First off, this is a great site. i have been readin gthrough the FAQ, and just about everything is covered.

I am wanting to apply a turbo to a motorcycle, so I will be using a small turbo. I have decided on the IHI RHF series, somewhere in the 3,4 or 5 range.

Anyway....

Since these turbos are ball bearing design they are a little more tolerant of lower oil pressure. I am still not sure of the flow tough. Certainly the flow could be less than a larger turbo, but as far as comparing it to the RHB31, they are probably going to be similar in flow needs.

My question is should I just use the recommended 2mm restriction before the turbo and hope that it doesn't hurt the motorcycle (the roller bearing bottom ends run lower pressure than the journal bearings used in cars), or can I keep a little more oil in the engine instead of sending it to the turbo, being that it is smaller than the average automobile turbo?

Thanks

 

why ball bearing? unless you going for an all out performance/race motorcycle whats the point? ball bearing turbos are very expensive and cant be rebuilt. ive built a few turbo bikes and i had great success with audi/vw k03 turbos. there the perfect size. i put one on an 05 gsxr 600 and it spooled at 6000 rpm and it was a blast to ride. use a .035 restrictor if you go ball bearing but honestly i wouldnt waste the money.

 

From what I have found online, they both are the same price, $300-$400. So I figuered why not, particularly if I can use less oil from the engine. This is going on a 4 stroke 350cc motard with a 9000-10000 rev limit, I'm shooting for 60hp, so these little guys should be perfect. Maybe if I put a bigger cylinder on it and end up with 500cc I can look into a bigger turbo, but these should be good for 85hp or so as well.

Thanks for the restricter info.