Compression ratios

[MMarauder03]

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?

[ImpalaSlayer]

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?

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.

[MMarauder03]

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.

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

[ImpalaSlayer]

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

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"

[SpartaPerformance]

I'd stay at a 10:1 compression. Unless it's a track car and you're going to pack in 20+ psi no reason to lower it.

[MMarauder03]

I'd stay at a 10:1 compression. Unless it's a track car and you're going to pack in 20+ psi no reason to lower it.

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:

[ImpalaSlayer]

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:

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.

[MMarauder03]

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.

The plan is to tide me over until i get an aluminator or build my own. Just tired of being slow

[ImpalaSlayer]

The plan is to tide me over until i get an aluminator or build my own. Just tired of being slow

i bet you will have an aluminator and will be wondering why the hell the stock one wont blow up lol

[FordNut]

I went with 9.5:1 cr

[MMarauder03]

i bet you will have an aluminator and will be wondering why the hell the stock one wont blow up lol

LMAO, hopefully!

[LANDY]

Put the blower on it first, when the stock engine blows up build a motor around 9.5;1 CR.
Done deal

[slickster]

Would you need headers for this upgrade

[burt ragio]

Depending on type of headers they would give you another apx 50 hp.

[slickster]

Wow 50hp from headers after forced induction. In that case it's worth a grand for headers

[MMarauder03]

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

[Mr. Man]

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.

[MMarauder03]

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.

I'm going to be doing a motor swap. I just want some oomph until then

[justbob]

Wow 50hp from headers after forced induction. In that case it's worth a grand for headers
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. :)

[MMarauder03]

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. :)

What's the weak point of our motors? The cast crank?

[SC Cheesehead]

Depending on type of headers they would give you another apx 50 hp.

+1

Long tubes will give you more, I picked up 27 hp and 38 lbs trq with my FRPP shortys.

[SC Cheesehead]

What's the weak point of our motors? The cast crank?

Nope, rods and pistons.

BTW, I'm running 11 lbs boost, 450 rwhp on the stock block, so far, so good.

[MMarauder03]

Nope, rods and pistons.

BTW, I'm running 11 lbs boost, 450 rwhp on the stock block, so far, so good.

Good to know. i was going to go with DR's vortech or paxton kit. I'm leaning towards paxton right now. Anybody running a centri style setup around here want to help me out. I want to make good power but not risk integrity of my stock motor

[Mr. Man]

In some cases, yes. I am at 445 without headers, add headers and Click, Click, BOOM. Maybe, maybe not. But I do not want to install my termi short block just yet. :)
Fixed it for you Bob

http://www.youtube.com/watch?v=0mPzu9DPr6E

Disco Sucks:P

:sorry::hijack: back to the OP:)

[SC Cheesehead]

Good to know. i was going to go with DR's vortech or paxton kit. I'm leaning towards paxton right now. Anybody running a centri style setup around here want to help me out. I want to make good power but not risk integrity of my stock motor

PM Marauderman, he's running a Vortech, IIRC around 13 lbs boost.

[LANDY]

Good to know. i was going to go with DR's vortech or paxton kit. I'm leaning towards paxton right now. Anybody running a centri style setup around here want to help me out. I want to make good power but not risk integrity of my stock motor
On my previous car I ran 456rwhp and 412rwtq at 12# on a vortech s-trim.
The car had been FI since 27k miles and I sold it with 72k.
On race gas I ran 502rwhp and 456rwtq. I did about 20 passes on the car at that power level, several high 11 sec passes with an 11.67 at 65* weather.
Before I sold the car I did a compression test and the lowest one was at 182.
The durability depends on the maintenance and tune.

[MMarauder03]

On my previous car I ran 456rwhp and 412rwtq at 12# on a vortech t-trim.
The car had been FI since 27k miles and I sold it with 72k.
On race gas I ran 502rwhp and 456rwtq. I did about 20 passes on the car at that power level, several high 11 sec passes with an 11.67 at 65* weather.
Before I sold the car I did a compression test and the lowest one was at 182.
The durability depends on the maintenance and tune.

The pros and cons between air to air and water to air? Sounds like it holds up way better than I expected under boost. What pulley size is 12#s on that setup?

[RacerX]

I would get a forged shortblock from a well known builder before I'd ever drop the coin for an aluminator. Btw, my original block with 130+k on it still has the original crosshatch on the cylinder walls!

[MMarauder03]

I would get a forged shortblock from a well known builder before I'd ever drop the coin for an aluminator. Btw, my original block with 130+k on it still has the original crosshatch on the cylinder walls!

