i am starting a rebuild with wiseco pistons and eagle connecting rods for starters.... i look to hit 30 lbs of boost.... do you think it will hold?????
12's......here i come
You may want to sleeve your block at that high psi.
"Sig under construction"
There's a lot more to running 30 psi than just pistons and rods bud. That's a LOT of boost and I think you are overshooting. Stay simple and work your way up. 15 psi is a pretty big project to start off with.
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HOLY BOOST!!!!! 30 psi. wow. Like said above you better stick with trying to get 15 first. 20 psi is a huge accomplishment. Now 30, your God.
With just pistons and rods, I don't think you'd even make it to 30 psi
fortune cookie say:
better a delay than a disaster.
I really don't understand what people's infatuation with PSI is, to me it shows a lack of what it really takes to make power. PSI means absolutely nothing.
You make a horsepower goal, and size the turbo to match. I can run 30psi on my stock engine if I pick an enormously undersized turbo, but make crap for power. Please learn what it takes to make power before you make claims of what you are going to do...
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Shifted wrote:I really don't understand what people's infatuation with PSI is, to me it shows a lack of what it really takes to make power. PSI means absolutely nothing.
You make a horsepower goal, and size the turbo to match. I can run 30psi on my stock engine if I pick an enormously undersized turbo, but make crap for power. Please learn what it takes to make power before you make claims of what you are going to do...
the man has a point
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99redz24 wrote:
the man has a point
the man has a head as big as a watermelon.....
and correct me if im wrong....didnt adam hahn just put down an 11.4 on 26-28 lbs....with basically pistons and rods?????
12's......here i come
It's not just all about boost pressure. You gotta consider cylinder pressure, timing, fuel, intake temp, all of it, including boost, can make or break you. Say you run a race turbo, say a Turbonetics Thumper, that's capable of making 30 psi and then some, and also capable of making your engine use it wether it wants to or not, you better do more than rods and pistons or bad things will happen.
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Shifted wrote:I really don't understand what people's infatuation with PSI is, to me it shows a lack of what it really takes to make power. PSI means absolutely nothing.
You make a horsepower goal, and size the turbo to match. I can run 30psi on my stock engine if I pick an enormously undersized turbo, but make crap for power. Please learn what it takes to make power before you make claims of what you are going to do...
I'd like to know how you're calculating exactly what compressor you'll need for X hp...
I feel most people would assume 30psi to be near 3x NA power (seeing as it's approximately 3x the air pressure, so 3x the air, at a similar a/f = 3x power)
Regardless, picking a compressor requires a guesstimate at the engine's VE...
fortune cookie say:
better a delay than a disaster.
Ahhh the "I have more boost than you therefore I make more power" conversation.
The amount of PSI you pressurize your engine is not the end of the discussion when talking FI engines.
While on most applications, raising the boost pressure will gain power, its just cause 10psi is more than 6psi.
**Flow is probably the single most important part of engine building if you want to make big power, N/A or FI.**
So now why do all of the big numbers come from running 20+ psi? The big turbo's flow more at those boost pressures.
Take a T76 compressor for example. It will flow around 75lb/min of air at a 3:1 pressure ratio. If you only run a 2:1 pressure ratio and try to keep the effciency in the same range, the turbo will only flow a around 55-60lbs/min. So with this turbo, sure running huge boost makes lotsa power casue the turbo is effcient and flows up at those high psi ranges.
When smaller turbos like a T04B S-3 compressor are used, anything more than a 2.4:1 P/R will just make charge temps scorcing hot, and you won't flow much more air than you would with a 1.8-2.0:1 P/R.
And this all assumes the turbine can spin fast engough to even create boost. Thats a whole can of worms itself.
PSI also has quite a bit to do with system restriction. In almost all cases, if your engine's VE increases by the way of less restrictive intake, ported heads or less restrictive exhaust, you will gain power, but the max psi the turbo is pushing will drop. The engine can flow more air and it will make more power.
Now, there isn't anything wrong with big boost numbers. You just wanna make sure you have a stout engine, the right fuel and tuning, and extra cash. Just remember Murphy's law, "If something can go wrong, then it will."
I think its even more fun to keep compression high, intercool with water and use lower boost pressures. You should see the torque curve of the Norwood TwinTurbo Ferrari F50. With the stock 11.5:1 compression, E80 for fuel and water to air intercooling, the "curve" looks lieka table top.
As for compressor sizing, assuming 30psi is 3x the engine's air flow isn't correct. You have to factor in engine VE, abiatic effciency of the compressor, intercooled or not, and a host of other factors.
Forged rods and forged pistons on the eco should be good for at least 400hp. And I have a feeling that you will make more than 400hp way before you reach 30psi if you do it right.
1988 Pontiac Fiero, engine transplant underway.
2004 ECOtec, built and boosted
Sorry, as I've been trying to explain to others, when I say XXpsi vs XXpsi, I'm referring to the air availible to the cylinder, nothing else. I'm assuming that the compressor has been changed to one that will run with the same ideal efficiency at the same flow rate, but higher pressure ratio. I'm negating VE, sompressors, weather, altitude, and every other possible variable, only comparing apples to apples.
fortune cookie say:
better a delay than a disaster.
OHV notec wrote:Sorry, as I've been trying to explain to others, when I say XXpsi vs XXpsi, I'm referring to the air availible to the cylinder, nothing else. I'm assuming that the compressor has been changed to one that will run with the same ideal efficiency at the same flow rate, but higher pressure ratio. I'm negating VE, sompressors, weather, altitude, and every other possible variable, only comparing apples to apples.
Ya, then thats correct to what I am talking about.
1988 Pontiac Fiero, engine transplant underway.
2004 ECOtec, built and boosted
