Do they sell low-compression pistons for the modular 4.6???

drexebo

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Mar 3, 2004
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I haven't seen any around. Would they be beneficial to any blower cars, or would they just be unnecessary for a built engine? Is there anything you can do with a low-compression 4.6 that you can't do with a stock compression 4.6? Like 30psi turbo + Nitrous or something? :shrug:
 
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im sure if your looking for serious boost than low compression pistons wouuld be benificial assuming you had a block that could handle that kind of power. but i dont think it is too necessary for a boosted street driven car
 
Yes the lower the static compression ratio the better it is for boost well if you dont go too low that is. If you had a forged rotating assembly with 8.5:1 and a turbo that would be a sweet high power set up.
 
mogs01gt said:
lol@30 psi from a turbo.

I guess not really since I don't know why that's funny
:shrug: That was just a hypothetical example, though. I know it's a very high expectation but I didn't realize it wasn't possible. (if that's what you were suggesting)
 
30 psi your looking at... well with the right sized turbo... a pro 5.0 car. i dont think any modular engine will take continuous 30 psi + nitrous day after day.. those pro 5.0 engines are torn apart an rebuilt after every race to make sure they are perfect. 15-20 psi is on the high end but more within the realms of reality, for a daily driver + big power.
 
bdcardinal said:
a buddy of mine has a Sean Hyland built motor that he runs a ProCharger F1 at 32psi of boost for a daily driver. its a 2v btw. it can be done but its expensive.
That is sick :nice: does he have to run 110? i was looking to make the move to either a D-1SC or the F1; in your opinion which do you think is better? i know the D-1SC upgrade is about $1000 but I havent heard much about the F1.
 
um, ive only experinced the F1. the story i heard about the car is the Sean Hyland was the only builder who would agree to build him a motor knowing full well that the car would be run on pump gas in CA. the downsides are the 2mpg that he gets. the car was dynod at 495rwhp when it was only making 6lbs of boost on 19lb injectors. now the car has 54lb injectors on 32lbs of boost. the F1 is supposedly a race only blower, now his only real concern is passing somg....
 
ya a more normal person that isnt psychotic i would recommend a D1 or P1 i guess. this guy also has a pinto with a 5 speed fuel injected 302, it has a fuel cell dont worry. the car hasnt been driven a lot in a while because he just got a job abour 25 miles from home.
 
bdcardinal said:
the car was dynod at 495rwhp when it was only making 6lbs of boost on 19lb injectors.

I have an extremely hard time accepting this statement at face value. I don't believe you can possibly force 19# injectors to support 500 rwhp, nor do I believe any 2V can possibly make 500 rwhp on only 6# of boost. Particularly not when the blower is parasitically eating horsepower. Given that the 9 psi KB blower kits are not making that type of power (and I can't think of an 8 psi centri blower kit that makes that kind of power on a 2V) I'm calling BS on this one.

This car combination doesn't even pass the ho-ho test.
 
Aaron 4.6 said:
I have an extremely hard time accepting this statement at face value. I don't believe you can possibly force 19# injectors to support 500 rwhp, nor do I believe any 2V can possibly make 500 rwhp on only 6# of boost. Particularly not when the blower is parasitically eating horsepower. Given that the 9 psi KB blower kits are not making that type of power (and I can't think of an 8 psi centri blower kit that makes that kind of power on a 2V) I'm calling BS on this one.

This car combination doesn't even pass the ho-ho test.

Aaron, I particularly like the 32# on pump gas, Cali no less. You are right on with the injectors, even with an FMU they would have gone static long before 495rwhp. They'd be pumping foam at the fuel pressure needed to support 500rwhp on pump gas.
 
ProCharger GT said:
im NOT calling bs because the F1 blower flows 1525 CFM, and outflows mine by 325 CFM. Im making 431 @ 7 psi so 500 is certainly attainable with a good build @ 6 psi.

I am. I don't care if it flows 14000 cfm, the F1 is not even close to it's effeciency range at 6#. I doubt they even have a pully that for 6#.
 
RedGTvert said:
I am. I don't care if it flows 14000 cfm, the F1 is not even close to it's effeciency range at 6#. I doubt they even have a pully that for 6#.


if you increase the efficiency of an engine, IE: P&P heads, cams, exhaust, a 12psi pulley may only produce 6psi. also intercoolers cause a drop in boost pressure. i have a Vortech SQ with an 8psi pulley. before my exhaust, i saw upto 9 psi. now i see 6, maybe 7 on a cold night.
 
im just repeating what i was told by the owner, i wasnt there when it was dynod. also what i forgot to mention was the severe starvation of fuel they were experiencing. this car has full exhuast, massively ported heads, custom ground cams. its also running a ported bullit intake manifold.