Selecting a supercharger
11-01-2012, 09:00 PM
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Selecting a supercharger
I've been researching superchargers for my 598 build and it is very very confusing due to the many combinations available. So I thought I would start a thread to get some dialog started to try and sort it out.
I've talked to every known supercharger builder I can find besides whipple and PSI. A little more than what I want to spend. Thought I would stick with the 71 series.
What sets one builder apart from the rest? Does this depend on application?
Why is it depending on who you talk to some recommend the 8-71 and some the 14-71? If that was all you had to choose was the size. On top of that there are many other things to consider such as; high helix or standard helix, front discharge or regular discharge, two lobe or three lobe, teflon strip or no teflon strip, billet rotors or cast rotors and so on.
I understand it all depends on your specific HP goals, but what is the best bang for the buck?
I've talked to every known supercharger builder I can find besides whipple and PSI. A little more than what I want to spend. Thought I would stick with the 71 series.
What sets one builder apart from the rest? Does this depend on application?
Why is it depending on who you talk to some recommend the 8-71 and some the 14-71? If that was all you had to choose was the size. On top of that there are many other things to consider such as; high helix or standard helix, front discharge or regular discharge, two lobe or three lobe, teflon strip or no teflon strip, billet rotors or cast rotors and so on.
I understand it all depends on your specific HP goals, but what is the best bang for the buck?
11-01-2012, 10:43 PM
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Every blower place out there who deals with the GMC blowers, has came out with some sort of modification, to make it more effiecient. Thats the ultimate goal. Roots blowers were notorious for being inefficient, and they have developed ways to help it.
Size wise, on a 598, I wouldnt choose a 8-71. I'd probably opt for the 14-71. Its size relative. A 14-71 bolted on a 454, wouldnt really be the way to go, especially on a low boost marine setup. To run a pump gas compatible boost psi, the large blower would be so underdriven, that you get lots of air leakage past the rotors, at their slow speed. In otherwords, less effiecient, less power made.
Same goes for bolting on a 6-71 on a 598. To make acceptable boost psi, the blower will have to be so overdriven, it will create lots of heat. Heat=less power.
Screw blowers are much more effiecient, but do carry a hefty price tag. At the end of the day, its all about how much power your trying to make. If 800-1000HP is your goal, the roots works fine with the 598. If 1400HP is your goal, you might want to look into a big procharger and big intercooler.
On certain 14-71 blowers, you need to watch the case style. Some of them by design, will run hot in either the front, or the rear half. Hard to go wrong with the Blower shop stuff, or BDS. The Billet blowers look pretty sweet too compared to the cast style stuff. With a normal rear offset 14-71, you need a intercooler, or spacer plate to clear the distributor. Or, a offset distributor .
I wouldnt have a problem running a 10-71 on a 598, with a intercooler or meth injection.
Size wise, on a 598, I wouldnt choose a 8-71. I'd probably opt for the 14-71. Its size relative. A 14-71 bolted on a 454, wouldnt really be the way to go, especially on a low boost marine setup. To run a pump gas compatible boost psi, the large blower would be so underdriven, that you get lots of air leakage past the rotors, at their slow speed. In otherwords, less effiecient, less power made.
Same goes for bolting on a 6-71 on a 598. To make acceptable boost psi, the blower will have to be so overdriven, it will create lots of heat. Heat=less power.
Screw blowers are much more effiecient, but do carry a hefty price tag. At the end of the day, its all about how much power your trying to make. If 800-1000HP is your goal, the roots works fine with the 598. If 1400HP is your goal, you might want to look into a big procharger and big intercooler.
On certain 14-71 blowers, you need to watch the case style. Some of them by design, will run hot in either the front, or the rear half. Hard to go wrong with the Blower shop stuff, or BDS. The Billet blowers look pretty sweet too compared to the cast style stuff. With a normal rear offset 14-71, you need a intercooler, or spacer plate to clear the distributor. Or, a offset distributor .
I wouldnt have a problem running a 10-71 on a 598, with a intercooler or meth injection.
11-02-2012, 11:17 AM
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So in researching other forums, mainly drag racing forms since they talk a lot more about superchargers this is what I found. Not saying any of this is true because this still seems to be very controversial.
Hi-Helix or Standard Helix
-A hi-helix or 120* rotor is not needed when you are not spinning above 7000 rpms
Cast Rotor or Billet Rotor
- Was told a billet rotor can produce about 100+ more hp than a cast but a cast rotor is lighter so it has the tendency to spin up faster and less wear on the snout and bearings
Teflon or non teflon
-With teflon you can make tighter clearances than with out but there are people out there that say the complete opposite
Front discharge or standard discharge
-The front discharge allows no air reversion due to the air not hit the bottom part of the supercharger and reverting back toward the center of the rotors
This is just some of the info I found. Again some makes perfect sense in theory and some does not at all. I guess that is why you have all the blower builders suggesting something different. In a perfect world I would like to do a back to back comparison on the dyno with all 14-71 combos available.
