Boost on 11.5:1 Compression
 

Having a 416 LS3 built by one of our sponsors. Set it up with -8cc pistons and TFS 245's.

The builder mentioned that I should be fine on 93 octane up to about 7 psi or so of boost, more with E85.

I didn't realize that I could run boost at all on this motor given the compression ratio. What do you guys think? I wasn't planning on boost, but the idea does interest me a little bit down the line. Just curious what you guys' opinions were.

How much would 7 psi net on that larger CI motor? 700-800 to the tire?

Again, no plans just curious.

7-8 PSI is roughly a 35-50% increase in power depending on a few factors.
You could get away with 93 and meth on 11.5:1 with low boost.

I find just posting whst people get away with helps put things into perspective...

My compression is no where near you but i can give you an idea of what i see. Stock ls1 compression (stock engine) i see 6psi..ish. with about a steady 16.5 degrees of spark on 93 with intake temps around 175 and no intercooler from a powerdyne. On e50-60 i have stock ls1 timing (24-25) in it with the same boost with no detonation at all. I love e50.

e85 - yes, I run the stock ls3 10.7:1 and have seen as high as 20psi on e85 and meth

I wouldn't bother with pump gas you will be on the edge all the time and one bad tank of gas could be all it takes to be catastrophic

Exactly. Unless you are boost limited by a racing class, there is no need to push things to the edge all the time. Some (a lot) of what you see people getting away with on here involves near perfect tunes that they are always working on.

Run Methanol. I run it on a Stock LS3 pushing about 12.5lbs of boost with a separate container holding methanol. the methonal is only sprayed at certain boost levels. get with East coast supercharging. they have good kits and dual nozzle kits. They can explain it a bit better. But yes, you can run boost at that level with proper octane.

Use meth. Not on your motor, but personally. Wont be long before you dont care about the engine. ;)


This was a joke.

SMH...yeah...that was a good one!

Stock LS3? No aftermarket cam or anything? Got any rough idea of what horsepower you are seeing? My engine is stock except a cam/headers and I was going to drop on a Supercharger but was a little worried about the 10.75 CR.

One advantage,, of Ethanol over methanol is that its Way less corrosive to Aluminum.
The Octane and burn are very close,, You can run E85 on the street, and bump to E100 if your local distributor is cooperative..

If your just using supplemental injection Ethanol works just fine in place of methanol. (With the correct tune.. ) and its about 1/2 the price if you have a pump source.. I've purchased it at big chemical distributors,, but they often require a 50GAL drum purchase.. ;)

^^^ This right here... If you have access to E, then use it.

My buddy has a forged internals LSA block 377" on E at 11:1CR. He street drives it everywhere and has more passes than I can remember. 25+PSI with a YSi. It's in a C5Z. He's run 158 so far still tuning.

What cam are you running? Looking at different manufacturers, they seem to be all over the map for a supercharged positive displacement camshaft. If you don't mind, what psi are you running?

I'm Bone stock on the motor. Only thing I have done to the car is ECS Supercharger, LT Headers with x-pipe, no cats, borla exhaust, Methanol kit, hardened output shafts, and Yank SC3000 Converter. I believe the PSI is at around 12-12.5. Just go to east coast supercharging and you will see all these setups pushing this rwhp running low to mid 10's.