5 speed options

[pacdesign1]

I am new to this forum but I have already gained a wealth of knowledge. Currently I am having my 62 E-Type OTS motor rebuilt and am looking for the best 5 speed option to replace my Moss box. I looked into getting a 5 speed gearbox about 8 years ago and had decided on the JT5 by Medatronics. At the time I wasn't aware of some of the UK boxes available and the JT5 seemed solid. Fast forward to today and it seems like I waited too long as the JT5 is no longer available. On this forum and others it seems like most of the other options have had a variety of problems. A couple of exceptions are the units being offered by E-Type Fabs, and to a lesser extent the Quaife box, (not a lot of data available), offered by New Forest Classics. I just found out today that ETF only sells their box for customers cars. At this point I am at a lost. I haven't contacted NFC but my guess is that they will have the same policy as EFT, where they only offer their box for customer's cars. All of the other options that I know of seem to have issues with fitment, gear ratios, reliability etc. I am hoping that I am missing something and that there is a good solid 5 speed currently available. Any thoughts or suggestions are appreciated.

[JJC]

The Driven Man, Cookeville, TN. Everything you need. About $5500.00 US . Great folks, great product.
Give them a call : 931 646 4836. I have had one in my Series 3 for over 11 years, never had a problem.

JJ

[johnetype]

I believe Realm Engineering are still offering a 5 speed conversion based on a Toyota gearbox.

See http://forum.etypeuk.com/viewtopic.php?t=2621 for details.

[mgcjag]

Hi..plenty of info on 5 speed option....just use the search function....here is one very long thread to start with..Steve http://forum.etypeuk.com/viewtopic.php?f=9&t=7226 dont dismiss the option of a 2.88 diff instead of a 5 speed box.... some of our forum members highly recommend it

[Peter27]

I would echo previous comment and seriously think about keeping the Moss box and save $5k.

[Heuer]

Hutson's sell the ETF box - give Andy Rayner a call. Another option is to have your Moss box converted to all synchro: http://jb-engineering.co.uk/?page_id=80

I would avoid the 2.88 diff (I have one in my car) as it makes town driving a real pain. The 3.07 is the best IMHO.

[PeterCrespin]

Hutson's sell the ETF box - give Andy Rayner a call. Another option is to have your Moss box converted to all synchro: http://jb-engineering.co.uk/?page_id=80

I would avoid the 2.88 diff (I have one in my car) as it makes town driving a real pain. The 3.07 is the best IMHO.

But David, doesn't that car also have a five speed? The 5-speed makers almost universally warn against a 2.88 diff with their boxes, which are generally designed for a 3.54.

A 2.88 goes nicely with a Moss gearbox first gear, or small saloon all synchro with a low first gear.

[Tom W]

The 2.88 seems to go fine with the all synchro box in my S2. 1st is only necessary once I’ve come to a stop, and the engine is tractable enough for 4th at 30mph on the flat.

[Barry]

The Quaife box is still having problems the last I heard from NFC. Give them a ring to see if things have changed. The other Quaife box of a different design is sold by Eagle but only to their customers. Personally, and having posted on here many times about 5 speed alternatives, I wouldn’t do it! Stick to the 4 speed Jag box and fit a 2.88 diff. That’s what I have in my V12 with 16” diameter wheels. 88mph at 3500rpm.

[Heuer]

But David, doesn't that car also have a five speed? The 5-speed makers almost universally warn against a 2.88 diff with their boxes, which are generally designed for a 3.54.

The T5 gearbox has practically the same ratio's as the Jaguar 4 speed box All you get is a 5th overdrive. My engine produces 340lb/ft so effortlessly handles the high ratio but at low speeds the 2.88 is damn annoying. With all the camera enforced 50mph limits I have to drive around in 3rd and rarely get to 4th, let alone 5th. My FHC has 3.07 + Moss box and it is quite civilised to drive by comparison.

Barry - you did not mention that your car has a 500bhp 6.0l fuel injected engine and an embarrassing amount of torque!

Try using this calculator to see what you will be getting yourself into:
RPM to MPH calculator: https://wahiduddin.net/calc/calc_speed_rpm.htm

Angus has a 2.88 with the Jag box in his OTS and is of the same view as me - avoid!

[angelw]

Hello David,
A little Off Topic, but a 2.88 is a great choice (in my opinion) for an S3 and standard 4 speed gearbox. I currently have a client's S3 OTS in work, that has a 2.88 diff ratio. The car is great to drive in all situations.

Regards,

Bill

[Heuer]

Yes Bill, it seems to suit the V12. Barry and I had a chat about his experiences with his Eagle and it is clearly a very well developed car. Not sure if it is to do with kerb weight or the silky smooth V12 but the 2.88 does not seem to work well in the 6 cylinder cars.

[pacdesign1]

Thanks for the feedback. David, I will give Andy Rayner at Hutson's a call about the FTF box. I am also talking with XK's unlimited about their T5 based box. Lastly I may track down a used 4 speed synchro box and have it rebuilt if the cost or difficulty of finding a good 5 speed is too high. As much as I like the idea of a 5 speed my primary motivation is an all synchromesh gearbox to replace my original Moss unit.

Regards,

Scott

[Tom W]

Not sure if it is to do with kerb weight or the silky smooth V12 but the 2.88 does not seem to work well in the 6 cylinder cars.

I’m curious why your experience of the 2.88 is so different from mine, and, it would seem, a few others on here. Is your car a 3.8, or a 4.2? Are the first 3 ratios in the S2 synchro box much lower than the gearbox in your car?

