saph in dorset

Hi Guys,

I am using the T5 box, however I will no doubt have to rebuild this with a stronger gear kit at some point in the future.

I can fit either the T5 as is currently in the car or the RWD MT75 gearbox to my engine.
which gearbox is better after both have had a uprated gear kit fitted?

the MT75 is a newer box, and has a syncro on reverse.

any opinion would be appreciated, as I cant decide which to get rebuilt as I have an MT75 sat in my garage ad the T5 in the car.

thanks

Adam

dojj

iTrader: (3)

T5 has better ratios

saph in dorset

what about general strength of the boxes, and strength after the gear kits have been upgraded.

also the gear change on both, I think from memory the MT75 had a quicker gear change but cant remember.

from a practicality point of the view the T5 is better with the removable bell housing. makes it easier to take the box out.

R4N SS

iTrader: (6)

assuming this is to go on a yb and not boa or bob.

Surely the T5 is stronger

saph in dorset

its not going on a YB it is going on a BOA, but will be with around 400/400 bhp/lb ft hopefully end of this year, so doesn't matter which engine it is really.

is the T5 really stronger once both have been rebuilt with uprated hear kits.

I know as standard the T5 is stronger, but is it after?

R4N SS

iTrader: (6)

how are you getting 400/400 out of a boa mate - im interested, om me if need be

dojj

iTrader: (3)

Once you've got the bus together plus the rebuild costs I'd go with the T5 simply because it's got better ratios and once it's been built it'll be cheaper to rebuild than the MT75

saph in dorset

Its quite easy getting 400/400 from a boa.
Its safer going more 350/350 on the standard engine but i will be outting forged pistons in as this is the weak point really.

Essentially you just go either single or twin turbo with all other bits.
I already have the standalone ecu so just need to get manifolds and all ancillaries then just mapping.
I think it will cost me around Ł1250 to get about 350/350

saph in dorset

fair point maintainability is easier on the T5 and it does have better ratios. but is that just the standard ratios. are another ratios available as a kit for the MT75?

better maintainability and ratios still doesn't make it a better gearbox.

it will be used mainly as a track car with limited road driving, so need the gearbox to withstand the stresses best.

R4N SS

iTrader: (6)

Ive been toying with idea of a turbo'd boa as its just soo much cheaper compared to a yb.

what mgmt are you using?

saph in dorset

im actually using the V4 ecu from Mtech automotive,

but if I was buying stuff again I would use omex or similar. something more people are happy to map.
I only used that ecu as it was the closest place to me that did mapping down on the south coast that I knew about at the time.

the BOA/BOB will take around 10psi with standard internals giving between 300 & 350 depending on your install.
if you have a good mapper I have heard if you back off the ignition around peak torque you can then increase it again and then push the power closer to 400bhp. its all about detonation. get any detonation and the standard pistons will just melt, and by reducing the ignition at peak torque it will reduce the cylinder pressure and reduce the detonation.

dojj

iTrader: (3)

With the mt75 I was always killing the input shaft bearing with my big torque load from my 2.9 twin turbo
When I finally bit the bullet and spent some money is done about 300 miles before I blew the engine

R4N SS

iTrader: (6)

I had Omex on my saph and if going aftermarket will be using that again as it was a piece of piss to map with their ui