Help understanding timeslips KB GT 500RWH

rcn4him · Nov 23, 2004

MustangLife said:
Launching the car at idle on et streets. You might be bogging. Hell i couldn't even launch my car on nittos less than 3000 without bogging. 14psi is way to much. Air them down to 10psi and believe me it makes a good bit of difference. You'll just have to get used to the swaying. But powershifting is not your problem. Your trapping way to low of a mph. What rpm are you shifting at? How about letting a friend that is used to drag racing a car, drive it and see if he can do anything different with it.

Josh

Amen, 14lbs is way too much tire pressure, 10lbs is a good starting point!

YellowJacketGT · Nov 24, 2004

MustangLife said:
Launching the car at idle on et streets. You might be bogging. Hell i couldn't even launch my car on nittos less than 3000 without bogging. 14psi is way to much. Air them down to 10psi and believe me it makes a good bit of difference. You'll just have to get used to the swaying. But powershifting is not your problem. Your trapping way to low of a mph. What rpm are you shifting at? How about letting a friend that is used to drag racing a car, drive it and see if he can do anything different with it.

Josh

I don't think I'm bogging at all.. The front tires are almost off the ground. 2nd gear close also. Any more RPM and tires spin.. I shift at 6200.. Car is like a bucking bronco. All the way up, slam down, all the way up. Shocks should help keep transfer. Instant 500 tq is a bunch to handle down low.

Shocks, diet, 10psi, heat'em up.

I datalogged the run. AIT 138 1st, 144 2nd, 156 3rd, 163 4th.
Water / methonal injection (375 spray). Timing drops 3 degrees in 2nd and 3rd. Loosing some hp at top end..

BTW: Water injection did not cool the temperature down or make any difference in times.

mogs01gt · Nov 24, 2004

DING DING DING, you are shifting WAY too early. Look at your dyno. You power goes to 6.5k. You should actually be shifting after your power starts to drop off so possible around 6.6k or around 6.7k.

If that was mine, I would be banging the gears at 7k but that's me.

Saleen s281 · Nov 24, 2004

hey yellowjacketgt i have 488rwhp and 502 rwtq and i ran 12.073@117mph launching at 2500rpmand shifting at 6100.i see cobra's with similiar power running 11.40 @121 mph.i think we should be launching little bit harder and shifting around 6500
60' 1,741
330 5.128
1/8 7.833
mph 89.78
1000 10.151
1/4 12.071@117

YellowJacketGT · Nov 24, 2004

Saleen s281 said:
hey yellowjacketgt i have 488rwhp and 502 rwtq and i ran 12.073@117mph launching at 2500rpmand shifting at 6100.i see cobra's with similiar power running 11.40 @121 mph.i think we should be launching little bit harder and shifting around 6500

Great to see someone with similar setup...

Yea I agree.. 6500 is about at the max (18000) rpm for the blower.
I need to fix the launch hookup. If I come out any harder my 60' gets worse. If I had skinnies I will probably be off the ground. And this is at idle comming out. Can't imagine what it will be like when I can launch at higher RPM.

Do you have a dyno so I can compare?

Saleen s281 · Nov 24, 2004

YellowJacketGT said:
Great to see someone with similar setup...

Yea I agree.. 6500 is about at the max (18000) rpm for the blower.
I need to fix the launch hookup. If I come out any harder my 60' gets worse. If I had skinnies I will probably be off the ground. And this is at idle comming out. Can't imagine what it will be like when I can launch at higher RPM.

Do you have a dyno so I can compare?

here it is

reeber · Nov 24, 2004

o3redfire said:
if you are not power shifting you will need to, gas pedal should stay to the floor, and I agree, at this power level clutches burn up quick and a built auto and stall would help
I was launching my 03 cobra at 4,000 rpms on the irs with bfgs and simular hp/tq. numbers, 18lbs boost.

The mustang manual transmissions are very resistant to power shifting. You are going to find yourself missing more than hitting second and third gear... The third to fourth shift is easy to powershift, but I just jump off the gas for .1 second and shift to ensure it finds second... It could be just my opinion, but I have had vettes and japanese cars that power shifted with no problem at all.. Mustangs are the only cars I've ever had trouble with..

