what would be better a turbo or supercharger
08-27-03, 03:16 PM
#26
Nikki-Modder Rex-Rodder
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Originally posted by DriveFast7
FWIW a few months ago I asked about superchargers on a rotary and some info that was replied:
1. Superchargers are not intercooled therefore intake temps are hotter than turbos. Therefore you cannot run as high as boost with s/c. (~10psi max)
You can intercool an SC if you're doing a blow-thru configuration. You can also run ridiculous boost with anything that will give it to you if you run water injection.
2. Atkins Rotary's s/c kit is ~$3k and turbo with blow thru carb and an NPR intercooler or other such good used IC can be done for lots less.
Atkins' kits are expensive, but comparable to what's offered for other vehicals. Difference is, they know they're pretty much the only game in town for 1rst gens rexs, and they don't even try to offer IC-ability for their kit.
3. No parasitic loss with turbo. Better MPG and HP potential.
First part is true, but the second part...I'll explain later.
4. People that had a S/C LOVED them and didn't have anything bad to say.
5. Turbo guys said pretty much the same thing
6. Not a lot of shops selling S/C's these days. Any concerns about getting parts or rebuilds? What is the longevity of a S/C?
Forever. -At least when you compare them to turbos. A turbo has to endure tremendous heat, and ridiculous changes in inertial direction. They truely are amazing. But they are punished more than any other part of the car.
...'Course that does'nt mean you can't go buy a shitty SC that'll fail ya. But you get the picture.
7. Someone here was trying to get a Thunderbird S/C to work on rotary power.
FWIW a few months ago I asked about superchargers on a rotary and some info that was replied:
1. Superchargers are not intercooled therefore intake temps are hotter than turbos. Therefore you cannot run as high as boost with s/c. (~10psi max)
You can intercool an SC if you're doing a blow-thru configuration. You can also run ridiculous boost with anything that will give it to you if you run water injection.
2. Atkins Rotary's s/c kit is ~$3k and turbo with blow thru carb and an NPR intercooler or other such good used IC can be done for lots less.
Atkins' kits are expensive, but comparable to what's offered for other vehicals. Difference is, they know they're pretty much the only game in town for 1rst gens rexs, and they don't even try to offer IC-ability for their kit.
3. No parasitic loss with turbo. Better MPG and HP potential.
First part is true, but the second part...I'll explain later.
4. People that had a S/C LOVED them and didn't have anything bad to say.
5. Turbo guys said pretty much the same thing
6. Not a lot of shops selling S/C's these days. Any concerns about getting parts or rebuilds? What is the longevity of a S/C?
Forever. -At least when you compare them to turbos. A turbo has to endure tremendous heat, and ridiculous changes in inertial direction. They truely are amazing. But they are punished more than any other part of the car.
...'Course that does'nt mean you can't go buy a shitty SC that'll fail ya. But you get the picture.
7. Someone here was trying to get a Thunderbird S/C to work on rotary power.
That was jr(lotsa #s in his name).
He tried, but used a Bonneville SC (Eaton M-62) that had Teflon coated rotors. He used it in draw-thru configuration and, well...you can guess the rest.
I've posted alot about plans I have to SC a 12a with an Eaton M-90 from a T-bird Supercoupe.
Eaton uses a bypass valve for their blower applications. While at cruise, the valve opens, allowing the boost to drop off. Basically, the blower is no longer compressing (not producing heat, either) at cruising speed. When the manifold vacuum drops due to throttle planting, the valve shuts, and "Whammo!" insta-boost.
This is GREAT for two reasons- Gas mileage; and ; according to Eaton their M-90 draws 45-55 HP at 10 psi but only 3 HP at zero psi.
(BTW, Mike Bassi @ Mazspeed tested the Camden 7 incher at 70 HP engine draw @ 10 psi!)
The debate between blower and turbo will go on forever, often turning into a flamefuckfest, but the truth is that there are more choices out there for configuring a blower than most people ever bring up.
I plan to blow my stockport 12a thru an IC from a Volvo, into my modded Nikki, and use water injection.
I'll pulley the thing to max redline at my desired shift point (probably 7K-there's just no need to go higher as the boost is supposed to bring the power band down in the rpms anyway) and basically boost it for all it's worth- Hopefully about 15 psi.
Then, I'll fabricate another valve like the bypass, but this will be operated from inside the car- on the console. It's essentially a bleeder valve that will decrease the boost level to whatever I want.
-No more pulley change crap for different boost!
In theory, running the SC at its limit but decreasing the work it has to do to compress (by bleeding compressed air) should extend it's life the same as if I had simply changed the pulley.
