the block is sleeved @ 85mm....had alittle mishap. Now we wanna go 86mm forged rods/pistons, keeping the compression at 12:1 with a 60-70 shot. He would like to hit 300whp. cams are skunk pro 3's, intake mani will be an eldelbrock. Has anyone done this?
I know there are plenty of 86mm NA cars out there, just haven't found any info on 86mm b20 nitrous setups.

 

A friend of mine added a 50 shot wet kit on a setup similar to yours. 94 Civic Hatch street power trim ran 11.4 @ 119 mph on the motor with 248 whp. With the 50 shot nitrous, the car turned a 11.0 @ 122 mph. Yes it's possible and yes it's been done before. Good luck.

 

thanks for the reply, and this is my buds setup. Does your friend put miles on it? track only?

 

my friend did a stock b20 block and a built gsr head no nos and made 243 to the will tuned by jeff evans

 

If it's sleeved and you tune it right you can run more than a 60 shot at 86mm even at 12.1. If I was going to run that motor on the bottle I would be shooting for more of a 150 shot. Good luck

 

he's decided on a 100 shot. Thanks guys for the info!

 

86 is big for nos i do not suggest it watched a friend do it and he blew the head gasket between the cylinder's and got a nice burn mark on the top of the sleeve had to pull the motor after and redeck it to fix it and regretted doing it after i told him not to

 

The issue with 86mm is indeed head gasket issues, blowing between the cylinders.

I had alot of problems with an 86mm block a few years ago, I sent it back to Golden Eagle and started from scratch again.

 

even if both surfaces are straight?

 

Yes, because there is so little sealing surface between cylinders. Resleeving a sleeved block [to 84mm] isn't very expensive. Its probably the same price as honing to 86mm and buying custom pistons. You'll loose a very small amount of displacement, but can run extra nitrous to more than make up for it.