Who is serious about twin turbocharging their 928?
10-01-2004, 07:00 PM
#31
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Just a thought, but did the magical cost of $9280 have anything to do with the 928?
Chris--my understanding of sequential boost had to do with a smaller turbo building manifold pressure and therefor additional exhaust gas to turn the larger turbo's impeller. Incidently, the Porsche 959 is a sequential bi-turbo as I recall. 415 DIN HP out of a 2.8L flat-six...yes please!
John...- I am looking forward to seeing the dyno tuning results. Please post them as soon as possible. However, no need to rush, I need as much time as possible to save up the $$$ for one of your kits. I expect to see amazing things.
As for 951s pushing extreme HP, I read about one once. Total custom job, lots of $$$, not streetable at all, mega-boost, and so on. I guess it's nice, but having the power to use and using the power you have are two totally different animals. I suspect that John's kit will satisfy most anyone's need for speed in a streetable, well-mannered vehicle. Heck, we're talkin' twice the freakin' HP here folks, that's no small thing when you get right down to it.
Chris--my understanding of sequential boost had to do with a smaller turbo building manifold pressure and therefor additional exhaust gas to turn the larger turbo's impeller. Incidently, the Porsche 959 is a sequential bi-turbo as I recall. 415 DIN HP out of a 2.8L flat-six...yes please!
John...- I am looking forward to seeing the dyno tuning results. Please post them as soon as possible. However, no need to rush, I need as much time as possible to save up the $$$ for one of your kits. I expect to see amazing things.
As for 951s pushing extreme HP, I read about one once. Total custom job, lots of $$$, not streetable at all, mega-boost, and so on. I guess it's nice, but having the power to use and using the power you have are two totally different animals. I suspect that John's kit will satisfy most anyone's need for speed in a streetable, well-mannered vehicle. Heck, we're talkin' twice the freakin' HP here folks, that's no small thing when you get right down to it.
10-01-2004, 07:24 PM
#32
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Oh Heinrich,
FWIW, As the HP number for the Devek Car was RWHP on a 5spd 6.5L stroker. Assuming 17% driveline losses, the Crank HP would be about 670HP. In addition, Bob De Vore (DEV) and Lucky Ekman (EK) (DEVEK) built a 701 HP 2 valve Turbocharged car many years ago.. I have never been in it, but I can only imagine what it might have been like with the White Car as a baseline...
Louie Ott mentions on another thread that they knocked back the timing to keep the torque around 500 Ft/Lb to avoid creaming the drivetrain..... The motor has more in it, I am pretty certain..
Cheers,
FWIW, As the HP number for the Devek Car was RWHP on a 5spd 6.5L stroker. Assuming 17% driveline losses, the Crank HP would be about 670HP. In addition, Bob De Vore (DEV) and Lucky Ekman (EK) (DEVEK) built a 701 HP 2 valve Turbocharged car many years ago.. I have never been in it, but I can only imagine what it might have been like with the White Car as a baseline...
Louie Ott mentions on another thread that they knocked back the timing to keep the torque around 500 Ft/Lb to avoid creaming the drivetrain..... The motor has more in it, I am pretty certain..
Cheers,
10-01-2004, 08:13 PM
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Tim,
You're right, the 959 did have a sequential setup. It was (and is IMO) needlessly complex. Even Porsche abadonded it on the 911. Today's turbo's are so much better designed and efficient, work-arounds such as this are no longer neccessary for a streetable setup.
Your understanding of the seq. setup is correct. I didn't explain properly. The inital exhaust pulses are sent to the smaller of the 2 first, once a pre-determined threshold has been met (say 5psi), a check-valve or bypass opens which now feeds BOTH turbo's.
Again, on a v-type motor, I just don't see how this is realistically feasible... especially under the hood of a 928
You're right, the 959 did have a sequential setup. It was (and is IMO) needlessly complex. Even Porsche abadonded it on the 911. Today's turbo's are so much better designed and efficient, work-arounds such as this are no longer neccessary for a streetable setup.
Your understanding of the seq. setup is correct. I didn't explain properly. The inital exhaust pulses are sent to the smaller of the 2 first, once a pre-determined threshold has been met (say 5psi), a check-valve or bypass opens which now feeds BOTH turbo's.
