Vixen diff numbers
Discussion
Anyone know the original diff fitted to S2 & S3 Vixens ?
Not the cast in casing numbers but the 2 letters which are followed by numbers and stamped in the high point on the very bottom rib of the front casing. It will probably start with FH, FR KC or KD and these determine the differences in ratio, bearing sizes and possibly other more minor differences.
The TVR Owner manual states the diff ratio as 3.89. Was this always the case or did they change at any point?
I ask because mine runs a 'FR' diff which as I understand from researching was fitted to the very last home market Spitfire 1500 cars (my car was the last S3 made, so may tie in with this). But this is a 3.63 ratio? So question is whether this is original or has changed at some point in it's life. If other cars are also running the 'FR' diffs it may suggest it could be original.
Moto
Not the cast in casing numbers but the 2 letters which are followed by numbers and stamped in the high point on the very bottom rib of the front casing. It will probably start with FH, FR KC or KD and these determine the differences in ratio, bearing sizes and possibly other more minor differences.
The TVR Owner manual states the diff ratio as 3.89. Was this always the case or did they change at any point?
I ask because mine runs a 'FR' diff which as I understand from researching was fitted to the very last home market Spitfire 1500 cars (my car was the last S3 made, so may tie in with this). But this is a 3.63 ratio? So question is whether this is original or has changed at some point in it's life. If other cars are also running the 'FR' diffs it may suggest it could be original.
Moto
Cheers for that.
The diff is working fine with no noises or anything other than a slightly weeping drive shaft seal. However with just one more event to go in my second season in the TVRCC Sprint Championship I've decided to fit a Quaife ATB. I'm losing too much time spinning the inside wheel out of slow corners.
So being as I'll take the diff out it's going to get a full rebuild - either by Quaife or Jigsaw Racing. Haven't decided yet. (Andy, yes I've asked if they can drill and tap a drain plug for the reasons you've said)
Alan, if it is the same unit from 1982 - she's done pretty well. Especially considering that over the past 2 years I reckon I've done around 100 race / practice starts of dumping the clutch at 4,500 revs.
Jacking the wheel to count the turns revealed a surprise that the diff is in fact a 3.63 (I'd always assumed it was a 3.89). Maybe the 3.63 is stronger than the 3.89 ? It also explains why it is such a nice road car having slightly longer gearing.
The other surprise is how fast she has been off the line. All the events provide electronic times for the start, measuring the time taken to travel the first 64'. I will usually match the stripped out race Vixens which are 100kg lighter and have 30 ish more bhp, and also the V8 cars. The Vixens are running 4.11 diffs which on paper should also make them faster off the line. All very strange really - I can only put it down to them struggling to get traction and spinning the tyres more.
All good fun though.
The diff is working fine with no noises or anything other than a slightly weeping drive shaft seal. However with just one more event to go in my second season in the TVRCC Sprint Championship I've decided to fit a Quaife ATB. I'm losing too much time spinning the inside wheel out of slow corners.
So being as I'll take the diff out it's going to get a full rebuild - either by Quaife or Jigsaw Racing. Haven't decided yet. (Andy, yes I've asked if they can drill and tap a drain plug for the reasons you've said)
Alan, if it is the same unit from 1982 - she's done pretty well. Especially considering that over the past 2 years I reckon I've done around 100 race / practice starts of dumping the clutch at 4,500 revs.
Jacking the wheel to count the turns revealed a surprise that the diff is in fact a 3.63 (I'd always assumed it was a 3.89). Maybe the 3.63 is stronger than the 3.89 ? It also explains why it is such a nice road car having slightly longer gearing.
The other surprise is how fast she has been off the line. All the events provide electronic times for the start, measuring the time taken to travel the first 64'. I will usually match the stripped out race Vixens which are 100kg lighter and have 30 ish more bhp, and also the V8 cars. The Vixens are running 4.11 diffs which on paper should also make them faster off the line. All very strange really - I can only put it down to them struggling to get traction and spinning the tyres more.
All good fun though.
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