I have a rover v8 with the old lt77 strapped to it... I seem to have beaten 3rd to death and need to do something about it. One option would be a new box. Now being a porky car of 650 kgs I'm always looking to save a little weight. Any suggestions for a lighter box either 5 or 6 speed?
A
light weight gearbox
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Hi
convert an auto to full manual, replace the internals with aftermarket ally internals add a 4 1/4" clutch and pump drive and with something like a powerglide you can get a very light transmission indeed, you should be able to do the same with a THM200 and THM200 4R, they already have some lightweight internals. If you went powerglide and added an aftermarket overdrive tail housing you could have a very light close ratio 4 speed box, power capacity wise it would be total overkill for a rover.
A final thought, you could go fully aftermarket and use a Lenco, the CS3 would be plenty strong enough http://www.lencoracing.com/CS3MasterPage.html or a jeffco http://www.jeffcoperformance.com/Transm ... rmance.php you don't have to have all the leavers, you can use compressed air.
best regards
Mike
convert an auto to full manual, replace the internals with aftermarket ally internals add a 4 1/4" clutch and pump drive and with something like a powerglide you can get a very light transmission indeed, you should be able to do the same with a THM200 and THM200 4R, they already have some lightweight internals. If you went powerglide and added an aftermarket overdrive tail housing you could have a very light close ratio 4 speed box, power capacity wise it would be total overkill for a rover.
A final thought, you could go fully aftermarket and use a Lenco, the CS3 would be plenty strong enough http://www.lencoracing.com/CS3MasterPage.html or a jeffco http://www.jeffcoperformance.com/Transm ... rmance.php you don't have to have all the leavers, you can use compressed air.
best regards
Mike
poppet valves rule!
I went from a LT77 to an R380 and then to a Borg and Warner T5. The T5 seems to be half the weight of the first two!
Personally I don't think that the ratio's in any of the above boxes are all that great when you are talking about a large-ish engine in a light car, first gear is way too short. I ended up with a tall first gear in my T5 which sort of forces all the other gears to end up being 'close ratio' (Basically the Quaife close ratio gearset sold by 'Gearbox man')
The T5 has two main forms TVR and Cosworth, the main difference as far as I know is the position of the gear lever. Also the T5 come in two forms, World class and non-world class, as far as I know the World class one uses better bearings. (and maybe other stuff).
You can use a TVR bellhousing and this should fit all of the versions mentioned above but having said that my mate had to have the main engagement hole at the back machined out a few mm before his Cossi box would fit. The input shafts are the same length for the TVR and Cossi as far as I know but we found that there was very little spline engagement between the shaft and the friction plate so we had the back of the bellhousing machined to be thinner. We are using a Helix plate which has a deeper offset central boss, this has given us about 22mm spline engagement.
I use a JE bellhousing....thats a whole other story!
Oh the T5 is 5 speed!
Oh on top of that on my mates engine we decided to check the location of the bellhousing with respect to the crank, the results were not very good so we made some offset bellhousing dowels (20 thou from memory) and then spent several hours dialing in the bellhousing. (I know that Rover don't do this sort of stuff we we wanted everything to be as good as possible)
Personally I don't think that the ratio's in any of the above boxes are all that great when you are talking about a large-ish engine in a light car, first gear is way too short. I ended up with a tall first gear in my T5 which sort of forces all the other gears to end up being 'close ratio' (Basically the Quaife close ratio gearset sold by 'Gearbox man')
The T5 has two main forms TVR and Cosworth, the main difference as far as I know is the position of the gear lever. Also the T5 come in two forms, World class and non-world class, as far as I know the World class one uses better bearings. (and maybe other stuff).
You can use a TVR bellhousing and this should fit all of the versions mentioned above but having said that my mate had to have the main engagement hole at the back machined out a few mm before his Cossi box would fit. The input shafts are the same length for the TVR and Cossi as far as I know but we found that there was very little spline engagement between the shaft and the friction plate so we had the back of the bellhousing machined to be thinner. We are using a Helix plate which has a deeper offset central boss, this has given us about 22mm spline engagement.
I use a JE bellhousing....thats a whole other story!
Oh the T5 is 5 speed!
Oh on top of that on my mates engine we decided to check the location of the bellhousing with respect to the crank, the results were not very good so we made some offset bellhousing dowels (20 thou from memory) and then spent several hours dialing in the bellhousing. (I know that Rover don't do this sort of stuff we we wanted everything to be as good as possible)
Having experienced a full manual "auto" in the Dakar i would say they are best avoided unless used for drag racing.kiwicar wrote:Hi
convert an auto to full manual,
No Kickdown and you have to be sure of the engine/road speed before changing down because unlike a syncro manual which will refuse to go into gear, the manual auto will happily oblige - get it wrong and you will over-rev the engine and box.
