Turbo vs. S/C
Rocket Pilot
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From: gettysburg pa.
Originally Posted by Bill Ball
Yep, Kevin, the right tools make a big difference - Gearwrench saved a ton of time in this case.
Enjoy!
Enjoy!
Under the Lift
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From: Buckeye, AZ
Wait until you do the pan gasket. There is no F'ing way to remove several of the almost hidden bolts w/o a Gearwrench. It took me 35 minutes to remove a couple of the bolts turning a face at a time with an open end wrench. Gearwrench had them off in 35 seconds.
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How is the problem of denotation on pump gas addressed in an SC motor already running 10-1 compression - particularly without intercooling? What is the max boost possible?
Denotation (pre-ignition) may not seem to cause any short term problems, the the millions of stress cracks kill motor life spans. How do you SC guys run a supercharger on pump gas in your 10-1 S3s and S4s?
Mark O
Denotation (pre-ignition) may not seem to cause any short term problems, the the millions of stress cracks kill motor life spans. How do you SC guys run a supercharger on pump gas in your 10-1 S3s and S4s?
Mark O
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From: Ft. Lauderdale FLORIDA
Originally Posted by DFWX
How is the problem of denotation on pump gas addressed in an SC motor already running 10-1 compression - particularly without intercooling? What is the max boost possible?
Denotation (pre-ignition) may not seem to cause any short term problems, the the millions of stress cracks kill motor life spans. How do you SC guys run a supercharger on pump gas in your 10-1 S3s and S4s?
Mark O
Denotation (pre-ignition) may not seem to cause any short term problems, the the millions of stress cracks kill motor life spans. How do you SC guys run a supercharger on pump gas in your 10-1 S3s and S4s?
Mark O
Read Corky Bell's book on Turbocharging or his othe book about supercharging for the exact formulas, but my S2 with 10.4:1 compression could only do 5 psi with these calculations at best, and this low boost means too low HP for the coin....though 928 Specialists is developing a good kit for these cars, along with Mark Robinson out in Austin. Stay tuned.
Your car? www.928gt.com has your supercharger kit. I suggest you read Andrew Olson's threads to see how much fun this particular "personal roller coaster" can actually be.
N!
Burning Brakes
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From: Portland, Oregon
Have fun with the IC debate, LarryGTS would have you believe an IC is not needed 
I don't think the S4's actually measure out at 10:1, as I recall it's more like 9.5:1.
The pentroof design is boost friendly, also.
I don't think the S4's actually measure out at 10:1, as I recall it's more like 9.5:1.
The pentroof design is boost friendly, also.
Originally Posted by Normy
Yes you need intercooling to run any significant boost with 10:1 compression!
Read Corky Bell's book on Turbocharging or his othe book about supercharging for the exact formulas, but my S2 with 10.4:1 compression could only do 5 psi with these calculations at best, and this low boost means too low HP for the coin....though 928 Specialists is developing a good kit for these cars, along with Mark Robinson out in Austin. Stay tuned.
Your car? www.928gt.com has your supercharger kit. I suggest you read Andrew Olson's threads to see how much fun this particular "personal roller coaster" can actually be.
N!
Read Corky Bell's book on Turbocharging or his othe book about supercharging for the exact formulas, but my S2 with 10.4:1 compression could only do 5 psi with these calculations at best, and this low boost means too low HP for the coin....though 928 Specialists is developing a good kit for these cars, along with Mark Robinson out in Austin. Stay tuned.
Your car? www.928gt.com has your supercharger kit. I suggest you read Andrew Olson's threads to see how much fun this particular "personal roller coaster" can actually be.
N!
Last edited by pmotts; Jul 19, 2006 at 01:43 AM.
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From: Green Bay Wisconsin
Originally Posted by Normy
Yes you need intercooling to run any significant boost with 10:1 compression!
Read Corky Bell's book on Turbocharging or his othe book about supercharging for the exact formulas, but my S2 with 10.4:1 compression could only do 5 psi with these calculations at best, and this low boost means too low HP for the coin....though 928 Specialists is developing a good kit for these cars, along with Mark Robinson out in Austin. Stay tuned.
Your car? www.928gt.com has your supercharger kit. I suggest you read Andrew Olson's threads to see how much fun this particular "personal roller coaster" can actually be.
N!
Read Corky Bell's book on Turbocharging or his othe book about supercharging for the exact formulas, but my S2 with 10.4:1 compression could only do 5 psi with these calculations at best, and this low boost means too low HP for the coin....though 928 Specialists is developing a good kit for these cars, along with Mark Robinson out in Austin. Stay tuned.
Your car? www.928gt.com has your supercharger kit. I suggest you read Andrew Olson's threads to see how much fun this particular "personal roller coaster" can actually be.
N!
From vortech's website in the FAQ section:
26. Why don't Vortech superchargers need an Aftercooler or an intercooler?
Vortech Engineering, LLC has conducted extensive testing of most intercoolers/aftercoolers currently on the market. Test results indicate that for street driven purposes below 8-9 PSIG, installing an aftercooler has marginal effects when using a Vortech supercharger (due to the high efficiency of the supercharger). Nearly all of the intercoolers/aftercoolers available on the market have poor effectiveness and actually can cause parasitic losses equal to or greater than the power gained by installing a intercooler/aftercooler. Vortech has developed systems which are substantially more effective at lowering discharge temperatures without causing driveability problems and pressure drops thru the cooling core and ducting.
The Murf928 Stage One will run between 7-8psi. It will run close to 7 psi with an intercooler and make another 35-40 rwhp. This is the max you can run with the stock injectors.
