GMT 900 Trucks General Discussion 2007 - 2013 Trucks | General Discussion

I dyno'd my truck today! 2011 6.2L

Thread Tools
 
Search this Thread
 
Old Feb 4, 2012 | 08:53 AM
  #21  
Mang213's Avatar
Launching!
iTrader: (1)
 
Joined: Jun 2009
Posts: 205
Likes: 0
From: Washington DC/NoVa
Default

to the OP

Turbos are used in small aircraft engines because of the thin air. They help to maintain a more consistent amount of charge air to keep you from dropping out of the sky lol

Btw Im in the Mount Vernon area near Fort Belvoir. Where are you in Lorton? What shop did you get dyno'd at?
Reply
Old Feb 4, 2012 | 10:33 AM
  #22  
NKPPhil's Avatar
TECH Fanatic
 
Joined: Jan 2011
Posts: 1,074
Likes: 0
Default

Well, yeah, boost is boost, as far as that goes. But, a positive displacement supercharger is going to take ambient air and compress it "X" number of times. A turbo on the other hand isn't limited by a given internal displacement in the same way - which is why a turbo needs a blow-off valve. Once the rpm's are up and the exhaust flow gets it spinning, no matter what your ambient air pressure, it's gonna build pressure to the limit of the blow-off. The trade-off of the turbo is that you don't get the immediate low- and mid-rpm boost that you would get from a positive displacement supercharger.

At least that's what I think I know. Following that logic I would think a turbo would be better for racing, especially at higher elevations, but I'd pick a supercharger for a daily driver for that instant response. Does that make sense to anybody else?
Reply
Old Feb 4, 2012 | 11:21 AM
  #23  
TECH Fanatic
iTrader: (2)
 
Joined: Nov 2001
Posts: 1,124
Likes: 1
From: Michigan
Default

Originally Posted by NKPPhil
Well, yeah, boost is boost, as far as that goes. But, a positive displacement supercharger is going to take ambient air and compress it "X" number of times. A turbo on the other hand isn't limited by a given internal displacement in the same way - which is why a turbo needs a blow-off valve. Once the rpm's are up and the exhaust flow gets it spinning, no matter what your ambient air pressure, it's gonna build pressure to the limit of the blow-off. The trade-off of the turbo is that you don't get the immediate low- and mid-rpm boost that you would get from a positive displacement supercharger.

At least that's what I think I know. Following that logic I would think a turbo would be better for racing, especially at higher elevations, but I'd pick a supercharger for a daily driver for that instant response. Does that make sense to anybody else?
A wastegate is what controls the boost level of a turbo. It reroutes the exhaust gas around the turbine, regulating its RPM...A blow off valve releases the pressure that builds up between the turbo compressor wheel and the throttle blade, when the throttle is slammed shut upon deceleration. It is the "squeal" you hear on all the ricers, as they shift gears. They are both needed on a turbo setup.

As for a turbo vs. a supercharger at elevation...A turbo will more easily adapt to changing elevations, since it is boost pressure regulated. If you have the wastegate set to 10psi, it will run 10psi at sea level and at 8000 ft. (provided the turbo is sized properly). The turbo will have to turn more RPM to provide that boost at elevation, however. A supercharger that produces 10psi at sea level will be lucky to produce 6psi at 8000ft. Only way to change that is to run a smaller pulley, but then it will run more boost at sea level.
Reply
Old Feb 4, 2012 | 12:00 PM
  #24  
NKPPhil's Avatar
TECH Fanatic
 
Joined: Jan 2011
Posts: 1,074
Likes: 0
Default

Originally Posted by MyLS1Hauls
A wastegate is what controls the boost level of a turbo. It reroutes the exhaust gas around the turbine, regulating its RPM...A blow off valve releases the pressure that builds up between the turbo compressor wheel and the throttle blade, when the throttle is slammed shut upon deceleration. It is the "squeal" you hear on all the ricers, as they shift gears. They are both needed on a turbo setup.

As for a turbo vs. a supercharger at elevation...A turbo will more easily adapt to changing elevations, since it is boost pressure regulated. If you have the wastegate set to 10psi, it will run 10psi at sea level and at 8000 ft. (provided the turbo is sized properly). The turbo will have to turn more RPM to provide that boost at elevation, however. A supercharger that produces 10psi at sea level will be lucky to produce 6psi at 8000ft. Only way to change that is to run a smaller pulley, but then it will run more boost at sea level.
Aha ... thank you!
Reply
Old Feb 4, 2012 | 06:03 PM
  #25  
Mang213's Avatar
Launching!
iTrader: (1)
 
Joined: Jun 2009
Posts: 205
Likes: 0
From: Washington DC/NoVa
Default

Originally Posted by MyLS1Hauls
A wastegate is what controls the boost level of a turbo. It reroutes the exhaust gas around the turbine, regulating its RPM...A blow off valve releases the pressure that builds up between the turbo compressor wheel and the throttle blade, when the throttle is slammed shut upon deceleration. It is the "squeal" you hear on all the ricers, as they shift gears. They are both needed on a turbo setup.

As for a turbo vs. a supercharger at elevation...A turbo will more easily adapt to changing elevations, since it is boost pressure regulated. If you have the wastegate set to 10psi, it will run 10psi at sea level and at 8000 ft. (provided the turbo is sized properly). The turbo will have to turn more RPM to provide that boost at elevation, however. A supercharger that produces 10psi at sea level will be lucky to produce 6psi at 8000ft. Only way to change that is to run a smaller pulley, but then it will run more boost at sea level.
+1 exactly
Reply
Old Feb 5, 2012 | 01:55 PM
  #26  
stg313's Avatar
Thread Starter
On The Tree
 
Joined: Aug 2011
Posts: 183
Likes: 0
From: Lorton Virginia
Default

ah gotcha........
Reply
Old Feb 7, 2012 | 09:15 PM
  #27  
stg313's Avatar
Thread Starter
On The Tree
 
Joined: Aug 2011
Posts: 183
Likes: 0
From: Lorton Virginia
Default

Originally Posted by Mang213
to the OP

Turbos are used in small aircraft engines because of the thin air. They help to maintain a more consistent amount of charge air to keep you from dropping out of the sky lol

Btw Im in the Mount Vernon area near Fort Belvoir. Where are you in Lorton? What shop did you get dyno'd at?
I am about 3 miles away from mount vernon! Lets meet up! PM incoming!
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
wrb002
PROJECTS GALLERY
18
Aug 31, 2015 12:00 PM
USMCvet0311
SHOW & SHINE DISCUSSION
8
Aug 13, 2015 09:59 PM
black6spdz
Trucks and SUV Classifieds
9
Jul 16, 2015 01:32 AM
Nimoryan
GMT 800 & Older GM General Discussion
0
Jul 5, 2015 03:50 PM




All times are GMT -5. The time now is 04:41 AM.