Supercharger vs. Turbo
02-13-2005, 12:27 PM
#31
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A positive displacement blower basically takes your torque curve and bumps it up maintaining the basic characteristics and usually providing huge low speed torque. Translated into driving, you get a feeling of big thrust without winding up the motor. Modded turbo cars like mine on the other hand give you that big slug of torque one the turbo spools and have basically nothing low down. Most love this characteristic of 'all hell breaking loose'. Take a look at the torque curve for this 928 S4 with a twinscrew blower on it, notice the massive torque just off idle. ~400 ft.lb just off idle which is more that most modded 951's make on-song.......FUN!
http://www.928supermodel.com/album/i...p?object_id=72
This car would feel like a moster to drive. Notice how it keeps the torque curve flat all the way out to 5,500rpm. For a street car, thats exactly what you want.
You really need a good candidate for a blower conversion. 928's are great as they hell for stout with a reasonable compression ratio. They are already are torquey and the blower enhances this. A smaller NA motor like a 944 will benefit, but nothing that will floor you unless you got crazy with a S2/968 etc. My 3.6 C2 used to knock a litte as it was such high comp to start with and I used the less efficient Eaton blower with no intercooler. You had to retard timing too much and the torque used taper off up top.
Compared to my 951, my old SC's 3.6 911 would not stand a chance, while it was fun, the 951 would dust it once you get it in the powerband (keep the rpms up). The 3.6 felt like an american V8 with steering and brakes, but funnily enough, I enjoyed it a lot better than any 951/S2 I have owned. I am currenty looking into getting a 928 S4 and bolting on a blower as my next project.
http://www.928supermodel.com/album/i...p?object_id=72
This car would feel like a moster to drive. Notice how it keeps the torque curve flat all the way out to 5,500rpm. For a street car, thats exactly what you want.
You really need a good candidate for a blower conversion. 928's are great as they hell for stout with a reasonable compression ratio. They are already are torquey and the blower enhances this. A smaller NA motor like a 944 will benefit, but nothing that will floor you unless you got crazy with a S2/968 etc. My 3.6 C2 used to knock a litte as it was such high comp to start with and I used the less efficient Eaton blower with no intercooler. You had to retard timing too much and the torque used taper off up top.
Compared to my 951, my old SC's 3.6 911 would not stand a chance, while it was fun, the 951 would dust it once you get it in the powerband (keep the rpms up). The 3.6 felt like an american V8 with steering and brakes, but funnily enough, I enjoyed it a lot better than any 951/S2 I have owned. I am currenty looking into getting a 928 S4 and bolting on a blower as my next project.
02-13-2005, 05:08 PM
#32
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Originally Posted by J Chen
It's a 400 hp 944s2 . Opcon Autorotor installed one with
Laminova air to water intercooler. Search their website.
You may be able to find it.
Laminova air to water intercooler. Search their website.
You may be able to find it.
02-13-2005, 05:10 PM
#33
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so it seems to me that the turbos are better for track with longer periods of track between shifts and that a eaton or twin screw sc would be best for around town or autocross...
Originally Posted by B951S
A positive displacement blower basically takes your torque curve and bumps it up maintaining the basic characteristics and usually providing huge low speed torque. Translated into driving, you get a feeling of big thrust without winding up the motor. Modded turbo cars like mine on the other hand give you that big slug of torque one the turbo spools and have basically nothing low down. Most love this characteristic of 'all hell breaking loose'. Take a look at the torque curve for this 928 S4 with a twinscrew blower on it, notice the massive torque just off idle. ~400 ft.lb just off idle which is more that most modded 951's make on-song.......FUN!
http://www.928supermodel.com/album/i...p?object_id=72
This car would feel like a moster to drive. Notice how it keeps the torque curve flat all the way out to 5,500rpm. For a street car, thats exactly what you want.
You really need a good candidate for a blower conversion. 928's are great as they hell for stout with a reasonable compression ratio. They are already are torquey and the blower enhances this. A smaller NA motor like a 944 will benefit, but nothing that will floor you unless you got crazy with a S2/968 etc. My 3.6 C2 used to knock a litte as it was such high comp to start with and I used the less efficient Eaton blower with no intercooler. You had to retard timing too much and the torque used taper off up top.
Compared to my 951, my old SC's 3.6 911 would not stand a chance, while it was fun, the 951 would dust it once you get it in the powerband (keep the rpms up). The 3.6 felt like an american V8 with steering and brakes, but funnily enough, I enjoyed it a lot better than any 951/S2 I have owned. I am currenty looking into getting a 928 S4 and bolting on a blower as my next project.
http://www.928supermodel.com/album/i...p?object_id=72
This car would feel like a moster to drive. Notice how it keeps the torque curve flat all the way out to 5,500rpm. For a street car, thats exactly what you want.
You really need a good candidate for a blower conversion. 928's are great as they hell for stout with a reasonable compression ratio. They are already are torquey and the blower enhances this. A smaller NA motor like a 944 will benefit, but nothing that will floor you unless you got crazy with a S2/968 etc. My 3.6 C2 used to knock a litte as it was such high comp to start with and I used the less efficient Eaton blower with no intercooler. You had to retard timing too much and the torque used taper off up top.
