iv seen some putting the 75 box'es on 1.2 16v engines, does this make it quicker? cos the sporting has a very short first gear, and you have to change upto 3rd to get to 60, but i think the 75 box you can just about hit 60 in 2nd gear, so is it quicker? any one know? thanks

or do they have good/bad points? cos the sporting having short first does it mean it gets to 30 quicker but the 75 gets to 60 quicker? thanks lol

If I think of it....I'll see how it goes to 60 in second on the way to work tomorrow for ya Beau.

crabbo_1 said:

If I think of it....I'll see how it goes to 60 in second on the way to work tomorrow for ya Beau.

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im not sure it quite hits 60, but its not far off.

I very much doubt it more like 45-50 at the most. My alfa 156 2.0TS only just hits 61 at the limiter in second.

ChrisUK said:

I very much doubt it more like 45-50 at the most. My alfa 156 2.0TS only just hits 61 at the limiter in second.

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well theres a sporting on psc which hits the limiter at 65 in 2nd and its a 75 box i think.

The gearboxes have different final drives and ratios.
Final drive
The highest and therefore the best (providing you have enough oomph to push it) is the 60 with 3.563 this is higher than the 75s 3.733 and explains why a tweaked 60 can be quicker 0 to 60 as you don't have to change for 60 as long as you over rev a bit (with some boxes you'll even make 60 without over revving)

Ratios
Contrary to opinion the ratios on the 55,60,75 are the same although some do vary there are some with a different 3rd, 4th, 5th gear ratios (all slightly higher....see below


The sporting has a final drive of 4.071
The ELX gearbox has the final drive of a 75, 3.733, and the same ratios as a standard 55,75,60.

To help compensate for that low final drive , 4.071, the sporting gearbox has slightly different ratios,
1st is the same as the 60 etc.
second is a teeny bit lower
third is the same as the normal 55 60 etc
fourth is the same
fifth is the slightly higher.

The best box for top speed and (if you have the ompph) comes from the 55 60 with body codes
for the 55
176bq53f, 55f, 53p, 55p

for the 60
176BR53F, 55F, 53P, 55F

All of these have higher, 2nd, 3rd, 4th, 5th (0.808) and a final drive of 3.563 FD.
To put this in perspective a GT has a FD of 3.353 and top gear is 0.872

Ignore the six speed, the FD is 4.923 which is very low even given the 6th gear ratio of 0.744


So for a high top speed track down one of the 60 gearboxes from the body codes above. You'll have a final drive that is only a little lower than a GT

All you need now is between an extra 58bhp to push it

in my mk2 8v 60mph comes at 6000 rpm in second gear no problems. . . it then pulls 3000 at 70 in 5th and 3500 at 80 in 5th so i think it is quite a good gearbox tbh

Yeah as long as you don't mind waiting to hit 80

longer gearing often has the effect of reducing acceleration without increasing top speed because you dont have the power to get up to high revs. shorter gearing will increase acceleration and usually give you the same top speed, or as i've found more than once a higher top speed. strange i know but its true.

i once fitted the gearbox from a 1985 1.1 escort to a 1985 1.6 orion. it turned that orion into an animal, proven more than once to be faster than an xr3i accelerating 0-100 and top speed was at least 20mph faster than with the stock box (had over 140mph). for the money no other mod on earth could have had the same effect. it mades a remap look pointless.

i want quickest acceleration, so for this.... what box is best? i did read all through your post dave but it kinda went straight over my head and i probably should of said when i started... i want best acceleration, i dont care so much about top speed, just want best acceleration around town, so is the sporting box best for 0-60 acceleration?

Yeah it will as the ratios are closer together so.

beau said:

i want quickest acceleration, so for this.... what box is best? i did read all through your post dave but it kinda went straight over my head and i probably should of said when i started... i want best acceleration, i dont care so much about top speed, just want best acceleration around town, so is the sporting box best for 0-60 acceleration?

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Leave it as it is - its fun and its quick. You won't see 60 around the town much anyway!



JUG
longer gearing often has the effect of reducing acceleration without increasing top speed because you dont have the power to get up to high revs. shorter gearing will increase acceleration and usually give you the same top speed, or as i've found more than once a higher top speed. strange i know but its true.

Spot on.

davethetrike said:

Leave it as it is - its fun and its quick. You won't see 60 around the town much anyway!

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i know im not going to hit 60 round town, but you know what i mean i just wanted best gearbox for town acceleration, hopefully see off my friends fiesta si 1.6's :yuck: lol

beau said:

i know im not going to hit 60 round town, but you know what i mean i just wanted best gearbox for town acceleration, hopefully see off my friends fiesta si 1.6's :yuck: lol

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I know what you mean
Still, I'd leave that one alone. Until you put a tune on it

Tried it for ya Beau...the 75 hits 40 in second at 6k revs....60 is not a possiblity without busting the box to smithereens or bouncing of the limiter.

crabbo_1 said:

Tried it for ya Beau...the 75 hits 40 in second at 6k revs....60 is not a possiblity without busting the box to smithereens or bouncing of the limiter.

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ok thanks

I can do about 56 or 57 in second in a s reg 60s

bouncing off the limiter