When I get all the bugs worked out, I plan to persue making the alternator brakets, SC mounting hardware, carb box, and other fabricated crap into a kit for people. They would have to buy the SC and the IC. Either could be had at the yard or on Ebay for $600 total. Add a few hundred for pump, reg, gauge, + a few hundred for my kit, and I hope to be the first one to be able to offer bolt-on boostability to 12 psi for the 12a for under 1500 bucks!
08-27-03, 04:29 PM
#27
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a very simple question,
if a turbo is better than a supercharger, than whay does every top fuel dragster run a supercharger?(same thing as a *BLOWER*!)
on the other hand i realise on a rotary it puts too much strain on the e-ehaft but he drives a boinger
if a turbo is better than a supercharger, than whay does every top fuel dragster run a supercharger?(same thing as a *BLOWER*!)
on the other hand i realise on a rotary it puts too much strain on the e-ehaft but he drives a boinger
08-27-03, 04:43 PM
#28
Got Boost?
Sterling, hows that project going anyway? I really hope to see it running, because that is how supercharging should be done. Hopefully when you get there, you'll actually have a viable system.
Ripp Mods supercharger kits for the '00+ Eclipse, IMO are the wrong way of doing it. First off, I'm not a huge fan on the vortech, centrifigal blowers, because the boost they make is more or less proportional to RPM. Its not really a instant on boost, because it virtually doesn't make any at low rpm. So you have a turbo-like power curve, but lacking a few things that a turbo has, namely power potential,on the fly tunablity, and efficiency. These blowers compress the air more efficiently than positive displacement blowers like Eaton, but in comparison to a turbo, the parasitic losses are higher, thus at a given boost level, the TC will ultimately make more power. They are a bit easier to intercool than their roots-type counterparts(aftercool as some supercharger guys call it), but Ripp doesn't seem to be offering any IC, which in my opinion is even more critical for a SC system than a TC one. Thus it lack power potenital, because you have to keep the boost low to avoid detonation. On the fly tunability is only possible with a bleed of some sort, much like Stirling suggests, but is not extremely easy to make due to the amount of air it has to bleed off -- literally hundreds of CFM.
Ripp Mods supercharger kits for the '00+ Eclipse, IMO are the wrong way of doing it. First off, I'm not a huge fan on the vortech, centrifigal blowers, because the boost they make is more or less proportional to RPM. Its not really a instant on boost, because it virtually doesn't make any at low rpm. So you have a turbo-like power curve, but lacking a few things that a turbo has, namely power potential,on the fly tunablity, and efficiency. These blowers compress the air more efficiently than positive displacement blowers like Eaton, but in comparison to a turbo, the parasitic losses are higher, thus at a given boost level, the TC will ultimately make more power. They are a bit easier to intercool than their roots-type counterparts(aftercool as some supercharger guys call it), but Ripp doesn't seem to be offering any IC, which in my opinion is even more critical for a SC system than a TC one. Thus it lack power potenital, because you have to keep the boost low to avoid detonation. On the fly tunability is only possible with a bleed of some sort, much like Stirling suggests, but is not extremely easy to make due to the amount of air it has to bleed off -- literally hundreds of CFM.
08-27-03, 04:46 PM
#29
Got Boost?
if a turbo is better than a supercharger, than whay does every top fuel dragster run a supercharger?(same thing as a *BLOWER*!)
08-27-03, 07:55 PM
#30
Nikki-Modder Rex-Rodder
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fatboy,
The project has been put on the back burner while Carl and I start the Nikki modding thing. Money we each make from that are for our individual rotary projects.
When the money's there to do it, I will start on it.
The project has been put on the back burner while Carl and I start the Nikki modding thing. Money we each make from that are for our individual rotary projects.
When the money's there to do it, I will start on it.
08-28-03, 11:00 PM
#31
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i know u cant Intercool a S/C but they got something called a aftercooler it works the same way but its located after the supercharger right before it goes to the engine
08-29-03, 12:19 AM
#33
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I have NO problems cooling my Supercharger down....and yes FATBOY is correct...ask any shop....
Honestly I am game to take anyone on that has a Turbo in a 7....with my Supercharger....I will get you in the start.....yeah you might get me in the end....but by the time you try to catch up....I probably will be gone....POOF
Just kidding...but will give it my best shot...anyway....All in fun...
I want a 20B with a 9in supercharger someday....maybe thrown in the 2nd gen
GO SUPERCHARGER
Honestly I am game to take anyone on that has a Turbo in a 7....with my Supercharger....I will get you in the start.....yeah you might get me in the end....but by the time you try to catch up....I probably will be gone....POOF
Just kidding...but will give it my best shot...anyway....All in fun...
I want a 20B with a 9in supercharger someday....maybe thrown in the 2nd gen
GO SUPERCHARGER
08-29-03, 10:22 AM
#34
Got Boost?
i know u cant Intercool a S/C but they got something called a aftercooler it works the same way but its located after the supercharger right before it goes to the engine
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