Hello everyone


I live in saint louis Missouri and I have a 96 xjr... I have been doing modifications to it since i got it years ago and noticed my differential seals are leaking.. My question is does the newer xjr 98 and above have a better gear ratio as far as racing? I am looking to find a better differential with better gears for street racing......Any suggestions?

 

Street racing in an XJR/6? Really? Hope you choose your adversaries carefully

AFAIK the later V8 XJRs use the same 3.27 ratio....but the diff is a different design. I'm not even sure if it could be (easily) installed in the XJR/6. Others will chime in.

However, you're in luck with the X300 because 3.58, 3.77, and 4.09 ratios were used. The 3.58 (which is what I installed in my XJR) was standard issue for the normally aspirated X300 4.0 litre....and easy to find. The 3.77 and 4.09 won't be as easy to find, at least not in the USA.

Going from the 3.27 to 3.58 made a modest improvement in acceleration.

Cheers
DD

 

Doug

I wanted to thank you for all your posts I notice a lot of your replys to people.. Thank you I was needing to pull my differential out anyway was thinking of taking it to a shop or sticking in a newer better xjr in...Thank you for responding I understand about the street racing thing I really just and trying to get more power out of it with putting in a m112 instead of m90 and water injection just trying to do something with this hobby of mine...

 

Hey Doug, given your knowledge of diffs, what's the position with regard to the diff on my 4.0l and the one on my 3.2 donor car? Can they be swapped and if so, what would the difference in performance be? I don't intend to do so, but as a spare, would my donor diff be any good? I think I might lose some acceleration with the 3.2, would this be correct?

Thanks.

 

The differentials with directly interchange; no problem there.

Your 3.2 diff is likely the 3.77 ratio (automatic trans) or 4.09 (manual trans). Your 4.0 is likely the standard 3.58.

Going from the 3.58 to either of the others will give you more acceleration and response. The car would feel a bit snappier whenever you accelerate.

The downside is that the engine will be turning faster and using more fuel. Perhaps not too significant going from 3.58 to 3.77 but going from 3.58 to 4.09 would be a bit much.

Cheers
DD

 

Good stuff and thanks for that. Both cars are auto, so you reckon the change is perfectly do-able, with more response, offset by a slight increase in fuel consumption. Not so bad as I average about 28mpg at present, so I could live with that. Nice to have a spare!

Thanks again.