Today I dynoed my 95 z28 road race car. I installed the le2 cam/and heads.

The car has a mail order tune, and has some issues, seems to be missing from time to time.

I have all of the bolt ons, but here is what I did not do yet.

I did not degree the cam when I installed it.
I did not install my 255lph fuel pump yet.
I did not port my intake for a 58 mm TB.

First run the car really was missing results were horrible. Looks like we have an optispark going out? Any opinions appreciated as to the problem. I am going to get a new opti in any case, the car has 64k miles with original opti.

Here is the graph 346 hp...

http://69.73.156.222/problem.jpg
...I was going to give up, since obvioulsy something is seriously wrong, but wanted to try the car with the cutout open, I had noticed that it felt much stronger this way.

The car did not miss and pulled to 380hp/340tq
Graph

http://69.73.156.222/le2.jpg

I stopped the run a bit early, the hp still was picking up...I have the rev limiter set to 6700.

The second line on the graph is the car through the flowmaster catback, what a huge difference 363/328, 17 hp! I have to say I have heard flowmaster bashing, but it really does suck!

This car has a mail order tune. I want to get the opti (or whatever it is ) sorted and I think the car will pick up some more. The torque seems low on the bottom end and picks up on the top end, maybe not degreeing the cam could have shifted the torque curve if it was off from the factory? Still 380 is nothing to sneeze at.

 

Get your ignition squared away and you should be golden. Also ask for the A/F ratio on your graph. On LT1's the only thing degreeing the cam does is verify that your cam was ground correctly so don't worry about it.

 

That first run was TERRIBLE!

 

dayum, what is up opn that first run . . . . . .

something helped alot on that second run and I doubt if the cut out smoothed the graph out that much. I am guessing that whatever the problem in the firts graph (knock retard, way lean, way rich, coil, opti, plug wires, etc, etc) decided to perform a lil better the second run.

It is "possible" to have the fuel pressure dropping and the pump fiox it but if the fuel pressure is the problem, it will usually not allow the #'s to climb any more and this has problem all the way through the pull. I would still install the pump and a new filter soince it will need to be there once everything is sorted out but I would keep looking for the problem also as I doubt that is it.

A scan would help find some problems but checking for KR (real or false), getting ignition squared away, playing with timing and A/F, etc, etc will help the #'s tremendously. Befoire you can even START to tune the car, you have to get the ignition squared away and then make sure TPS is good and adjusted correct, MAF is working correctly, O2's are working correctly, etc, etc, will all get thge thing ready for tuning. Then find someone that knows how to "hands on tune" to adjust everything. If you do not have anyone local that can do a good job of this, get some more data logs (AFTER you fix some of the problems) and get with your tuner to tweek the tune a lil for YOUR stuff.

Lloyd

 

IMHO considering the problems you are having that is not bad powerwise. Get things squared away and you will have a real winner. Looks like a very good combination.

 

Thanks for your response LLoyd. Lloyd has been wonderful to deal with during this whole process!

As far as the first run goes, I feel that something was seriously wrong to cause it to miss like that, like coil or ignition, coil wire etc....I am going to replace the opti, have already done coil, and will check everything.

I did have a lean left bank code, due to an exaust leak on the left side collector right before the o2. I replaced a bolt that had fallen out before the run. I had thought that this would not affect wot in any case???

As far as the IAC counts, I did check them, and they look ok.

One question, does the car look low on torque down low? On the top end the car feels very good, and I think this car would pull up to 6700 +

This is a roadrace car, and I am not interested in getting every single hp out of the car, I want good power, but I don't want to blow it up. Even with 380 hp I am pretty happy, as this is 50 rwhp over what the same car had with stock heads and hotcam.

I plan to get the car dyno tuned after I get it squared away. We will see.

 

man, my typing suck. I guess I should spell check more often. . . .

anyway, most people with LE2 heads and cam in a car with most of the complimeting parts and basic mail order tunes will usually make over 350 RWTQ from before 3000 to after 5500 RPM (2800-5700 RPM or so) and peak about 365-370 RWTQ

Some cars with all the complimenting parts and REAL good tuning will be over 360 RWTQ from 3000-5500 RPM and peak in the 375-385 RWTQ range but these are not "typical" results since most people are missiing "some" complimenting parts and do not have a "perfect" tune.

You can see the graph is choppier than it should be and there are dips in the curves where it should be "more like" a rainbow in that it should always have a bend in one direction above 2500 RPM on the HP and TQ lines and not "s" shaped at all.

Once you just get the graph shaped right and not as choppy, the car will perform alot better at every RPM and I am sure by that time, the HP and TQ #'s will be higher also. Just keep tuning after the problems are fixed and I am sure your results will be more like everyone elses.

Lloyd

 

I think Lloyd said it all, keep tweaking on it and I'm sure you will get that thing to 400rwhp+.

Bret

 

Why did you NOT degree the cam? You should've done some research, as I have done the same not knowingly when I should've degreed the cam.

I did make 400 rwhp though on a dyno tune.

Im lovin' my LE2 setup. The car is just unbelievable to drive. Just wants to keep pulling and pulling... wish I could rev my stock bottem higher.

 

You can----- at least once

 

I just want to second this. He will be doing the heads on every hotrod I build from now on.

 

Ditto on the great service from Lloyd. It has been since June that I've been enjoying my car with the LE2. Before the install, I have talked with Lloyd on numerous occassions and he has been there to answer all the questions I threw at him, even though I asked some more than once.

Thanks Lloyd! Im going with his setup from now on on my future vehicles.