Again, on a v-type motor, I just don't see how this is realistically feasible... especially under the hood of a 928
10-01-2004, 08:47 PM
#34
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All you need is a cutting wheel and some imagination....just kidding.
Richard- do Mr. Devore and Mr. Ekman still have the engine specs? I recall they used 944(951?) heads. However, I never knew it was turbo. 700HP is what I would think a custom tuned TT'd 4.5L V-8 ought to be producing, with more than enough "under the curve." What happened to that car/motor?
Richard- do Mr. Devore and Mr. Ekman still have the engine specs? I recall they used 944(951?) heads. However, I never knew it was turbo. 700HP is what I would think a custom tuned TT'd 4.5L V-8 ought to be producing, with more than enough "under the curve." What happened to that car/motor?
10-01-2004, 08:55 PM
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In any case John, how much boost does your proposed system develop? What is the compression ratio of your engine?
And gaskets: I owned a VW Scirocco with a factory-approved turbo system. It accelerated like a bottle rocket, but kept blowing it's downpipe gasket. Not fun...
Oil return: the Scirocco's four cylinder engine was nearly vertical, so oil flow to the pan wasn't an issue. How have you managed to make this work on your 928?
Sounds like a fascinating project! Keep me informed. I've got plenty of extra fuel lying around...
N!
And gaskets: I owned a VW Scirocco with a factory-approved turbo system. It accelerated like a bottle rocket, but kept blowing it's downpipe gasket. Not fun...
Oil return: the Scirocco's four cylinder engine was nearly vertical, so oil flow to the pan wasn't an issue. How have you managed to make this work on your 928?
Sounds like a fascinating project! Keep me informed. I've got plenty of extra fuel lying around...
N!
Last edited by Normy; 10-02-2004 at 02:58 AM.
10-01-2004, 09:09 PM
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dyno sheets
Tim,
I am not sure what happened to the car, and I may be incorrect in my statement above that it was a turbo. I just got a PM from someone who claims to have seen the car run, and they claim it was a Naturally Aspirated car. If this is the case, I stand corrected....
The only person who could shed some light on the thing, would be Lucky himself. I know he is still around, as I saw him at DEVEK Days this past August... I am sure Marc and Susan have his number if you want to track him down to find out what he did to the car, or what became of it..
As far as heads, I don't see any reason why a properly prepared 928 motor should not be able to produce 700+ hp..... Emphasis on properly... The David Raines in Arizona are getting 500+ HP from a 2.8L 944Turbo, and also from a 968 3.0L Turbo...... As the 928 is essentially two of these engines, then why would it be such an impossibility is beyond me.
DRIVETRAIN:
BEFORE: AFTER:
CYLINDERS 4 4
BORE 104mm 104mm
STROKE 88mm 88mm
DISPLACEMENT 2990 cc 2990 cc
CAMSHAFTS
Twin Overhead Twin Turbo Profiled
COMPRESSION 11 to 1 8.9 to 1
MAXIMUM POWER
236 @ Flywheel 532 @ Flywheel
208 @ Rear wheels 452.7 @ Rear wheels
MAXIMUM TORQUE
225 @ Flywheel 500 @ Flywheel
191.2 @ Rear wheels 451.2 @ Rear wheels
EXHAUST SYSTEM Mild Steel Free Flow Stainless Steel
6 Speed Manual Transmission, Non Limited Slip Differential
Above from Powerhaus...
Dyno charts attached for viewing from their site...
I am not sure what happened to the car, and I may be incorrect in my statement above that it was a turbo. I just got a PM from someone who claims to have seen the car run, and they claim it was a Naturally Aspirated car. If this is the case, I stand corrected....
The only person who could shed some light on the thing, would be Lucky himself. I know he is still around, as I saw him at DEVEK Days this past August... I am sure Marc and Susan have his number if you want to track him down to find out what he did to the car, or what became of it..
As far as heads, I don't see any reason why a properly prepared 928 motor should not be able to produce 700+ hp..... Emphasis on properly... The David Raines in Arizona are getting 500+ HP from a 2.8L 944Turbo, and also from a 968 3.0L Turbo...... As the 928 is essentially two of these engines, then why would it be such an impossibility is beyond me.
