So i have a 2003 s2000, it was comptec supercharged and dynod to 333rhp. Now i melted a piston, and decided to get it rebuild with forged parts. The shop used cp 8.5 or 9:1 comp pistons, and eagle rods. Now they call me and tell me its done, and dynod at 200whp at 7 or 8 psi. Now this seems like **** to me becuase orginally at 6psi it made 333rwhp, so what do you s2000 guys think they could of fucked up? I know that going from around 11:1 to 8.5 or 9:1 makes a difference, but i feel its a bit rediculous.

 

Compression has something to do with it. You'd need 8.5-9 CR when you're planning to run 20+ lbs of boost. With that 8lbs, 10:1 would still have been fine. Slap your motor builder.

 

the deal is i stilll owe the shop about 3k....so what now?

 

New parts = more money.

Either follow through and go high boost, or sell that motor to a booster and start over.

 

yeah but dont you think that even with lower compression. 200 hp is a bit low for 8psi?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EJ8 GSR-T &raquo;</TD></TR><TR><TD CLASS="quote">yeah but dont you think that even with lower compression. 200 hp is a bit low for 8psi?</TD></TR></TABLE>

8.5 is a very low compression. Up your boost to about 14- 16lbs at that compression.

 

prob. is that its a comptec supercharger, and i dont really know how high the boost will go without overstressing the charger

 

You can go up to 14, but your loosing effeciency. Youll need all new engine management, inj, fule pump, though.

333 sounds high, you must have been running very lean hence melted piston. Cut 30whp off that by running a safe a/f and 8.5:1 pistons, 200whp might be right.

Also each dynos different.

 

200whp! i mean that like stock numbers! the thing is, i have spent tons on it, new engine managmetn, larger injectors, new fuel pump everything, and 200whp is way shy of what it should be.

 

Go to a higher boost pulley, who told them to use such low compression pistons?

 

Low comp pistons like that are fine really, you can usually work that out with cam timing anyway. Those numbers seem very low -- increase the boost!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Atheist &raquo;</TD></TR><TR><TD CLASS="quote">Low comp pistons like that are fine really, you can usually work that out with cam timing anyway. Those numbers seem very low -- increase the boost!</TD></TR></TABLE>

what's the spec of the timing?

are you still running the fuel map from last set up?

 

no last setup was on vafc...now its running greddy emanage ultimate. My feeling is they had no idea what they were doing on any of head headwork, timing included. They are the ones who figued those were the correct pistons to use. The prob is it allready has a pretty small pully in it, i dont know how much more i could get outa it