Compared to my 951, my old SC's 3.6 911 would not stand a chance, while it was fun, the 951 would dust it once you get it in the powerband (keep the rpms up). The 3.6 felt like an american V8 with steering and brakes, but funnily enough, I enjoyed it a lot better than any 951/S2 I have owned. I am currenty looking into getting a 928 S4 and bolting on a blower as my next project.
02-13-2005, 11:55 PM
#34
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Originally Posted by 944J
so it seems to me that the turbos are better for track with longer periods of track between shifts and that a eaton or twin screw sc would be best for around town or autocross...
02-14-2005, 10:48 AM
#37
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It seems superchargers don't produce more than 10 PSI or so. Why is this a limitation? Why can't a blower produce 20+ PSI like a Turbo. It would seem that if that were possible then a SC would be the way to go over a turbo.
02-14-2005, 11:05 AM
#38
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Where on earth did you hera that Superchargers
can't produce more that 10 psi ? If you let the
Hot Rodders here this, you get smack in the face.
The reason you see most install running under
10 psi is mainly due to the fact that most SC
install are done on N.A engines which run higher
compression to begin with. With a correctly sized
SC theres no reason that you can't run much higher
boost on a low compression engine.
can't produce more that 10 psi ? If you let the
Hot Rodders here this, you get smack in the face.
The reason you see most install running under
10 psi is mainly due to the fact that most SC
install are done on N.A engines which run higher
compression to begin with. With a correctly sized
SC theres no reason that you can't run much higher
boost on a low compression engine.
02-14-2005, 12:48 PM
#39
Rennlist Member
Originally Posted by Re-animator
Yup, which is why Porsche ran their turbo 951 motored (GTP) with a "one of" head in LeMans 1981. It won an award for least time in the pits. Re-fuelling and tires only was all it needed. The jury is still out on longevity of NA belt drivin supercharging. Using only an FMU is not that comforting in this technocratic age. Food for thought.
I guess once you consider that the average guy probably won't apprciate the advantages a turbo presents for endurance racing / events, a blower starts looking pretty good for steet driving.
02-14-2005, 10:28 PM
#40
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the kennebell.net site has kits for fords with 86%-90% efficient twin screw superchargers that (I think) go up to 24psi with no drop in boost towards the high rpm range... they have a low parasitic loss too...
My Eyes
02-15-2005, 12:50 AM
#43
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SFR's Stage 2 Supercharger intercooled kit for the S2 makes 268 ft-lbs of peak torque at 7 psi. I think a stock 951 makes peak torque of 258 @ the crank. Kind of makes one wonder if aftermarket belt driven or factory exhaust driven superchargers are better regarding the 951. For the cost of a good chipset, a 951 can surely make more torque at the wheel with a fatter curve. 
"The Level 2 SC kit comes with everything in the level 1 kit and a few extras. The level 2 supercharger system makes even more power with slightly higher boost levels and the use of a factory 951 intercooler. The intercooler will help combat intake temperatures from soaring to dangerous levels. It will also add horsepower since it will lower the charge air temp over 100 degrees! Boost will now be set at 7 psi. Adding an intercooler increases the reliability and performance of this supercharger system which ultimately leads to years of trouble free operation.
This supercharger kit looks like it came from the factory! It uses the stock intake manifold so your car remains factory looking. This supercharger installation does not require the removal of your intake manifold either! You also get your choice of 304 stainless or 6061 aluminum intake and intercooler piping. The pictures have aluminum piping. You can also get your parts polished or powder coated (for an additional charge). Installation time is about 6 hours. This system has been dyno proven to deliver 270 horsepower and 263 ft/lbs of torque at the wheels."
http://www.speedforceracing.com/prod...hargers_s2.php
"The Level 2 SC kit comes with everything in the level 1 kit and a few extras. The level 2 supercharger system makes even more power with slightly higher boost levels and the use of a factory 951 intercooler. The intercooler will help combat intake temperatures from soaring to dangerous levels. It will also add horsepower since it will lower the charge air temp over 100 degrees! Boost will now be set at 7 psi. Adding an intercooler increases the reliability and performance of this supercharger system which ultimately leads to years of trouble free operation.
This supercharger kit looks like it came from the factory! It uses the stock intake manifold so your car remains factory looking. This supercharger installation does not require the removal of your intake manifold either! You also get your choice of 304 stainless or 6061 aluminum intake and intercooler piping. The pictures have aluminum piping. You can also get your parts polished or powder coated (for an additional charge). Installation time is about 6 hours. This system has been dyno proven to deliver 270 horsepower and 263 ft/lbs of torque at the wheels."
http://www.speedforceracing.com/prod...hargers_s2.php
02-15-2005, 06:41 AM
#44
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Hey Guys,
I found the copy of a 400hp SC install on a 944S2.
It's not very clear. Does anyone have a photoshop ?
Maybe you could make it clearer & post it here for
every one to see. Oh pls enclose you e-mail address.
Thanks
I found the copy of a 400hp SC install on a 944S2.
It's not very clear. Does anyone have a photoshop ?
Maybe you could make it clearer & post it here for
every one to see. Oh pls enclose you e-mail address.
Thanks
02-15-2005, 07:55 PM
#45
Rennlist Member
hotpinkporsche,
you must be of the female persuasion
It's just like out in the bars; the women never come out and introduce themselves. The guys always have to do all the work and say hello.
you must be of the female persuasion
It's just like out in the bars; the women never come out and introduce themselves. The guys always have to do all the work and say hello.
