Re: Trap RPM help
[Re: sjs64polara]
#909868
01/20/11 09:39 PM
01/20/11 09:39 PM
|
Joined: Jun 2009
Posts: 644 Minnesota
Barnstorm
mopar
|
mopar
Joined: Jun 2009
Posts: 644
Minnesota
|
Peak hp @ 7400..shift 7600 and cross the stripe @ 7600. 4.88 gear..14x32 tire. Wallace calculator says 3.64 slip.
The little old lady from Pasadena is back!
|
|
|
Re: Trap RPM help
[Re: sjs64polara]
#909872
01/21/11 11:05 AM
01/21/11 11:05 AM
|
Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
|
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
|
Quote:
Wallace calculator says 6.2 slip for my 4200 9.5" Dynamic , Bummer
That's reasonable for a converter w/ that much stall, IMO. My 9.5" Dynamic calcs somewhere in the 7+% slippage and that's about 3% better than the converter it replaced. Even a stock converter may still have 3-4% slippage, IIRC.
My engine hit peak HP at 6300-6400 on an engine dyno and crosses the traps at 6800-6900 (depending upon how good the air is). It's definitely at the point where the power curve is staring to taper off as shown on the dyno. I still have a set of older slicks that are 1+" taller than the DOT-legal radials I run now; it would be interesting to see if the MPH picked up running the taller tires that lower the max RPM on the big end.
|
|
|
Re: Trap RPM help
[Re: sjs64polara]
#909873
01/21/11 11:46 AM
01/21/11 11:46 AM
|
Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
Wallace calculator says 6.2 slip for my 4200 9.5" Dynamic , Bummer
I have about 6.8% slippage on my 8" conv and I dont think its too bad... I know we would all like to see 3% but I wouldnt want to change my conv (I would like to increase the stall about 500 rpm but afraid it might come back messed up)... mine stalls at 5600 and would like it at 6100
|
|
|
Re: Trap RPM help
[Re: sjs64polara]
#909876
01/21/11 01:00 PM
01/21/11 01:00 PM
|
Joined: Apr 2007
Posts: 2,028 Trumbull,CT.
jim sciortino
top fuel
|
top fuel
Joined: Apr 2007
Posts: 2,028
Trumbull,CT.
|
Quote:
Automatic transmission guys, how much over max hp are you guys crossing the lights at Do you consider torque slip
It depends if the engine drops like a rock or hangs on after peak.
|
|
|
Re: Trap RPM help
[Re: jim sciortino]
#909877
01/21/11 02:09 PM
01/21/11 02:09 PM
|
Joined: Aug 2003
Posts: 43,292 Bend,OR USA
Cab_Burge
I Win
|
I Win
Joined: Aug 2003
Posts: 43,292
Bend,OR USA
|
Quote:
Quote:
Automatic transmission guys, how much over max hp are you guys crossing the lights at Do you consider torque slip
It depends if the engine drops like a rock or hangs on after peak.
I had a 8 inch Art Carr when Art first started making converters, it would drop less than 1000 RPM on each gear change The stock 11 inch street hemi converter would drop 1300 to 1500 RPM, depending on what RPM I shifted it at The 8 inch was .3 to.4 slower on the ET and 3 to 4 MPH slower than the stock converter was We ended up with a BM 069J 9 inch converter, which was .3 to .4 quicker than the stock converter was and maybe 1 mph slower, it would drop almost identicle RPM as the stock converter did on the gear changes. To figure the converter slippages I measure the circumference of the tires(actual, not what is stated by the tire company (tires wear and all tires are not create equally ) I take the circumference and the trap RPM to figure the calculated MPH and divide the actual MPH into the calculated MPH and that is the actual percent of slpppage, IE calculted MPH = 133 and time slip MPH is 127 the percent of slippage is 4.52 % (or whatever the calculator says )Tire circumference and accurate tach RPM play a big role in getting a accurate number
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
|
|
|
Re: Trap RPM help
[Re: Cab_Burge]
#909878
01/21/11 02:55 PM
01/21/11 02:55 PM
|
Joined: Mar 2009
Posts: 1,058 bigfork mn
dragram440
super stock
|
super stock
Joined: Mar 2009
Posts: 1,058
bigfork mn
|
My 8" coan 5000 looks like about 7.382 if im doing it right.But it looks like that could vary if it is actually going through at 6400 or 6500 and looks like it makes a pretty big difference. Looks like I should be going through at atleast 7000 or higher.
Last edited by dragram440; 01/21/11 02:58 PM.
67' charger 499 RB
10.57 at 127
|
|
|
Re: Trap RPM help
[Re: jim sciortino]
#909879
01/21/11 05:36 PM
01/21/11 05:36 PM
|
Joined: Jan 2008
Posts: 449 Wisconsin
sjs64polara
OP
mopar
|
OP
mopar
Joined: Jan 2008
Posts: 449
Wisconsin
|
Quote:
Quote:
Automatic transmission guys, how much over max hp are you guys crossing the lights at Do you consider torque slip
It depends if the engine drops like a rock or hangs on after peak.
