plz Advice on Best Diff Ratio

[MR.E36i]

Hi

what whould you advice me with the best diff ratio on E36 M3 putting down 260WHP approx .. using Drag redials 225/50/R15 wheels and front slim Runner light weight wheels (135/50/R15 )


looking to hit the 1/4 mile with full thrust / power


plz advice

[MR.E36i]

what can/will you rev to
i think 3.91 might do it....i assume you might rev your engine to 7400 with the built head. if thats the case its gonna be really close to needed to shift into 5th gear. if i were you id skip out on the shift into 5th unless your gonna make it so your at the top of fifth just past the line...but that would be really crazy gears. the 3.91 should produce silly results. in the calculations i saw youd get 109 with a 7400 rpm in 4th gear. you may trap higher than that. do you know the weight of your vehicle.

ya i can rev up t0 7500 with no problem as i had modified head

i was using 3.73 befor and i hit 1/4 mile with almost complete 3rd gear but i have to shift to 4th which result delay:nono:nono

my car is approx.. 1200 KG , what ratio will let me get the 3rd or 4th gear full thrust with the finish line :devillook

[MR.E36i]

i think 3.91 would be minto. what did you trap when you went to the track. knowing that we can better asses what gears will get you the top of 4th just after finish line. again that 4th gear, 7500rpm and those 225/50/15 tires will get you ~110 mph with a 3.91. should work out great with your car.

i will try to test it now with my 3.46 LSD and will be looking for the 3.91 :rolleyes:rolleyes

i let you know the result's