ZW99GT

So I assume that i remember correctly and that its best to run boost on LOW compression and Nitrous on HIGH compression. Is this right?

So say you have an 100% forged assembly that is rated at say 600hp and the compression ratio is 10.8-1. Thats on the high side, so that would be a nice nitrous motor. Say I get tired of nitrous and I want to run boost. Why couldnt you do this? Why are HIGH compression engines said not to be as good for boost? Detonate easier? Somebody please teach me.

HaV

You can boost that motor.. look at turbo diesels.. 18:1 compression. You make more power with a higher compression motor and a supercharger than you would on a lower compression motor and a supercharger quite honestly...

BUT

The reason you cant run as much boost has quite a bit to do with fuel (among other things). The higher the compression, techincally the higher octane you have to run. When you boost a motor it also requires a higher octane.. unless its tuned otherwise. between the higher compression and the increased air flow you will get detonation much quicker from fuel. You have to either run a methanol kit or higher grade fuel to account for that... so you hit the wall where you require race gas much quicker in a higher compression motor (meaning you really cant street drive it). Also, creating more power on stock internals at boost is a bad idea... your motor will only take so much.

There are other reasons, but thats honestly the main one I can think of. You have to run lower boost on a higher compression motor if your limited to pump gas.


*edit: typed higher meant quicker.. fixed now. lol.

ZW99GT

ok that makes sense. So I could run low boost (say 8PSI) on the street, but I could run higher PSI at the track as long as my internals would hold it and I have high enough octane? Makes sense to me. I will be Sticking with nitrous for a long while, just wondering for down the road. Thanks

ZW99GT

Anybody else?

GodAmGT00

I would think though, that if you've got a higher compression ratio, and added boost, you'd blow out things like Head gaskets, or intake seals before you blew your internals..

But HaV pretty much summed it up.. Running high compression and high boost also means you lose any reliability that you thought you had.. Bummer..



JT

lizzyfan

Check out my signature. I'm running about 10:1 C/R with the PI swap and have a S/C. My tune has alot to do with it. I can't really go crazy with the boost, it's very conservative! I'll be adding a water/meth injector in the next few weeks just for piece of mind. Right now I have a 93 octane tune and throw in some 100 octane (3-4 gallons) every fill up or so. Bottom line is get a good tune and you'll be fine. Remember compression=power!