11 replies to this topic

[useless]

Hello,

I race my mini at santa pod drag strip and i'm trying to incress the way it accselarates! i've been told to change the gear box, thats all they said and with little to no knollege thats proving very hard!

can you please help and give some advice on what diff i need to use and what final drive and if i even need to change the gear box at all in order to get maximum accelaration?

Thanks very much!

[Mini-Dave]

depends on you spec really, and if you use it on the road, as you could put a very high final drive in it,(good accel) but then it would be reving its nuts off at 70mph

i think the standard fd for a 1275 engine before injection, was 3.4 the citye 1000 had a 2.9 you could go for a 3.7, i think you can get a 4.1?? (not sure about that tho) but you might find if you put a 4.1 in it, you wouldnt reach the 80 - 90mph top speed before the 1/4 mile was over.

and if your loaded, you could always buy the new jacknight CloseRatio StraightCut DOG 5 speed gearbox but there 1200 quid or somthing!!

Youd probably be better off buying a Close Ratio gear set from mini spares! so you keep your gearbox and just change the gears inside!

So whats the rest of your spec? if its standard theres other things you could do first!

Dave

thats probably quite a vague description, imsure someone will better it!

Edited by Mini-Dave, 12 February 2007 - 11:39 AM.

[biggav]

everyone says that the 3.44:1 makes for good a celeration and comfortable motorway cruising(70mph just over 4000rpm). increase this to 3.7 and you sacrifice some top end speed and will end up at nearer 5000 rpm for 70mph.

Try Guessworks calulator (CLICK HERE) to play around with ratios and wheel sizes.

I'm going the other way and fitting a 2.76:1 to give a higher top end... and using a little nitrous to compensate

[useless]

Hi Dave Not loaded! wish i was!

It's a 1380 with alot of nos!!! need to do something with my gears as it's as fast as it could be! thanks for your help! think i'm going to go with a set of close ratio s/c gears with a 3.7 fd! any ideas on what diff to run?

[useless]

Hi,

thanks for the help going to go with the 3.7 that sounds like the stuff, any advice on diffs?

speak soon

dom

[biggav]

Guessworks is the man to ask.....

[Guess-Works.com]

If you're running NOS, then I would seriously think about going SC box and drops.... the extra horses you will be pushing when on the bottle will probably shoot std helicals out the side of the box...

Likewise with the increase in torque, then you will probably want to be crossing the 1/4 mile in 3rd, so would suggest something like a 3.2 or 3.1 final drive, so the majority of the run is in the one gear...

As for the actual Diff, at least a x-pin, or maybe worth going ATB but you're then limited to the final drive availability...

Bottom line, a box specifically for 1/4 miling needs to be strong, if you have the cash I would even be considering a 4 speed dog box to get you through the gears even quicker.

What sort of times are you running on the 1/4 ?

[useless]

If you're running NOS, then I would seriously think about going SC box and drops.... the extra horses you will be pushing when on the bottle will probably shoot std helicals out the side of the box...

Likewise with the increase in torque, then you will probably want to be crossing the 1/4 mile in 3rd, so would suggest something like a 3.2 or 3.1 final drive, so the majority of the run is in the one gear...

As for the actual Diff, at least a x-pin, or maybe worth going ATB but you're then limited to the final drive availability...

Bottom line, a box specifically for 1/4 miling needs to be strong, if you have the cash I would even be considering a 4 speed dog box to get you through the gears even quicker.

What sort of times are you running on the 1/4 ?

well at the mo with standered box and no nos it does it in 16.1 @88mph,

i've now changed the cam to a 286 and put some 1.5 roller rokers in and also fitted a lightened and balenced steel flywheel and back plate on too it's a 1380cc engine.

Not really got the cash to go for a dog box but can get the s/c c/r kit to put in my box, does the diff have anything to do with the way it a accellerates? sorry for the spelling!

[Guess-Works.com]

Not far off me then, running n/a 1330 @ 16.2, GT box and A series drops, but it's about at it's limit, Xpin diff with 3.44 fd and 10" wheels...

I can JUST cross the line in 3rd, but it's pushing the rev limit..

Defintely go for SC drops, that's the weakest part...

I assume you're hoping to knock a second maybe two off the time, and all that will be achieved in the 3rd gear... If you're sticking with Helical gears, maybe worth thinking about the GT set as 1st/2nd/3rd are a little longer than std...

I would still be considering at least a 3.2 diff just to make that 3rd last across the line... with a Minispares/Tran-X xpin diff.

What's the redline and torque curve like on the engine ?

[useless]

Not far off me then, running n/a 1330 @ 16.2, GT box and A series drops, but it's about at it's limit, Xpin diff with 3.44 fd and 10" wheels...

I can JUST cross the line in 3rd, but it's pushing the rev limit..

Defintely go for SC drops, that's the weakest part...

I assume you're hoping to knock a second maybe two off the time, and all that will be achieved in the 3rd gear... If you're sticking with Helical gears, maybe worth thinking about the GT set as 1st/2nd/3rd are a little longer than std...

I would still be considering at least a 3.2 diff just to make that 3rd last across the line... with a Minispares/Tran-X xpin diff.

What's the redline and torque curve like on the engine ?

hi,

not sure on the tourue off the top of my head but redline is at 7600rpm, yes in fact i'm hoping to beat my friend in his supra 3.0l running twins! i've also got fiber glass doors bonnet and boot to put on when racing to lighten the car a bit!

what would you do if you were me?

[biggav]

hi,

not sure on the tourue off the top of my head but redline is at 7600rpm, yes in fact i'm hoping to beat my friend in his supra 3.0l running twins! i've also got fiber glass doors bonnet and boot to put on when racing to lighten the car a bit!

what would you do if you were me?

To be honest, id be building the car to a spec most comfortable for what its going to be used for, either way, sccr gears and x-pin are going to be needed in the near future or you may end up wrecking whats already there.

I think you need to make up your mind whether you want a day to day fast road car, a track day car or a drag racer as all 3 have differing needs.

I also have 1380 stage 4, 296 cam and a nitrous kit (not yet fitted) and i have just changed the interior back to day to day use (normal seats and seat belts) as i find the buckets and harnesses to restrictive and can't get my kids in the back!!!!

Once the nitrous is fitted it will only be used occasionally on track days and drag racing and i don't plan on making any changes for those days (exept maybe some different tyres)

[useless]

hi,

not sure on the tourue off the top of my head but redline is at 7600rpm, yes in fact i'm hoping to beat my friend in his supra 3.0l running twins! i've also got fiber glass doors bonnet and boot to put on when racing to lighten the car a bit!

what would you do if you were me?

To be honest, id be building the car to a spec most comfortable for what its going to be used for, either way, sccr gears and x-pin are going to be needed in the near future or you may end up wrecking whats already there.

I think you need to make up your mind whether you want a day to day fast road car, a track day car or a drag racer as all 3 have differing needs.

I also have 1380 stage 4, 296 cam and a nitrous kit (not yet fitted) and i have just changed the interior back to day to day use (normal seats and seat belts) as i find the buckets and harnesses to restrictive and can't get my kids in the back!!!!

Once the nitrous is fitted it will only be used occasionally on track days and drag racing and i don't plan on making any changes for those days (exept maybe some different tyres)

Yeah your right, i want to use it as a full on racer for the drag strip!! thanks very much for your help it's been really usefull! love your car by the way! very nice! if you get a chance have a sneaky peak at my one go to

http://www.talkminis...ser/?P=hooligan


Thanks again!!!


speak soon!

Dominic