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We didn't set out with drastic goals because this is primarily a show car...But... I wanted to atleast get the car in the high 11's on motor. It's a full weight 2001 Coupe with a completely stock suspension. The bottom end was built for a small nitrous shot so I built it with a stock bore, stock crank, 6.125" Eagle H-Beams, Probe flat top nitrous pistons, nitrous ring gaps and all ARP bolts/studs. Valvetrain is a COMP XER 281 (232-234 .595"-.598") on a 112 LSA, COMP 850 lifters, and Lunati dual springs. Heads are ported 241 castings with 2.02" valves. LS6 intake and ported stock throttle body. The car has made 386 RWHP through a locked 3200 stall and 3.15 gears. That combination want 12.2 @ 113 with a 1.76 60 ft. time on Hoosier drag radials.
In the attempt for high 11's, I swapped to 3.90 gears and a 3600 stall. It made 370 RWHP with the converter UNLOCKED. Took the car to the track again. Granted weather was worse and track prep was terrible, but could only run the best of a 12.39 @ 112 MPH with a 1.84 60 ft. Trying to launch the car off stall was useless because the higher the stall, the worse the 60 ft. because it was spinning. The ONLY other changes were a swap to colder NGK plugs that replaced the AC Delcos and a new PCM (reloaded with same tune).
We have cured a couple other issues since the last track outing. I have a new set of M/T drag radials, had the car aligned (it was WAY out), and lowered our 2-3 shift point because it didn't like 6700 RPMs. I did a compression check. Average was 160. Lowest was 155 and highest was 163.
Next step is wait for cooler weather and see what happens.
Temperature, elevation (DA) play a part in this. 12.2 is pretty decent really for what you have. It would be nice to see high 11's but your trap speed is too low, being in the low teens.
Others will chime in, but I am going to say its your tune. You didn't mention what headers and exhaust you have either.
Temperature, elevation (DA) play a part in this. 12.2 is pretty decent really for what you have. It would be nice to see high 11's but your trap speed is too low, being in the low teens.
Others will chime in, but I am going to say its your tune. You didn't mention what headers and exhaust you have either.
Previous times were ran on 325/35-17 Hoosier drag radials. They were pretty old though. I have a new set of M/T "R" ET Street drag radials for the next trip.
Your whp numbers should theoretically get you into the very high 11s (probably about 11.55-11.9), but as Roddy13 points out different factors (elevation, temperature, humidity, etc) can affect performance.
Tires might help some, but learning the right leave and auto shift points to bring down the 60' as junk c5 suggested will help a lot.
You should not be falling off that much at 6300. The LS6 intake and ported TB should be sufficient for at least 6800 if not more. Several considerations include the throttle body. You mention it was ported, but was this ported by an engine shop, an induction specialist or someone just learning? An improper port job can be worse than a stock TB. How about your injectors? Are you getting good fuel flow from the pump through the lines? And as Roddy13 also suggested - what about your tune? If it's the tune or whatever else is affecting the abrupt drop off at 6300 then your 3.90 rear may be hampering you. Your decision to drop your shift point appears good based upon your power drop off point. Roddy is right suggesting you run it to a much higher RPM IF it's producing power but right now, I'm not sure anything is gained.
Good luck and please let us know what you find. Looking forward to your 11.xx time slip!
Depending on how it's tuned, inlet air temp or spark knock retard could be causing it to pull timing at the track that was not seen on the dyno with the hood open.
Car is fine it the driver. You need to learn how to do a burn out, leave harder. Your 60' is deplorable and that's what's killing you.
Right now its an 11 sec car with a 12 sec driver.
Your whp numbers should theoretically get you into the very high 11s (probably about 11.55-11.9), but as Roddy13 points out different factors (elevation, temperature, humidity, etc) can affect performance.
Tires might help some, but learning the right leave and auto shift points to bring down the 60' as junk c5 suggested will help a lot.
You should not be falling off that much at 6300. The LS6 intake and ported TB should be sufficient for at least 6800 if not more. Several considerations include the throttle body. You mention it was ported, but was this ported by an engine shop, an induction specialist or someone just learning? An improper port job can be worse than a stock TB. How about your injectors? Are you getting good fuel flow from the pump through the lines? And as Roddy13 also suggested - what about your tune? If it's the tune or whatever else is affecting the abrupt drop off at 6300 then your 3.90 rear may be hampering you. Your decision to drop your shift point appears good based upon your power drop off point. Roddy is right suggesting you run it to a much higher RPM IF it's producing power but right now, I'm not sure anything is gained.
Good luck and please let us know what you find. Looking forward to your 11.xx time slip!
Thanks for the suggestions. Lingenfelter ported the throttle body. Tune has been gone through several times. The injectors are 42LB Racetronix. I can't remember exact fuel pressure, but I had the shop check it the last time it was dynode and they confirmed it was good.
Depending on how it's tuned, inlet air temp or spark knock retard could be causing it to pull timing at the track that was not seen on the dyno with the hood open.
This guy is on the right track...
Lots of things can happen while going down the track that you, as a driver, have no knowledge of. This is how a car making 390 on a dyno, runs slow at the track.
You need to log your passes.
You should have reasonably fresh tires.
09-08-2017, 04:29 PM
Why is our Car this slow?