DRIVETRAIN:
BEFORE: AFTER:
CYLINDERS 4 4
BORE 104mm 104mm
STROKE 88mm 88mm
DISPLACEMENT 2990 cc 2990 cc
CAMSHAFTS
Twin Overhead Twin Turbo Profiled
COMPRESSION 11 to 1 8.9 to 1
MAXIMUM POWER
236 @ Flywheel 532 @ Flywheel
208 @ Rear wheels 452.7 @ Rear wheels
MAXIMUM TORQUE
225 @ Flywheel 500 @ Flywheel
191.2 @ Rear wheels 451.2 @ Rear wheels
EXHAUST SYSTEM Mild Steel Free Flow Stainless Steel
6 Speed Manual Transmission, Non Limited Slip Differential
Above from Powerhaus...
Dyno charts attached for viewing from their site...
10-01-2004, 10:08 PM
#37
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Richard,
700rwhp is absolutely do-able! I never stated, nor implied, that it was. It it just going to cost you (or whomever) a LOT of money.
1. We don't have double the displacement of the 968 in the attached graphs. Add a stroker kit.
2. The 928 motor doesn't rev that high, stock anyway. Perhaps with the beefing-up of the stroker it will...
3. Lower compression pistons (as the aforementioned 968 has)... more $$$...
4. An A2W intercooler
5. Some sort of engine management system (and someone to tune it AND the dyno-time)... you wouldn't want to attempt making such power with just bigger injectors and an AFPR would you?
6. 19 psi is a lot of pressure for a motor that wasn't designed for it and without certain safeguards (lower compression pistons, a really good intercooler, and an EMS... just for starters) you would just asking for trouble. I doubt the S/C guys would want to run 19psi either. (manifold pressure is manifold pressure, no matter the source)
Side note (and directed at no one in particular): In the data that was in your last post, I see mentioned hp at the crank. Honestly, who cares? It's all about the power that the car puts to the ground. What's at the crank isn't getting you down the 1/4 any faster.
As the old adage goes, "Speed costs money, how fast do you want to go?"
Again, I never said it was impossible, just far more expensive than the $9280 kit being sold. I bet if we took a look at how much $$$ Mr. 968 spent, it would probably wow a lot of us.
Looking at those graphs again, something is fishy. Horsepower and Torque have a fixed relationship (5252 rpm) and those lines don't cross where they should... I wonder what's going on.
700rwhp is absolutely do-able! I never stated, nor implied, that it was. It it just going to cost you (or whomever) a LOT of money.
1. We don't have double the displacement of the 968 in the attached graphs. Add a stroker kit.
2. The 928 motor doesn't rev that high, stock anyway. Perhaps with the beefing-up of the stroker it will...
3. Lower compression pistons (as the aforementioned 968 has)... more $$$...
4. An A2W intercooler
5. Some sort of engine management system (and someone to tune it AND the dyno-time)... you wouldn't want to attempt making such power with just bigger injectors and an AFPR would you?
6. 19 psi is a lot of pressure for a motor that wasn't designed for it and without certain safeguards (lower compression pistons, a really good intercooler, and an EMS... just for starters) you would just asking for trouble. I doubt the S/C guys would want to run 19psi either. (manifold pressure is manifold pressure, no matter the source)
Side note (and directed at no one in particular): In the data that was in your last post, I see mentioned hp at the crank. Honestly, who cares? It's all about the power that the car puts to the ground. What's at the crank isn't getting you down the 1/4 any faster.
As the old adage goes, "Speed costs money, how fast do you want to go?"
Again, I never said it was impossible, just far more expensive than the $9280 kit being sold. I bet if we took a look at how much $$$ Mr. 968 spent, it would probably wow a lot of us.
Looking at those graphs again, something is fishy. Horsepower and Torque have a fixed relationship (5252 rpm) and those lines don't cross where they should... I wonder what's going on.
10-02-2004, 02:49 AM
#38
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Chris,
My comments were directed to Tim about possibilities, and I think you may have misunderstood my point..
To answer your questions:
1.. I plan on building a 6.0L supercharged stroker, and have said this repeatedly
2..The Dyno charts shown peak at less than 6500rpm, and are RWHP
3.. There are low compression pistons available in non 968 bores for the 928
4.. I have designed an AWIC, for use with my supercharger system, and others have their doubts about its efficiency, and have said Air to Air is more efficient than AWIC. Whether this is the case or not, I prefer my design and use of the AWIC I am going to use after doing my research on available systems.
