Turbos and centrifugals
07-06-2015, 09:22 AM
#21
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Location: rapid city, sd
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Yeah there's a lot of variables for sure. I can look and see what my diesel head for intake temps but that's so far from the boating world it's not worth comparing. I to have herd the roots take more power and run hotter. Probably because they make boost a lot sooner and are big mother humpers! My PC has a 4.10-1 built in step up radio so the guys running a serp belt have good luck not slipping belts due to the larger pulley's. Mine runs pretty cool with the remote mounted IC running child lake water through it. Size does play in to heat. A smaller red lined blower will run hotter than a bigger one working efficiently. My M3 is only spinning about 42,000 rpm @ 6300 and red line is 50,000 ish conservatively per ATI. I also think that since I'm only under boost while in the throttle I think that helps keep heat down compared other positive displacement units. Some of the mustang street guys I know like to over drive the centrifugals to get the boost in sooner then use a waste gate to bleed off the top end but that's more heat and power to do.
My turbos run hot. 1200 + EGTs . air to air IC.. Drive pressure with my compounds at 40+ psi is 75+. That's a big exhaust restriction. A big single would run cooler with less back pressure, but I would sacrifice either low end spool up or top end flow that way.
My turbos run hot. 1200 + EGTs . air to air IC.. Drive pressure with my compounds at 40+ psi is 75+. That's a big exhaust restriction. A big single would run cooler with less back pressure, but I would sacrifice either low end spool up or top end flow that way.
07-06-2015, 01:04 PM
#22
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From what I understand, a roots style blower makes more power on the bottom end (low RPMS) and the centrifugals make more at higher RPMs.
Most old school guys like the roots style, probaly since they were made popular by drag cars, muscle cars and the type.
To me, a centrifugal makes more sense in boat application. You don't need power below 3000 rpms.
Of course the roots style looks cooler...
They do require tall hatches or cutouts (there goes using the sunpad).
I have centrifugals. I don't pull any boost at all until 60 mph so its very fuel efficient at low RPMs (3500 and below). There is a whine with the hatch open, but not anoying at all.
Good comparison here (lot of negatives for roots and screw ):
http://www.superchargersonline.com/i...page=page&id=7
Here's another comparison (but may be biased):
http://www.vortechsuperchargers.com/page.php?id=749
I love this:
"So, when choosing a supercharger system: Do you want power, or do you want a decoration?"
Most old school guys like the roots style, probaly since they were made popular by drag cars, muscle cars and the type.
To me, a centrifugal makes more sense in boat application. You don't need power below 3000 rpms.
Of course the roots style looks cooler...
They do require tall hatches or cutouts (there goes using the sunpad).
I have centrifugals. I don't pull any boost at all until 60 mph so its very fuel efficient at low RPMs (3500 and below). There is a whine with the hatch open, but not anoying at all.
Good comparison here (lot of negatives for roots and screw
):http://www.superchargersonline.com/i...page=page&id=7
Here's another comparison (but may be biased):
http://www.vortechsuperchargers.com/page.php?id=749
I love this:
"So, when choosing a supercharger system: Do you want power, or do you want a decoration?"
Last edited by Rambocj7; 07-06-2015 at 01:17 PM.
07-06-2015, 05:25 PM
#23
Registered
^^^ good info.
One thing i have noticed during some testing. I had always been told roots blowers make tons of heat. I think that can be misleading somewhat.
On icdedppls non intercooled 10-71s on his 540s, making 7ish lbs of boost, intake temps are around 130-140, as long as you hold it wot. Intercooled setup like that around 115*. Now, thats on a blower that isnt spinning to the moon. Ive heard of procharged aetups running similar temps intercooled. Not sure on turbos?
One thing i have noticed during some testing. I had always been told roots blowers make tons of heat. I think that can be misleading somewhat.
On icdedppls non intercooled 10-71s on his 540s, making 7ish lbs of boost, intake temps are around 130-140, as long as you hold it wot. Intercooled setup like that around 115*. Now, thats on a blower that isnt spinning to the moon. Ive heard of procharged aetups running similar temps intercooled. Not sure on turbos?
07-06-2015, 05:49 PM
#24
On your setup, what size intercooler core was it, and how big of water lines did you have feeding it? I've seen some procharger setups using the stock intercooler with little -8 line feeding the core, didnt seem like enough to me?
