Lets talk superchargers + gas mileage (z32)

[k3smostwanted]

you may want to re-think your position LLTZ...i love turbos also but belt driven superchargers have come a long way.

how about a volumetric efficiency of up to 98%??? Whipple Twin Screw Supercharger...
http://www.whipplesuperchargers.com/...sp?ProdID=1162

i think turbos are only about 85%, arent they?

i like turbos but i also like superchargers...matter of fact, i just like boost.

no matter how you look at it, FI is the world's best power adders.

[xXxRocker5150]

lol, well I'm sold, now all I wanna know is how much it'll cost to get a euro zx into the country...

[DeleriousZ]

too much

until you're able to invent some sort of clutched pulley that saps less than say 15 hp from the engine and you're able to adjust the boost by adjusting the clutch, turbochargers will always have the edge in driveability and practicality for street driven applications... hell turbo's will always be better.. lets just leave it at that

[DeleriousZ]

quoted from that site...

"Centrifugals and turbos have tremendous lag time during shift points, on-off throttle and off the line boost."

leave it to the blower bitches to be spreading slander

[k3smostwanted]

Originally Posted by DeleriousZ

too much

until you're able to invent some sort of clutched pulley that saps less than say 15 hp from the engine and you're able to adjust the boost by adjusting the clutch, turbochargers will always have the edge in driveability and practicality for street driven applications... hell turbo's will always be better.. lets just leave it at that

you turbo guys are so neive. yes turbos are good...but just because something is belt driven doesnt mean its worse than exhaust driven.

like i just showed you...the whipple twin screw can be 98% efficient as where a turbo is only ~85%.

and for turbos being more practical for street use...i have to disagree. i think superchargers and especially this whipple twin-screw would have to be the best for short jaunts like street driving usually is because it is instantaneous. turbos are more practical for track use by a long shot...

im not saying turbos are bad and im not saying superchargers are bad...i am saying, they both have their ups and downs.

superchargers have instantanrous boost. this is a plus with modding because the bigger the turbo the more the lag no matter how you look at it. also, superchargers in most cars cases sit right on top of the motor making it much simpler to work on. turbos tend to make a mess of an engine bay.

turbos tend to be mroe efficient that superchargers...they tend to last longer, and alot more versatile...they can be controlled from inside teh car with a push or turn of a knob.

[King Of Crunk]

i have driven both a turbo'd car (plymouth laser turbo) and now drive a supercharged car and both are equally enjoyable, however i do like the instantaneous boost off the line and off the corners that i get from a supercharger....and i think that a supercharger is much better at a drag strip where a turbo is better for roll on/highway races....that is why you see 1000hp supras haul ass on the highway but go to the track and run a 10 second quarter mile because of the turbo lag....where a 1000hp supercharged LS1 or something like that would be running low 9s high 8s with an okay driver (both with drag radials of course)...

kind of on a side not but has anyone seen that video of the doug levin motorsports viper? That is some supercharger whine for ya....sheesh

[k3smostwanted]

yeah...we have a 02 saleen mustang around town that sounds like a friggin helicopter at idle. very beautiful sound...and balls to the walls fast. i think he is boosting a little over 20psi last time i checked...i think he was making about 3 or 4 psi at idle...ill have to check that out next time i see him.

[longlivetheZ]

ooooOOOOOOOOOOO...this debate is so aggrivating some times.

Come on, man...don't fall for a sales pitch. Try to find credible info about how a S/C is more efficient that a turbo in the real world. That site says "up to 98% efficient"...I'm sure that that's NOT the norm. Of COURSE they're going to put the best case scenerio on there so people will buy them. They're just positive displacement, screw type S/Cs (which are actually the least efficient of the S/C bunch, if I'm not mistaken...I'll have to check...don't quote me on that yet). They're directly limited by their size due to the means that they make boost. To run 20psi on a positive displacement S/C would require a pretty damn big S/C. The Stillen S/C for the 350Z requires a cowl hood and it only runs...what...5 psi or something...to run 20 psi, you'd need a much physically larger blower...MUCH larger. You'd need one HELL of a cowl hood...lol.

