2.6 pulley only making 16.2 psi
06-20-2011, 11:59 PM
#26
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You've missed the point by a mile.
Original statement in question is "psi doesn't mean power", too many people have heard that crap. When you're comparing pressures between manifolds of the same volume flowing into the same head - it means a ton.
PSI, while being a measure of restriction - is the easiest way to measure flow in a lot of cases, the same manifold at a higher pressure is obviously going to be flowing more air - therefore, more power.
Original statement in question is "psi doesn't mean power", too many people have heard that crap. When you're comparing pressures between manifolds of the same volume flowing into the same head - it means a ton.
PSI, while being a measure of restriction - is the easiest way to measure flow in a lot of cases, the same manifold at a higher pressure is obviously going to be flowing more air - therefore, more power.
06-30-2011, 02:25 AM
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I know the previous generations didn't even have it. It's just for a closer tolerance making the blower slightly more efficient from what I understand. But when I put this blower on 10k mi ago I didn't look like that. So since then I have been running a 2.8 and now its like almost all worn off lol its weird.
I only had the 2.6 on for 2 days. Now I'm back to a 3.25 till my turbo is done being rebuilt.
I only had the 2.6 on for 2 days. Now I'm back to a 3.25 till my turbo is done being rebuilt.
06-30-2011, 02:30 AM
#30
I know the previous generations didn't even have it. It's just for a closer tolerance making the blower slightly more efficient from what I understand. But when I put this blower on 10k mi ago I didn't look like that. So since then I have been running a 2.8 and now its like almost all worn off lol its weird.
I only had the 2.6 on for 2 days. Now I'm back to a 3.25 till my turbo is done being rebuilt.
I only had the 2.6 on for 2 days. Now I'm back to a 3.25 till my turbo is done being rebuilt.
07-11-2011, 12:38 AM
#33
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Supercharged, Turbocharged, Turbocompound, Naturally aspriated.
I think what the OP is saying, that your intake manifold pressure *IS* an indication of power. IE: The more you have the more power, or the harder the engine is working, when compared to itself.
If you modify the engine, then of course you can no longer compare the unmodified boost level to the modified boost level.
My car made 212 whp with 16.7psi boost on a 2.85" pulley stock exhaust, zzp 3" intake (heat soaked, yes I need cooling mods). I then swaped out the exhaust for the ZZP Long tube header/catted downpipe. Now I made 227 whp heat soaked, and only boosted to 15.3psi. I lost a full PSI, but gained ~ 8 horsepower. This is because the engine doesnt have to work as hard to get rid of the exhaust gasses. So when you modify your engine, then of course your boost doesnt mean power...
However...
I think this is more what the OP was takling about when saying Boost is like power when compared to itself.
When droving along on the road at 2500 RPM in 5th Gear going level, your boost/vac will be whatever (don't know the value but the - or vacume range) Then when you go up a hill, you havn't modified your engine at all, and the engine, to maintain that same speed, must work harder, you will see an increase in your boost. Going down the other side, your boost will go way down, then back to where it was when you level out.
So yes,
When compared to itself then boost is a good indication of power.
But keep in mind: Pumps like superchargers and turbochargers create flow not pressure, Restriction to flow creates pressure. This is why my boost level went down when I added my header.
I hope I have explained my point well.
I think what the OP is saying, that your intake manifold pressure *IS* an indication of power. IE: The more you have the more power, or the harder the engine is working, when compared to itself.
If you modify the engine, then of course you can no longer compare the unmodified boost level to the modified boost level.
My car made 212 whp with 16.7psi boost on a 2.85" pulley stock exhaust, zzp 3" intake (heat soaked, yes I need cooling mods). I then swaped out the exhaust for the ZZP Long tube header/catted downpipe. Now I made 227 whp heat soaked, and only boosted to 15.3psi. I lost a full PSI, but gained ~ 8 horsepower. This is because the engine doesnt have to work as hard to get rid of the exhaust gasses. So when you modify your engine, then of course your boost doesnt mean power...
However...
I think this is more what the OP was takling about when saying Boost is like power when compared to itself.