My engine drops 10 hp from 5500rpm to 6000rpm but my torque drops 66 ft lbs So now what
|
|
|
Re: Trap RPM help
[Re: sjs64polara]
#909880
01/21/11 06:15 PM
01/21/11 06:15 PM
|
Joined: Apr 2007
Posts: 2,028 Trumbull,CT.
jim sciortino
top fuel
|
top fuel
Joined: Apr 2007
Posts: 2,028
Trumbull,CT.
|
Quote:
Quote:
Quote:
Automatic transmission guys, how much over max hp are you guys crossing the lights at Do you consider torque slip
It depends if the engine drops like a rock or hangs on after peak.
My engine drops 10 hp from 5500rpm to 6000rpm but my torque drops 66 ft lbs So now what
Forget the torque. If your valvtrain can take it, gear and converter it to cross where HP drops around 40hp or so, for starters. You wouldn't believe how far past peak HP well scienced out cars go. The converter is critical not only for flash stall, but also fall-back rpm on the shift. It takes numerous changes to hit the right combination.
The fastest SS cars in the country cross at almost 10K. They make peak well below that.
|
|
|
Re: Trap RPM help
[Re: jim sciortino]
#909881
01/22/11 10:30 AM
01/22/11 10:30 AM
|
Joined: Jan 2008
Posts: 449 Wisconsin
sjs64polara
OP
mopar
|
OP
mopar
Joined: Jan 2008
Posts: 449
Wisconsin
|
Quote:
Quote:
Quote:
Quote:
Automatic transmission guys, how much over max hp are you guys crossing the lights at Do you consider torque slip
It depends if the engine drops like a rock or hangs on after peak.
My engine drops 10 hp from 5500rpm to 6000rpm but my torque drops 66 ft lbs So now what
Forget the torque. If your valvtrain can take it, gear and converter it to cross where HP drops around 40hp or so, for starters. You wouldn't believe how far past peak HP well scienced out cars go. The converter is critical not only for flash stall, but also fall-back rpm on the shift. It takes numerous changes to hit the right combination.
The fastest SS cars in the country cross at almost 10K. They make peak well below that.
WOW , I have good stuff in my 505 but that seams a little over board for a weekend warrior like myself.
|
|
|
Re: Trap RPM help
[Re: Cab_Burge]
#909883
01/22/11 03:31 PM
01/22/11 03:31 PM
|
Joined: Jan 2008
Posts: 449 Wisconsin
sjs64polara
OP
mopar
|
OP
mopar
Joined: Jan 2008
Posts: 449
Wisconsin
|
Quote:
My 518 C.I. low deck pump gas street motor made peaak torque at 4600, peak HP at 5800 RPM(CNC ported Eddy RPM and a stock Eddy six pak intake and stock type Holley 1970 440 vacume carbs. The car ran the quickest and fastest by shifting it at 7300+ RPM in 1st and 2nd gear, it would cross the finish line at or close to 6200 RPM best ever Way past peak anything on the gear changes work best for the results I did later change converters in the car with a different motor and pick up 4 MPH in the 1/8 mile
What weight car and stall I'm listening
|
|
|
Re: Trap RPM help
[Re: sjs64polara]
#909884
01/22/11 04:08 PM
01/22/11 04:08 PM
|
Joined: Apr 2007
Posts: 2,028 Trumbull,CT.
jim sciortino
top fuel
|
top fuel
Joined: Apr 2007
Posts: 2,028
Trumbull,CT.
|
Quote:
Quote:
Quote:
Quote:
Quote:
Automatic transmission guys, how much over max hp are you guys crossing the lights at Do you consider torque slip
It depends if the engine drops like a rock or hangs on after peak.
My engine drops 10 hp from 5500rpm to 6000rpm but my torque drops 66 ft lbs So now what
Forget the torque. If your valvtrain can take it, gear and converter it to cross where HP drops around 40hp or so, for starters. You wouldn't believe how far past peak HP well scienced out cars go. The converter is critical not only for flash stall, but also fall-back rpm on the shift. It takes numerous changes to hit the right combination.
The fastest SS cars in the country cross at almost 10K. They make peak well below that.
WOW , I have good stuff in my 505 but that seams a little over board for a weekend warrior like myself.
It probably is overboard for a "WW"......but if you want to squeeze every last bit, that's how you run em'.
|
|
|
Re: Trap RPM help
[Re: sjs64polara]
#909885
01/22/11 04:25 PM
01/22/11 04:25 PM
|
Joined: Aug 2003
Posts: 43,292 Bend,OR USA
Cab_Burge
I Win
|
I Win
Joined: Aug 2003
Posts: 43,292
Bend,OR USA
|
Quote:
Quote:
My 518 C.I. low deck pump gas street motor made peaak torque at 4600, peak HP at 5800 RPM(CNC ported Eddy RPM and a stock Eddy six pak intake and stock type Holley 1970 440 vacume carbs. The car ran the quickest and fastest by shifting it at 7300+ RPM in 1st and 2nd gear, it would cross the finish line at or close to 6200 RPM best ever Way past peak anything on the gear changes work best for the results I did later change converters in the car with a different motor and pick up 4 MPH in the 1/8 mile
What weight car and stall I'm listening
The 10 inch converter would foot stall right at 2300, flash stalled 3800 to 4300 depending on which motor and the track altitude. The 8 inch converter foot stalls near 3000 RPM, flashes 5100 - 5200 RPM. The car weighs 3450 lbs with me in it, 4:10 gears.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
|
|
|
|
|