Bottom end strength question - Saxperience

fletchbog · 23rd March 2015, 14:51

I read somewhere a long time ago that JP4 conrods are thinner around the little end bush and narrower than a J4 rod. Is this the case?

I'm thinking ahead to a low pressure 16v turbo build and which engine to use. If the J4 bottom end is stronger, it would make sense to use that...

Ross^p · 23rd March 2015, 14:58

I ran a 300hp engine on a stock JP4 bottom end (with ARP bolts) and just forged pistons for over a year of pretty hard abuse. No drama. You'll be fine with either bottom end on a sub 300hp spec engine IMO.

fletchbog · 27th March 2015, 12:18

Thanks Ross, I'm going by the theory that it won't be as stressful for the rods as, say, raising the rev limit, though I may go ahead and add ARP bolts.

Another point regarding engine choice is that I'd read that the J4 has under piston oil squirters whereas the JP4 doesn't. Can anyone confirm?