variable turbine geometry on a 951
07-14-2009, 05:59 AM
#16
Nordschleife Master
VGT would be awesome.
But don't forget that modern engines use variable camtiming and often variable intake runner lengths as well to optimize the whole powerband.
But don't forget that modern engines use variable camtiming and often variable intake runner lengths as well to optimize the whole powerband.
07-14-2009, 06:02 AM
#17
Burning Brakes
Join Date: Apr 2007
Location: University of Denver and Portland, OR
Posts: 1,003
Likes: 0
Received 2 Likes
on
1 Post
Yea well it wont, but the op posted that he is looking for "where the turbo works good at all rpm's. " And boost controlled by tps and rpm would accomplish a lot, without trying to engineer a complex system to work on a 944 engine.
07-14-2009, 10:25 AM
#19
Rainman
Rennlist Member
Rennlist Member
definitely. the long 951 crossover pipe is a big detriment to performance.
FWIW this is what the callaway cars (280HP @ 10psi at 8:1 CR) exhaust mani looks like. high energy exhaust goes straight into the turbo (mounts to the flange on the far left)
FWIW this is what the callaway cars (280HP @ 10psi at 8:1 CR) exhaust mani looks like. high energy exhaust goes straight into the turbo (mounts to the flange on the far left)
07-14-2009, 11:17 AM
#20
Race Car
I have thought long and hard about this myself. The only way I can see it being done is by relocating the turbo. I have seen the VGT's up close and the turbine housing are so big that there is no way they will fit w/o a custom manifold. Controlling them would probably not be too hard, in a crude manor. There is a guy on HMT that has one on a 2.0 mitsu using a diaphram/rod WG to change nozzle angle.
Myself, at this point, I am undecided. I have a 1/2 way done twin/compound charge setup that I can install on the current car and finish up. Or I have been messing around making some items for a compound charge TT setup. Either way it is way custom and use either side of the headlight area.
Myself, at this point, I am undecided. I have a 1/2 way done twin/compound charge setup that I can install on the current car and finish up. Or I have been messing around making some items for a compound charge TT setup. Either way it is way custom and use either side of the headlight area.
07-14-2009, 11:58 AM
#21
Race Car
Thread Starter
I have thought long and hard about this myself. The only way I can see it being done is by relocating the turbo. I have seen the VGT's up close and the turbine housing are so big that there is no way they will fit w/o a custom manifold. Controlling them would probably not be too hard, in a crude manor. There is a guy on HMT that has one on a 2.0 mitsu using a diaphram/rod WG to change nozzle angle.
Myself, at this point, I am undecided. I have a 1/2 way done twin/compound charge setup that I can install on the current car and finish up. Or I have been messing around making some items for a compound charge TT setup. Either way it is way custom and use either side of the headlight area.
Myself, at this point, I am undecided. I have a 1/2 way done twin/compound charge setup that I can install on the current car and finish up. Or I have been messing around making some items for a compound charge TT setup. Either way it is way custom and use either side of the headlight area.
07-14-2009, 12:57 PM
#22
Three Wheelin'
Here's a couple things I have been think about.
#1 Theres got to be a way to get the turbo technology into a 951. They way that 997 tt's are doing it where the turbo works good at all rpm's.
#2 Is it possible to take the 951 motor and put new technology into it. All new top of the line sensors and new computer specially made to go with a new harness. added technology that you see in the new 911's like abs or traction control.
theres got to be a way.
#1 Theres got to be a way to get the turbo technology into a 951. They way that 997 tt's are doing it where the turbo works good at all rpm's.
#2 Is it possible to take the 951 motor and put new technology into it. All new top of the line sensors and new computer specially made to go with a new harness. added technology that you see in the new 911's like abs or traction control.
theres got to be a way.
I've been wondering the same thing (well, not about VGT but along the same lines.) I don't see why the 2.0T in my Audi or the 1.8T in my GTI can make good boost and power at 2000 RPM and pull strong through 5500, yet I have to wait for 3500 in the 951 (and still run out of breath by 5500.) Am wondering what the difference is... small turbine side with a big WG opening, perhaps? *shrug*
VGT was done in the 80s. Look up the '89 Shelby CSX (reworked Dodge Shadow) and '90 Dodge Shelby Daytona. Both were available with VGT on their 2.2L SOHC 4 cylinder. Instant spoolup. Not sure if it was just the lack of electronic processing power and control at the time, but they were VERY sensitive to modifications. Swap in a low restriction muffler and the computer could no longer effectively control the boost. As we know technology and control systems have advanced a LOT in 20 years, I'm sure something like this is probably doable now. I believe the turbo used in the Dodges was a Garrett VNT25.
In theory, and depending on the turbo unit you select, you wouldn't even need a really fancy control system. The vanes can be controlled via a vacuum line just like a WG. Just send full manifold reference to the vanes. It won't be IDEAL (just like sending a reference signal straight to a WG wouldn't be ideal) but it would work. I know there was a company out there a few years ago making bolt-on turbo systems for Harley Davidsons. They used a VGT and just had a manifold signal run to the vanes.