I'm betting that that Saleen you refer to is running a centrifugal S/C (which is just the compressor side of a turbo driven by a belt). Now...if he ran the SAME 20psi out of a turbo, that dude would make MORE hp cuz the turbo isn't sapping anywhere near as much power right off the crank. I don't get why people run S/Cs. Select the right turbo and design a system around it and you could have comperable lag to a centrifugal S/C. I'v seen turbos making boost at idle.

Here's something cool I found in my quest for more turbo knowledge:

"This wait time--the period between hitting the throttle at low engine speed and the creation of appreciable boost--is properly called boost response. Many people incorrectly call it lag, which is really something different. Lag actually refers to how long it takes to spool the turbo when you're already at a sufficient engine speed to create boost. For example, let's say your engine can make 12 psi at 4000 RPM. You're cruising along at a steady road speed, engine spinning 4000 RPM, and now you floor it. How long it takes to achieve your usual 12 psi is your turbo's lag time. Between the two, slow boost response usually causes the most complaints."

--Source

So it's not lag that's actually the problem...it's sluggish boost response. Some good fyi. I'd never heard it put like that...always kinda thought that lag and boost response were pretty much the same.

I wanna go to school for this shit. That way I can gain credibility and I'll KNOW without a doubt how all this shit works. Compression...to lower or not...turbo or S/C...I'll KNOW what's going on. I have a good idea what's going on with it, but I'd LOVE to go to school for it. If there was a Forced Induction U, I'd be there in a heart beat.

[k3smostwanted]

Originally Posted by longlivetheZ

ooooOOOOOOOOOOO...this debate is so aggrivating some times.

Come on, man...don't fall for a sales pitch. Try to find credible info about how a S/C is more efficient that a turbo in the real world. That site says "up to 98% efficient"...I'm sure that that's NOT the norm. Of COURSE they're going to put the best case scenerio on there so people will buy them. They're just positive displacement, screw type S/Cs (which are actually the least efficient of the S/C bunch, if I'm not mistaken...I'll have to check...don't quote me on that yet). They're directly limited by their size due to the means that they make boost. To run 20psi on a positive displacement S/C would require a pretty damn big S/C. The Stillen S/C for the 350Z requires a cowl hood and it only runs...what...5 psi or something...to run 20 psi, you'd need a much physically larger blower...MUCH larger. You'd need one HELL of a cowl hood...lol.

I'm betting that that Saleen you refer to is running a centrifugal S/C (which is just the compressor side of a turbo driven by a belt). Now...if he ran the SAME 20psi out of a turbo, that dude would make MORE hp cuz the turbo isn't sapping anywhere near as much power right off the crank. I don't get why people run S/Cs. Select the right turbo and design a system around it and you could have comperable lag to a centrifugal S/C. I'v seen turbos making boost at idle.

Here's something cool I found in my quest for more turbo knowledge:

"This wait time--the period between hitting the throttle at low engine speed and the creation of appreciable boost--is properly called boost response. Many people incorrectly call it lag, which is really something different. Lag actually refers to how long it takes to spool the turbo when you're already at a sufficient engine speed to create boost. For example, let's say your engine can make 12 psi at 4000 RPM. You're cruising along at a steady road speed, engine spinning 4000 RPM, and now you floor it. How long it takes to achieve your usual 12 psi is your turbo's lag time. Between the two, slow boost response usually causes the most complaints."

--Source

So it's not lag that's actually the problem...it's sluggish boost response. Some good fyi. I'd never heard it put like that...always kinda thought that lag and boost response were pretty much the same.

