller will help with keeping the air speed high and not create turbulance bu the air bouncing off the walls of the flange. Larger will get more air in but could create turbulance of the air bouncing off the flange on the way in.

Can you do samll on the way into the engine and large for the way out?

Ive mounted the coil on plugs. Painted the engine and made engine mounts. The inlet manifold now fits too.

The rest of the bends tuned up for the exhaust manifold. (smaller than the ports) i now have bends larger than the ports and bends smaller than the ports and im not sure which ones to go with.

Hi D, PM sent.