Dogsbody47uk Posted February 23, 2016 Share Posted February 23, 2016 Hi people. The diff in my Vitesse Mk2 is not an HC prefix, but is an FH prefix, which I believe is a 3.89 ratio from a Spitfire IV. Is the diff the same as a Vitesse diff, is it strong enough to cope with the extra torque, or should I consider replacing it? Thanks for any info/ advice. Cheers, Dave. Quote Link to comment Share on other sites More sharing options...
Richard B Posted February 23, 2016 Share Posted February 23, 2016 Same ratio, and AFAIK no difference in strength. (Willing to be proven wrong) Quote Link to comment Share on other sites More sharing options...
Dogsbody47uk Posted February 24, 2016 Author Share Posted February 24, 2016 Thanks, Richard. Having now looked at parts catalogues they seem to use the same bearings, oil seals etc., so I think you are correct. Thanks, Dave. Quote Link to comment Share on other sites More sharing options...
don cook1 Posted February 24, 2016 Share Posted February 24, 2016 Do you have overdrive, assume that you have. If not you need a 3:27 for longer legs. I take it the Vitesse has the same arrangement as a GT6? Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted February 24, 2016 Share Posted February 24, 2016 Nah, just stick a 4.11:1 in it and blow everything out the water until 60mph. Great fun. Quote Link to comment Share on other sites More sharing options...
glang Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Don Cook Do you have overdrive, assume that you have. If not you need a 3:27 for longer legs. I take it the Vitesse has the same arrangement as a GT6? Hi Dave, I wouldnt worry about the internal strength of this diff and the ratio is correct (the Vit had the same diff regardless of OD or not) but I believe it'll only have 4 studs instead of the 6 of the original. This was to allow the use of a 'swing' leaf spring to counter the wheel tuck under problem exhibited by the earlier design however Im not sure what difference fewer studs makes........ Quote Link to comment Share on other sites More sharing options...
RobPearce Posted February 24, 2016 Share Posted February 24, 2016 My Vitesse (Mk1) is running a Spit 1500 diff with only four studs. It hasn't been a problem. I don't know if the Mk2 stresses it more? Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted February 24, 2016 Share Posted February 24, 2016 Same, my Vitesse has only four fixing studs in it due to the spring. No problems here. Quote Link to comment Share on other sites More sharing options...
John Bonnett Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Don Cook Do you have overdrive, assume that you have. If not you need a 3:27 for longer legs. I take it the Vitesse has the same arrangement as a GT6? As far as I'm aware Don, the Vitesse had a 3.89 with or without overdrive. Possibly because it is a heavier car than the GT6. Quote Link to comment Share on other sites More sharing options...
John Bonnett Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Jonny-Jimbo Nah, just stick a 4.11:1 in it and blow everything out the water until 60mph. Great fun. You are a hooligan Sir! Man after my own heart 🙂 Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted February 24, 2016 Share Posted February 24, 2016 The current project list below should indicate that to be the case... My Vitesse has a strong 4.11:1 in it. It's done a few seasons racing, track days, RBRR and 3 years daily driving... Quote Link to comment Share on other sites More sharing options...
John Bonnett Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Jonny-Jimbo The current project list below should indicate that to be the case... My Vitesse has a strong 4.11:1 in it. It's done a few seasons racing, track days, RBRR and 3 years daily driving... I'm planning a step further. a 4.5:1 Quote Link to comment Share on other sites More sharing options...
Rallyspit Posted February 24, 2016 Share Posted February 24, 2016 Are you using the Marina van cwp, John? The 4.85 (Atlas van and early herald) was made of pastry and not to be advised. Quote Link to comment Share on other sites More sharing options...
John Bonnett Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Rallyspit Are you using the Marina van cwp, John? The 4.85 (Atlas van and early herald) was made of pastry and not to be advised. Early stages yet but I was going to have a word with Mike Papworth and see if it is possible to build a reasonably strong diff from standard parts. If the answer is no then I'll investigate having a custom cwp made.The ratios of the GT6 three rail box are excellent but my car did bog down a bit in first and a shorter diff would solve that problem. However, the engine has been rebuilt to a different spec since the Coupe Florio so we'll see how it performs before taking any decision.Sorry for the thread drift. Quote Link to comment Share on other sites More sharing options...
