Turbo
09-06-2005, 11:24 PM
#31
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Originally Posted by special tool
Tony - I think you need to go to school. 
I'll give you a headstart, and if you have enough time to read my license plate when I blow your doors off - you win.
I'll give you a headstart, and if you have enough time to read my license plate when I blow your doors off - you win.
well look at all the turbo stuff that comes out of the wood work all of a sudden
I got a ride in a Powerhaus built turbo last year...
this is the fastest car i have ever been in. Full interior, stereo and AC
You can give me all the head start you want.....you however, get to add 1100lbs though ..you wont catch me then.
09-07-2005, 01:10 AM
#32
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/flame off/ please!! stick to discussion: not better or best.. anything can beat anything else given infinite resource ($$$$). It's the hardware itself and the design that's most interesting - not what is absolutely FASTEST... That's why most of us drive 15-20 year old Porsches over something modern.
09-07-2005, 02:11 AM
#33
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A 928 motor is basically two 944 motors with a common crankshaft - for which an equally turbo charged 928 would be vastly faster than a 944 turbo - presuming the 928 motor can withstand the power output - as it would be basically twice that of the 944 - with an 928 weighing only 10-20% more, depending upon the year model.
Turbos are more energy efficient as they do not consume as much horsepower as a supercharger and there is less weigh having to be moved (less mechanical weight of moving components.)
However, the benefit of a supercharger is that it provides nearly a consistent boost level across the rpm scale - while a turbo's boost increases with rpms (meaning either overboosting and using wastegate and blow-off valve) for lower rpm power - which is inefficient and generates more heat. There also is substantially less "lag" with a supercharger and virtually no over-boosting at shifts.
Racing does tell which is "faster". For drag racing, a supercharger is "faster". For road course work, a turbo is faster.
The other advantage of a supercharger - particularly for a 928 - is simplicity of installation and operation. Kits such as that by 928 Motorsports are a very, very good deal - despite seemingly high price - as it is can be installed by the owner with little to no mechanical experience and is a project easily done in a weekend. However, particularly if modern computer engine management is used and the right system with all the components, the turbo is faster.
The power potentials of turbos has been understood for over 2 decades. The F-1 guys were making over 1,000 horsepower out of 1.5 liter motors on gasoline. Even restricting fuel capacity and setting a maximum boost allowed, the turbo F-1s at 1.5 were increasingly so fast (and lightweight) that turbos were banned.
Superchargers consume require more and more horsepower to make more boost. 700 cubic inch AA fuel drag motors now make as much as 6,000 horsepower (on very potent and exotic fuels) - and the supercharger requires as much as 900 horsepower from those motors.
The "best" would be a supercharger/turbo combination - with the supercharger establishing a consistent boost (relative compression) of a low compression motor, with the turbo being the kick-in-the-*** in upper mid to high rpm range. Actually, I would like to build that motor off my single turbo 928 motor, but it would take a positive displacement blower on top - meaning a custom intake (that is not cheap).
Except for the 928, basically ever VERY fast Porsche for it's model year has been turbocharged. I don't think Porsche ever made a supercharged car, did they?
While a 928 can drag race, that is not what they were built for. Turbos are not the choice for drag racing and putting a turbo or turbos on a 928 is not easily done.
I read my first Turbocharger book in the very early 70s and turbo Corvair folks were making big horsepower in lightweight cars. I still do not know how to read a "turbo map" and, for me, there is no such thing as simple algebra.
The turbo from the Volvo truck probably is too large - or maybe not - a lot of factors go into turbo size selection and housing size does not actually define the boosting factors of a turbo of itself. It also has to do with the relative ratios between the exhaust side and the compressor side. Generally, big turbos make low boost if too big for the motor, but too small a turbo(s) will over rev and fry the bearings.
He is very correct that replacing the turbo if necessary is the easiest part of any turbo project, nor that expensive (used decent turbos are a couple hundred dollars). If in doubt, he is better being too large than too small a turbo. Too small a turbo would build massive boost levels that could damage the motor before the turbo fried. A boost pressure gauge will tell him what boost he is making when done.
Obviously he is really going at it seriously, I admire his effort and enthusiasm, and wish him the best. Hopefully, he has increased the size of his injectors and possibly fuel pump upgrade so he does not burn up the motor being too oxygen rich.
Mark
Turbos are more energy efficient as they do not consume as much horsepower as a supercharger and there is less weigh having to be moved (less mechanical weight of moving components.)
However, the benefit of a supercharger is that it provides nearly a consistent boost level across the rpm scale - while a turbo's boost increases with rpms (meaning either overboosting and using wastegate and blow-off valve) for lower rpm power - which is inefficient and generates more heat. There also is substantially less "lag" with a supercharger and virtually no over-boosting at shifts.
Racing does tell which is "faster". For drag racing, a supercharger is "faster". For road course work, a turbo is faster.
The other advantage of a supercharger - particularly for a 928 - is simplicity of installation and operation. Kits such as that by 928 Motorsports are a very, very good deal - despite seemingly high price - as it is can be installed by the owner with little to no mechanical experience and is a project easily done in a weekend. However, particularly if modern computer engine management is used and the right system with all the components, the turbo is faster.
