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trap rpm

Posted By: 440lebaron

trap rpm - 03/14/22 02:02 AM

hi, whats a real would finish line rpm 1/4 mile, 4:56 29" 30" tire 727 stk ratio...? cars not running yet
Posted By: CMcAllister

Re: trap rpm - 03/14/22 02:15 AM

How fast?

140MPH, 30" tire, 4.56 = about 7100 plus whatever converter slippage is. Few hundred on a decent one.

130 goes to 6600.
Posted By: Cab_Burge

Re: trap rpm - 03/14/22 02:53 AM

Originally Posted by 440lebaron
hi, whats a real would finish line rpm 1/4 mile, 4:56 29" 30" tire 727 stk ratio...? cars not running yet

What size motor, how much HP and converter stall?
Posted By: StealthWedge67

Re: trap rpm - 03/14/22 05:17 AM

I run 4.56ā€™s with a 30ā€ tire (PBR 29.5x10.5). Typically Iā€™m right at 120MPH. 727 with a 9-1/2ā€ converter. I see 6600 right at the stripe.
Posted By: rb446

Re: trap rpm - 03/14/22 01:55 PM

Originally Posted by 440lebaron
hi, whats a real would finish line rpm 1/4 mile, 4:56 29" 30" tire 727 stk ratio...? cars not running yet


Impossible to know without knowing weight@the line and estimated fwhp and then you have verter slip to calculate in.
As an example, 600fwhp in a 3500@the line car with 4.56 with a 29" tyre and a good hook would look something like this>

60 Foot E.T. : 1.46 Seconds
1/8 Mile E.T. : 6.62 Seconds
1/8 Mile Trap Speed : 102.74 MPH
1/4 Mile E.T. : 10.49 Seconds
1/4 Mile Trap Speed : 128 MPH
1/4 Mile Trap RPM : 6,757 RPM+ 8% slip?=7297

with a 30" tyre
60 Foot E.T. : 1.46 Seconds
1/8 Mile E.T. : 6.62 Seconds
1/8 Mile Trap Speed : 102.74 MPH
1/4 Mile E.T. : 10.49 Seconds
1/4 Mile Trap Speed : 128 MPH
1/4 Mile Trap RPM : 6,532 RPM+8%=7054
so your looking on average around 250>300rpm difference from a 29>30" tyre across a wide range of hp/weight combo's.

And that works the same for our RR at 3800lbs with 4.10's and 675fwhp with 29's going to 30's, with an 11.39 SLR.
And similar for my old Cuda with 660fwhp@3300lbs with a 32" tyre and 4.88's and then with a 31" tyre around 260rpm more@the stripe.


Posted By: 440lebaron

Re: trap rpm - 03/14/22 02:52 PM

est 500 hp 112/115 mph 4800 stall 4355 wgt

Posted By: 73DAD

Re: trap rpm - 03/14/22 03:02 PM

With a hypothetically perfect torque converter with no slippage and no growth from the tires:

30" Tires

At 130 mph 6642rpm
At 120 mph 6131rpm
At 110 mph 5620rpm

29" Tires

At 130 mph 6871rpm
At 120 mph 6343rpm
At 110 mph 5813rpm
Posted By: rb446

Re: trap rpm - 03/14/22 03:05 PM

Originally Posted by 440lebaron
est 500 hp 112/115 mph 4800 stall 4355 wgt



With a 29" tyre>
60 Foot E.T. : 1.67 Seconds
1/8 Mile E.T. : 7.56 Seconds
1/8 Mile Trap Speed : 89.89 MPH
1/4 Mile E.T. : 11.98 Seconds
1/4 Mile Trap Speed : 112 MPH
1/4 Mile Trap RPM : 5,912 RPM+8%slip=6348

30" tyre>
60 Foot E.T. : 1.67 Seconds
1/8 Mile E.T. : 7.56 Seconds
1/8 Mile Trap Speed : 89.89 MPH
1/4 Mile E.T. : 11.98 Seconds
1/4 Mile Trap Speed : 112 MPH
1/4 Mile Trap RPM : 5,715 RPM+8%slip=6172
Posted By: DusterKid

Re: trap rpm - 03/14/22 04:03 PM

73 Duster - 3200lb ish race weight, stock stroke 360 running 11.70s with 4.56 gears, 8" 5000 stall converter 30" tire crosses at 6300, with 28" tire crossed close to 7K, I only did that once and said that was to much.

75 Duster - 3150lb ish race weight, stock stroke 440 running 10.70s with 4.56 gears 8" 5000 stall converter 30" tires crosses at 6700, 31" tire crossed at 63-6400.

Both cars are shifted at 6,000 and have stock 727 with just a Turbo Action Manual Valve body (Forward pattern).
Posted By: 440lebaron

Re: trap rpm - 03/14/22 07:07 PM

looks good did not want t be buzzing the motor at 7000
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