Hi-Helix or Standard Helix
-A hi-helix or 120* rotor is not needed when you are not spinning above 7000 rpms
Cast Rotor or Billet Rotor
- Was told a billet rotor can produce about 100+ more hp than a cast but a cast rotor is lighter so it has the tendency to spin up faster and less wear on the snout and bearings
Teflon or non teflon
-With teflon you can make tighter clearances than with out but there are people out there that say the complete opposite
Front discharge or standard discharge
-The front discharge allows no air reversion due to the air not hit the bottom part of the supercharger and reverting back toward the center of the rotors
This is just some of the info I found. Again some makes perfect sense in theory and some does not at all. I guess that is why you have all the blower builders suggesting something different. In a perfect world I would like to do a back to back comparison on the dyno with all 14-71 combos available.
11-02-2012, 12:10 PM
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Jason: A lot depends upon your HP goals and how you intend to run. If you want to make 1000+ HP and run balls out then a Whipple 5.0 is what you want. If you just want to make 800 hp and run it hard only once in a while then a 12-71 or 14-71 will work great.
But you need to match the camshaft and HP goals with the " whole engine packges" . Are you going to go carb or EFI? big difference in cost and what setup to use.
Talk to your engine builder and decide on goals, HP , set up (carb or EFI etc.) and level of boost.
You also need to make sure the boats fuel system will accomadate the increased flow.
Good Luck
Wannabe
But you need to match the camshaft and HP goals with the " whole engine packges" . Are you going to go carb or EFI? big difference in cost and what setup to use.
Talk to your engine builder and decide on goals, HP , set up (carb or EFI etc.) and level of boost.
You also need to make sure the boats fuel system will accomadate the increased flow.
Good Luck
Wannabe
11-02-2012, 01:57 PM
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Jason: A lot depends upon your HP goals and how you intend to run. If you want to make 1000+ HP and run balls out then a Whipple 5.0 is what you want. If you just want to make 800 hp and run it hard only once in a while then a 12-71 or 14-71 will work great.
If understand you correctly you are saying that a 14-71 can not make over 1000 hp and maintain reliability??? I do not find this to be correct. I have seen dyno sheets and proof of the reliability.
But you need to match the camshaft and HP goals with the " whole engine packges" . Are you going to go carb or EFI? big difference in cost and what setup to use.
Fuel injection is the plan. That's a whole different topic. Different thread different day. Actually there is a bunch of them on here and no body can agree on that either. LOL!!
Talk to your engine builder and decide on goals, HP , set up (carb or EFI etc.) and level of boost.
I will building these myself. I am using two very respectable marine engine builders when it comes to this black art of part selection. I just like to understand why I may be buying something. Since I am working with two different builders their oppinions differ at times. Thats where it becomes confusing.
You also need to make sure the boats fuel system will accomadate the increased flow.
Good Luck
Wannabe
If understand you correctly you are saying that a 14-71 can not make over 1000 hp and maintain reliability??? I do not find this to be correct. I have seen dyno sheets and proof of the reliability.
But you need to match the camshaft and HP goals with the " whole engine packges" . Are you going to go carb or EFI? big difference in cost and what setup to use.
Fuel injection is the plan. That's a whole different topic. Different thread different day. Actually there is a bunch of them on here and no body can agree on that either. LOL!!
Talk to your engine builder and decide on goals, HP , set up (carb or EFI etc.) and level of boost.
I will building these myself. I am using two very respectable marine engine builders when it comes to this black art of part selection. I just like to understand why I may be buying something. Since I am working with two different builders their oppinions differ at times. Thats where it becomes confusing.
You also need to make sure the boats fuel system will accomadate the increased flow.
Good Luck
Wannabe
Last edited by Jason3603; 11-02-2012 at 02:08 PM.
11-02-2012, 03:39 PM
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heres a 581ci whipple build that gives you everything but my tuning to make 1100hp,1100tq.
http://forums.boatfreaks.org/showthread.php?t=16735
http://forums.boatfreaks.org/showthread.php?t=16735
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11-05-2012, 10:24 AM
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Thanks for the info, but not really enough to make an educated decision. I guess what I will do is list every maker of supercharger on a spinning wheel then spin it like I'm playing wheel of fortune and whatever manufacturer the wheel lands on I will order the most expensive one from that manufacturer. LOL! It is very hard to make a decision when everyone claims they make the best supercharger out there and nothing else compares. I do not have the bank roll to start trying them all to see what really is the best.
