Too much compression ratio?
Thread Starter
Burning Brakes
Joined: Feb 2004
Posts: 831
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From: Country Boys Can Survive.
Too much compression ratio?
What I mean to ask is; What is the highest compression ratio you can run with a magnuson? I'm contemplating doing a heads/cam install, (for monetary reasons), first, and then possibly installing a supercharger later. I would like to have the ported ls6 heads I buy milled for about 11:1 compression, except I wouldn't want to have to remove them later, if I want to supercharge. I'd appreciate some views on this please.
Thanks,
Loudsam
Thanks,
Loudsam
Burning Brakes
Joined: Oct 2002
Posts: 797
Likes: 1
From: Sunny Earthquake Country, USA On the Left Coast (which is becoming more Right!)
CR w/Magnuson...
I assume you are getting a new intercooled model.
11 to 1 compression is high if you are installing a short duration blower or street type cam.
If you get a cam w/a lot of duration (hence overlap), maybe you could get away with 5-6 psi max. if your engine never gets very hot.
The roots type blowers give lots of boost down low-say 2000-3000 rpm and with a tight duration cam your cylinder pressures in this lower range would probably be high enough to intiate detonation. The centrifugal blowers, ATI/Vortech have relatively low boost in that range and high boost comes in at 4000+ rpm where there is less chance of detonation (assuming adequate fuel delivery).
My thought would be to stay closer to 10 to 1 on CR, especially if we are talking stock pistons.rods.
I'm sure that there are lots of Magnuson guys who will chime in with their experiences and more specific recommendations!
Roy
11 to 1 compression is high if you are installing a short duration blower or street type cam.
If you get a cam w/a lot of duration (hence overlap), maybe you could get away with 5-6 psi max. if your engine never gets very hot.
The roots type blowers give lots of boost down low-say 2000-3000 rpm and with a tight duration cam your cylinder pressures in this lower range would probably be high enough to intiate detonation. The centrifugal blowers, ATI/Vortech have relatively low boost in that range and high boost comes in at 4000+ rpm where there is less chance of detonation (assuming adequate fuel delivery).
My thought would be to stay closer to 10 to 1 on CR, especially if we are talking stock pistons.rods.
I'm sure that there are lots of Magnuson guys who will chime in with their experiences and more specific recommendations!
Roy
Thread Starter
Burning Brakes
Joined: Feb 2004
Posts: 831
Likes: 0
From: Country Boys Can Survive.
Thanks for the insight!!!
The 427 cid must be awsome with the procharger! I've thought that if your going to mod at all, you should just save the bucks and go "all the way" with it! Thanks for the great info! You made alot of sense.
Loudsam
Loudsam
