looking for a better gearbox!!

[REGGY5GT]

im currently running a standard gt box on my b18ft now it accelerates amazing but im looking to drop the revs top end because at 60mph you sitting at 3500rpm and the car is topping out to quick if you know what i mean and it cant be good for it revving that high,i can near enough hit the limiter in 5th, now would a scenic gearbox or megane sport box be any better dropping the revs wise,or could i even take 5th gear from something else?? any help appreciated, Tim

[Bigfoot]

If your doing 3500 and only 60mph you got something wrong with your speedo or your running very tiny tyres. You should be hitting 70 at just over 3k revs. Are you sure you got a gt turbo box in there?

[REGGY5GT]

im running standard speedlines with 195/45/13 tyres, as for the box its the one that came off my gt engine but not 100% sure if it hasnt been changed for a campus,ect by a previous owner, is there any way of telling if its a gt box??its defo sitting at 3500 at 60mph,as ive tested also with my sat nav, so do you suggest i get some bigger wheels or can i change 5th or even a box off something else?? thanks

[Bigfoot]

im running standard speedlines with 195/45/13 tyres, as for the box its the one that came off my gt engine but not 100% sure if it hasnt been changed for a campus,ect by a previous owner, is there any way of telling if its a gt box??its defo sitting at 3500 at 60mph,as ive tested also with my sat nav, so do you suggest i get some bigger wheels or can i change 5th or even a box off something else?? thanks

The wheels will only make a small difference between your speeds. Gearbox will have a tag on it and say JB3 then some numbers, not sure which ones are for the gt turbo. Does the speedo still work? is it electrical or mechnical pickup? If you look at the JC5 boxes it will be about 3.6k for 70mph I think it works out at.

[Bigfoot]

195/45/13 ?????

Are you sure this is the size your running?

[Scoff]

GT box will have a tag on it saying JB3, campus will say JB5. GTT gearbox is wider too and has that 3 bolt mounting flange on the top, the campus does not have those bolt holes. GTT box will have a hole for the electronic speedo sensor like the volvo gearbox, the campus will not. The volvo gearbox will say something like "M59" on a metal tag, renaults will all have JB something or other.

[REGGY5GT]

yep they are defo the tyres im running, 195/45/13 continentals, going to try changing my wheels me thinks for some 15's ill have a look at the gb numbers after, spent a bit of time on them tyre convertors on google and it says if i put 205/45/15's on it will take 400rpm off my 60mph rev count.

[SCHWARTZ]

why not use the volvo box? Apparently 1234 gears are closer together than the gt box but 5th is longer so get a better top end 140mph aparently:eek:

[Bigfoot]

yep they are defo the tyres im running, 195/45/13 continentals, going to try changing my wheels me thinks for some 15's ill have a look at the gb numbers after, spent a bit of time on them tyre convertors on google and it says if i put 205/45/15's on it will take 400rpm off my 60mph rev count.

Running 195/55r13 (normal size for the renault 5) will add 5mph onto your speed at those revs.

With a GT Turbo box you will be doing 79 mph at 3.2k with 195/55r13 but with 195/45r13 your looking at 3.45k revs. Thats how much the wrong size tyre is doing, but your gears are not even close to that either.

Does your speedo work?

[James George]

why not use the volvo box? Apparently 1234 gears are closer together than the gt box but 5th is longer so get a better top end 140mph aparently:eek:

you sure?? have an M59 box which i got from a 480 turbo. All i found on ratio's from a volvo forum was they are exactly the same as GT. Only diff can be final drive which was quoted same as renault 11 at 4.07. Happy to be corrected but don't believe 5th to be any longer.

[SCHWARTZ]

it was written in a thread i read on here il look for it and see who said it and see if they know a bit more;)

[Andrew Cooke]

Running 195/55r13 (normal size for the renault 5) will add 5mph onto your speed at those revs.

With a GT Turbo box you will be doing 79 mph at 3.2k with 195/55r13 but with 195/45r13 your looking at 3.45k revs. Thats how much the wrong size tyre is doing, but your gears are not even close to that either.

Does your speedo work?

the speedo won't know which size tyres are fitted, so the numbers should be as the standard car.

[Matt Cole]

i could do with longer gears to take advantage of all the torque at low rpm i have!:sad2:

[Andrew Cooke]

i could do with longer gears to take advantage of all the torque at low rpm i have!:sad2:

diesel diff is what you want, 3.29 from memory.

[SCHWARTZ]

ratios for the m50 gearbox according to haynes
final drive 4.07:1
1st 3.09:1
2nd 1.84:1
3rd 1.32:1
4th 0.97:1
5th 0.79:1
reverse 3.55:1
dono if this helps but thought id put it up, only mentions the m50

[Andrew Cooke]

ratios for the m50 gearbox according to haynes
final drive 4.07:1
1st 3.09:1
2nd 1.84:1
3rd 1.32:1
4th 0.97:1
5th 0.79:1
reverse 3.55:1
dono if this helps but thought id put it up, only mentions the m50

so same as the R11T then.

I wonder if the OP has a valver box fitted? I think that has a 4.21 final drive

[SCHWARTZ]

http://www.rtoc.org/boards/showthread.php?t=312
think it was in this thread.

[Bigfoot]

the speedo won't know which size tyres are fitted, so the numbers should be as the standard car.

Speed would be on his sat nav, im just thinking of an easier way to see if its still got a gt turbo box in there if its got the gt turbo clocks and speedo is working :)

[James George]

just learnt something. the final drive on a volvo box is in the code...
so if you have a m59 373e then its a 3.73 final drive and if you have a M50 407 for example then its 4.07 final and the e or m is for electric or mechanical speedo drive.
so an M59 is prob exactly same ratios and final drive as GT box

[REGGY5GT]

when i bought the donar car 5th gear was nackered in the volvo box, thats why i used the gt box, speedo does work but i had adjusted it to the sat nav.

[Matt Cole]

diesel diff is what you want, 3.29 from memory.

Ah thats good info. I suppose i need a decent diesel box. Any suggestions?