Differential ratios
Discussion
wellyone said:
Anyone had experience of running a 4.09 diff in a wedge. Current diff is 3.54:1. I 'm hoping it will make a significant difference to the accelleration. Gearbox has standard ratios in type 9 Ford gearbox,with 215 X 50 tyres on 15" wheels
Depends on what your be using your car for, but I'd say for a road car it's too high.Yes you will get increased acceleration, but also you have a lot more gear changes, plus your have quite high rev's at cruising speeds.
Do you currently have the diff, as I'm looking 4.xx one for one for the racer.
TVRleigh_BBWR said:
Depends on what your be using your car for, but I'd say for a road car it's too high.
Yes you will get increased acceleration, but also you have a lot more gear changes, plus your have quite high rev's at cruising speeds.
Do you currently have the diff, as I'm looking 4.xx one for one for the racer.
I guess this is for his Tasmin track car Yes you will get increased acceleration, but also you have a lot more gear changes, plus your have quite high rev's at cruising speeds.
Do you currently have the diff, as I'm looking 4.xx one for one for the racer.
On a V8 you'll be running out of revs and using more expensive fuel.
There is already enough torque to pull the higher gearing without too much pointless wheelspin.
I wouldn't bother unless you're putting in a screamer of an engine.
(If you want to experiment, fit a set of rear wheels and tyres with a smaller rolling radius, which will give a similar effect to lowering your diff).
There is already enough torque to pull the higher gearing without too much pointless wheelspin.
I wouldn't bother unless you're putting in a screamer of an engine.
(If you want to experiment, fit a set of rear wheels and tyres with a smaller rolling radius, which will give a similar effect to lowering your diff).
Edited by grahamw48 on Thursday 9th June 16:22
As Leigh says, I have a 4.09:1 diff in my race car mated to a T5 close ratio Tuscan race box. It all works very well in my car as it has only got a V6 running at about 250 bhp and 230ftlb of torque. Not sure how it would be in a V8 though. I assume it would be wheel spin city! Although acceleration is tremendous, top speed is limited to 138mph. The only time I have maxxed it out though is on the old Snetterton track, up the Revit straight 
7300rpm, 138mph, bouncing off the limiter in a 30 year old Tasmin is very er....... interesting and kind of focusses the mind 
Oh, by the way, car is now up for sale (It's not going cheap though)
7300rpm, 138mph, bouncing off the limiter in a 30 year old Tasmin is very er....... interesting and kind of focusses the mind Oh, by the way, car is now up for sale (It's not going cheap though)
i had a tr7 that i converted to rover v8 but left standard diff ratios in and it went like s**t of the line in second, couldnt use first just spun the wheels but car ran out of steam at 110 and never got more than 20mpg, was great fun but when i changed the ratios it was a far better car.
Many thanks for all the info chaps, the diff is for a 2.8 V6 sprint car where the prformance is all at the top end of the rev range. The max speed is not too critical and I have calculated the top speed as 134mph on 15" wheels with 215 x 50 tyres at 6500 rpm.
Now all we have got to do is get it to rev that high in 5th! it pulls it in the lower gears, but in our first event we never got out of second gear! hence the quest for lower gearing.
Now all we have got to do is get it to rev that high in 5th! it pulls it in the lower gears, but in our first event we never got out of second gear! hence the quest for lower gearing.
jon haines said:
i had a tr7 that i converted to rover v8 but left standard diff ratios in and it went like s**t of the line in second, couldnt use first just spun the wheels but car ran out of steam at 110 and never got more than 20mpg, was great fun but when i changed the ratios it was a far better car.
This sounds very much like my situation at the mo,having put the 5ltr lump in my wedge to replace the 3.5 lump. Aint got a clue what ratio my diff is though,John.Gassing Station | Wedges | Top of Page | What's New | My Stuff