VGT was done in the 80s. Look up the '89 Shelby CSX (reworked Dodge Shadow) and '90 Dodge Shelby Daytona. Both were available with VGT on their 2.2L SOHC 4 cylinder. Instant spoolup. Not sure if it was just the lack of electronic processing power and control at the time, but they were VERY sensitive to modifications. Swap in a low restriction muffler and the computer could no longer effectively control the boost. As we know technology and control systems have advanced a LOT in 20 years, I'm sure something like this is probably doable now. I believe the turbo used in the Dodges was a Garrett VNT25.
In theory, and depending on the turbo unit you select, you wouldn't even need a really fancy control system. The vanes can be controlled via a vacuum line just like a WG. Just send full manifold reference to the vanes. It won't be IDEAL (just like sending a reference signal straight to a WG wouldn't be ideal) but it would work. I know there was a company out there a few years ago making bolt-on turbo systems for Harley Davidsons. They used a VGT and just had a manifold signal run to the vanes.
The main problem with 951s is that the VE of the engine is low, and there is not much that can be done without spending a load of money.
And the pic of the exhaust manifold is a performance version, not stock (the turbo is internally gated)
07-14-2009, 01:20 PM
#23
Pro
Join Date: Jun 2005
Location: Napa Valley, CA
Posts: 589
Likes: 0
Received 0 Likes
on
0 Posts
Ahhh, yes we need high a compression ratio 10:1 engine and direct fuel injection to make it work.
Similar to the dual "charging" turbo + supercharger WV TSI engine:
http://www.youtube.com/watch?v=Pdp5i...elated&search=
now if only some of you smart guys can reverse engineer something like this for the 951
Similar to the dual "charging" turbo + supercharger WV TSI engine:
http://www.youtube.com/watch?v=Pdp5i...elated&search=
now if only some of you smart guys can reverse engineer something like this for the 951
07-14-2009, 06:10 PM
#24
Three Wheelin'
Dual charging really is the only way to get the best of both worlds, its been done on several high hp subarus with huge turbos... the super charger actually aids in spoolup.
I wonder how hard it would be to dual charge a 951? Then we could really get away with a monster sized turbo!
I wonder how hard it would be to dual charge a 951? Then we could really get away with a monster sized turbo!
07-14-2009, 06:46 PM
#25
Nordschleife Master
Twin turbo, or dual charge, would no doubt be cool but from a practical point of view not necessary. With a nice 3.0l setup you really don't feel the need...
07-14-2009, 10:10 PM
#26
Addict
Rennlist Member
Rennlist Member
I would like to save you alot of trouble and time and mention that the inherent lag even with the new Borg-Warner VTG's in the 997 turbos is not much less than a ball-bearing turbo. It has been a big disappointment for 997 turbo owners who have previously owned 996 turbos since there is not a big difference at all. The dyno plot showing full torque at 2100 rpms is a farce. The only way to produce that is using an engine dyno with immense (not of real world) loading from off idle onward. On the road even in 6th gear mashing the throttle from 1k rpms full boost will not come on until well past 2700 rpms.
07-14-2009, 10:31 PM
#27
Rainman
Rennlist Member
Rennlist Member
Ahhh, yes we need high a compression ratio 10:1 engine and direct fuel injection to make it work.
Similar to the dual "charging" turbo + supercharger WV TSI engine:
http://www.youtube.com/watch?v=Pdp5i...elated&search=
now if only some of you smart guys can reverse engineer something like this for the 951
Similar to the dual "charging" turbo + supercharger WV TSI engine:
http://www.youtube.com/watch?v=Pdp5i...elated&search=
now if only some of you smart guys can reverse engineer something like this for the 951
by a guy in colorado who buys alcohol 20 gallons at a time and goes through it in a week...and its not to keep warm in those winters
(hint hes on this page!)
07-14-2009, 10:49 PM
#28
Drifting
Motorsport in SLC has done a few VGT on 951 cars. Send me a PM if you are interested in a contact. It's not cheap, but neither were the original Garrett turbo setups for our cars.
George
George
Here's a couple things I have been think about.
#1 Theres got to be a way to get the turbo technology into a 951. They way that 997 tt's are doing it where the turbo works good at all rpm's.
#2 Is it possible to take the 951 motor and put new technology into it. All new top of the line sensors and new computer specially made to go with a new harness. added technology that you see in the new 911's like abs or traction control.
theres got to be a way.
#1 Theres got to be a way to get the turbo technology into a 951. They way that 997 tt's are doing it where the turbo works good at all rpm's.
#2 Is it possible to take the 951 motor and put new technology into it. All new top of the line sensors and new computer specially made to go with a new harness. added technology that you see in the new 911's like abs or traction control.
theres got to be a way.
07-15-2009, 08:54 AM
#29
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Just get an exceptionally well bored head, and make sure you have ZERO exhaust leaks, between the head and the turbo...or build a 3.0. eclou pretty much debunked the rest.
07-15-2009, 11:33 AM
#30
Rainman
Rennlist Member
Rennlist Member
I would like to save you alot of trouble and time and mention that the inherent lag even with the new Borg-Warner VTG's in the 997 turbos is not much less than a ball-bearing turbo. It has been a big disappointment for 997 turbo owners who have previously owned 996 turbos since there is not a big difference at all. The dyno plot showing full torque at 2100 rpms is a farce. The only way to produce that is using an engine dyno with immense (not of real world) loading from off idle onward. On the road even in 6th gear mashing the throttle from 1k rpms full boost will not come on until well past 2700 rpms.