5.. I am in process of resolving engine mgt issues, and have stated in the past that for the race car I plan on building, I will most likely go to a Motec or Electromotive Tec3
6.. 19psi is not the only measurable or important variable. There are many others, of which density ratio and flow are IMHO more important, and I have always stated this. IMHO, Manifold pressure is not just that.
7..RWHP is only a function of the driveline losses. As far as what gets you down the 1/4, it is of no interest to me, as I am not doing this for a drag race, and there are many other variables to consider besides RWHP. Traction and driver skil play a serious part as well. Power at specific points or rpm are what interest me, as these summed, they equate to the "area under the curve"
With this said, I am building my project to test an idea, and just that. None of the existing vendors, nor any of the current suppliers of 928 high perf systems that I asked when I decided to get involved with this had anything even remotely close to what I have designed, and still do not.
I have spoken to all of them on an individual basis, (except John Kuhn), and we have all compared notes, and all have been helpful. I have also discussed my project with other engine designers and high performance car and aerospace persons.
As far as speed costing money, I am well aware, and for what I plan to do, and have done to date, I could have bought several other cars of various marques. Having owned several other high performance cars, this is someting I have wanted to do for some time.
Further, I have always stated in reference to my project, that it is my money and time, and I can spend it as I wish. I never asked ANYONE to buy any of the products I have designed, and never claimed to be doing this for resale. Others have approached me with offers to buy, and I have told them that I would consider it, but have not decided to sell or not sell any part or equipment as of yet. After I am done with the installation and testing, I will make this decision.
However, if one offers a product for sale anywhere, they should be prepared to answer any and all questions regarding their product. This is common "good business" If it is not construed as such, then so be it, as I have a different philosophy.
In any event, it will be a very expensive option if anyone wanted to buy my system, as it incorporates many parts, and I have upgrades on my list that would make any reasonably sane person ask me if I am "off my rockers." Some of the persons on this forum with whom I have shared the list can attest to this.
To give you an idea, My exhaust system alone costs over 3.5k, the engine radiator costs 1.5k, and the intercooler radiator is from a Reynard Race car made by HM Marston Aerospace (you don't want to know what that goes for, but if you do, call them in england, and they will happily sell you one.) As before, it is not for everyone, just an execution of my idea. If I add my time at a reasonable bill rate for designing, measuring, and research on this stuff, it becomes more ludicrous.
Granted, I am not an engineer, but I also never claimed to be. It does not mean I don't have a phone, and can ask engineers to help me solve my design problems. I wanted to build the best system I know how within the confines of a 928 S4.
FYI, I have stated that 800RWHP is possible from a 6.0L 928 motor. How? I am too tired to go through all the calculations again.
Oh, something I learned from a guy that is not an engineer. Boost pressure is resistance to flow, and a pound of air is a pound of air no matter if it is 10000 degrees F or 1 Degree F.
Thanks,
My comments were directed to Tim about possibilities, and I think you may have misunderstood my point..
To answer your questions:
1.. I plan on building a 6.0L supercharged stroker, and have said this repeatedly
2..The Dyno charts shown peak at less than 6500rpm, and are RWHP
3.. There are low compression pistons available in non 968 bores for the 928
4.. I have designed an AWIC, for use with my supercharger system, and others have their doubts about its efficiency, and have said Air to Air is more efficient than AWIC. Whether this is the case or not, I prefer my design and use of the AWIC I am going to use after doing my research on available systems.
5.. I am in process of resolving engine mgt issues, and have stated in the past that for the race car I plan on building, I will most likely go to a Motec or Electromotive Tec3
6.. 19psi is not the only measurable or important variable. There are many others, of which density ratio and flow are IMHO more important, and I have always stated this. IMHO, Manifold pressure is not just that.
7..RWHP is only a function of the driveline losses. As far as what gets you down the 1/4, it is of no interest to me, as I am not doing this for a drag race, and there are many other variables to consider besides RWHP. Traction and driver skil play a serious part as well. Power at specific points or rpm are what interest me, as these summed, they equate to the "area under the curve"
With this said, I am building my project to test an idea, and just that. None of the existing vendors, nor any of the current suppliers of 928 high perf systems that I asked when I decided to get involved with this had anything even remotely close to what I have designed, and still do not.