Jackie Chan · Nov 24, 2004

YellowJacketGT said:
Great to see someone with similar setup...

Yea I agree.. 6500 is about at the max (18000) rpm for the blower.
I need to fix the launch hookup. If I come out any harder my 60' gets worse. If I had skinnies I will probably be off the ground. And this is at idle comming out. Can't imagine what it will be like when I can launch at higher RPM.

Do you have a dyno so I can compare?

you dont need to fix the launch, you need to fix your driving and tweak a couple things....drop the psi, heat the slicks and learn to launch the car. i would say dump the clutch while bringin the rpms up to about 4500rpms. 12psi in the slicks to start

Instigator-101 · Nov 24, 2004

Looking at the 1/8 mile trap speed I would say that you are losing mph on the top end. You are up on the vortech'd car by 5mph in the 1/8, but only 2mph in the quarter. Are you letting off early? I would think that with a trap speed of almost 95 in the 1/8 you would definately be traping in the 120's.

mogs01gt · Nov 24, 2004

reeber said:
The mustang manual transmissions are very resistant to power shifting. You are going to find yourself missing more than hitting second and third gear... The third to fourth shift is easy to powershift, but I just jump off the gas for .1 second and shift to ensure it finds second... It could be just my opinion, but I have had vettes and japanese cars that power shifted with no problem at all.. Mustangs are the only cars I've ever had trouble with..

Its you then. I have never heard of such bull**** about power shifting in a mustang. Actually, stangs are easier because its a cable clutch and not an hydraulic clutch. You can get more feel with a cable clutch.

learn to drive the stang and you wont have any problems.

YellowJacket,
Im trying to figure out something. Were you aware when you bought the cams and motor setup that you would have shift close or above 6.5k? I do not understand why you went with a blower that you really cant use on your setup. A YS/YF(cant remember the name) or an F1 would have been a much better choice with your setup. All you would have need would have been some taller gears.

of a turbo is ideal.

JBVobra · Nov 24, 2004

first off, just for apple to apple comparisons, that 500rw dyno is STD corrected, that would equate to about a 480rw SAE dyno.

But even with that, those traps are awefully low. This is why I hate dyno drum racing....it's not reality. A car can be tuned to run great on a dynojet drum, but wreak havoc out on a road with a much different load factor. Your PCM could be sensing knock and pulling mega timing on the road. Only god and autotap would know whats really going on when tire meets pavement. From the looks of the timeslip, it's not panning out to no 480rw....

Now as far as your other setup items, I'm not sure why everyone keep mentioning the et street psi and low traps.....if anything, too much psi is going to actually INCREASE trap speed from the additional spinning downtrack. That is drag race 101 phenomona.

I think you need a wide-band bung welded in, a true a/f meter, and an experienced tuner who is willing to tune out on the road. You're going to realize max value that way. And, gulp, if all else fails, it might be time for a compression/leakdown test. Something could be wrong. I don't like the looks of how you seem to be slowing down really bad on the back half of the track. That is not a good sign.

Good luck!

YellowJacketGT · Nov 24, 2004

Saleen s281 said:
here it is

Thanks for the dyno..
You have one with a torque line...

silver04stang · Nov 24, 2004

what is your reaction time?? I notice when i go to the track it makes a small difference... just a thought might make a difference between 12.0 and 11.9...

YellowJacketGT · Nov 24, 2004

Instigator-101 said:
Looking at the 1/8 mile trap speed I would say that you are losing mph on the top end. You are up on the vortech'd car by 5mph in the 1/8, but only 2mph in the quarter. Are you letting off early? I would think that with a trap speed of almost 95 in the 1/8 you would definately be traping in the 120's.

I really believe this is part of the characteristic of the 1.7 KB blower...
Heat increases as you make your way through the gears. Timming gets reduced therefor less hp .

I have attached an Autotap of one of my runs.