I wanna go to school for this shit. That way I can gain credibility and I'll KNOW without a doubt how all this shit works. Compression...to lower or not...turbo or S/C...I'll KNOW what's going on. I have a good idea what's going on with it, but I'd LOVE to go to school for it. If there was a Forced Induction U, I'd be there in a heart beat.

nah...it is the pulley ratios that determine boost. the stillen supercharger for the 350Z has a preset of 5psi to not cause damage to the rather high compressioned motor. it can be swapped to a smaller pulley in which it will allow it to make more boost but then you risk doing internal damage.

im not saying that superchargers are better...i was just bringing a valid point that teh whipple twin screw can be more efficient at 98%. the best a turbo can do is 85% so you cant argue with numbers...

the whipple might be 98% efficient from 4000rpms on up but 4000rpms below it could only be 60% efficient. i have not really looked into it...nor do i care to do so. just was making a point, that superchargers have came a long way...my grand prix has a bypas valve system that will not allow boost before a certain RPM and when in OD it will not allow boost before 3000rpms. that means...i can be cruising on the highway at 3000rpms and i will not be making boost. this is just one of many things that have changed over the years of your typical belt drivin spuerchargers.

i will stick with my TT's on my 300zx and i will stick with my supercharger on my grand prix. both add power and both make modofying easy. i prefer a turbo over a super but i am not gonna deny the supercharger its benefits.

as for that saleen...that had no relevance to this debate. yaggus just reminded me of it when he was talking about the whine on that viper.

[xXxRocker5150]

lol, wow, that's a freakin' earfull...

didn't they make turbo 2+2's in Canada??? (that were manual????)

[King Of Crunk]

the efficiency of a supercharger and turbo are about the same, IMO i like superchargers because of the instantaneous power and the driveability.....it may be more of a gas guzzler with the supercharger but whether you have a 800hp supercharged corvette or an 800hp twin turbo supra....gas milage doesn't really matter at that point, they're both going to be dumping a ton of gas out of the tailpipe and using a ton making all those performance parts work...

[DeleriousZ]

Originally Posted by xXxRocker5150

lol, wow, that's a freakin' earfull...

didn't they make turbo 2+2's in Canada??? (that were manual????)

yep, but only in z31's.. and i've only ever seen one that was 5 speed... all the rest have been auto's... there's one sitting at the local dealership with 60k km on it and they're asking like 9 grand for the thing...


anyway... i was thinking about it this morning, and those efficiency numbers are only compression related.. of course if you have something 3 times the size doing the same job it's going to do a better job of it... however, that efficiency doesn't take into account the amount of power it takes to drive the system comparitively...

[nastyNater]

Originally Posted by xXxRocker5150

I like instant boost... but I was also looking for an alternative to TTing an n/a becuase I wanted a 2+2 with forced induction, and it just seems like the TT swap would be a btich

two small turbos will give the same or better boost response than a supercharger. turbo all the way.......

[longlivetheZ]

Originally Posted by Supercharging, Turbocharging and Nitrous Oxide Performance Handbook by Earl Davis and Diane Perkins-Davis

The size of the air space, or displacement, remains consistent and defines the size of the supercharger as well as its output potential.

That is what I was referring to. Sure you could make the screws turn faster, but that would create more heat and more wear and tear on the S/C. You'd need to get QUITE a large screw S/C to be able to run 20PSI. Doesn't matter...just commenting on the mustang comment.

This is also some interesting reading:

http://members.tripod.com/tomak3/page10.html

[k3smostwanted]

Originally Posted by longlivetheZ

That is what I was referring to. Sure you could make the screws turn faster, but that would create more heat and more wear and tear on the S/C. You'd need to get QUITE a large screw S/C to be able to run 20PSI. Doesn't matter...just commenting on the mustang comment.

but superchargers are just like turbos...they have a maximum. teh stock Garret GT25's on the Z32 have a maximum pressure rating of 16 psi before they create more heat than anything else. if you buy a larger turbo it can handle more boost....

a supercharger is the same way...it has a maximum and car engineers do not put a supercharger on a car that has a maximum clsse to what they plan to run the boost at.

superchargers and turbochargers are closely related upon how they work. superchargers used a belt to push the air and the turbo used the exhaust to pressurize the air on the other side.

both have benefits and both have downfalls. neither is better than the other...it all depends on what you want and when you want it.

also a plus to a supercharger is that it is rather simple to have a good set-up. when making your own turbo set-up it takes knowledge to know you are picking the right things and that they will work appropiately.

anyways, enough of this...i hate arguments without an ending.