ricoisme26

So I'm looking to start my first build, I currently drive a 94 ls that was auto but I swapped a GSR tranny into. I DD and auto cross it currently and was going to build an ls/vtec originally but I decided to go with a gsr for the girdle, oil squirters and not having to tap the block.

Anyhow it seems an ls crank with gsr rods and pistons in the gsr motor give about 11.1:1 compression which is what i wanted from an ls/vtec

Looking to make 190-200whp what kind of supporting mods do people suggest? I have an idea of what i want to do but would like to hear everyones opinion.

Thanks for looking!

whitesihatch

You have to use the ls rods, due to the ls crank having a larger stroke. unless you are using aftermarket rods. I would use ls rods and pr3 pistons, this will up the compression.

BTW there are aftermarket companies that make girdles for ls and b20 blocks.

A simple b16 head with mild porting on the intake side, and oversized flat valves and ctr/itr cams will put you at your goal; dyno dependent.

whitesihatch

an 8lb flywheel and b16 tranny with lsd will make this car very fun to drive.

ricoisme26

well $400 for a gsr long block is hard to beat, do the gsr rods fit on the ls crank?

I read that the gsr pistons and rods on an ls crank brings it pretty much flush to the block at TDC I didn't see anywhere saying that the rods wouldn't fit on the crank, I'll have to look in to this......

kyden

you have to use ls rods. ls rods are 5.394" and gsr rods are 5.433". with gsr rods you would be out of the hole.

motoxxxman

and he doesn't mean in the holeshot type way lol.
gsr rods would make the pistons come 0.039" above the block, which would raise compression even higher, and may end up causing piston to head contact

whitesihatch

not only that, but the stroke of the ls crank is a bit larger, this is why you can not use the gsr rods.

Uncle Dave

Non of you have any idea a GSR/ITR rod WILL NOT FIT LS/B20 crank they are to narrow on the bigends.

ricoisme26

Thank you!!! this is what I was looking for! is there any way to remedy this? different bearings? this is my first full build and I just picked up the motor so I haven't got to tear in and see how things work yet

also the zealautoworks compression formula table thing says piston to deck height would be -0.002 I know this is sticking up above the block but the heads combustion chamber is not completely flat so with upgraded valve springs this would not cause a problem would it?

another route I would consider would be ls rods/crank with usdm type r pistons.... 11.15, 0.026 piston to deck height I want to maintain the larger stroke if at all possible

Uncle Dave

I use this combo alot B18c block B16a pistons B20/LS crank and conrods this will give you 11.2 + to 1 compression depending on what Vtec head you use and is perfect for mid range torque which for an AutoX car is spot on.

ricoisme26

Thanks! that sounds like a pretty good set up

I think with the gsr head it will get 11.5:1 compression

whitesihatch

you may achieve this use an oem head gasket.

ricoisme26

yeah I don't think I'd ever run anything other than an OEM head gasket