The V8 Owners Forum -

Any advice appreciated on whether to buy a 4 speed or a 5 speed box to go behind the 3.5 V8 in a light track car?
Need one with a short bellhousing otherwise the gear stick will be near the diff if you know what I mean. The front of the engine is on the front axle line so set back a bit putting gearbox alongside drivers knee area.
ta

Quaife 6 speed sequential

So long as its reliable and you can find them easily enough- the more gears the better, else modern sports/super cars wouldn't have 7 & 8 speed boxes. Obviously not an H gate though, think you'd get lost after 2nd

topcatproduction wrote:Quaife 6 speed sequential

So long as its reliable and you can find them easily enough- the more gears the better, else modern sports/super cars wouldn't have 7 & 8 speed boxes. Obviously not an H gate though, think you'd get lost after 2nd

Thing is, mine will have a nice flat torque curve and I will have no use for 5th in a 5 speed box at Oulton or Anglesey.
So I was wondering if a 4 speed Rover P6 or similar would do the job as I will be in third and fourth 90% of the time.
I find modern cars soon run out of puff and need plenty gears to keep moving

I would be saying a box with 5 or 6 gears, and a Non Overdrive final ratio, so 5th or 6th is 1:1, a CR box will allow you to use a more radical cam, with a shorter power band further up the range, hopefully producing MORE POWER

Oh and i forgot, the Rover 4 speed is made of something akin to Toffee or was it Tofu,

ian.stewart wrote:I would be saying a box with 5 or 6 gears, and a Non Overdrive final ratio, so 5th or 6th is 1:1, a CR box will allow you to use a more radical cam, with a shorter power band further up the range, hopefully producing MORE POWER

Cant afford more power so it's a matter of making the best use of what is available, looks like a 5 speed then from a TR7 or SD1 would suit if the 4 speeds are a bit naff.
The annoying thing is that I sold a mustang type 4 speed last year thinking that I would never need it..

Ok a bit different as they are transaxles as opposed to gearboxes only

GT40 people that race tem seem to be going for the Porsche 930 gearbox at the moment - firstly they are only 4 speed and on top of that they take off in second gear (even from standing starts)

Less gear changes means more traction being appliied to the track

Sure the new buzz boxes have 6 /7 / more gears but their engines are made to rev up and down quicker than a V8 does so the length of time for a gearchange is reduced.

That said on the Ferrari F1 boxes they change the gears really quickly and the driveshafts are made out of elastic steel that can twist up to 1.5 times (540 degrees) along the length for shock loading

But at what budget>

Ian

burble wrote:

topcatproduction wrote:Quaife 6 speed sequential

So long as its reliable and you can find them easily enough- the more gears the better, else modern sports/super cars wouldn't have 7 & 8 speed boxes. Obviously not an H gate though, think you'd get lost after 2nd

Thing is, mine will have a nice flat torque curve and I will have no use for 5th in a 5 speed box at Oulton or Anglesey.
So I was wondering if a 4 speed Rover P6 or similar would do the job as I will be in third and fourth 90% of the time.
I find modern cars soon run out of puff and need plenty gears to keep moving

I got through 3 boxes in not many more years on my P6 3500S - so I'd avoid that box if possible. Nor is it nice to use.
An SD1 5 speed would be obvious choice.

ian.stewart wrote:I would be saying a box with 5 or 6 gears, and a Non Overdrive final ratio, so 5th or 6th is 1:1, a CR box will allow you to use a more radical cam, with a shorter power band further up the range, hopefully producing MORE POWER

You might find it difficult to find a box without an overdrive ratio - but does it matter? Unless you're stuck with the final drive ratio.

DaveEFI wrote:

ian.stewart wrote:I would be saying a box with 5 or 6 gears, and a Non Overdrive final ratio, so 5th or 6th is 1:1, a CR box will allow you to use a more radical cam, with a shorter power band further up the range, hopefully producing MORE POWER

You might find it difficult to find a box without an overdrive ratio - but does it matter? Unless you're stuck with the final drive ratio.

Finding it difficult to locate a box, best one I can find at the moment is a 5 speed from a Rover 3500S for 400 squid. It will have new bearings fitted though.
Thinking now of cheaper alternatives and maybe using an adaptor late. Any advise on cost by going this route would be appreciated.
Thanks..

Toyota Supra

ian.stewart wrote:Toyota Supra

ooooh , that sounds like a nice box, how much for an adaptor kit?

The P6 gearbox dates back to the 50's and has an incredible slow baulky change, it would be useless on a track.

Kevin

If your looking for a short distance from gearbox to shifter then look out for a TVR T5 as they have a spacial linkage that mounts the shifter several inches further forward.

I think you have just explained why the gear change was so horible on the Tuscan I once took for a test drive.
Best regards
Mike