Im gonna get in ----
unless the turbo is super tiny it shouldn't spool
03-09-2006, 06:04 PM
#22
1.5 BAR
Join Date: Nov 2004
Posts: 1,065
Re: Im gonna get in ----
yeah, your right. the wastegate does route exhaust gas around the turbine wheel. but how is the wastegate gonna open when it doesn't see any boost?? it's not. so, exhaust gas is still going to go through the turbo and will keep spinning the turbo faster and faster. how hard is this to understand?
03-09-2006, 08:43 PM
#24
0.0 BAR
Join Date: Nov 2003
Posts: 0
Re: Im gonna get in ----
Originally Posted by mrnubs1
Well if you're not getting any positive pressure at the manifold, and because of that, you're not getting any increase in exhaust volume (above and beyond NA engine against load exhaust volume) - how is the turbo going to reach dangerous speeds? It's not able to feed itself, right?
I was just saying that without the extra exhaust volume created by positive manifold pressure, the turbo can't reach dangerous/harmful speeds.
An engine under load may not act like an engine revved in neutral, but the difference beween how a turbo engine acts in neutral vs. how it acts against a load is MUCH different in comparison to how an NA engine acts revved in neutral vs. how it acts against a load.
In an NA engine, the load on the engine changes - atmosphere remains constant.
In a turbo engine, teh load on the engine changes - atmospheric pressure continually increases.
.
I was just saying that without the extra exhaust volume created by positive manifold pressure, the turbo can't reach dangerous/harmful speeds.
An engine under load may not act like an engine revved in neutral, but the difference beween how a turbo engine acts in neutral vs. how it acts against a load is MUCH different in comparison to how an NA engine acts revved in neutral vs. how it acts against a load.
In an NA engine, the load on the engine changes - atmosphere remains constant.
In a turbo engine, teh load on the engine changes - atmospheric pressure continually increases.
.
03-09-2006, 10:44 PM
#25
0.0 BAR
Join Date: Nov 2005
Posts: 13
Re: Im gonna get in ----
Yeah man, I'm actually only half black. So, you're only half right with that completely relevant point.
Last point for me in this thread.
The turbo, like any other fan, is free to spin as fast as the air/exhaust directed at it propels it. It's not free to spin as fast as it wants. A fixed amount of exhaust will only spin a turbo up to a certain speed. A turbo won't just keep spinning faster and faster with a fixed volume of exhaust propelling it. It always requires more exhaust to increase it's speed.
If you rev a turbo engine in neutral, you'll see 1 to 2 psi on a guage. If you put the car in gear and drive, you increase the load and start building boost pressure - the engine is moving slower and the compressor has more time to pressurize the intake. Then the cycle of +boost/+exhuast volume begins.
The NA engine will spin the turbo, but only to a fixed speed since NA exhuast volume (even at WOT load) is fixed. I'm saying that even at high NA engine loads, without boost to help increase the amount of exhaust available to spin the turbo, the turbo will never reach dangerous or harmful speeds. It might spin faster than it would if charge pipes were connected and you were revving in neutral (1 -2 psi), because of the higher load when you were actually driving. I don't think it would harm the turbo, though.
That guy was right, It really isn't worth arguing about and we obviously don't agree.....so............connect the charge pipes and go.
Last point for me in this thread.
The turbo, like any other fan, is free to spin as fast as the air/exhaust directed at it propels it. It's not free to spin as fast as it wants. A fixed amount of exhaust will only spin a turbo up to a certain speed. A turbo won't just keep spinning faster and faster with a fixed volume of exhaust propelling it. It always requires more exhaust to increase it's speed.
If you rev a turbo engine in neutral, you'll see 1 to 2 psi on a guage. If you put the car in gear and drive, you increase the load and start building boost pressure - the engine is moving slower and the compressor has more time to pressurize the intake. Then the cycle of +boost/+exhuast volume begins.
The NA engine will spin the turbo, but only to a fixed speed since NA exhuast volume (even at WOT load) is fixed. I'm saying that even at high NA engine loads, without boost to help increase the amount of exhaust available to spin the turbo, the turbo will never reach dangerous or harmful speeds. It might spin faster than it would if charge pipes were connected and you were revving in neutral (1 -2 psi), because of the higher load when you were actually driving. I don't think it would harm the turbo, though.
That guy was right, It really isn't worth arguing about and we obviously don't agree.....so............connect the charge pipes and go.
03-09-2006, 11:18 PM
#26
0.0 BAR
Join Date: Nov 2003
Posts: 0
Re: Im gonna get in ----
I like how you generalize the whole thing, a t25 on a 350 v8 would be alot different the a t3 super 60 on a lawn mower. what you think and what I and the other turbo educated guys know are two different things princess.
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