LE2 Dyno. What's Wrong??
 

Here is the first dyno run without any tuning except turning the injectors down.
http://i28.photobucket.com/albums/c2...mEmberton1.jpg

Here is the best dyno of the day.
http://i28.photobucket.com/albums/c2...mEmberton2.jpg

And here is the last dyno of the day. I'm not sure what the spike is.
http://i28.photobucket.com/albums/c2...ynolastrun.jpg

I also remember him saying that adding fuel was actually causing me to lose power. That's probably why the AF ratio is where it is. Okay, post your opinions. What's wrong with my car? I should have well over 400rwhp with my mods.

I had a spike like that around 4700 RPM and turned out to be my LT4 Knock Module. They turned it off worked like a charm. Your A/F seems to be off also.


http://i31.photobucket.com/albums/c3...r96/rdyno1.gif

I would still get that air/fuel ratio down, 14 to 1 under wot is not optmial, more like 12.5 to 1 or less if i remember corectly

if your car is not tuned thats where your problems lies...

This was a dyno tune.

Did you install the cam the way lloyd wanted it installed?

It came out to be 2 degrees advanced. He said that would be fine. Maybe my engine is just weak. :(

your AF ratio is way off. They should have had it at low 13's to high 12's by the time you were done with the dyno tune. Assuming everything else is nominal, the tune changes should net you a little more power.

Taking the ratio #'s down is adding fuel right? The tuner made the comment that usually these cars like to be around 13, but everytime he tried adding fuel it lost power.

DAMN! Did you pay for that tune? On that Dyno? Might want to find a better shop?

yes, lower number = richer. If they cant tune you for optimal power in the correct ratio, either they have a problem with the tune, or there is an underlying condition. It wouldn't be uncommon for each motor to be a little off and like a little more, or a little less fuel, but 14.1:1 is way in the wrong direction.

$250 for 13 pulls and tuning sounded fair to me. I know the guy from a few friends. He has had many LT1 cars and now has a turbo LS1 car. He has always seemed to know what he's doing.

I have thought about trying another shops dyno tune. I haven't been driving it, because I noticed a knocking noise. I hope it's not a rod. I haven't had time to check into it yet.

thats might be your "underlying problem".


Either way, 14.1 is no good for PE mode. Not just for performance, but for safety. It's just far too lean. Thats why stock you hit in the 11's, it's safer.

I made 400 rwhp and 365 rwtq. I forgot to degree the cam though, my fault. I was expecting something in the 410-415 rwhp range, but I guess not.

The knocking might be coming fom your RR's. My friends were louder than a diesel. He called the company and they sent him out new ones.

Well, I haven't done a compression check yet, but I'm pretty sure I have a major shortblock problem. We started the car tonight and let it run for a few minutes. Then we took the temp of the header primaries and cylinder #8 was showing about 150-200 degrees cooler than the rest. This find along with the knocking pretty much assures me there is a big problem. If that cylinder isn't firing properly, I guess that would explain the dyno being so low. I don't know a lot about the way things work, but I also was thinking that could be why I was losing power when the tuner was adding fuel. It wasn't buring properly. It wasn't knocking when we dynoed the car, but maybe pushing it to 6500rpm a few times finally made the problem noticeable.
I would like to thank Lloyd for trying to help me and he has been great the whole time dealing with him.

Don't jump to motor rebuild just yet. I would really advise that you yank the valve cover off that side and look at the valve train. Maybe you dumped a rocker or have a valve issue on that cyl. That would also explain the noise, and the cold temps due to non combustion.

Maybe it's simple, maybe not. But I would really start there first, considering thats the area you were just in while doing the install.