gearbox??? which one???

nickh · Post by **nickh** » Mon Feb 19, 2007 8:48 pm

im thinking of a rv8 project but id want a manual box behind it, but i want a nice slick change and able to handle a good dose of power

well im sure you knowledgable gents will offer some top advice

cheers in advance nick

v8alex · Post by **v8alex** » Mon Feb 19, 2007 11:03 pm

A difficult question to answer as it is very subjective and application dependent. Are you planning 2WD or 4WD, light car or heavy car, track day / sprints etc etc...The gear ratios of the boxes together with the ratio of the differential final drive need to be right to provide you a drivable end product. Though saying that, if you're planning on building a kit car you're stuck with oodles of torque / power and no weight

which kind of renders 1st gear a little pointless and 5th gear an overdrive.

LT77, R380 or T5 are the three boxes that are commonly used for the RV8.

The LT77 can suffer from a stiff gearchange particularly when cold and the R380 (Rated for 380Nm of torque) is a better box in that respect and can handle more power. Don't know very much at all about the T5, though I do believe it is better again. I don't know how much power you're thinking of generating, but all these boxes can handle 250BHP. I know of one car with 310BHP and an R380.

Hope that is of some help - I'm still a novice !

Alex

Lewis · Post by **Lewis** » Tue Feb 20, 2007 1:06 am

Yea, I'm still not convinced by the shift on my LT77 although I guess a lot of it is down to still not being comfortable with it (and not having a complete gearknob, which makes a change a bit interesting).......

Lots of adjustment points on the box I've noted though! Any of them actually make any difference?

adamnreeves · Post by **adamnreeves** » Tue Feb 20, 2007 3:59 pm

I'm building a westfield kit car. I have not sourced my transmission yet but I am going for the R380. A few reasons. The LT77 and R380 I believe have the same footprint in terms of mounting to the chassis. Also bell housing compatibility etc. Be warned though that the R380 for 4WD is different in the 2WD, which is what I need. The R380 gear ratios are better suited to my application where I am using a 3.36 diff and 15" wheels. The T5 is the best in terms of strength and gear ratios but.... It is much bigger and not compatibile and I would need to cut my chassis and re-weld new cross members, etc and also need to get a specially made bellhousing as well I think.

nickh · Post by **nickh** » Tue Feb 20, 2007 8:37 pm

hi guys the project im thinking of is a ford 100e popular and was thinking rv8 nice box 3.9 diff ratio

you mentioned r380 are good where do i get one of these from ?? also t5 was the one i was thinkin but they seem very hard to find (ex tvr) and there also expensive limited budget

cheers nick

v8alex · Post by **v8alex** » Tue Feb 20, 2007 9:26 pm

RPI should be able to sell you a new R380 www.v8engines.com
They have a good overview of this box together with the ratios. Rimmer Bros also advertise new R380s www.rimmerbros.co.uk

If you want a recon box, you're going to have to shop around - they appear on eBay occasionally, TMTRANSMISSIONS occasionally do them and offer a 12 month guarantee.

I got my recon R380 from Competition Transmission Services (www.gearboxman.co.uk), though they don't usually specialise in this type of box. They have an excellent ratio / speed calculator allowing you to easily work out speeds per gear including final drive ratio and wheel / tyre combinations. It's worth a look.

There are plenty of other sources no doubt, as I said - just have to shop around. You will usually have to provide an exchange item, or pay a surcharge.

Alex