Hey guys I tried this on CF first since there are more vettes over there, but nothing constructive has been said. I figure my LS1 Tech brothers won't let me down.

The cliff notes are basically I'm putting 400/393 SAE to the wheels with a Non Intercooled Maggie with 1 3/4" LPE headers and standard Borla exhaust. Not only that it's rather "jagged" compared to some of my other cars. AFR was about 11.6 on the red run. I had to add some fuel because it was running around 12.0 and the dyno operator notice some knocking (I got zero KR though) on the first run. Other than adding some fuel it's pretty much the stock programmer tune.

I'm just wondering because when it got done at LPE by the original owner it did 420/414 SAE on LPE's dyno. I just can't see there being a 20+ hp difference between dynos unless LPE's dyno is pretty liberal. The original graph was a lot smoother; however, I don't know how much smoothing they had on it, and it doesn't say what the AFR was or the conditions.

Any thoughts? spark plugs? I have fairly new TR6s, despite Magna saying use stock heat range with stock gap. For me when I think boost I think TR6. I don't think belts would be an issue with only 5 psi. Hmm... valve springs?

Here's the graph too FWIW.

http://i7.photobucket.com/albums/y25...27/c5magna.jpg

Original dyno sheet.

http://i7.photobucket.com/albums/y25...27/lpedyno.jpg

Some other things I noticed are that my injectors are going static after 6000 RPM. 106% DC. On the street they get into the the mid 90s. Fuel pressure problem? If not I need new injectors.

Some other thoughts... Could it have have anything to do with the clutch? I need to replace the hydraulics and clutch because I get the "stuck clutch” syndrome after really getting on it. So I have no clue how much life is in that clutch. So when I do the hydraulics I might as well put in a good clutch.

Also please only post constructive ideas. Stuff like "your number are low, or looks about right" doesn't help. I'm trying figure out how I went from 420 to 400. I plan on putting on an intercooler and a pulley, but I want to figure out what's going on right now... Thanks!

 

Well first I will say that I would have a FP gauge to monitor it. And as far as injectors it sounds like you are pushing them to the limit and might consider picking up a larger injector to help with the high duty cycles may or maynot be a problem though and as far as 20rwhp difference in dynos that is very normal also the weather will play a large part in that to it doesn't really sound like you are far enough off of the original mark to be jumping to conclusions just yet. Although I think there are some gains to be had from a good dyno tune from a reputable tuner in the area if possible. I wouldn't be afraid to put an intercooler on it or a smaller pulley JMO. Definately if you have any doughts about your own knowledge about the car and what it is doing let a good shop take a look at it and give your there opinion.

 

how many miles on the car and the blower?

the numbers do seem low.....

i made 400rwhp with a 222 cam and ported stock heads....

i woulda guessed 450rwhp with a blower.....
maybe try a re-tune? or throw in a bigger blower cam?

 

Like was said, definitely need a FPG... if your FP is falling off, the injector duty will increase to make up for it. The injectors will max out early...

What does your timing curve look like?

 

Great responses so far... But I thought that's why we always try to use SAE CF for different altitudes, weather conditions, etc.

It's a 99 FRC with 39k on the entire car. The blower has about 23k on it. I might end up putting in a FP gauge. I was going to put in boost and Wide Band A/F ratio... I'll just have to figure out where to put it. I want the WB in there for tuning reasons. I'll be able to get the tune spot on. The injectors are GM/Bosch ones that are white and around 38 lb/hr. depending on who you ask.

Here's the timing table graph

http://i7.photobucket.com/albums/y25...7/timing02.jpg

Here are the actual values

http://i7.photobucket.com/albums/y25...7/timing03.jpg

 

I hooked up the boost gauge temporarily just to see what it's doing, and it's hitting 5 psi exactly.... So one thing eliminated.

 

I don't know what the IATs look like on that setup, but that (advance) seems to be very conservative... If you aren't getting any KR, I would add a few degs and log and repeat.

 

Frost, I found out that LPE didn't relocate the IAT sensor. I moved it to the plenum base a few days ago, and I've seen IATs of 145-150 under boost, and that was on a cool 75 degree night, I should try logging during the day lol.

I'm just guessing if IATs are almost double that of ambient temperature then I could be anywhere from 180-200 on a hot day.

I'm hesitant to add timing right now because on my very first run I was running into the 12s AFR and dyno operator noticed some audible knock so he shut it down. I didn't get any KR whatsoever... so that tells me I can't always rely on the knock sensors. But I do agree that the timing is very conservative. sometime I won't even hit the full 15 degrees. I think the computer pulls a degree or two because of the IATs. It hasn't pulled a full 5 like that table indicates.

 

We do use the CF to get as close as possible, but It doens't always equal out like you might think. And some shops don't up date there software on there dynos to keep the number some what higer although that won't matter if you use the same dyno all the time. I agree your numbers are low, but they have always been on the low side so no real supprise on that. I know they are a little low, but not everyone will have a freak or make the same numbers. If you want more I would start with adding the intercooler or a Boost cooler from Snow performance or ECS to lower IAT, and give you a little more octane rating to let you increse your timming a little bit. Just a few suggestions. Hope you figure it out.
Jeff

 

upgrade your fuel system before you melt your motor

106%DC? Yikes.