i have just brought a locost chassis and am planning to put a r1 engine in it eventully have read that the best diff to use is a sierra 3.62 just not sure how much of a difference is if i get one with a lsd like the ones on a xr4x4 i think or just a normal one am after a donor now also do a sierra sapphire have the same running gear as a sierra any help would be greatful thanks adam

Hi and welcome have a few of these .............. i had some spares

I have a 3.62 LSD on my R1 BEC and its just fine. That said, I've never driven one with an open diff.

A 3.38 might be a good investment if you're keen on the track or do a lot of motorway work. Mine just nudged the red line in 6th at 120 MPH at Mallory Park. Go to a longer circuit and you'll be marooned at the red line. It also revs at 6860 RPM at 70. It would be 6400 with a 3.38.

not really thought about track use although prob will do some more really for a weekend blast so sounds like a 3.62 is needed just need try find a slippy diff one