The power potentials of turbos has been understood for over 2 decades. The F-1 guys were making over 1,000 horsepower out of 1.5 liter motors on gasoline. Even restricting fuel capacity and setting a maximum boost allowed, the turbo F-1s at 1.5 were increasingly so fast (and lightweight) that turbos were banned.
Superchargers consume require more and more horsepower to make more boost. 700 cubic inch AA fuel drag motors now make as much as 6,000 horsepower (on very potent and exotic fuels) - and the supercharger requires as much as 900 horsepower from those motors.
The "best" would be a supercharger/turbo combination - with the supercharger establishing a consistent boost (relative compression) of a low compression motor, with the turbo being the kick-in-the-*** in upper mid to high rpm range. Actually, I would like to build that motor off my single turbo 928 motor, but it would take a positive displacement blower on top - meaning a custom intake (that is not cheap).
Except for the 928, basically ever VERY fast Porsche for it's model year has been turbocharged. I don't think Porsche ever made a supercharged car, did they?
While a 928 can drag race, that is not what they were built for. Turbos are not the choice for drag racing and putting a turbo or turbos on a 928 is not easily done.
I read my first Turbocharger book in the very early 70s and turbo Corvair folks were making big horsepower in lightweight cars. I still do not know how to read a "turbo map" and, for me, there is no such thing as simple algebra.
The turbo from the Volvo truck probably is too large - or maybe not - a lot of factors go into turbo size selection and housing size does not actually define the boosting factors of a turbo of itself. It also has to do with the relative ratios between the exhaust side and the compressor side. Generally, big turbos make low boost if too big for the motor, but too small a turbo(s) will over rev and fry the bearings.
He is very correct that replacing the turbo if necessary is the easiest part of any turbo project, nor that expensive (used decent turbos are a couple hundred dollars). If in doubt, he is better being too large than too small a turbo. Too small a turbo would build massive boost levels that could damage the motor before the turbo fried. A boost pressure gauge will tell him what boost he is making when done.
Obviously he is really going at it seriously, I admire his effort and enthusiasm, and wish him the best. Hopefully, he has increased the size of his injectors and possibly fuel pump upgrade so he does not burn up the motor being too oxygen rich.
Mark
09-07-2005, 04:10 AM
#34
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Originally Posted by DFWX
A 928 motor is basically two 944 motors with a common crankshaft - for which an equally turbo charged 928 would be vastly faster than a 944 turbo - presuming the 928 motor can withstand the power output - as it would be basically twice that of the 944 - with an 928 weighing only 10-20% more, depending upon the year model.
I think turbos are better because you can tune them to reduce lag, have a broad torque curve, and have a great top end. They're also more efficient. A supercharger is either great for the top end (centrifugals) or bottom end (roots or twinscrew). Due to the fact that supercharger performance is linked directly to engine speed limits them.
09-07-2005, 07:32 AM
#35
Tony - that's Joe's car (3 liter, 16 valve). I asked him to let me work on it - put Vitesse controls and install a turbo designed after 1970. He has a triple K turbo on there still!!!
I believe his car could make 600 RWHP with more modern equipment......
I believe his car could make 600 RWHP with more modern equipment......
09-07-2005, 11:48 AM
#36
"Racing does tell which is "faster". For drag racing, a supercharger is "faster". For road course work, a turbo is faster. "
Actually, that's not the case either.
Turbos are banned from NHRA top fuel classes because they give an unfair advantadge(An 8-71 roots blower such as those used in Top Fuel takes as much as 800hp- or approx 10% of the total engine output- to run at redline!)
An auto-trans turbo car with a sufficient stall speed will blow the doors off an otherwise identical SC car with equal boost level any day of the week in a drag race.
Turbos work best with A/Ts for drag racing. Manual trans and turbos do not work so well together for drag racing because you can't stage under boost.
BTW, the turbo Gulipien is using should EASILY deliver over 1000hp if the fuel system is up to the task. That is a truly massive unit.
Actually, that's not the case either.
Turbos are banned from NHRA top fuel classes because they give an unfair advantadge(An 8-71 roots blower such as those used in Top Fuel takes as much as 800hp- or approx 10% of the total engine output- to run at redline!)
An auto-trans turbo car with a sufficient stall speed will blow the doors off an otherwise identical SC car with equal boost level any day of the week in a drag race.
Turbos work best with A/Ts for drag racing. Manual trans and turbos do not work so well together for drag racing because you can't stage under boost.
BTW, the turbo Gulipien is using should EASILY deliver over 1000hp if the fuel system is up to the task. That is a truly massive unit.
09-07-2005, 11:51 AM
#37
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the powerhaus car is impressive..at a reasonable 16.6psi as well....but with a TO5 turbo, I wonder how the bottom end torque, & how the cars driveability is affected? I do like the 180hp/liter it gets....so even a stock 5.0L 928 would be 900hp...or 1170hp for 6.5L!