I have spoken to all of them on an individual basis, (except John Kuhn), and we have all compared notes, and all have been helpful. I have also discussed my project with other engine designers and high performance car and aerospace persons.
As far as speed costing money, I am well aware, and for what I plan to do, and have done to date, I could have bought several other cars of various marques. Having owned several other high performance cars, this is someting I have wanted to do for some time.
Further, I have always stated in reference to my project, that it is my money and time, and I can spend it as I wish. I never asked ANYONE to buy any of the products I have designed, and never claimed to be doing this for resale. Others have approached me with offers to buy, and I have told them that I would consider it, but have not decided to sell or not sell any part or equipment as of yet. After I am done with the installation and testing, I will make this decision.
However, if one offers a product for sale anywhere, they should be prepared to answer any and all questions regarding their product. This is common "good business" If it is not construed as such, then so be it, as I have a different philosophy.
In any event, it will be a very expensive option if anyone wanted to buy my system, as it incorporates many parts, and I have upgrades on my list that would make any reasonably sane person ask me if I am "off my rockers." Some of the persons on this forum with whom I have shared the list can attest to this.
To give you an idea, My exhaust system alone costs over 3.5k, the engine radiator costs 1.5k, and the intercooler radiator is from a Reynard Race car made by HM Marston Aerospace (you don't want to know what that goes for, but if you do, call them in england, and they will happily sell you one.) As before, it is not for everyone, just an execution of my idea. If I add my time at a reasonable bill rate for designing, measuring, and research on this stuff, it becomes more ludicrous.
Granted, I am not an engineer, but I also never claimed to be. It does not mean I don't have a phone, and can ask engineers to help me solve my design problems. I wanted to build the best system I know how within the confines of a 928 S4.
FYI, I have stated that 800RWHP is possible from a 6.0L 928 motor. How? I am too tired to go through all the calculations again.
Oh, something I learned from a guy that is not an engineer. Boost pressure is resistance to flow, and a pound of air is a pound of air no matter if it is 10000 degrees F or 1 Degree F.
Thanks,
10-02-2004, 11:20 AM
#39
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For the sake of all on hand, and more vilification of Johns system, the UberTurbo conversion for the 968 runs about $19K from Powerhaus. I have contacted them in the past about a 928 Twin Turbo and they gave me a ballpark price of approximatley $22-23K based on using a 5.0L short block and their custom pistons (low compression). Power was expected to be in the 600 RWHP range.
Very impressive, but a bit unreal. Johns kit might actually happen for me if the periphary interst is high enough. Or I get the $$$ to buy the prototype.
Very impressive, but a bit unreal. Johns kit might actually happen for me if the periphary interst is high enough. Or I get the $$$ to buy the prototype.
10-04-2004, 01:24 PM
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Oh, you can have the Goldmember.... for a fee. It will be for sale by the start of the year. The only question is will it be a one of a kind, or one of several? Realistically, I wanted to get 4 or 5 of them built to get my name on the map, then move forward. The issue is people will drop more $ on a 911 than a 928, that is just the way it is.
As I have said before the next version will be 5.0 liter based, but this might be a long way off for me. I am still kicking myself for passing up the car I could have purchased last year. I think with the S4 heads and combustion chamber and proper CR you could push quite a bit of boost into the engine and be fine.
I thought I would get my short block assembled this weekend, but my piston and alignment pins didn't make it home with the block. The block does look like a work of art, the bores are just perfect, even better then last years example.
Hey, once we all have these blown cars we should call European Car for a U-Boat shootout. I'm sure they would be game.
As I have said before the next version will be 5.0 liter based, but this might be a long way off for me. I am still kicking myself for passing up the car I could have purchased last year. I think with the S4 heads and combustion chamber and proper CR you could push quite a bit of boost into the engine and be fine.
I thought I would get my short block assembled this weekend, but my piston and alignment pins didn't make it home with the block. The block does look like a work of art, the bores are just perfect, even better then last years example.
Hey, once we all have these blown cars we should call European Car for a U-Boat shootout. I'm sure they would be game.