Gsr Turbo?

[posol]

but the pressure of air that YOU are taking a reading from and basing all of this off of, is NOT the proper pressure.

Boost psi is the measure of pressure at the TB that is NOT making it in to the motor.

the way i see you to be reading it is as the pressure of the actual "boosted" air itself.

 

[SnailOnARampage]

Originally posted by pissedoffsol@Mar 19 2003, 12:17 PM
the thing i think you are getting mis-guided on is the fact that psi is the measurement of air NOT making it in.

Yes that is correct. That is the measurement of the air NOT making it in. SO what happens to it if its not going into the engine? Its diverted by the waste gate.

 

[SnailOnARampage]

All that happens with a larger turbo on a small engine is that you have MORE AIR NOT making it into the engine

 

[posol]

no.

the wastegate controls the EXHAUST wheel, NOT the compressor wheel.

when the reading goes back to the waste gate from the vacuum line, depending on the spring in the gate, it will open or close a little CONSTANTLY based on that reading. Now, this exhaust wheel simply spins. it is connected to an axel which in turns counter-spins the compressor wheel.

 

[SnailOnARampage]

So all that means is that the turbo is not operating at full capacity. Meaning, the exact same amount of air is getting into the engine at the same PSI and temperature.

 

[posol]

not at all dude.

i give up.

 

[SnailOnARampage]

Whats the difference between a 1000 cf/m @ 14.7 psi turbo running at half capacity, and a 500 cf/m @ 14.7 psi running at full capacity?

Just a lot of lag.

 

[SnailOnARampage]

Originally posted by pissedoffsol@Mar 19 2003, 12:34 PM
not at all dude.

i give up.

don't give up. prove you are right. Offer something to back up what you are saying.

 

[SnailOnARampage]

Originally posted by pissedoffsol+Mar 19 2003, 03:40 AM-->

SnailOnARampage

@Mar 19 2003, 05:01 AM
Look sol, all those charts prove is that a t70 CAN push more air than a t3. The problem is that if the extra air from the t70 can't go into the engine, it builds up pressure, and is expelled a different way.

i want to know, whats stopping it?

there is no dam.
with the TB open 100%, whats to stop it?

What is stopping it is the displacement of the engine x rpms. You can not exceed that number with a big turbo, a small turbo, or no turbo.

This is why I said at 10 psi the most you will increase torque is 70 percent. That is the same reason why, if you want to get a gsr to get 400 whp at 10 psi, you have to either raise the rpms or bore the engine some more.

 

[SnailOnARampage]

If anyone wants to prove me wrong, or prove me right, this is how you do it. Go find all the dynos you can find of turbo'd engines, domestic or import. When you find the charts, compare the before turbo torque, with the after turbo torque.

If I am right:

15 psi will be a maximum (maximum meaning its gonna be less than this) of a 100 percent increase in torque
10 psi will be less than 69 percent

7 psi will be less than 50 percent


Please post you results. Everyone is encouraged to participate

 

[mwasnp]

dude if that were the case there would be no point in buying larger turbo chargers, etc. You are clearly a moron, if you get a big turbo @ 10 psi, it is pushing ALOT more cfm that a little turbo would, regardless of what you think the engine can "handle" or take in. The wastegate opens when the amount of pressure the turbo is making exceeds what you tell it that it should. And the blow off valve opens when your tb closes and the back pressure increases to the point where it would cause your turbo to spin in reverse, which would wreck it. Neither have anything to do with there being more pressure than the motor could take in. Or there would be no point in raising the psi that the turbo is making. Is that simple enough. Honestly I am by no means an expert, brian knows a shitload more than me, but maybe his technical lingo confuses you or something? I dont know but its a fairly simple concept to grasp. Bigger turbos make bigger horsepower.

 

[SnailOnARampage]

oh lets not even start this. be careful who you call a moron, what goes around comes around.

If you are planning on running 10 psi on a stock GSR you will need a turbo that can push more or less 500 cf/m at 10 psi. If you get a turbo that can push 1000 cf/m at 10 psi you are simply lagging yourself up.

Now, if you take that same GSR and bore it, stroke it, and raise the rpms. You will need a larger turbo, and a larger turbo will do well on that gsr, whereas it would provide no benefit on the stock GSR.

The only need to get a larger turbo if:

1. you increase the cubic feet per minute your engine can displace...by either raising rpms, boring, stroking, or whatever.

2. if you plan to run more pressure at the same cubic feet per minute.

The more powerful your engine is to start with, the larger the turbo you will need. Not the other way around. A larger turbo will not make your engine more powerful than a small one, if they are running at the exact same pressure (to the map sensor).

This seems to be seriously mis understood, because in cases where you have a turbo that is too small for an engine, you are not actually running the amount of boost that your waste gate is set for. Even though your wastegate is set for 10 psi, with an undersized turbo at your redline, you might only be making 3 psi. If you left that setup the same, and put a larger turbo and changed nothing else. Your torque would increase from 20 percent over stock, to just shy of 70 percent over stock. but that is as high as it would go, as long as your waste gate was set to 10 psi.

If I am such a moron, go look up all those dynos, and post the results of the torque before the turbo and after.

 

[mwasnp]

Lag is your friend in a fwd car. And just because you have lag doesnt make the car slower. It just means your slower in half of first gear!!! in the end you're faster

 

[SnailOnARampage]

Lag makes you car gutless until 5k rpms....

 

[SnailOnARampage]

In the end you are only faster if your waste gate is not limiting the amount of air your big turbo can put into your engine.

 

[mwasnp]

Its not, its limiting the PSI not the cfm's. CFM's are what gets you more hp not PSI.

 

[SnailOnARampage]

yeah and the engine displacement x rpm is limiting the cf/m's

 

[SnailOnARampage]

Originally posted by SnailOnARampage@Mar 19 2003, 10:31 PM
yeah and the engine displacement x rpm is limiting the cf/m's

want a reference?

http://www.gnttype.org/techarea/turbo/turboflow.html

The key words in this article being:

This holds true for both cars, both intercooled and nonintercooled will be moving 334.2 cfm of air into the cylinders at 5000 rpm. As we will see however, the mass of air flowing is not the same.

 

[posol]

Originally posted by SnailOnARampage+Mar 19 2003, 02:35 PM-->

pissedoffsol

@Mar 19 2003, 12:34 PM
not at all dude.

i give up.

don't give up. prove you are right. Offer something to back up what you are saying.

i shouldn't have to.

the larger turbo simply flows more cfm at any given psi.

period.

 

[SnailOnARampage]

If you are not fitting any more cf/m into an engine, and you are not increasing pressure. You are not getting anymore air into the engine....unless you lower the temperature.