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Joined: Apr 2002
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Hard-core CEG'er
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RPM RPM RPM RPM RPM not RPM's. 
-Giovanni
One turbocharger. Two intercoolers. All love.
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Joined: Jun 2000
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Originally posted by RedSVT:
Exhaust velocity is RPM dependant. 
Well, now you've got me confused. Are you saying there is more exhaust available to spin a turbo at 1/4 throttle @ 4000rpm than WOT @ 3000rpm? ..or are you just stating that "velocity" is not the right term to describe the phenomenon that forces a turbo to spool up? ..aaargh, you always "fuel the debate"!! Put an end to my misery and lay the facts down already!   
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Joined: Jul 2000
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Really fun reading this. I don't know enough to give any extra comments. But using my logic and all the engineering classes I've taken so far, I'd say Rara is right on this. Now you said see what happens on the boost guage when you rev up right? I'll tell you what happens, it depends on how heavy your foot get on the gas pedal. If you're in full throttle, it'll jump up to almost full boost right the way. If not, it'll not get to full boost anywhere. It's almost the same all through the rpm range as long as your foot is holding the throttle at the same position. I do it with customer's turbo'ed cars all the time, try it you'll see too.
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Joined: Feb 2002
Posts: 211
CEG\'er
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CEG\'er
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Posts: 211 |
Originally posted by Ausgedient:
RPM RPM RPM RPM RPM not RPM's.
I am talking about more than 1 Rpm so the term RPM's is deemed appropriate !!!! By the way, I am about ready to go out side and shoot myself in the foot over this thread, it's driving me crazy  I dont know how to get the point across, even the sight pascal posted agrees exactly with what I said!!! If you dont think more exhaust flows in the higher rpm's, then why does the exhaust note change as thr rrr's rise?? Please some one jump in here and set this strait, I meen think about it the more air the engine takes in, the more it has to put out..... 
1998.5 CSVT #3617
K&N Custom Intake
Custom 2 3/4 Magnaflow cat back
Ram HD Power Grip Clutch
Energy Suspension Inserts
Bosch Platnium +
Bf-Goodrich G-force radials "KDWS"
Alpine deck CDA-7863
Boston mids
More to come: Stock Sucks!!!!
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Joined: Sep 2002
Posts: 84
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OP
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Originally posted by TommyBoy:
Originally posted by Ausgedient:
RPM RPM RPM RPM RPM not RPM's.
I am talking about more than 1 Rpm so the term RPM's is deemed appropriate !!!!
rotations per minute(rpm) or rotations per minutes (rpm's)
juust to be appropriate
anyway, my knowledge of turbo applications are to agree with
AIRKNIGHT. but i don't want to fight cause of my opinion which really doesn't matter because everyone believes that they're opinion is always right, until proven wrong.
all i did was ask which kit is the best for the money and only a couple few answered without arguing if the turbo works off rpm('s)  
seems like i'll play with the vortec
export the imports
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Joined: Jul 2001
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Originally posted by TommyBoy:
If you dont think more exhaust flows in the higher rpm's, then why does the exhaust note change as thr rrr's rise?? Please some one jump in here and set this strait, I meen think about it the more air the engine takes in, the more it has to put out.....
This is true, but it works both ways. Say you're cruising at 4000RPM and you slightly increase the amount of throttle being used. The sound it makes right away at 4000RPM is different than if you pushed the pedal all the way down right away. Or if that doesn't make sense, say you're just cruising at 4000RPM, compare that sound and the amount of exhaust coming out, to that of say 2000RPM with the pedal all the way down.... maybe? It makes so much sense in my head, but when I go to type it...it comes out completely different, haha
'03 SRT-4
50 trim turbo + support
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Joined: Jun 2000
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- You're driving in 5th gear at 3500 RPM on flat terrain.
- A steep grade comes up.
- You're hell-bent on maintaining 3500 RPM
- You're having to almost floor it to maintain 3500 RPM
Don't tell me there's no more exhaust gas coming out the tailpipes then when you were just cruising. Yet RPM haven't increased. What has changed? Throttle position!
BTW, I'm not about being "right or wrong".. I'm maintaining the argument in an effort to understand the whole concept... wishfully thinking for Rara or RedSVT to cut in with the hard facts.
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Joined: May 2001
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New CEG\'er
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I'm no expert, but here's my take on the situation.
We all agree that turbos are powered by exhaust gas. So the question is
Where does the exhaust gas come from?
It is the product of fuel combustion and is expelled during the exhaust stroke of the engine. Therfore we can make the following cases:
1)More fuel => definately more exhaust gas.
2)More rpm => more revolutions (cycles) per minute (fuel injected every cycle) => more fuel per minute => so we're back to #1
So yes, both statements are true, but rpm is an indirect relationship for the turbo, where it is a direct relationship for the S/C.
T-Red SVT E0 #2321 of 6535
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Joined: Feb 2002
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It doen't get much more simple than this!!!We all agree a turbo needs exhaust gases to function!!, right??? Well you can not get exhaust gases intill there is RPM's and as the rpm's increase so do the exhaust gases!!! This is why some cars with after market larger turbo's dont spool intill 3500-4000 Rpm, because there is not enough exhaust to spin the turbine untill upper rrrr's, thus creating lag because of the back presure from the unit!!!!!! I do see your point about Climbing an inlcline, to a degree. However this is a an exception the rule, when ever you peg the gas to maintain rpm's there is an increase in combustion how ever the added stress from the incline doest allow the rpm's to climb as the normally would!!!! Now do the same thing but at 1500 rpm's and watch the boost gauge will it climb?? I honestly don't know!!!! However lets not stray from the statment: That a turbo is not Rpm dependent!!! Because if your car is just sitting there not running I am sure the turbo is not spooling up!!!
1998.5 CSVT #3617
K&N Custom Intake
Custom 2 3/4 Magnaflow cat back
Ram HD Power Grip Clutch
Energy Suspension Inserts
Bosch Platnium +
Bf-Goodrich G-force radials "KDWS"
Alpine deck CDA-7863
Boston mids
More to come: Stock Sucks!!!!
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Joined: Jun 2000
Posts: 585
Veteran CEG\'er
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Originally posted by TommyBoy:
However lets not stray from the statment: That a turbo is not Rpm dependent!!!
You're right. A turbo is NOT directly RPM dependant. Did you just contradict yourself?
Originally posted by TommyBoy:
Because if your car is just sitting there not running I am sure the turbo is not spooling up!!!
Absolutely not.
Actually, if you push my turbo car down a steep incline in 2nd gear with the key out of the ignition, when the engine spins up to 7000 RPM, there still won't be any air coming from the turbo's compressor side, because it won't be spinning.
However, if you pushed a S/C'c car down the same incline, with the engine spinning at 7000 RPM, you would have air coming out of the compressor.. because the S/C would be turning at the exact same speed as if you had actually been driving the car at 7000 RPM.
Don't treat me like stupid. I know the turbo will not make boost without the engine running. What I'm maintaining is that the amount of air pushed by the turbo is not directly proportional to the engine RPM... very unlike the s/c car, where you have a mechanical connection!
Doesn't that make any sense?
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