Drag Racing Mph V's Gearing

[madrolla68]

OK i am looking to run a bigger MPH next time i run at the drags cause at the moment i have hit a brick wall at 103 because the gearing is wrong for the given RPM limit.

 

SO

 

What i am running is 205/60 R13" tyres K50 gearbox in fourth 1/1 ratio and 4.11 diff ratio which equals 103 MPH at 7000 RPM.

 

SO

 

Even if i run the same tyres ,same rev limit BUT 3.9 diff ratio that will only improve the MPH by 5% which equals 108 MPH

 

The car CANNOT go any faster MPH wise with said gearing unless i raise the rev limiter REGARDLESS of how much power it makes cause it is till turning the SAME RPM even if it is making more power CORRECT???.

 

SO

 

To run a higher MPH then i would need to run SAY 3.65 diff ratio or maybe a 14" 60 series tyre RIGHT.

 

Am i right here or am i way of the mark.

 

Food for thought.

 

Matt

Edited March 22, 2007 by madrolla68

[Felix]

So are you hitting the rev limiter before the line? 5th no good?

 

What is 1st gear like, does it go anywhere or just fry the tyres until you hit second? Couldn't launch in second and use 5th with a lower ratio diff (say 4.3)?

[madrolla68]

So are you hitting the rev limiter before the line? 5th no good?

 

What is 1st gear like, does it go anywhere or just fry the tyres until you hit second? Couldn't launch in second and use 5th with a lower ratio diff (say 4.3)?

 

Yeah its hitting the limiter before i hit the line,just not enough time to hit 5th gear.

 

First is ok but it does fry the tyres a bit 2.3 60' times.

 

I was hoping to maybe use some bigger tyres .

[Felix]

Yea, bigger tyres should hopefully do the trick

[Taz_Rx]

Yeah that may give you a higher MPH, but it may also make you slower overall.

 

I took mine to the drags once (before it was turbo'd) with a mates 14" supra wheels with 60 series tyres. ran like a 18.2 or something. That meet got rained out and we got free entry the next week. That time I ran 185/60/R13 (being the only thing different about the car) and then ran a 17.6!!!!! and that was half way through 4th, with the 14's I was still in 3rd accross the line.

[Trev]

If you use Tyre Size Calculator you should be able to calculate what size tyre you need to run to get higher MPH.

[madrolla68]

Yeah that may give you a higher MPH, but it may also make you slower overall.

 

I took mine to the drags once (before it was turbo'd) with a mates 14" supra wheels with 60 series tyres. ran like a 18.2 or something. That meet got rained out and we got free entry the next week. That time I ran 185/60/R13 (being the only thing different about the car) and then ran a 17.6!!!!! and that was half way through 4th, with the 14's I was still in 3rd accross the line.

 

Yeah once i change the clutch to a button or one with a heap more centrifugal weight and i can run the car in real race trim ie: high boost then it will pull some bigger gears and or bigger tyres.

 

So now you have it tuned it should be able to pull the bigger wheels ey. :D

 

How did it go ???????/

Edited March 23, 2007 by madrolla68

[Taz_Rx]

Had to cancel the tune till tomoz, cause I had to change the hot box gasket :D :fuzz:

 

So I'll no doubt update my projects thread with a power figure tomorrow or tuesday. :yes: