Camaro90RS

Well several weeks ago I went to a local track, Byron Dragway and made 7 passes with it. The car was very consistant running 12.70's at 105.5-106 mph. My 60's were low 1.70's with a best of 1.70. The car sounded and ran great, except for the fact that once it got into 2nd and 3rd gear, it kinda fell on its face. I mean it still pulled, but it just seemed like it didnt have any torque. I am running a Vig 3600, 3.73 gears along with 26x11.5 ET streets at 16 psi. The car didnt spin and it dead hooked every run. The car also weighs 3700 lbs with me in it. The temp that day was low 70's, average humidity and the elevation of the track is about 600 ft if memory serves me correct. Almost of the track runs were made with the converter unlocked and the runs that were locked the car somewhat slowed down and really fell on its face.

I had the car dynoed the week before, and it put down 375 rwhp at only 6000 rpm with the torque converter locked and 355 rwhp with it unlocked at 6000 rpm. Right at 6K, the power went flat but didnt drop. With the XE 236/242 that I have, it should be making power to 6600-6800 rpm. But that is also a problem in itself. The torque with the converter locked was steady at about 345-350 rwtq all the way through the rpm band. With the converter unlocked, the peak torque was at 2800 with 397 rwtq and then went in a straight line down. At 6000 rpm, it was making about 290-300 rwtq and at 6500 it was even lower.

Here is a link to my dyno graph from before we had to freshen the motor up back in July. You can pick one of the 3 charts that are here.
http://groups.msn.com/BriansFbodyPic...ct.msnw?Page=2

For a complete list of mods and a flow chart on the heads go here--
http://www.smknta95.cz28.com/mods.html

The only things that arent added in this list are--Comp "R" lifters, Comp 985 springs, RollerMaster timing chain, and a freshened up bottom end with new rings, bearings, main studs, oil pump and rod bolts, and a 255 in-tank pump.

Since I now have most of the info out of the way, what could cause the car to only run 106 mph with 375 rwhp?? Since the track outing, I did change the fuel pump to a 255 in-tank and the fuel filter. Could this help my mhp and times or is there something else that I need. So if you guys could help me before I completely give up on this car, I would greatly appreciate it.

Brian

Cory1994z28

could the large porting cause the car to not have a lot of tq.... which would keep you from pulling in your higher gears.... maybe your heads are suited best for a different cam.. is that possible or am I way off

Z97LT1

^You gotta be way off. His car made the power...375 rw should be 114 or better at his raceweight. Maybe the tranny is sick? Thats about all I could think of....I'd say hit the dyno again and see whats up..

QCKZ28

start with the obvious things, hold long ago was the dyno? when did you run at the track? ill bet you wont dyno 375 now and only trap 106, did you dyno with the et streets on?
hook up the scanmaster and see all your readings? its probably something simple. good luck

Jesse

Camaro90RS

Ok, I dynoed the car on 9/13 which was a sat. I drove the car around a little bit that day and some on sunday and then the car sat until the next weekend as I went back to school for the week. I came home on 9/19 and got the car ready to drive to the track and drove it some. The car never changed any from the time I dynoed to now. The car still feels the same, pulls like a bitch on street, but doesnt pull as hard with the ET streets on. I will bet 100% that the car will dyno the same numbers within a few hp because I have done nothing to the car and it drives the same. We have hooked datamaster up to it several times and the car is running great, no problems. On the dyno it is running right around 13.0-13.2 A/F all through the rpm band. I know for one thing that the tranny is NOT sick at all. It was built probably about 2500 miles ago and has no problems. If anybody knows of FLP, they will know that an FLP Level 4 trans is a solidly built one. Hopefully one of my friends will chime in here and say that the tranny is not the problem and the car runs the same now as it did right after I dynoed it. The only thing that has changed since the track/dyno is the replacement of the fuel pump with an intank 255 lph pump. Anybody else have some ideas.

Brian

QCKZ28

just curious what was your 1/8 et and mph?
is that SAE corrected? what kinda dyno?

Camaro90RS

Well right now I dont know what my 1/8 et numbers were as I dont have my time slips here with me at school. I am going to call home tomorrow morning and get them from my dad so that I cant post them up to. The car was on a Dynojet 248c I believe. For some reason, I looked for my dyno sheets and they are no where to be found. But my computer tuning buddy has a copy of them and hopefully I can get him to chime in here about the correct/std/sae thing either tonight or tomorrow sometime. Well gotta go.

Brian

Camaro90RS

any other ideas

NVetro

Well if you said the only thing you did was change your fuel pump. Perhaps you should check your fuel presure at idle, and at WOT. My FINALLY fixed my low rpm sputter, and the car falling on its face after a certin rpm and it was the pump. Just something to think about. Ya know?

LS1_03

Tranny definitely isn't sick. Shifts like it should and doesn't slip. I suppose I should update your site someday Brian.

GaRn

If you put on a high pressure pump, it can overrun your stock(or sometimes aftermarket) FPR.. try lowering your fuel pressure or buying an adjustable FPR and tuning it.. good luck..

Camaro90RS

The fuel pump was replaced after I went to the track. I allready have checked the fuel pressure before and after the replacement and it is the at the same 44psi. But before I changed the pump, the pressure would drop between 4-8 psi under WOT and it would dip about 3-5 psi when I reved it up when idling. Now the pressure doesnt dip at all under WOT or idling so maybe I have fixed the problem.

Brian

GaRn

take that beast back to the track and let us know! that sounds like what it could be..

Camaro90RS

BTW, I now have the 1/8 mi ET and mph fom those 12.70 runs.

1/8 ET's--8.04, and 8.05

1/8 MPH--84.78, 86.68

The higher mph on the one 1/8 mi run was that I had the cutout open versus closed for the others.

Brian

Camaro90RS

any one else