Spoken from a man who pulled the lever in the wrong direction in the heat of the moment and did a WOT 2:1 shift instead of a 2:3 shift.
Hi
yes you are missing something, the point of my reply . .
An "auto box" (sun and planet type) is inherently lighter than a "manual" box for a given torque capacity. Hence the suggestion that considers a fully manualised auto box with a clutch ie a fully manual planetary gearbox, as all the suggestions I have made are. As you can see I have also made several suggestions on how to get the required number of ratios and with the exception of the 'glide with overdrive you can get to 5 or 6 speeds quite easily. Working on the sole information that it is to go behing a rover and it has to be light with multiple speeds in a 650kg car then I took a guess and thought a high first close ratios and shifts that allow full power to be transmitted during a shift would also be an advantage.
If you are still confused about the reply I made consider for a minute what a "flappy paddle" gearbox fitted to most super-cars actually is. . .
Eliot
it is not just manualised autos that will go into gear if you select the wrong gear, any motorcycle box will also do it you learn this very quickly, come to think of it any box without syncro will do the same (ie a dog engagement rally box) so really the best thing to do is make sure you know which way to push the shifter, the flappy paddle box on a Ferrari track cars at Silverstone certainly will do as it is told!
best regards
Mike
PS I do wonder why you would want 6 speeds with such a light car and a low specific output, low rev engine like the rover but hay ho
yes you are missing something, the point of my reply . .
An "auto box" (sun and planet type) is inherently lighter than a "manual" box for a given torque capacity. Hence the suggestion that considers a fully manualised auto box with a clutch ie a fully manual planetary gearbox, as all the suggestions I have made are. As you can see I have also made several suggestions on how to get the required number of ratios and with the exception of the 'glide with overdrive you can get to 5 or 6 speeds quite easily. Working on the sole information that it is to go behing a rover and it has to be light with multiple speeds in a 650kg car then I took a guess and thought a high first close ratios and shifts that allow full power to be transmitted during a shift would also be an advantage.
If you are still confused about the reply I made consider for a minute what a "flappy paddle" gearbox fitted to most super-cars actually is. . .
Eliot
it is not just manualised autos that will go into gear if you select the wrong gear, any motorcycle box will also do it you learn this very quickly, come to think of it any box without syncro will do the same (ie a dog engagement rally box) so really the best thing to do is make sure you know which way to push the shifter, the flappy paddle box on a Ferrari track cars at Silverstone certainly will do as it is told!
best regards
Mike
PS I do wonder why you would want 6 speeds with such a light car and a low specific output, low rev engine like the rover but hay ho
poppet valves rule!
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stevieturbo
- Forum Contributor
- Posts: 4067
- Joined: Sat Nov 18, 2006 6:22 pm
- Location: Northern Ireland
Toyota W55 series is probably best bet.
Biggest cost will be making it fit, whether DIY or via a full kit.
But it would be strong, it's all alloy case so relatively light, and should be cheap to buy
But no manual boxes are particularly light
Biggest cost will be making it fit, whether DIY or via a full kit.
But it would be strong, it's all alloy case so relatively light, and should be cheap to buy
But no manual boxes are particularly light
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0
Jeeze man chill out!kiwicar wrote:Oh I give up, if you won't read what I have written there is no point in posting
best regards
Mike
I did read what you posted but unless the OP has a shed load of money then I doubt that he was thinking of a 6 speed flappy paddle gearbox. a T5 will work and it is half the weight of an LT77.
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stevieturbo
- Forum Contributor
- Posts: 4067
- Joined: Sat Nov 18, 2006 6:22 pm
- Location: Northern Ireland
Some googling
T5 = 34kgs
R380 = 50kgs dry
LT77 = 50kgs ( dont recall them being that heavy though ? )
W55 = 35-40kgs
R154 = 55kgs
http://www.v8wizard.com/Tremec_T5.php
And off topic...sort of, found this good video
http://www.youtube.com/watch?v=H7CLT4PDA7g
T5 = 34kgs
R380 = 50kgs dry
LT77 = 50kgs ( dont recall them being that heavy though ? )
W55 = 35-40kgs
R154 = 55kgs
http://www.v8wizard.com/Tremec_T5.php
And off topic...sort of, found this good video
http://www.youtube.com/watch?v=H7CLT4PDA7g
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0
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stevieturbo
- Forum Contributor
- Posts: 4067
- Joined: Sat Nov 18, 2006 6:22 pm
- Location: Northern Ireland
If he's drag use, then I'm sure there are many options.
If non-drag, then I'm sure a conventional manual is what he is after, and whilst vague, this is what the query is about.
Some clarification would stop the arguing.
If non-drag, then I'm sure a conventional manual is what he is after, and whilst vague, this is what the query is about.
Some clarification would stop the arguing.
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0
