how many psis to run
- Thread starter shttygtstang
- Start date
- Jun 2, 2004
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TT91
Active Member
- Jun 2, 2004
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shttygtstang said:
Ehh, I just assumed cause of the 8.5 compression ratio that you had a 2g...
Im running a 50 trim which is just slightly bigger than a 20g and slightly more efficient. I dont see how more than 350-400 hp is a drag car in any way. Thats just getting started on having some street fun in an AWD car
-Dallas J
saleenx029
New Member
shttygtstang you are wasting your time building a sc and turbo combo setup, but go ahead, your headache not mine. Why? Super expesive operation, lots of fabrication needed, the turbo is actually slowed down on the top end by the sc because it is more innefficient. A 302 v-8 has the bottom end torque for off the line, use a big turbo for top end. Why would you want to waste so much time, you already admitted that you don't know everything about stangs so I suggest doing a lot more research before you commit yourself fully.
- Jun 2, 2004
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as far as the sc and turbo commit go i have no replies to that ive argue that too much.... i wanna no abought boost numbers on mustangs
Michael Yount
Mustang Master
There are other issues here - that head gasket is gonna ruin your quench. It's a terrible way to lower the compression ratio - it will make the car much more prone to detonation, which you don't want with boost. If you want to run a bunch of boost, be sure it's intercooled, be sure your chip richens the mixture and reduces the timing enough to cope with the boost, and lastly, you probably ought to pull the heads and install head gaskets that the supercharged guys tell you will last, along with removing the head bolts and replacing them with studs. If you insist on running so much boost you need to lower the stock compression ratio, you should do it with replacement forged pistons, not with a thicker head gasket. You won't need a replacement ecu - just a chip with the adjustments to deal with the supercharger or turbo charger. As others have said - you need to shift your thinking from small 4 cyl mode to larger V-8 mode. The motor has enough displacement to make good torque down low - so lag or lack of bottom end til the boost comes on isn't an issue.
BlackFox5.0
Founding Member
You should keep in mind you want to make the most power with as little boost as you can, because the more boost you run the hotter the discharge air becomes, and the less power you will be able to make. Unless you have some kind of cooling, like water/alky injection or an intercooler, then more boost is ok, but there is a such thing as too much as it can become ineffiecent.
- Jun 2, 2004
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i am gunna be running an intercooler i also have a fmu from paxton that could be calibrated for higher psi ...also in every engine i seen the compression has been dropped to a freindly 8.5 ...I ve heard people making 500 horse with stock insides im sure i can turn the boost up a little bit with a dropped compression no?
Michael Yount
Mustang Master
The other challenge you're gonna face is the strength (or lack of) of the stock block. While there's no absolute limit, people start experiencing block failures -- as in cracking right down the middle -- right around the 500 hp mark. If you keep turning up the boost/power on a stock block you will split it right down the middle. If you're serious about that much power, you need to start your buildup with a stouter block -- Dart or equivalent.
Don't know how many 5.0L's you've seen with boost, but the vast majority that are supercharged are running the stock 9.0:1 compression ratio.
Don't know how many 5.0L's you've seen with boost, but the vast majority that are supercharged are running the stock 9.0:1 compression ratio.
- Jun 2, 2004
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well heres my thing and please pull this theory apart if .. but my thing is i want the mostpower i can make with out jeperdizing anthing so hers my set up so far im going with a head gasket thats 65 thousands thicker to drop compression to 8.5 (boost freindly).set of arp head bolts dont want thoughs head gastes to blow or crank walk .IALSO WENT A HEAD GOT A PAXTON SN 93 SC.75MM TB.XPIPE .LOOKING INTO A FRONT MOUNT INTERCOOLER NOW. paxtons fmu the dighaphram on the in side will be decided once i decide psi.im also looking into a intake manifold and cam.
TT91
Active Member
By using a .065 thick headgasket, yes you are dropping your compression, which isnt needed with a stock 5.0, but your also changing the geometry of the motor. The Piston quench is going to be horrible, meaning, the psitonis going to be .065 farther from the combustion chamber at TDC when the spark plug fires. I would recommmend some aftermarket heads with ported chambers, so far, everything you said has been a complete waste of time.
- Jun 2, 2004
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Ive had no luck past 16 psi on my stock longblock. Realistically Id say over 11-12 psi is exiting the "safe-zone". The first time I blew my headgaskets I was seeing around 17 psi (on 93 octane, not too wise of me...). I just took the engine apart now because Im wanting to build a real engine then boost it. A SBF is a world away from a 4G63.
- Jun 2, 2004
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also you were runing high compression ... i ve heard of mustangs running high boost numbers they all had a 8.5 compression ratio .thats y any one runing over 12 psi has to bring there compression down ..thats not just dsm facts thats engine facts.
Michael Yount
Mustang Master
You came on to the site and asked folks for their input. Almost everyone on here told you there's no reason to drop the compression, and that doing it with a thicker head gasket will cause other problems (lack of quench, detonation). Yet you're going forward with that anyway. I'm curious why you even asked since you already seem to know what you're going to do? Good luck with it nonetheless.
- Jun 2, 2004
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js are you mad that my ricer is faster that you lx....its a ford with a 302 if i blow the engine up i might have to pay to 10 bucks to get a new one there a dime a dozen who cares get real loser
- Jun 2, 2004
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micheal thank you and your right and im not being cocky but have you ever met a person who thinks they know what there doin and wont take advice from some one else a person that has to learn the hard way thats me.if so i wont mind blowing this engine up its a learning experince for me
