How high of Compression can I run using pump gas on my '97 LT1 engine? I am also at 4,400 ft. elevation if this makes a difference.

I plan to install a 383 stroker kit with a cc306 and ported heads if any of this makes a difference. And it will be ALL NA, no nitrous, no blower, no turbo.

Please help i want the most NA HP i can get on pump gas.

Thanks.

 

I wouldn't go higher than stock compression. One fourth to half a point of compression will net you something like a 5-10hp gain (minimmal). It can hurt you though, due to pinging. If you go too high in compression and the gas starts to preignite, your knock sensor is going to pull timing which will end up taking away alot more power than the 5-10hp that you orginially gained. For a N/A Lt-1 I'd say 10.5- 10.75 is about as good as it gets.

More importantly there's dynamic compression, but that's a whole other story....if you do a search you will probably find threads that have discussed this before.

 

I'm here in Albuquerque, New Mexico--altitude,5,600 feet. This helps with a compression motor.

Motor is in sig with 12.5.1 compression. When racing I run VP103 unleaded, but for everyday use, pump gas. runs great. You should be ok with pump gas, super unleaded of course.

 

Depends on the cam. You want a dynamic CR not higher than ~8-8.5:1. There were some good discussions of this in Advanced Tech a while back, you may want to do a search.

Rich Krause

 

Can you tell me more specs about your motor?

 

I also ru na 12.3:1 compression 383 stroker with solid roller cam on pump gas daily, and 110 leaded at the track

 

11.5-12:1 static should be ok assuming your cam selection isnt crazy. However, go with waht rich said. Some VERY good topics in advanced tech on static/dynamic compressions, how it works and why.

 

actually the "Crazier" the CAM the better the engine will handle 93 octane with high compression. I longer duration cam will bleed off some cylinder pressure and allow high compression with less chance of detonation.

 

Instead of using a 'guess' for what works best or sounds most impressive, it is certainly best to use a dynamic compression ratio calculator to find what works best.

7.5-8.5 is what I have read to shoot for. Of course the highest safest DCR will require a lot of attention to detail... if you mess up your calculations... you just might mess up a new engine.

Download the formula from advanced tech. EngineerMike made a speadsheet for it actually. Figure it out, and ask questions as you go.

I'd recommend this route over word of mouth.

Ben T.

 

Its all about valve event timing, and overlap more so than duration which will be effected by all sorts of things (ramp rates for example). Cant simplify things into duration only.