When droving along on the road at 2500 RPM in 5th Gear going level, your boost/vac will be whatever (don't know the value but the - or vacume range) Then when you go up a hill, you havn't modified your engine at all, and the engine, to maintain that same speed, must work harder, you will see an increase in your boost. Going down the other side, your boost will go way down, then back to where it was when you level out.
So yes,
When compared to itself then boost is a good indication of power.
But keep in mind: Pumps like superchargers and turbochargers create flow not pressure, Restriction to flow creates pressure. This is why my boost level went down when I added my header.
I hope I have explained my point well.
07-12-2011, 04:14 AM
#34
Chris that sounds right considering your elevation and ported head.
at 1100', airbox mod, 2.6 m62, ported m62, 3gph 100% methanol, stock exhaust mani, stock head, stock dp w/ modified 3" exit and 3" catback. I'm seeing 15.1-15.5 psi at 6700-7000 rpm in 3rd.
Temperature outside is up, keep that in mind.
What rpm are you seeing the 16-17 psi?
at 1100', airbox mod, 2.6 m62, ported m62, 3gph 100% methanol, stock exhaust mani, stock head, stock dp w/ modified 3" exit and 3" catback. I'm seeing 15.1-15.5 psi at 6700-7000 rpm in 3rd.
Temperature outside is up, keep that in mind.
What rpm are you seeing the 16-17 psi?
Last edited by 100% METH; 07-12-2011 at 04:19 AM.
07-12-2011, 10:56 PM
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07-13-2011, 07:07 AM
#40
On a properly funcitoning blower car the boost will progressively climb with the rpms. My car along with every other SS/SC I have ever worked on has always built boost in a linear fashion. You should not be "spiking" from 15psi - 17psi before your shift point or limiter. I hope you are not going off your boost gauge in the car for your readings, because it is not the most accurate thing in the world.
Last edited by Staged07SS; 07-13-2011 at 11:29 AM.
07-13-2011, 07:23 AM
#41
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Superchargers don't just spike. Because they would have to jump in how fast the rotors spin. That's why boost starts lower, and works it's way up. But it won't "spike" Basically. I believe. That's how I understood it
07-14-2011, 01:44 AM
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You obviously don't understand how boost builds on a blower car..... (not trying to be rude)
On a properly funcitoning blower car the boost will progressively climb with the rpms. My car along with every other SS/SC I have ever worked on has always built boost in a linear fashion. You should not be "spiking" from 15psi - 17psi before your shift point or limiter. I hope you are not going off your boost gauge in the car for your readings, because it is not the most accurate thing in the world.
On a properly funcitoning blower car the boost will progressively climb with the rpms. My car along with every other SS/SC I have ever worked on has always built boost in a linear fashion. You should not be "spiking" from 15psi - 17psi before your shift point or limiter. I hope you are not going off your boost gauge in the car for your readings, because it is not the most accurate thing in the world.
...i have also been noticing what i think is some slip as well. It could be that maybe its slipping and catching? Im not sure. It doesnt slip all the time, but i've noticed a belt squeal around 6500rpm a few times...usually when its humid and/or been raining out.
07-14-2011, 06:59 AM
#43
Well yes, i do understand how boost works in a blower car... And yes, i WAS going off the stock gauge. Apologies for thinking it was accurate?
...i have also been noticing what i think is some slip as well. It could be that maybe its slipping and catching? Im not sure. It doesnt slip all the time, but i've noticed a belt squeal around 6500rpm a few times...usually when its humid and/or been raining out.
...i have also been noticing what i think is some slip as well. It could be that maybe its slipping and catching? Im not sure. It doesnt slip all the time, but i've noticed a belt squeal around 6500rpm a few times...usually when its humid and/or been raining out.
What belt are you using?? Hopefully not the crappy one ZZP provides with their stage kits. If so, I suggest picking up a genuine GM Stage 2 belt.
07-14-2011, 03:42 PM
#46
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that reminds me! you should look into getting the phenolic IM spacer from zzp, say goodbye to heatsoak! it works so good i was blown away. EVERY S/C CAR SHOULD BE RUNNING IT!
Last edited by hungryhip-ccp; 07-14-2011 at 03:57 PM.
