hopefully you guys can figure this thing out. Its a 383 stroker, xe 224/230, lt's 52mm tb, heads ported intake ported and matched, ported maf pcmforless tune. The motor was originally a blower motor but the blower went and decided to keep it na with a 175 shot. the cr is at 10.1:1. the #'s on the dyno were 327 hp at 6700 and 287 tq seems real low for the mods the only good thing today was that it went to 6700 before it dropped off. is it possible that the cam is still to small for the set up or is the cr to low. please help. oh by the way the a/f was right around 13.1 the whole time and the graphs are nice and smooth also. no drop offs any where untill the end.
thanks nate

 

Ouch. Maybe you need a real tune?

 

hmmm, there seems to be a bottleneck effect there...

 

^ Are you talking about the cam?

 

no, not the cam.

have you tried getting the compression checked...might be a leak? this sounds stupid, but have you checked your fuel delivery system? have you checked your plugs? how about an exhaust leak?

get a free diagnostic program, and run it...u might find something that u havent thought of.


it's usually the really simple things that SHOULDNT cause problems, that cause BIG problems.

 

Thanks for the replys keep them coming please. the fuel system should be good, I'm running 30# svo's and an inline pump(vortech t-rex) the only thing I dont have is a afpr dont trust them 2 bad expierences,the y pipe does have a slight leak as well as the slip pipe on the header but how will that cause a problem. also rage whats on your mind about the compression leak.

 

well, anytime u have a leak, it takes away power. so, it doesnt hurt to take care of those.

althought you have enough fuel, it wouldnt hurt to check your A/F ratio...could be running TOO lean. no gas--no go.

as far as the compression leak, it doesnt hurt to get it checked...if there's a compression leak, then that can cause a pretty good chuck of power to fly out the window.

as i suggested, it would be good to run a diagnostic program to see exactly how the pcm is telling your motor to act....once u do that, u can let some of the guys, who're pcm gurus, take a look and give ya some advice.

 

Are you still running the tuning from the blower? That might be causing a problem NA.

Ben

 

Thats what I was thinking. I know a kid with heads/cam/blower on his 350 LT1 and he made 250rwhp with stock tune! He then tuned it and is cranking out just under 450rwhp.

 

I see you are in Colorado. Will the altitude affect the numbers, or is that compensated for on the dyno. ie, make sure you are looking at SAE.

 

who ported your heads?

your compression is awfully flow, especilly for big cam that is going to bleed off compressoin

 

The tuning was done after the blower this is a new cam and I had the computer was done after the blower went. Do you think the compression is to low and what would be a god ratio to get this thing up to 400 at the rear wheels.
thanks nate

 

it made 287 PEAK rwtq? wow.. uh, something is major wrong. heh.

but yes, your compression is very low. if you wanna stay away from forced induction, bump it up to 11.5:1. if the heads are good, that should make the power you want.

 

I dont see how compression has anything to do with it. Lots of stock bottom end LT1's out there with cams making more power than that. Look at my sig with homeported heads. Compression on LT1's are typically 10.4-10.5. I am sure I bleed off some compression, but those numbers are pitiful. He has something majorly wrong. Maybe your opti is taking a dump on you?

Also, even with poorly ported heads or even close to stock flow numbers, his toque should be alot higher. I made 301rwhp and 338rwtq with bolt-ons!

 

Check out the sig he's in Colorado = high elevation thinner air = less hp right?
I think the compression needs to be raised to compensate for the high elevation. Also what kind of chassis dyno, Dynojet or Mustang because that can make a difference also.