Apart from Weber DCOEs, a tubular manifold, and 123 ignition my engine is (I think) otherwise standard, and probably a little tired. On the flat, the car is fine at 30mph in 4th, and will accelerate from 30 in 4th, but for more brisk progress I prefer 3rd. For relaxed driving anywhere above 30, 4th is no problem. For more spirited driving down country lanes, it’s a mix of 3rd and 4th, with 2nd for maximum acceleration from lower speeds. First is only really needed for starting from a standstill.

I’ve not tried a 3.07, so can’t comment on which is better, but the 2.88 certainly works well for me.

[PeterCrespin]

I’m curious why your experience of the 2.88 is so different from mine, and, it would seem, a few others on here. …..First is only really needed for starting from a standstill.

I’ve not tried a 3.07, so can’t comment on which is better, but the 2.88 certainly works well for me.

Which is really the point - there is no one set of ratios to suit every scenario or driving requirement and what Jaguar did was pick a compromise. The one thing that can be said with certainty is that the wider the powerband the fewer gears are needed to stay in the meaty part and the higher the red line the more scope there is to hang onto a ratio before changing up, which even if it puts you fractionally beyond the torque peak can be very useful in saving a gear change between two corners.

But running any kind of overdrive ratio on top of a 2.8 final drive was inevitably going to be a stretch, which is why no 5-speed sellers recommend it.

[politeperson]

Yeah!

No problems with my 2.88 and 4 speed Jag box.

Then again, I try to avoid Central London in my E type! (or any other car).

137 mph at the Ring with the speed still climbing when I had to jam the brakes on. No problems.

[Tom W]

I do wonder what an overdrive 5th gear with the 2.88 would be like. It feels like it would pull it, but I’d probably be changing down to 4th every time the traffic slowed much below 65mph. Maybe only really any use for those interested in sustained cruising well above the speed limit, or for trying to crack 150mph, neither of which I can try in the UK.

[Heuer]

Can I suggest you put your figures through the calculator and post them here?
https://wahiduddin.net/calc/calc_speed_rpm.htm

We can then be sure we are talking about real world figures rather than impressions. My car with a 2.88, 185 tyres and T5 box is doing 100mph at 3,000 rpm in 5th (08.:1 IIRC) which matches the calculation with observation. I published the figures for other ratios and speeds somewhere on the Forum - I will see if I can find them and insert them here. Difficult to argue with the math!

[Tom W]

I’ve just plugged some numbers into the calculator. With a measured rolling radius of 12.5in, at 2700rpm in 4th, the calculator says I should be doing 69.7mph. At 1150 rpm, the speed would be 29.7mph. At 5000rpm, the maximum speed would be 129.1mph. I thought it would be higher than that.

I have 205r70 Pirelli Cinturato tyres. According to Longstones website, the inflated diameter of these is 677mm. 185 Cinturatos have an inflated diameter of 676mm.

What did you measure your rolling radius at? Maybe the 205 tyres squash more than the 185s, or maybe I just need to pump the tyres up a bit? I’ll go and check the pressures later and re-measure.

If I put the rolling radius in as half the inflated dia, that brings the top speed at 5000rpm up to 135.6mph, and brings the revs down to 2600rpm 70.5mph. I imagine the rolling radius grows slightly as wheel speed increases.

What all of this would indicate to me is, that if the engine is tractable between 1100rpm and 4000rpm (which an XK should be), then a 2.88 diff with a 1:1 top gear is suitable for UK driving. Which is what I’ve found since I did the swap.

If I can find the ratios for 1st to 3rd on the S2 box, I can work out what the speed ranges are on the intermediate gears.

[Heuer]

Approx figures at 3,000rpm (3.8 & 4.2 cars) in 4th:

2.88 - 81mph
3.07 - 75mph
3.31 - 70mph
3.54 - 65 mph

The various ratios for Jaguar and 5 speed boxes are as follows:

3.97, 2.34, 1.46, 1.0, 0.76 - JT5 (recommended for 2.88 and 3.07 diffs, discontinued)
3.57, 2.07, 1.38, 1.0, 0.76 - Getrag 225
3.37, 1.86, 1.28, 1.0, n/a - Moss box
3.35, 1.99, 1.33, 1.0, .68 - JT5 variant
3.35, 1.99, 1.33, 1.0, .73 - JT5 variant
3.35, 1.99, 1.33, 1.0, .83 - JT5 variant
3.35, 1.99, 1.33, 1.0, .90 - JT5 variant
3.23, 1.90, 1.39, 1.00, n/a - Jaguar KP/KM
3.04, 1.97, 1.32, 1.00, n/a - Jaguar EJS
2.95, 1.94, 1.34, 1.0, 0.8 - Watjag T5/T5
2.95, 1.94, 1.34, 1.0, .63 - JT5 variant
2.95, 1.94, 1.34, 1.0, .73 - JT5 variant
2.95, 1.94, 1.34, 1.0, .80 - JT5 variant
2.93, 1.90, 1.39, 1.0, n/a - Jaguar K* series box
2.68, 1.74, 1.27, 1.0, n/a - Jaguar EJ series box

Bear in mind that maximum torque of the XK engine (3.8 and 4.2) starts at 2,250 rpm and plateau's there until maximum revs. While we are on this subject it might be useful to know the matching speedos. The turns per mile are printed on the face and are as follows:

3.54 - 1312
3.31 - 1216
3.07 - 1125
2.88 - 1058