Dyno sheet shows 340 hp......wouldn't that put the car in the high 12's at the track........

Secondly, if the dyno sheet said one thing and the car does something else when its at the track.......what are the differences the car is seeing when at WOT on a dyno and on the track other than the lauch?

 

Your driving ability, altitude, weather conditions.

 

It may be a combination of things. Driving (poor launch off the line, slow manual trans shifts), poor traction (street tires), Etc. You need to break-down the run by first looking at your 60ft times. A high 12 sec car should have approx 1.8 sec for 60ft. Also, your 1/8 mile ET and speed to determine where you or, your car is not performing.

 

Well...before all the work i felt a stonger launch with the stock set up...which sucks....i also am not spinning off the line which actually i was expecting a lot of spinning. One run was 60'- 1.88....1/8- 8.7......1/4- 13.6 @100 MPH....Does this sound about right or am way off.......it feels like there is nothing at the top end........with the re-build and upgrade in parts i would think i would increase MPH to around 105-110....i mean i was going 100-101 with a tired old engine with no mods.....

 

Something isnt right. Did your dyno have a wideband? what was your A/F.

 

A/F ratio went from 14.7- 12.4....not sure what a wide band is?.......what might be wrong if dyno says one thing but the car produces something different on the track?

 

The wideband measuse the A/F which looks ok.

It could have just been the conditions. They dyno doesnt lie, unless its way out of calibration, but it looks ok from what mods you have. How long ago was it dynoed?


With the mods in my sig i should be running much faster than a 12.8 at 112. But factor in altitude and weather and the fact that im not a professional driver and thats what I run.

I agree though, you should be running much faster.

 

Here are two silent LT1 power robbers to check.

1. The stock LT1 knock module (in the PCM) can cause the ESC to retard timing and lose top-end power. So, get an LT4 Knock Module for the PCM.

2. If the regulated fuel pressure can not be maintained "43 PSI" (weak fuel pump, or bad regulator) you will also lose top-end power. Check the fuel pressure, with vacuum line disconnected.

These two items should have, but may not show-up on the dyno test. Good luck!

 

Two problems mentioned were already addressed...

Knock modular was desensitized accordingly with th dyno tune......so i hope....

Also did a whole fuel pressure and vaccum check everything came out ok.....when its gets hot the fuel pressure drops a few pounds but still maintains the pressure.....

I was at the track this past weekend with another car and was talking with someone that had a bad MAF sensor....and said it robbed some horses....how can you determine if its good or not?

And any more things to check......i think it might be the convertor doing something...how can you check that?

 

Still looking for any more suggestions?.......within a re-build if nothing is done to the intake will it affect the way my new heads work?.....Any tests you could do on the car to determine efficiency of engine without pulling the engine again........Is there a way to read the computer to see if something is wrong even without SES codes?........if so what should the numbers be and what numbers to look at?

 

Put a scanner on it, do a compression check.

Z