high or low compression engines

Mustangboy89 · 01-26-2001, 12:44 AM

i was wondering what the difference is between 9 to 1 compression or a higher compression pistons.does high compression engines run stronger than a 9 to 1 or a low compression engine.the reason i ask is because i'm thinking about building me either a 331 stroker or a 306 engine and it's either going to have nitrous or a supercharger on it and i'm just wondering what would be my best bet.thanks for you help.

Capri306 · 01-26-2001, 12:57 AM

The higher the compression ratio, the more power you'll get. You HAVE TO be careful with compression (and timing and fuel mixture) when you're doing power adders, otherwise it'll go up in smoke. Personally, I would stay around 9.2:1 or lower for power adders, and a good FMU. I don't have that much experience with them, but I'm sure our other members will tell you a little more than I can.

------------------
Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch

<--- New Timeslips

WADS56 · 01-26-2001, 01:20 AM

It would be better if you could choose the nitrous, or the blower. Then you could build the motor for the setup you want.

------------------
blown347,free breathing heads and exhaust, solid roller cam, tremec,moser axles, 4.10's, role cage and all the other stuff.
11.8 @ 115 very untuned

1993lx5.0 AOD dailydriver

91blownpony · 01-26-2001, 02:06 AM

IF U GO WITH THE SUPERCHARGE YOU WILL WANT TO GO WITH LOWER COMPRESSION PISTONS, B/C THE SUPERCHARGER BUMPS UP THE COMPRESSION DEPENDING ON HOW MUCH BOOST U RUN.

01-26-2001, 02:09 AM

The latest trend I've noticed is more compression and less power adder. Some have done this with good results. I really don't plan on adding much more boost to my ride(daily driver) but I could because I have 9:1 compression.

After I read about a guy that ran a higher compression and about the same boost as I run with great results I started wishing I had done that. It really hasn't caught on yet, but it will. You might want to call a good engine builder and discuss it with them.

Actually this reminds me of JMS. I remember reading about this guy that was on a budget and added only the essentials and a Kenne Bell blower. Then he started screwing with the computer. He was able to get around 100hp more out of that white coupe, messing with the computer... Now look at him..

Most will tell you low compression for a power adder combo but times are changing. Hey you could always build a low compression engine and then push up the boost.

If you build a higher compression engine you may not need any boost at all. Example.. My cobra has 9.85:1 compression(I think). What compression does the infamous LS1 have? I don't remeber exactly but I can tell you its over 10.5:1... Someone please correct me.(Hmm.. time for another beer) Sorry for rambling..

rj_stang · 01-26-2001, 11:42 AM

If your going with a forced induction (blower) your going to want to go with lower compression. The higher compression you go in a regular motor the higher octane gas you will have to run 10:1 is alright for premium unleaded. With the higher compression your also want to get your timing tunned well. Otherwise you start causing detonation and blowing holes through your pistons. Which is not fun. Try to stay away for the detonation mixture of high compression and low octane.

Mach 1 · 01-26-2001, 03:04 PM

you can run nitrous with a high compression setup, but not a blower.

------------------
1993 GT/AOD
'93 Mustang GT

01-26-2001, 12:44 AM	#1
Mustangboy89 Registered Member Join Date: May 1999 Location: garrett,kentucky Posts: 77	high or low compression engines i was wondering what the difference is between 9 to 1 compression or a higher compression pistons.does high compression engines run stronger than a 9 to 1 or a low compression engine.the reason i ask is because i'm thinking about building me either a 331 stroker or a 306 engine and it's either going to have nitrous or a supercharger on it and i'm just wondering what would be my best bet.thanks for you help.

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01-26-2001, 12:57 AM	#2
Capri306 Moderator Join Date: Sep 1998 Location: Grand Rapids, Michigan, USA Posts: 1,001	The higher the compression ratio, the more power you'll get. You HAVE TO be careful with compression (and timing and fuel mixture) when you're doing power adders, otherwise it'll go up in smoke. Personally, I would stay around 9.2:1 or lower for power adders, and a good FMU. I don't have that much experience with them, but I'm sure our other members will tell you a little more than I can. ------------------ Capri306, Moderator, The Mustang Works Online 1979 Mercury Capri, 5.0L -- C4 -- 2.73 1987 Mustang LX Notch <--- New Timeslips

01-26-2001, 01:20 AM	#3
WADS56 gear banger Join Date: Aug 2000 Location: CHICAGO Posts: 1,144	It would be better if you could choose the nitrous, or the blower. Then you could build the motor for the setup you want. ------------------ blown347,free breathing heads and exhaust, solid roller cam, tremec,moser axles, 4.10's, role cage and all the other stuff. 11.8 @ 115 very untuned 1993lx5.0 AOD dailydriver

01-26-2001, 02:06 AM	#4
91blownpony Registered Member Join Date: Jan 2001 Location: baltimore Posts: 12	IF U GO WITH THE SUPERCHARGE YOU WILL WANT TO GO WITH LOWER COMPRESSION PISTONS, B/C THE SUPERCHARGER BUMPS UP THE COMPRESSION DEPENDING ON HOW MUCH BOOST U RUN.

01-26-2001, 02:09 AM	#5
rbatson Guest Posts: n/a	The latest trend I've noticed is more compression and less power adder. Some have done this with good results. I really don't plan on adding much more boost to my ride(daily driver) but I could because I have 9:1 compression. After I read about a guy that ran a higher compression and about the same boost as I run with great results I started wishing I had done that. It really hasn't caught on yet, but it will. You might want to call a good engine builder and discuss it with them. Actually this reminds me of JMS. I remember reading about this guy that was on a budget and added only the essentials and a Kenne Bell blower. Then he started screwing with the computer. He was able to get around 100hp more out of that white coupe, messing with the computer... Now look at him.. Most will tell you low compression for a power adder combo but times are changing. Hey you could always build a low compression engine and then push up the boost. If you build a higher compression engine you may not need any boost at all. Example.. My cobra has 9.85:1 compression(I think). What compression does the infamous LS1 have? I don't remeber exactly but I can tell you its over 10.5:1... Someone please correct me.(Hmm.. time for another beer) Sorry for rambling..

01-26-2001, 11:42 AM	#6
rj_stang Registered Member Join Date: Jan 2001 Location: Villa Park, IL Posts: 36	If your going with a forced induction (blower) your going to want to go with lower compression. The higher compression you go in a regular motor the higher octane gas you will have to run 10:1 is alright for premium unleaded. With the higher compression your also want to get your timing tunned well. Otherwise you start causing detonation and blowing holes through your pistons. Which is not fun. Try to stay away for the detonation mixture of high compression and low octane.

01-26-2001, 03:04 PM	#7
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	you can run nitrous with a high compression setup, but not a blower. ------------------ 1993 GT/AOD '93 Mustang GT