crossroads - let's talk boost and high compression
 

So my little 355lt1 with efi24x conversion (using the 411pcm) is running fine.

I'm going to use a rear-mount setup that I have for this car in my upcoming ls conversion. I went rearmount primarily because of street car and didn't want to mess with standing up radiator, relocating stuff, etc... I know I'm leaving power on the table, but so be it.

The question is what to do with this lt1. It's a 355 splayed caps/ SRP/JE pistons and with my 53cc heads, at 11.75CR built about 8 years ago, but only has about 5-6k miles. I know that is too much for boost based on research, but have no experience. The meth/e85 guys are telling me it will be ok up to about 8lbs of boost potentially. Can't find anyone that's done it, so not sure. Talked to Lloyd about a turbo cam and he gave me a recommendation I could use.

Guys with experience, do you think it will survive for long on 5-6lbs of boost on e85/meth with a proper tune ofcourse?

The only reason I would try it is because the motor is in the car already and I can get this rear mount in in a weekend. and if it let's go after the summer, it let's go, I'd be ok with it. If I have to pull the motor and start the swap, I've got at least three weeks of work on getting the new motor in with the new kmember/wiring, etc., I'd like to leave that for next winter if I can. (on the lsx side, I'll be running a 5.3 aluminum engine with ls6 intake and z06 cam)

Constructive thoughts?

The saying with running boost is that you should always prefer boost to timing.

with a good forged piston even with the highish CR 8# is fine. If you ran a good cooler and switch to e85 you could possibly run 12# street and 14-15# race.

The CR is definitely holding you back from running more than low boost numbers... but that doesn't mean that you still wont make good power.

Lol...The effective CR of adding boost would be way too much 16.55 CR :eek2:....you would need C16 race gas :D:

http://www.gtsparkplugs.com/Effectiv...ssionCalc.html

http://www.vpracingfuels.com/motorcy...ag-racing.html

This is a setup where I'd actually endorse the use of E85. If you tune it right, you can run all the boost. If it is tuned right and well taken care of, it will live a long happy life on corn and boost and you can put off the LS conversion for another 8 years.

Stay away from that secondary meth crap.

easily done with E85.

mine is 21 and we run on 110. its all in the tune up.

Exactly. Cam timing plays a big part too. Last year I ran 19 psi of boost on 8.5:1 compression on 91 octane PUMP gas. According to that calculator my effective CR was 19.49:1. :eek2:

This year it's going to be at least 23:1. :secret2:

thanks for the tips guys, I really appreciate it. I'm using HP Tuners, this will be a 2bar SD tune, no MAF, will also be a front mount intercooler. So are you guys saying no water/meth injection at all, straight e85?

Yes, straight E85.