Yamaha ThunderAce as a kit car engine.

[Dr Derek Doctors]

As said in the title really.

I have been offered a ThunderAce engine (YZF1000R) at a very reasonable price (half that of an R1) by a reputable engine dealer and I'm seriously considering using it for my Aries Motorsport Bike engine car build.

Does anyone have any ideas/knowledge/experience/reasoned opinion on using these engines for kit car applications? I appreciate that they only have a 5 speed box but that is the only real negative I can find.

Any help appreciated.

[Adam205]

I would talk to Steve about it as he'll be able to advise best, but i wouldn't have thought it would be a problem getting it fitted. I can't see any obvious issues, the FZR1000 engine (on which the thunderace engine is based i believe) used to be pretty popular!

The GSXR1100 engine I have in my Aries only has 5 gears and manages it fine due to the excellent mid range. The Thunderace engine is a similarly torquey engine with good mid range so 6 speeds just mean you have to change gear more often!

Edited by Adam205 on Thursday 2nd September 21:02

[Dr Derek Doctors]

yeah thats more or less what I was thinking, it seems to be praised for its low down grunt which would be beneficial in a kit car.

Really I need to know if there are any issues with things like lubrication, cooling, weak gearboxs or anything else that may trip up the build.

[Adam205]

Generally older bike engines are much less sensitive. Tolerances were lower so things were made beefier, and they're much less sensitive the the environment they're running in. I would be very surprised if you had any issues. The usual precautions such as an oil baffle plate and uprated pressure switch mightn't be a bad plan, also finding out whether it's hydraulic or cable clutch as slave cylinders can make things a bit awkward (it does on GSXR1100 engines anyway!).

[Adam205]

I was going to suggest asking on LB, but a quick search suggests you already have

[Richardsix]

Dont know about fitting it in a car, but had the bike................damn good lump, bullet-proof as long as you do usual maintanence.

[andygtt]

the sump is the issue, is it baffled in a way that will be able to cope with the different way a car handles without oil starvation.... I beleive the busa cant which is why its so expensive to fit a busa to a car as you need dry sump on top of the engine.

[Dr Derek Doctors]

andygtt said:

the sump is the issue, is it baffled in a way that will be able to cope with the different way a car handles without oil starvation.... I beleive the busa cant which is why its so expensive to fit a busa to a car as you need dry sump on top of the engine.

Well this is the big question... and the one that I can't find an answer to yet.

[antnicuk]

i have a thunderace. its basically the early R1 engine and it made the same power on the dyno. 135 rwhp so about 150 at the fly. Mine has a dyno jt kit and the exup valve removed. Not sure if you would keep this on a kit car. It does affect low down torque a little which isnt too bad on a bike but might be in a car with the wrong diff ratio.

The clutch is hydraulic. They like a drop of oil also! I cant help with the sump, sorry

[Adam205]

andygtt said:

the sump is the issue, is it baffled in a way that will be able to cope with the different way a car handles without oil starvation.... I beleive the busa cant which is why its so expensive to fit a busa to a car as you need dry sump on top of the engine.

Not entirely true. The busa has a tiny oil capacity for a large engine (3.1 litres), you can improve things by fitting a larger baffled wet sump. For comparison my GSXR1100 engine takes 5 litres. A quick google reveals that the thunderace has an oil capacity of 4 litres, which isn't bad for a 1000cc engine and would indicate that you're unlikely to have any major problems (obviously no guarantee). As long as you fit a baffle plate and a slight overfill i'd do it.