Dogsbody47uk Posted February 24, 2016 Author Share Posted February 24, 2016 Thanks for all the comments. Yes it has overdrive. No it is not a 4 stud casing, it is 6 stud, as it should be, probably from an early mk iv spit before they went to swing spring ( I have swing spring in my 13/60 and it's a lot better than swing axle. It was an easy conversion to do, but fit the bigger anti roll bar!) From my previous ownership of Mk2 vitesses ( this is my third), the standard 3.89 diff is fine...once she's rolling. Once on the move the gear ratios are great and overdrive is the icing on the cake. Cheers, Dave. Quote Link to comment Share on other sites More sharing options...
heraldcoupe Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Rallyspit The 4.85 (Atlas van and early herald) was made of pastry and not to be advised. The Atlas axle uses the larger Vanguard/TR/2000 type diff components and has nothing in common with the Herald/Spitfire diff design.Cheers,Bill. Quote Link to comment Share on other sites More sharing options...
Richard B Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Dogsbody47uk it is 6 stud, as it should be, probably from an early mk iv spit before they went to swing spring All Spitfire MkIV's were swing spring. Quote Link to comment Share on other sites More sharing options...
glang Posted February 24, 2016 Share Posted February 24, 2016 Quoted from Dogsbody47uk Thanks for all the comments. Yes it has overdrive. No it is not a 4 stud casing, it is 6 stud, as it should be, probably from an early mk iv spit before they went to swing spring ( I have swing spring in my 13/60 and it's a lot better than swing axle. It was an easy conversion to do, but fit the bigger anti roll bar!) From my previous ownership of Mk2 vitesses ( this is my third), the standard 3.89 diff is fine...once she's rolling. Once on the move the gear ratios are great and overdrive is the icing on the cake. Cheers, Dave. Looks like someone must have swopped over the back casing of the diff to keep the 6 stud fixing. It would have been much easier to do than change the gears on the original unit!I didnt understand your comment about being fine once she's on the move as my Vitesse with original diff could almost do without 1st gear and Im thinking of going to a 3.63 ratio (especially as there's no OD). Cheers Graham Quote Link to comment Share on other sites More sharing options...
Slimboyfat Posted February 25, 2016 Share Posted February 25, 2016 Quoted from Rallyspit Are you using the Marina van cwp, John? The 4.85 (Atlas van and early herald) was made of pastry and not to be advised. Atlas is 6.66:1 Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted February 25, 2016 Share Posted February 25, 2016 Aka The Devil's Diff! Quote Link to comment Share on other sites More sharing options...
Dogsbody47uk Posted February 25, 2016 Author Share Posted February 25, 2016 Quoted from glang Looks like someone must have swopped over the back casing of the diff to keep the 6 stud fixing. It would have been much easier to do than change the gears on the original unit!I didnt understand your comment about being fine once she's on the move as my Vitesse with original diff could almost do without 1st gear and Im thinking of going to a 3.63 ratio (especially as there's no OD). Cheers Graham You can set off in any gear on level ground in a Viteesse! Top is interesting but possible...I've done it, but what I mean't was that a Vitesse is very high geared in first ( 40 mph at 6000rpm) so she's a bit slow off the line for the 0 to 60 sprint, but she goes well once rolling! The close gear ratios are great for overtaking. Cheers, Dave. Quote Link to comment Share on other sites More sharing options...
Rallyspit Posted February 25, 2016 Share Posted February 25, 2016 Happy to be corrected, I must stop believing everything I read. (Atlas 6.66:1 Wow? No wonder they were ssllooww....) Quote Link to comment Share on other sites More sharing options...
glang Posted February 25, 2016 Share Posted February 25, 2016 Quoted from Dogsbody47uk You can set off in any gear on level ground in a Viteesse! Top is interesting but possible...I've done it, but what I mean't was that a Vitesse is very high geared in first ( 40 mph at 6000rpm) so she's a bit slow off the line for the 0 to 60 sprint, but she goes well once rolling! The close gear ratios are great for overtaking. Cheers, Dave. Ok looking at minty lamb then I think the 1600 vitesse gearbox ratios would suit you better giving 36mph @ 6000rpm in first (eek) while keeping other gears the same..... Quote Link to comment Share on other sites More sharing options...
don cook1 Posted February 28, 2016 Share Posted February 28, 2016 3:63 is a nice diff to have. Quote Link to comment Share on other sites More sharing options...
.thumb.jpeg.b15b81ef10abeea1c3039ae03c4a9f3a.jpeg)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.