So Normy, you would recommend reletivley untested systems (no dig on DR and Mark, I know they are doing their homework) and not even mention the one that's been out there the longest and has proven to be susccessful? Wassup?
Last edited by Tim Murphy; Jul 23, 2006 at 01:24 AM.
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Michael S. Palmer
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From: Princeton, NJ, USA
Actually, is there a way to fight knocking? I know that on Saabs they have knock sensors and when knock is detected the timing is retarded. Are there "stand alone" systems you could put on a CIS 928? Could water injection help in any way?
Thanks,
Klim
Thanks,
Klim
Burning Brakes
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From: Portland, Oregon
Tim,
It would seem your results conflict with Vortechs... I wonder what kind of crap intercoolers they were testing???
It would seem your results conflict with Vortechs... I wonder what kind of crap intercoolers they were testing???
Originally Posted by Tim Murphy
From vortech's website in the FAQ section:
26. Why don't Vortech superchargers need an Aftercooler or an intercooler?
Vortech Engineering, LLC has conducted extensive testing of most intercoolers/aftercoolers currently on the market. Test results indicate that for street driven purposes below 8-9 PSIG, installing an aftercooler has marginal effects when using a Vortech supercharger (due to the high efficiency of the supercharger). Nearly all of the intercoolers/aftercoolers available on the market have poor effectiveness and actually can cause parasitic losses equal to or greater than the power gained by installing a intercooler/aftercooler. Vortech has developed systems which are substantially more effective at lowering discharge temperatures without causing driveability problems and pressure drops thru the cooling core and ducting.
The Murf928 Stage One will run between 7-8psi. It will run close to 7 psi with an intercooler and make another 35-40 rwhp. This is the max you can run with the stock injectors.
So Normy, you would recommend reletivley untested systems (no dig on DR and Mark, I know they are doing their homework) and not even mention the one that's been out there the longest and has proven to be susccessful? Interesting.
26. Why don't Vortech superchargers need an Aftercooler or an intercooler?
Vortech Engineering, LLC has conducted extensive testing of most intercoolers/aftercoolers currently on the market. Test results indicate that for street driven purposes below 8-9 PSIG, installing an aftercooler has marginal effects when using a Vortech supercharger (due to the high efficiency of the supercharger). Nearly all of the intercoolers/aftercoolers available on the market have poor effectiveness and actually can cause parasitic losses equal to or greater than the power gained by installing a intercooler/aftercooler. Vortech has developed systems which are substantially more effective at lowering discharge temperatures without causing driveability problems and pressure drops thru the cooling core and ducting.
The Murf928 Stage One will run between 7-8psi. It will run close to 7 psi with an intercooler and make another 35-40 rwhp. This is the max you can run with the stock injectors.
So Normy, you would recommend reletivley untested systems (no dig on DR and Mark, I know they are doing their homework) and not even mention the one that's been out there the longest and has proven to be susccessful? Interesting.
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From: Green Bay Wisconsin
Originally Posted by pmotts
Tim,
It would seem your results conflict with Vortechs... I wonder what kind of crap intercoolers they were testing???
It would seem your results conflict with Vortechs... I wonder what kind of crap intercoolers they were testing???
Burning Brakes
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From: Portland, Oregon
Correct me if I am wrong but the TS is the most efficient FI option with
adiabatic efficiency in the region of 75 - 80%. So the only reason, theoretically, us TS'ers need an intercooler is because the power comes on so early? After, say, 4500 R's our IC's aren't helping much, if any?
I have a hard time believing my intercooler causes me any parasitic loss or that cooled intake air won't evercome the parasitic loss from my puny little water pump.
adiabatic efficiency in the region of 75 - 80%. So the only reason, theoretically, us TS'ers need an intercooler is because the power comes on so early? After, say, 4500 R's our IC's aren't helping much, if any?
I have a hard time believing my intercooler causes me any parasitic loss or that cooled intake air won't evercome the parasitic loss from my puny little water pump.
Burning Brakes
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From: Portland, Oregon
A little overkill on highlighting the parts of your post I was referring to. Please keep in mind I am questioning Vortechs claims, not yours.
Originally Posted by Tim Murphy
I believe they were refereing to more commercially available and home made intercoolers and the misapplication there of. I use the same core that Vortech uses in their air/water intercoolers. [I]And why all the yelling?[/I]
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From: Green Bay Wisconsin
Originally Posted by pmotts
A little overkill on highlighting the parts of your post I was referring to. Please keep in mind I am questioning Vortechs claims, not yours.
As far as efficiency goes, the cs and turbo are pretty close, the TS slightly less efficient and the roots is by far the worst.
Now, I'm not saying that you should not run an intercooler. I think intercoolers are a great idea. They add a lot of complexity to the installation as well as cost so one has to weigh out the pros and cons. Most sc systems sold today by the major manufacturers do not include intercoolers. As far as what I am doing, The 89GT and GTS cars are true 10:1 CR and they will get a pulley that will run slightly less boost if they are not going with the intercooler. So far, all the kits sent out for those cars have been intercooled. I can provide a pulley for whatever someone wants to run, as long as it is less than my recommendation.
Last edited by Tim Murphy; Jan 6, 2013 at 10:04 PM.
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Originally Posted by pmotts
Have fun with the IC debate, LarryGTS would have you believe an IC is not needed
There are quite a few non-intercooled supercharger kits available for other types of cars that have 10:1 or even higher compression ratios. There's a lot more than boost level and compression ratio that determines if detonation will occur or not.
People on here have done it without problems, and are still doing it without problems. You can believe them, or you can believe those who've never even tried it and say it can't work.