best gearing for quarrter mile

[ekjim]

does anyone have any ideas or experience of best back axle ratio for drag racing ? im currently using an anglia axle with escort 377 diff with 16 inch 205/45 toyo proxi tyres . best time on my last outing was 13.8 at 104 . was in 4th gear crossing the line at just over 6000 rpm . i was launching the car at about 3000 max & i was short shifting under 7000 rpm. any help would be much apreciated .

[Mk 1 Mark]

16 in wheels and a 3:77...way to tall 4.1 or even a 4.4...

4.1 will be easier to get though,If not a 3.89 with is just a bit taller than a 4.1

Ratman on here has 16 on his Mk1 Cortina and just put a 4.1 in his car Pm him he might be able to through some light on how it drives,

But i dont think he has been to the pod with his new diff in though

[V8ian]

I run a 3.7 in my cortina, the tires are 225/50/15s, so the rolling dia would be similar, I run mid 12s @ around 105, I probably have more torque than you so I can cope with a taller ratio

[ekjim]

thanks for the replys guys im hoping to up the power for this year last time it made 215 at the wheels so im thinking if ive got more power imay be through the gears quicker also some people think turbo cars prefer taller gearing just like to hear some more thoughts on this thanks jim

[RUSTYPUP]

If you are crossing the line in top at almost your maximum revs, then surely your gearing is spot on.

Any taller and you'll not get off the line as well.

Any lower gearing (numerically higher) and you will have to let off at the top or over rev your motor.

[ratman]

16 in wheels and a 3:77...way to tall 4.1 or even a 4.4...

4.1 will be easier to get though,If not a 3.89 with is just a bit taller than a 4.1

Ratman on here has 16 on his Mk1 Cortina and just put a 4.1 in his car Pm him he might be able to through some light on how it drives,

But i dont think he has been to the pod with his new diff in though

 

Ratman runs 17" on the tina NEW skool 4.1 with a type 9 5speed with 2.8 gearset 70mph on the moterway @ 3000rpm

 

not been on the strip yet but getting 13" for the strip with the 4.1 should be fun

[ekjim]

thanks for the replys my thinking was same as rusty pups but a my mate says i should have shorter gearing as drag racing is all about the first 60foot just wondering if anyone else agrees and has figures to convince me

[V8ian]

If you are crossing the line in top at almost your maximum revs, then surely your gearing is spot on.

Any taller and you'll not get off the line as well.

Any lower gearing (numerically higher) and you will have to let off at the top or over rev your motor.

If your engine revs to 7k, and the torque curve starts decaying at 4k, there is no point in in reving your engine past that,

Ideally for me, you should have your ratio at around max torque, I have my shift light set @300 rpm below my max torque, 300rpm for reaction time, go beyond that, and you are not accellerating as fast as you could be as the torque drops away,, my torque drops away at about 5400, , I go over the line @ 5900 in 4th, its a toss up if I go over the line as the torque drops away or change into 5th waisting time changing up, I may try a slightly taller tire so not coming off the torque, or go the other way with a smaller tire and use 5th

I will probably get castigated for this post.