07-06-2015, 06:18 PM
#25
From what I understand, a roots style blower makes more power on the bottom end (low RPMS) and the centrifugals make more at higher RPMs.
Most old school guys like the roots style, probaly since they were made popular by drag cars, muscle cars and the type.
To me, a centrifugal makes more sense in boat application. You don't need power below 3000 rpms.
Of course the roots style looks cooler...
They do require tall hatches or cutouts (there goes using the sunpad).
I have centrifugals. I don't pull any boost at all until 60 mph so its very fuel efficient at low RPMs (3500 and below). There is a whine with the hatch open, but not anoying at all.
Good comparison here (lot of negatives for roots and screw ):
http://www.superchargersonline.com/i...page=page&id=7
Here's another comparison (but may be biased):
http://www.vortechsuperchargers.com/page.php?id=749
I love this:
"So, when choosing a supercharger system: Do you want power, or do you want a decoration?"
Most old school guys like the roots style, probaly since they were made popular by drag cars, muscle cars and the type.
To me, a centrifugal makes more sense in boat application. You don't need power below 3000 rpms.
Of course the roots style looks cooler...
They do require tall hatches or cutouts (there goes using the sunpad).
I have centrifugals. I don't pull any boost at all until 60 mph so its very fuel efficient at low RPMs (3500 and below). There is a whine with the hatch open, but not anoying at all.
Good comparison here (lot of negatives for roots and screw
):http://www.superchargersonline.com/i...page=page&id=7
Here's another comparison (but may be biased):
http://www.vortechsuperchargers.com/page.php?id=749
I love this:
"So, when choosing a supercharger system: Do you want power, or do you want a decoration?"
Challenging to achieve high boost levels? Guess they havent tried a PSI blower, 8.3L whipple, quad rotors, etc.
As for roots, one of their negatives was "sometimes violent throttle response". Well, I can see that. Not sure thats a negative though, at least the top fuel guys don't think so. Roots are pretty old technology, but they still have their place today in offshore engines. Plenty of big name builders out there making 1200,1300HP with roots blowers and pump gas. With whipples/psi, even more. Engines that have very broad power curves. I've been on mike tkach's 38 fountain with twin 1200hp 8.3L whipple engines coupled to dry sump 6's. That thing will about put your nutsack in your back pocket when he whacks it at 3500RPM. Boat is a rocket from 60 to 120mph. It's no light boat either, weighing in around 11k lbs or so.
Problem my buddy had with his prochargers, was this. He had a 42 Fountain. Boat would run 115mph+ without even dialing boat in yet. That part was great. However, he had a setup that at top speed, the boat was geared/propped for twin 1200HP engines. Problem was, that at low rpm, like say planing, he was trying to turn 115+mph props/gears, with engines that were gutless "on motor". Like, nearly throttles pinned to the dash, trying to get boat to lay over. Being a centrifugal, he couldnt make any boost getting on plane.
I've seen some big power whipple torque monsters, lay 40ft boats over with 1/4 throttle like nothing. The power is there, if you choose to utilize it, by pushing the throttles forward, I don't see alot of prochargers in MTI's, Skaters, Nortech's, mystic's, etc. There must be a reason other than looks, and it surely isnt cost?
My original question was the whole on/off the throttle thing with turbos and centrifugals, and how they do in that aspect. I know they can make big dyno numbers and top speed numbers. I've been out in lots of rough water, where by the time i get to the harbor my arm is completely numb and about to fall off from throttling thru 20-30 miles of big water on lake michigan. Love the roots in that scenerio.
How would the prochargers work in say racing, in this video?
https://www.youtube.com/watch?v=4ccn53WzOCE
07-06-2015, 07:52 PM
#27
Registered
That is pretty awesome, for intake temps. I do like how much more flexibility with intercoolers you have, with turbo's and prochargers.
On your setup, what size intercooler core was it, and how big of water lines did you have feeding it? I've seen some procharger setups using the stock intercooler with little -8 line feeding the core, didnt seem like enough to me?
On your setup, what size intercooler core was it, and how big of water lines did you have feeding it? I've seen some procharger setups using the stock intercooler with little -8 line feeding the core, didnt seem like enough to me?
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