A4 4.56 1/4 mile trap RPM?
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Registered User
Joined: Aug 2003
Posts: 111
From: West Lafayette, Ohio
It is a new combination. I've switched over from the Impala SS side of the world and will be doing a bolt-on car; just bought a bone stock '94 Formula. Plans are to lighten it (AC, EGR, smog delete, etc.), Weld wheels (28" Hoosier QTPs), long tubes, no cats, race mufflers, Yank SS3600, FastChips pcm programming, BMR suspension components, ... Only plans on the engine now are to add a good set of valve springs, TB bypass, ... small things like that. My question is what RPM would it go through at with a 4.56 gear as compared to a 4.10. Hope to run IHRA Pure Stock Eliminator in street legal trim.
Registered User
Joined: Nov 2003
Posts: 1,756
From: West Linn, OR
Sorry I don't know the rules for the class your looking at but I hope I can answer some of your questions...
Without knowing exacts like race weight and actual power output, I can only guestimate when your max trap speed will be, but I can calculate the max speed available with your gear/tire combo per gear.
Hard numbers are:
In a 1:1 ratio gear your max road spead with the 4.56 gears and 28" tires assuming the converter is not too loose up top should be ~ 110 MPH @ 6000 RPM's
In a 1:1 ratio gear your max road spead with the 4.11 gears and 28" tires assuming the converter is not too loose up top should be ~ 122 MPH @ 6000 RPM's
The guestimates of where you would be with your combo would be assuming average power gains for the mods planed and moderate weight reduction and I would guess about 106 - 107 or so MPH Trap speed putting you through the trap at ~5800 RPM's with the 4.56 combo and ~5300 RPM's with the 4.11 combo assuming again that it is a rather tight converter up top. If your power or weight reduction nets better the average results then you might need to either raise the rev limiter and shift point on your 1:1 gear (normally 3rd) but that's not a big deal, however if you do anything serious for power, like H/C or power adder then those 4.56's will be too steep...
Without knowing exacts like race weight and actual power output, I can only guestimate when your max trap speed will be, but I can calculate the max speed available with your gear/tire combo per gear.
Hard numbers are:
In a 1:1 ratio gear your max road spead with the 4.56 gears and 28" tires assuming the converter is not too loose up top should be ~ 110 MPH @ 6000 RPM's
In a 1:1 ratio gear your max road spead with the 4.11 gears and 28" tires assuming the converter is not too loose up top should be ~ 122 MPH @ 6000 RPM's
The guestimates of where you would be with your combo would be assuming average power gains for the mods planed and moderate weight reduction and I would guess about 106 - 107 or so MPH Trap speed putting you through the trap at ~5800 RPM's with the 4.56 combo and ~5300 RPM's with the 4.11 combo assuming again that it is a rather tight converter up top. If your power or weight reduction nets better the average results then you might need to either raise the rev limiter and shift point on your 1:1 gear (normally 3rd) but that's not a big deal, however if you do anything serious for power, like H/C or power adder then those 4.56's will be too steep...
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Aug 15, 2002 09:04 PM