Autotap of 1/4 mile run

1st gear : 22 timing/138 AIT
2nd : 23 /144
3rd : 20 /156
4th : 20 / 163

Notice the slow climb of timing from lower rpm in 4th gear. Not a problem in 1st.

I'm shifting at 6200. Not letting up at all.
BTW: this run I have water injection (Did not seam to cool things down). I ran without injection. Not much difference.

This is the same car/suspension as the Vortec. 11PSI KB (14 PSI pulley). 14PSI vortec. The difference is blower /heads/cams..
I am driving the same way..

I can't help but feel its the type of blower .

I could run back to back runs with the Vortec. Never had to wait 30-40 minutes like I have to with the KB.

YellowJacketGT · Nov 24, 2004

silver04stang said:
what is your reaction time?? I notice when i go to the track it makes a small difference... just a thought might make a difference between 12.0 and 11.9...

My understanding is reaction time does not influence ET. Clock does not start until you pass a certain point.

reeber · Nov 24, 2004

mogs01gt said:
Its you then. I have never heard of such bull**** about power shifting in a mustang. Actually, stangs are easier because its a cable clutch and not an hydraulic clutch. You can get more feel with a cable clutch.

learn to drive the stang and you wont have any problems.

.

I guess I need to learn how to drive... You haven't obviously driven a newer vette... The clutch difference has nothing to do with it.. It's the way the transmission works.

YellowJacketGT · Nov 24, 2004

mogs01gt said:
Its you then. I have never heard of such bull**** about power shifting in a mustang. Actually, stangs are easier because its a cable clutch and not an hydraulic clutch. You can get more feel with a cable clutch.

learn to drive the stang and you wont have any problems.

YellowJacket,
Im trying to figure out something. Were you aware when you bought the cams and motor setup that you would have shift close or above 6.5k? I do not understand why you went with a blower that you really cant use on your setup. A YS/YF(cant remember the name) or an F1 would have been a much better choice with your setup. All you would have need would have been some taller gears.

of a turbo is ideal.

Had Vortec SQ.. I get the sense centrificals are better at the track and KB is more fun on the street. Since I spend more time on the street KB is a good choice for me. Had 410's .. Actually had some runs with KB and 410's. About 2 mph faster, about the same et's as 373.

If money was no object I would try a turbo. Best of both worlds. Torque quick, low heat, plenty of power.

YellowJacketGT · Nov 24, 2004

JBVobra said:
first off, just for apple to apple comparisons, that 500rw dyno is STD corrected, that would equate to about a 480rw SAE dyno.

But even with that, those traps are awefully low. This is why I hate dyno drum racing....it's not reality. A car can be tuned to run great on a dynojet drum, but wreak havoc out on a road with a much different load factor. Your PCM could be sensing knock and pulling mega timing on the road. Only god and autotap would know whats really going on when tire meets pavement. From the looks of the timeslip, it's not panning out to no 480rw....

Now as far as your other setup items, I'm not sure why everyone keep mentioning the et street psi and low traps.....if anything, too much psi is going to actually INCREASE trap speed from the additional spinning downtrack. That is drag race 101 phenomona.

I think you need a wide-band bung welded in, a true a/f meter, and an experienced tuner who is willing to tune out on the road. You're going to realize max value that way. And, gulp, if all else fails, it might be time for a compression/leakdown test. Something could be wrong. I don't like the looks of how you seem to be slowing down really bad on the back half of the track. That is not a good sign.

Good luck!

I think this is a function of the 1.7 KB. Heat increases, timing pulled etc.

Autotap of Run

YellowJacketGT · Nov 24, 2004

Saleen s281 said:
here it is

Opps .. Just noticed torque on dyno. I am used to both measurments on 1 graph..

BTW: what type comp cams did you have?

Saleen s281 · Nov 24, 2004

same as yours. by the way do u have any problem starting ur car up when its hot?sometimes i need to pump the gas pedal to get it started. i was told that it was the cams thats making it hard to start

Help understanding timeslips KB GT 500RWH

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