What Diff have I got ?
Discussion
I've been reading over some of the back posts about the various diff options that were fitted and I'm a little confused as to what one I might have. On the one had the car does around 80-81mph at 3k revs and hits somewhere between 155-160mph in 4th gear at around 7.5k revs. This makes me think its the 3.46 diff, but I appear to also have the CR gear box option as I can hit 60mph in 1st gear. Apparently, this is just about the most bland diff/gear ratio combination available yet I can hit 60mph in 4secs flat (I'm fairly convinced it will do it a bit quicker than this with practice), have done a 1/4 mile in 12.4 (again it will go quicker than this) and at Fighting Torque this year the car showed itself to be one of the quicker TVR's. All this points more to the 3.73 diff which is why I am a little confused. Any thoughts anyone ? Has anyone actually measured improvements in acceleration by changing from the 3.46 to 3.73 or 3.91 diffs ?
tail slide said:
Had a quick rummage thro' my file... something not adding up here as you say. Could it be 80 @ 3000rpm in 5th not 4th? Your 4th gear figs can't both be right I think.
Then would be 3.46, other than 1st gear .....
Apologies for not making it clear, but 80-81mph at 3k revs in 5th gear.Then would be 3.46, other than 1st gear .....
Edited by tail slide on Sunday 25th November 17:37
S5TVR said:
Has anyone actually measured improvements in acceleration by changing from the 3.46 to 3.73 or 3.91 diffs ?
Not measured it, but anything moving from what you have - 3,46 (especially with a 3,6L car) will be a significant improvement. I would suggest if your car runs 12,4 quarters now, you will drop under 12 if you can manage the new issues you will have with traction.Thanks guys. I have to confess to being a bit of a technical numpty and if I hadn't read the previous threads regarding the impact of diff changes, I could, like many others, have thought that throwing money at the engine would be the surest and most cost-effective way to make the car quicker. I have no interest really in the VMax of the car, but only in acceleration and handling improvements, so a diff change looks on the cards.
Edited by S5TVR on Monday 26th November 13:51
Daftlad said:
S5TVR said:
Has anyone actually measured improvements in acceleration by changing from the 3.46 to 3.73 or 3.91 diffs ?
Not measured it, but anything moving from what you have - 3,46 (especially with a 3,6L car) will be a significant improvement. I would suggest if your car runs 12,4 quarters now, you will drop under 12 if you can manage the new issues you will have with traction.but awesome on a 3.6
VARLEYHYD said:
YI8TVR said:
The ratio is usually written on a white tag on the diff. Have you had a good look at the diff ?
Like this; Don't try and clean it to heavily as the print may wipe off
My label blistered when diff got too hot
G
That's a mess...how come you've not manufactured some new easy clean heat resistant ones
Exhaust looks a bit grubby too !!
Edited by Daftlad on Tuesday 27th November 07:15
YI8TVR said:
TGJR said:
Does anyone have an idea of the going rate to change a diff from 3.46 to 3.73?
around £700. And why not go for a 3.9.Edited by YI8TVR on Tuesday 27th November 08:21
Don't think the CWP sets change in cost between 3,73 and 3,91 - the 3,91 is just harder to get (or it was)
Daftlad said:
YI8TVR said:
TGJR said:
Does anyone have an idea of the going rate to change a diff from 3.46 to 3.73?
around £700. And why not go for a 3.9.Edited by YI8TVR on Tuesday 27th November 08:21
Don't think the CWP sets change in cost between 3,73 and 3,91 - the 3,91 is just harder to get (or it was)
Targarama said:
Daftlad said:
YI8TVR said:
TGJR said:
Does anyone have an idea of the going rate to change a diff from 3.46 to 3.73?
around £700. And why not go for a 3.9.Edited by YI8TVR on Tuesday 27th November 08:21
Don't think the CWP sets change in cost between 3,73 and 3,91 - the 3,91 is just harder to get (or it was)
Was £1250 about right for the total job?
Daftlad said:
Graham,
That's a mess...how come you've not manufactured some new easy clean heat resistant ones
Exhaust looks a bit grubby too !!
Can I be excused; this was taken after the last trackday we had at Croft, which cooked my diff and discoloured my exhausts! (10 sessions and 170miles and the pace was just too quick!)
New heat resistant labels in manufacture for next season, including the engine compartment ones.
New ATB diff to ready to be fitted:-
Tip of the week;
Exhausts cleaned using welders pickle paste:-
Just brush on leave for 1hour then wash off, saves the fingers with that autosol stuff.
Essex progress?
Now that will keep you busy John!
G
Essex is with my man up Norf. The rest of the car starts work in earnest tommorow being split between chassis related work and body related work. T5 CR box with straight cut 5th being sourced.
Suprised at your diff problems (heat) although Ceejay has had problems on the T350 racer. Maybe a wee cooling kit is required, I had one on the Tuscan Challenge car and it cured diff cooking problems and made the rear underside of the car more interseting with all those braided hoses and aeroquip fittings.
Winter project for Varley Hydraulics? I'd like one please.
Suprised at your diff problems (heat) although Ceejay has had problems on the T350 racer. Maybe a wee cooling kit is required, I had one on the Tuscan Challenge car and it cured diff cooking problems and made the rear underside of the car more interseting with all those braided hoses and aeroquip fittings.
Winter project for Varley Hydraulics? I'd like one please.
jamie g said:
I did get a quote for a 3.7 cwp to be fitted along with new seals, bearings etc. It is around the £700 mark. I don't know weather to go as low as 3.9 though, maybe 3.7 is a good compromise. Anybody?
Go the whole hog and opt for the 3.9. Just watch the hard limiter though, you will tend to hit it quite quickly which wont do your rods a lot of good.Gassing Station | Tamora, T350 & Sagaris | Top of Page | What's New | My Stuff