I'm curious what kind of power gains come with higher compression? Here's my build list, will I break 200 with super tech 12.5:1 comp 81.5mm pistons?

Gsr head
Skunk2 valve train
Ctr cams
Oversized intake valves
Benen fuel rail
Blox fuel regulator
Ericks racing 66mm tb
Godspeed 68mm intake manifold
Rmf rep headers
Test pipe
2.5 inch catback

Made 179whp and 134 tq.

 

What fuel are you using? 93 or higher?

This is a very good article to read. It helps you understand exactly what high compression is doing and the pros/cons.

http://forums.anandtech.com/showthread.php?t=198458

 

Maybe with those cams, I would look into something bigger especially with that compression. Pro2's are always a good resort. Bigger exhaust, and definitely a bigger induction opening, at least 70mm.

 

Bigger cams would be ideal.

 

Before you go switching out cams and swapping pistons I would change your bolt-ons and see what that gets you with a retune?! There is still plenty of power left in this setup with just the induction and exhaust systems. You never mentioned what your block setup is Op, unless I missed it? I'm guessing a GSR bottom end? Switch the Rmf header out for a small tube tri-y or TODA Replica header, move to a 68-70 MM T-body and port match accordingly with the manifold, 3 inch full exhaust from the test pipe back. Not sure what intake pipe you're on but try out a full 3 in AEM CAI and put a V-Stack on the end of it. Then if you have access to it switch to E-85 fuel, this alone could give you a 6-10 Hp bump, not to mention the car will run much better during the summer months, you will probably need larger injectors for this. If you don't have access to Ethanol then just tune it on pump 93 and see what it does. I'm guessing you could be bumped from 180 Whp to around 190-195 Whp depending on your retune. Numbers are just numbers but by freeing up the exhaust and intake you should see some gains no matter. Do these things and retune before you go switching pistons and cams for just 15-20 more HP.

 

im assuming you're on a stock gsr block... which means your power is pretty good, but definitely can be better , with better bolt-ons like soloDC suggested. with a setup like this, increasing your compression to 12.5:1 might not be able to net you 200 because your limiting factors will still be the CTR cams, and the octane level. I would go with some better bolt-ons first, and maybe a set of cams if you are still not satisfied. then when the stock gsr block goes, maybe then you can upgrade it, or jus go into a 2L.

 

Sorry guys I thought I specified block. I'm on a 100% stock ls bottom end. From oil pump to the pistons.

 

Youre gonna wanna get rid of those stock rods or at the very least get some arp rod bolts if you havent

 

6500 miles on the rod bolts and rods still going strong.

 

With stock rod bolts that engine is a time bomb at 8k

 

Its a time bomb above 7200rpm imo. Those bolts may not break but will stretch enough to cause bearing failure.

 

Hell we'll wait till she blows then. I'm a firm believer that I won't have problems, and if I do it was time anyway the motor probably needs a good rebuild anyway. Or a b20 block lol

 

Building an LS-V with stock rod bolts is a well worn road. Are you seriously talking about putting in high compression pistons without spending $50 on rod bolts? That spun bearing you get is going to cost a lot more to repair than $50.

 

Fixing a spun rod bearing is so expensive its cheaper to buy another short block without spun bearings and just rebuild it.

Since thats basically what itll take to fix. At the very least you need a crank, a rod, balancing of the rods since theyre no longer a matched set, honing the cylinders. New bearings, new seals, etc.

I spun a rod bearing with the oem limiter. Spent something like 3-4k building a new engine and upgrading some things (cooling, s300, gauges, wideband, etc) decided to go all or nothing on it