I wouldn't bother changing heads or cam just yet. I would bolt it on like it is. Get a good safe tune in there and hang on. You'll probably need to upgrade your fuel system a good bit, but I don't know what you currently have.

 

^^^ I may do that and just build a motor on the side im not sure yet im going to try and start all this near the winter time cause i dont drive the car as much then. The kit from epp comes with injectors and a in tank fuel pump. Would be anything else i would need? If i stick with the motor i have now ill only be runing 8 maybe 10psi if i get meth and if a build a low compression motor ill be shooting for 800+rwhp and some 9sec timeslips.

 

I ran 10lbs with 11.3cr on 93oct & meth just fine.

 

If you can afford to purchase a Procharger kit you can likely afford a new set of pistons and rods. While it will be a major pain, you will likely be happier in the long run and be able to run more boost.

You could gain major power with a nitrous set-up - with the forged pistons already in place you could get there safely now for a lot less money.

 

im planning on doing the same thing here , i have a set of prc 227 heads milled 10k and comp ratio is 11.1 i plan on buying a twin turbo kit and was worried about the compression ratio

but from what ive gathered here running low boost and a meth kit would be ok untill i build the lower end

 

You'll be fine with 14psi, E85 and intercooler.

 

Can I run twin turbos on a5.3 with tr227/224 cam running 11.1 compression on pump gas if a have and intercooler?

 

Yes do it ASAP

 

I'm guessing a timing change could have made a big difference on that combo.

 

I was thinking the same thing. Bob

 

How did you decide on 24*? Did you start at 10* and move up? Have you verified commanded = actual (mechanical) timing? How much timing do you pull around peak torque? How wide is your peak torque window? Might want to check piston height at TDC to see if any rods got bent (piston down in hole more than expected).

 

You guys realize this threat has been brought back from the dead TWICE now! And the post that's been quoted and commented on is from 2010!!!!

 

Now ya tell me! Thanks for waking me up. Is it Wednesday yet?

 

11:1 and you want to run boost?... I would say don't do it..

 

To the guy who revived the thread from the dead (1994silverado), I think 11.1 CR is fine. You just need to tune accordingly. It doesn't matter wither it is a twin turbo or a single, all that matters is boost and IAT, as it relates to being able to tune the engine and make it work well.

There are tons of people that say don't run 11:1 static CR engines with boost on this board. The overlap of the cam does play into this as well, just a little overlap will drop the dynamic CR enough to help out considerably. I wonder how many of these guys that are saying "don't do it" have actually had problems with compression, or who of them that did have problems, actually had a good tune. My personal experience is, I'm running 11.4:1, and 15 psi of boost without problems on E70, and making over 700 wheel on an unlocked auto. I'm sure I could also make it work on pump 93 with a big shot of methanol too. Would I get there without either ethanol or methanol?, probably not, but in this world one of those 2 options are available to just about everyone.

My thought is that a considerable portion of these people shootin' down the moderate CR, are just repeating what they have read somewhere else and have never actually tried tuning an engine such as 1994silverado's setup at the 11:1 range. I'm not advocating 12:1 or 13:1 engines here, but turbo engines don't need to be the 8.5:1 they used to be 30 years ago.

As far as the TTIGeorge engine, no one should use that as an example IMO. I know people running higher compression than that on C16, making 1200+ rwhp on 23+lbs of boost. I'd think that George's engine had the wrong plug in it, or the intercooler was poor, or another problem he didn't have sorted out. Obviously the timing has been mentioned, running NA timing on a FI motor doesn't work well either.

 

11:1 here, just got my combo together. Billet 78/75 from vs racing. Drives out of boost just as wonderfully as it did when it was running mid 11's n/a. Extremely responsive and spool up is lighting quick. Very very pleased with my decision to go with the higher compression. Track times and dyno numbers soon, waiting on my new ptc converter.

 

Also 11:1 here. running meth with a big intercooler. 57/62 twins on a 418CI motor. runs great so far and made 808HP on pump and 1014 on race gas.

 

10.8:1CR and 16psi with 93 + meth with a single turbo... 16 degrees time up top.

 

Mine is LS3 block, TF225 heads, stock GM gaskets, 10.8 compression, 10-11# boost with a Magnuson TVS2300--for a lot of miles and many drag passes. Very easy to tune. 93 octane, No meth.

 

What kinda max timing and peak tq timing are you guys running? Mines baby soft right now, 5# and 13* on e85 right now haha. Had to upgrade my fuel system before I opened it up. Looking to be around 15# and 15* total soon.