1/4 mile trap rpm ?

[434nova]

What kind of rpm should I be turning thru the 1/4 with a 28 inch tall tire a 200r4 and 3200 non lock up converter. Thanks

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[pacecarta]

its dependent on the info above and you need your trap speed , converter slip and rear gear ratio ...and what gear will you be in 3rd or 4th

if you know your weight and HP you can get an estimated 1/4 trap speed.
do you know your 1/8 mile trap speed , ET and weight ?
on a 28" tire , 3.42 gear in 3rd (no OD) and with a PTC 9.5 (dusty ) non lock slipping 5.5% i was under 5900 at 139

 

[434nova]

I have 3.50 gears. I have a 9 inch rear. I made 470 rwhp and I am around 3500#s. Thanks

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[pacecarta]

your info 470 and 3500 comes out with a 1/4 et of 11.37

11.37 @ 119.8


119.8 with 28 tire and 3.50 gear assuming a 6% slip ) in 3rd gear (1:1)
should trap at just under 5300 , i wouldn't use 4th gear with that trap rpm and your converter slip could be more because your couple point with a 3200 (if thats at 0psi) may be over 5400 . youll need to look at your logs and see where the converter couples hard,

 

[434nova]

Thats with rwhp ?

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[pacecarta]

yes

 

[ULOSE2A6]

What specifically in the logs will tell you where it's coupling hard as opposed to Anytiing else? Thanks.

Regards,
Shev

 

[pacecarta]

youll see the rpm graph change slope at the couple point while going up in 1st gear , on a ptc it levels out for a few frames
, it will also be the low point where the rpm drops to during a shift from 1-2 once its in 2nd provided your trans shifts above the couple point
for my dusty PTC 9.5 its about 5150 at 600hp and 5200 at over 700hp,and i would consider my converter is running tight as at 0 psi its at 2800rpm (3400 @ 3psi, 3800 @ 6psi)
with my old AC 9" and 2004r it was at 5600 and as hp went over 600 the slip went up from 17% to 22%