Ok just wanted to get some feed back. I have a full built LS with 81.5mm bore and sleeve. Ferra 1mm over sized valves and ported head. JG intake. Full race mani 750's, 255walbro. I am running a t3/O4R .82 a/r at 28 psi. and only dynoed at 388whp. and on a much smaller t3/04e 60 trim .63 a/r. at only 23psi and made 382 whp. Any ideas why I am not making more power on the larger turbo? A/F is like 12.1. Any help please.

 

Do you have a dyno graph of both turbo setups?? If so put them up on here so we can compare... Maybe we'll be able to help out a lttle more Maybe with that smaller turbo you were able to hit around the sweet spot with it,... unlike (maybe) the larger turbo,... you may have to hit higher rpms to get the full power out of it...
Also,... check for any exhaust and/or boost leaks... That will cause some power loss problems

Someone else please chim in...

 

are you sure that you dont have any boost leak? its possible.

 

my stock ls had a t3 t4 a small one as soon as i put an sc61 on it the power jumped up at the same psi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmhonda &raquo;</TD></TR><TR><TD CLASS="quote">my stock ls had a t3 t4 a small one as soon as i put an sc61 on it the power jumped up at the same psi</TD></TR></TABLE>

Yea that's true!! same situation here! It might be in the tune or some kindda leak(s)

 

 

red is on the T3/04E 60 trim on 25psi and the blue is the Garrett Big K on 28 psi.

 

*bumP* for Pics

 

keep reving it hehe maybe boost leak or leak in the intercooler.
what kinda gas is that on and what kinda timing you running

 

the ls head flow like **** too that might be a big problem. go buy a gsr head and those numbers will be alot higher i know

 

If you read I am on a fully ported and Polished LS head with 1mm oversized valves.

 

a fully built ls head still willnt out flow a stock vtec head

 

I dont see how a Vtec will out flow this LS but ok. There are guys making the power levels I want on straight LS. Changing the head does not help solve the probablem at hand.

 

I'd tend to agree with the head issue too....I made an additional 138whp with vtec (I'm ls/vtec). But yea, I would check for any kind of leaks....what does your ignition map look like??

 

I would be curious to see that ignition map also. But I saw the same issue before were I taxed a fuel pump for all it was worth. Had it at like 70 psi at idle, then under boost to 1 bar (14lbs) I was only able to pull out 280 whp from it. That pump was just maxed out. But as soon as I was able to get the new pump put in, and readjust that fuel psi it made a big difference. This was on a VTEC set up and about 1.9L displacement. That Walbro just might be losing pressure on the top end of it. Somewhere to look I guess.

Good luck.

Jason

 

I suppose I can get the File and Post it. Or a pic of it. You think I have to much retard ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WEldin4fun &raquo;</TD></TR><TR><TD CLASS="quote">I suppose I can get the File and Post it. Or a pic of it. You think I have to much retard ?</TD></TR></TABLE>


Can't tell without seeing it. Can lie anywhere between 14-18 degress for that amount of boost. Too much retard can start to melt pistons though.

Jason

 

I think I am at 24 degrees under full boost