SS exhaust manifold power gains?

[aleph1]

All those SS exhaust manifolds (Megan, SS Autochrome, etc) claim to make spool up faster and more power, but a tuner at a local speed shop claims to have seen for himself that they actually lost power and make spool up 100rpms slower....any truth to back that up??

[aleph1]

any1?

[240TweakerNewbee]

Ill let you know when I put mine on... wasnt any of the ones you listed but about the same as those... not really professionally built, but doesnt carry the $1000 price tag either. http://cgi.ebay.com/ebaymotors...stingThats the one I got, Im waiting for my S15 Full BB turbo and Dump pipe to arrive in the next 2 days so I can do it all at once. Come to think of it, would be hard to tell if the manifold is going to help or hinder considering Im putting on a better turbo and better than stock dump pipe. But Ill let you know either way; I sill might try the stock manifold.

[twofourzeroSX]

i cant really say i noticed a difference either way with my megan racing. if anything at all it just made for a bit more kick once it starts boosting. i think it might hit full boost alittle sooner but start getting boost slower. havent payed all that much attention to the rpm differences.

[aleph1]

Yeah I got the redesigned XSpower/ssautochrome one "Silk Road" style...seems to be pretty decent quality, but Im not sure if I should replace it or not...

[95lstegman]

it should make boost come on a little slower. the total volume of the manifold is greater than the stock log manifold, which means the engine has to fill up a greater volume in order to build the same manifold pressure it did with the stock piece. for this reason spool-up is usually 100-300rpm slower, depending on diameter and length of runners, but is traded for better power on and off boost thanks to MUCH better flow characteristics (although since spool is a little slower this may show a loss as boost builds on the dyno, but by driving you should notice better power out of boost - the dyno only demonstrates full-throttle gains and losses).

[240TweakerNewbee]

well I put that A2Rinc manifold on with the new full BB S15 turbo, and the SS autochrom divorced chamber dump pipe and it wont stop boosting (goes to 20psi in a split second).. just keeps going.. I know the wastegate opens, because I tested it with air pressure and it opens right away at 7lbs like it should. This thing is killing me, it even blew the ceramic coating off of an Iridium plug.. thought I did worse, almost had a heart attack today. I had my AFC setup wrong (obviously needed more fuel for that much boost). I know this is kinda threadjacking but it might help this guy make some good decisions as to what parts to get:does anyone have any ideas... The only thing I can think of is removing the divider between the devorced chambers so the wastegate can let more exhaust out to stop the turbo from boosting itself to death.

[karmakaze]

check your vacuum lines and make sure that all unused lines and ports are capped. try running a single line from the wastegate actuator to your intake manifold.

[SR20Monster]

did you ever figure this out.. a divorced dump tube might have clearance issues with your WG flapper.. On our STI downpipe which was divorced, our Flapper kept opening, hitting the divider, and slamming back shut.... caused it to overboost as well.. change it