Ran at the track the other day. best slip was:

60- 1.96
1/4 13.2
mph 106.9

Car is a 1995 lt1 trans am Convertible A4. ALL the boltons, 2700 stall, some weight reduction, Ported heads, cc305 cam, 1.7rr. PCM for less tune. Car is not throwing any codes. It was spining the tires pretty good, geting sideways hitting 2nd gear.

Im not happy with the times and the MPH. I remember talking with Bryan at PCM for less and he told me that the cc305 cam is smaller than the hot cam? By the specs it is .510 lift with 1.5 rr. I have 1.7rr. and that would make the lift .578. Could it be a lousy tune that is holding me back???

 

What is the elevation of the track. And by all bolts...do you mean you have headers and dif gears also?

 

do you have proper valvetrain components?....did the car run strong before the mods?....tune up lately?

 

ALL bolt ons, headers, gears. Im at sea level. The temp was in the upper 80's lower 90's. I have 1.7rr and guide plates. I think it could be a tune issue????

Im kinda upset with my times.....

*oh yea, Before the cc305 cam and the 1.7rr, but everything else I ran a best of 13.1 @107 on the stock cam and ported heads and 1.6rr. This was at a faster track and a cooler day.

 

What springs are you running? What RPM were you shifting at? Ever been to the dyno?

 

LT4 springs- I know thats bad. Car seems to pull hard up top. PCM for less has the shift point at like 6100 or 6200. Seems like it wants to pull higher. I dont feel anything like "valves floating".

 

Get it on a dyno to see what kind of #'s it puts down and to see what the a/f is. Running in high 80's/low 90's will also KILL your time's more than you think.

 

Ya need more bite and a dyno tune.
The weather has a bunch to do with it.

 

Thats the problem right there. The LT4 springs almost aren't even good enough for the hotcam at .525 lift. You are running 570 lift. I'm surprised your combo is still even running at this point.

 

I have a heavy 96 z vert. I am at 1700 feet so that hurts a bit and with bad density air days hurts even more. I got a best of 14.3 at 95 or 96mph with a 2.18 60ft on very slippery track running nittos but did'nt bother heating them up like should have .This was last year. For mods at the time had 3.42 gears,tb bypass,magnaflo catback,g2 induction,maft and hpp but tuning out on the hpp.
I am following your thread with interest as have a comp 305 sitting in the box still. This year I threw in a similar to yours vig 2800 added asp underdrive balancer and bunch of suspension stuff,lower control arms,hotchkis drop springs,kyb agx and bmr lower control arm relo brackets and spohn adjustable tranny mount torque arm. I can hit 2.00 on the street with my nittos and the the torque arm and stuff .But can't seem to get under 2.0. I am getting around 94mph now.Think lost some mph from the stall and also went to heavy crome z06 rims and 17 inch rubber.

I am just hoping I am quite a bit faster with planned le2 heads and kooks longtubes. I was hoping to see mid to low 12s with even a 2.0 60ft but maybe I am dreaming also. My vert is very heavy around 3700 with me out I think have to reway it.I way 240 which don't help much either.

Anyway hope you get your car running better at least you are knocking on the door of the 12s. I was wondering if should have went up to maybe a 306 cam and for sure think since the vert is so heavy some 3.73 and mabye a 3200 vig would have been a better combo. I am not sure why I can't seem to get under 2.0. Maybe I need more power to do it,the bigger stall or more gear.

 

What does valve float feel like? Would get a better time or gain HP with better springs?

 

You are risking major damage to your engine keeping those springs in there. It has nothing to do with gaining more Horsepower it has to do with making your engine survive. You are compressing a spring farther than it was meant to be compressed. This can cause the spring to break as well as other problems, but yes to answer your question you would probably gain some horsepower with the springs.

 

It feels like it is missing,possible backfire through I/E
and a general loss of power above a certain RPM.
What is being said is your springs are going into coil bind from the lift. Ya would have bent pushrods if that happened and a very noisy valve train and the car wouldn't run right.

 

Springs.

 

Yea, that is your problem. Install some Comp Cam beehive springs and you'll see your "lost" power come back.