Brian
Brian
09-07-2005, 12:09 PM
#38
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Originally Posted by DFWX
The power potentials of turbos has been understood for over 2 decades. The F-1 guys were making over 1,000 horsepower out of 1.5 liter motors on gasoline. Even restricting fuel capacity and setting a maximum boost allowed, the turbo F-1s at 1.5 were increasingly so fast (and lightweight) that turbos were banned.
Mark
09-07-2005, 12:11 PM
#39
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Originally Posted by fraggle
/flame off/ please!! stick to discussion: not better or best.. anything can beat anything else given infinite resource ($$$$). It's the hardware itself and the design that's most interesting - not what is absolutely FASTEST... That's why most of us drive 15-20 year old Porsches over something modern.
Where do most 928s get there turbo inovations and ideas from anyway? Other turbo cars.
Perhaps when they are up and runnign the boost curves and power delivery can be compared to the above chart i posted. There, on topic enough for you.
09-07-2005, 12:12 PM
#40
"Interstingly enough within 1 year they were going faster with alot less HP. Probably because the cars were easier to drive and had better throttle response."
And active suspensions.
And active suspensions.
09-07-2005, 12:17 PM
#41
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Originally Posted by special tool
Tony - that's Joe's car (3 liter, 16 valve). I asked him to let me work on it - put Vitesse controls and install a turbo designed after 1970. He has a triple K turbo on there still!!!
I believe his car could make 600 RWHP with more modern equipment......
I believe his car could make 600 RWHP with more modern equipment......
Yup, Joe C. Myself and another 928 guy met up with him, heck almost 2 years ago now. Really nice guy. I think he had just gotten the car done...it never sees rain and he keeps it immaculate. I have never seen a speedometer increase at the rate this one did....i wasnt sure if i was looking at the tach for a moment. We were at 155-160 in no time at all.
Very impressed. Idled like a champ alsl, had a great sound to it when it did.
Looks like any other well cared for 951....pretty stealthy.
09-07-2005, 05:27 PM
#43
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"S4"
Its not a S4 chassie though, its a 928s from -81, less weight I hope.
"Buy a Tec III. I can tell you exactly how to set it up. Its expensive though."
Ok, Im interested.
How much and where is a good place to buy it from? Wich extras do I need so I can afford it (or not). I been thinking on/off about new ecu/ezk before but up to now thought it was to hard/expensive.
"Sent them"
Please try again...didnt receive any.
Large injectors, got it, fuelpump, soon - got zeitronix kit aswell to really know.
/Jonas
Its not a S4 chassie though, its a 928s from -81, less weight I hope.
"Buy a Tec III. I can tell you exactly how to set it up. Its expensive though."
Ok, Im interested.
How much and where is a good place to buy it from? Wich extras do I need so I can afford it (or not). I been thinking on/off about new ecu/ezk before but up to now thought it was to hard/expensive."Sent them"
Please try again...didnt receive any.
Large injectors, got it, fuelpump, soon - got zeitronix kit aswell to really know.
/Jonas
09-07-2005, 05:39 PM
#45
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"S4"
Its not a S4 chassie though, its a 928s from -81, less weight I hope.
Ohhh.
"Buy a Tec III. I can tell you exactly how to set it up. Its expensive though."
Ok, Im interested. How much and where is a good place to buy it from? Wich extras do I need so I can afford it (or not). I been thinking on/off about new ecu/ezk before but up to now thought it was to hard/expensive.
Electromotive and about $2500 roughly. Once the fuel side was set up and the crank trigger was set up it took me about 6 hours to install the last one I bought. Not too bad. It takes about 6 sensors. I assume that your engine has some sort of 0v - something v tps. Thats difficult too.
"Sent them"
Please try again...didnt receive any.
Yeah, I had someone else PM me with turbo comments and I thought that was you. Pm with with your email address.
Large injectors, got it, fuelpump, soon - got zeitronix kit aswell to really know.
You might need dual staged fuel pumps. I think the limit is about 400 hp for a single. If you are going to keep it around there you should be okay.
/Jonas[/QUOTE]
Its not a S4 chassie though, its a 928s from -81, less weight I hope.
Ohhh.
"Buy a Tec III. I can tell you exactly how to set it up. Its expensive though."
Ok, Im interested.
How much and where is a good place to buy it from? Wich extras do I need so I can afford it (or not). I been thinking on/off about new ecu/ezk before but up to now thought it was to hard/expensive.Electromotive and about $2500 roughly. Once the fuel side was set up and the crank trigger was set up it took me about 6 hours to install the last one I bought. Not too bad. It takes about 6 sensors. I assume that your engine has some sort of 0v - something v tps. Thats difficult too.
"Sent them"
Please try again...didnt receive any.
Yeah, I had someone else PM me with turbo comments and I thought that was you. Pm with with your email address.
Large injectors, got it, fuelpump, soon - got zeitronix kit aswell to really know.
You might need dual staged fuel pumps. I think the limit is about 400 hp for a single. If you are going to keep it around there you should be okay.
/Jonas
[/QUOTE]