The aluminator would be the easy way out just since everythings assembled. I like doing things myself anyways. "Built Not Bought" is my motto

[SC Cheesehead]

The aluminator would be the easy way out just since everythings assembled. I like doing things myself anyways. "Built Not Bought" is my motto

Sounds like you could be a candidate for an Eaton swap... ;)

[MMarauder03]

Sounds like you could be a candidate for an Eaton swap... ;)

As much as I'd LOVE to do an eaton swap I just don't have the patience to source a bunch of used parts to make it work.

[LANDY]

The pros and cons betwe en air to air and water to air? Sounds like it holds up way better than I expected under boost. What pulley size is 12#s on that setup?
Air to air is a way simpler setup, and you don't have to worry about a pump going bad
The bad is if you do long extensive burnouts the intake temp will rise incredibly quick.
I ran a 3.33 pulley and spun the engine to 6500rpms.

[MMarauder03]

Air to air is a way simpler setup, and you don't have to worry about a pump going bad
The bad is if you do long extensive burnouts the intake temp will rise incredibly quick.
I ran a 3.33 pulley and spun the engine to 6500rpms.

What do you set your 1-2 and 2-3 shifts at? My burnouts aren't that long and extensive. I know when I get my point across ;). Sounds like I'd want an air to air setup with the 3.33 pulley just to be safe. Now basically the only downside of the air setup is obviously always have to have airflow otherwise i'll burn right up.

[99SVT]

Good to know. i was going to go with DR's vortech or paxton kit. I'm leaning towards paxton right now. Anybody running a centri style setup around here want to help me out. I want to make good power but not risk integrity of my stock motor

If you're going centri, keep the CR high. They don't spike the dynamic compression at low RPM boost like a PD blower does, so you can get away with more compression. Use flat top pistons and call it a day.



i bet you will have an aluminator and will be wondering why the hell the stock one wont blow up lol

That's what happened with me, the transmission gave up before the engine did.

[MMarauder03]

If you're going centri, keep the CR high. They don't spike the dynamic compression at low RPM boost like a PD blower does, so you can get away with more compression. Use flat top pistons and call it a day.




That's what happened with me, the transmission gave up before the engine did.

I already built my transmission ;)

[dohc324ci]

High CR Aluminator + Vortech T-Trim would be my vote. BTW, I went 10:1.

[MMarauder03]

I decided eaton swap it is, where do I start??I know I need the eaton M112 blower, lower intake manifold, intake plenum, kenne bell boost-a-pump, ford gt supercar fuel pump, 39# injectors, handheld tuner, coolant reservoir relocation, move my battery, custom brackets (anybody in the know on who here can make 'em? If not I can fabricate my own, modify my coolant crossover tube 1 inch lower to clear snout and pulley, intercooler (which one? if not custom piping with a IC from frozenboost.com) IC pump and custom bracket to mount it. Anything else guys?

[SC Cheesehead]

I decided eaton swap it is, where do I start??I know I need the eaton M112 blower, lower intake manifold, intake plenum, kenne bell boost-a-pump, ford gt supercar fuel pump, 39# injectors, handheld tuner, coolant reservoir relocation, move my battery, custom brackets (anybody in the know on who here can make 'em? If not I can fabricate my own, modify my coolant crossover tube 1 inch lower to clear snout and pulley, intercooler (which one? if not custom piping with a IC from frozenboost.com) IC pump and custom bracket to mount it. Anything else guys?


PM gortch for the brackets
http://www.mercurymarauder.net/forums/showthread.php?t=54151

I highly recommend the Frozenboost Type 100 IC heat exchanger, you won't be disappointed with it.

PM me with your e-mail address and I can send you some info on parts needed, approx pricing, etc.

[Fosters]

I would get a forged shortblock from a well known builder before I'd ever drop the coin for an aluminator. Btw, my original block with 130+k on it still has the original crosshatch on the cylinder walls!

I saw the crosshatch on a crown vic cab motor that we were taking the pi heads off... thing had over 300k on it and still had the crosshatch hone marks. Mod motors will run forever if you leave them alone. But that's not fun. :D

[IndyMerc]

for people staying N/A is 10-1 the max?

[Joe Walsh]

My N/A engine build checked in at approximately 10.5:1
Just need a good tune to avoid any detonation.
What's amazing to me is that multiple companies put blowers on stock 12.0:1 Coyotes and offer a warranty....:eek:

[Black Terror]

I ran a Trilogy @ 425 RWHP for over 50000 with 10 to 1, new owner put another 20K without any problems. Don't know who has the vehicle now, it was on Streetside Classics last time I looked, haven't heard anyone new as owner yet.