Compression ratios

MMarauder03

MMarauder03

Screamin' Demon
So I'm doing a bunch of maintenance work getting ready to supercharge my MM. I'm going to be replacing timing chain and tensioner because it's about that time and was thinking 10.1:1 compression ratio seems wayyy too high to just throw a supercharger on it. Most supercharged applications are 8.5:1 if not lower. Now somebody correct me if I'm wrong, and I seem to be since a good portion of marauders are supercharged now doesn't that seem like a ticking time bomb?
 
MMarauder03 said:
So I'm doing a bunch of maintenance work getting ready to supercharge my MM. I'm going to be replacing timing chain and tensioner because it's about that time and was thinking 10.1:1 compression ratio seems wayyy too high to just throw a supercharger on it. Most supercharged applications are 8.5:1 if not lower. Now somebody correct me if I'm wrong, and I seem to be since a good portion of marauders are supercharged now doesn't that seem like a ticking time bomb?
Click to expand...

you can run boost with 23:1 compression just like diesels. idealy yes you would want lower compression on a gasser but you dont HAVE to have it. you just compensate for it in the tune and amount of boost you run.
 
ImpalaSlayer said:
you can run boost with 23:1 compression just like diesels. idealy yes you would want lower compression on a gasser but you dont HAVE to have it. you just compensate for it in the tune and amount of boost you run.
Click to expand...

That's what I was thinking, well if I were to bore my stock block .020 over since it does have 115k, forged pistons and crank. Now there are manley pistons with a 23cc dish that would put a 4valve 4.6 at 8.06:1. Would there be any qualms about boosting the piss out of it? Obviously with supporting mods
 
MMarauder03 said:
That's what I was thinking, well if I were to bore my stock block .020 over since it does have 115k, forged pistons and crank. Now there are manley pistons with a 23cc dish that would put a 4valve 4.6 at 8.06:1. Would there be any qualms about boosting the piss out of it? Obviously with supporting mods
Click to expand...

im no expert when it comes to this stuff but that seems low. i would bore it min amount possible if its needed at all. boring a motor to get more cubes on a street car is just stupid IMO. iirc stock cobras run about 8.5:1 CR. hell i pumped 14psi into my stock engine and fed it the full 14 every chance i got and so does the new owner.

if i were you and you are going into the engine regardless, id go 8.5ish with good forged rods and pistons and call it a day.

if it were me, id feed that ***** like it sits and buy stock in rubber, these motors are stronger then most give credit. they only fail when people do stupid things or push them beyond what is considered "safe"
 
MMarauder03 said:
Thanks sparta and dave. Looks like you guys saved me a ton of money! Now to throw 2,000 in my supercharger fund. I'm almost there :beatnik:
Click to expand...

np, i was a little nervous about putting boost to the stock motor but with a good tune you got nothing to worry about as long as you dont go attempting to make 500hp.
 
ImpalaSlayer said:
np, i was a little nervous about putting boost to the stock motor but with a good tune you got nothing to worry about as long as you dont go attempting to make 500hp.
Click to expand...

The plan is to tide me over until i get an aluminator or build my own. Just tired of being slow
 
Put the blower on it first, when the stock engine blows up build a motor around 9.5;1 CR.
Done deal
 
You can get them for 830 new if you look around. you can also pick up a used set for pretty cheap if you want to go that route
 
From what I've read here over the years the stock engine is good for up to about+/- 430 rwhp. Much more than that and your pushing your luck. If you want 500+ an engine swap would be in order.
 
Mr. Man said:
From what I've read here over the years the stock engine is good for up to about+/- 430 rwhp. Much more than that and your pushing your luck. If you want 500+ an engine swap would be in order.
Click to expand...

I'm going to be doing a motor swap. I just want some oomph until then
 
slickster said:
Wow 50hp from headers after forced induction. In that case it's worth a grand for headers
Click to expand...
In some cases, yes. I am at 445 without headers, add headers and tick, tick, BOOM. Maybe, maybe not. But I do not want to install my termi short block just yet. :)
 
You must log in or register to reply here.
Back
Top