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Discussion Starter · #1 ·
I wuold just like to set a few things straight . People with superchargers tend to bash turbochargers . I would just like to set a few things straight . There are a few advantages to the supercharger

SUPERCHARGER ADVANTAGES
1) low underhood temperatures
2) no special exhaust manifolds and plumbing
3) feels like a big engine all the time (6 psi all the time), lots of low end grunt
4) less chance of blowing your engine, since you are stuck with low 6 psi and cannot change boost easily.

SUPERCHARGER DISADVANTAGES
1) low boost = low overall hp
2) low effeciency at higher boost levels 9psi
3) parasitic drag by belts
4) lower gas milage than turbo

TURBO ADVANTAGES
1) 30% more effecient than a supercharger in most cases
2) capable of alot more hp than a supercharger can ever produce
3) Boost is easily adjusted, adjsutable HP
4) Low parastic HP loss or drag , milage is almost equal to normally aspirated vehicle on highway under no boost

TURBO DISADVANTAGES
1) must pay alot more attention to actual turbo selection and sizes to make a drivable car
2) responce is not as quick to throttle although this is a bit of a trick, most turbocars will produce equal the boost at 2000rpms and above. It will take you a little under a half a second to get it .
3) It is easy to get HP crazy and want another 100 hp over that damned engine that is twice as big as you .Ooops you turned up the boost too much, preignition and big holes in your pistons .

The turbo has got a bad wrap mostly during the 80's when a dodge 1.8 liter with turbo and low boost setup very terrible by todays turbo standards just plain sucked . The supercharger they think small block already powerfull with 50% more power wow that is fast . Turbocharging takes research, knowledge and planning .

I would also like to leave you something to ponder . Why did INDY cars have turbos not superchargers . 2liter 1500hp .

I thought you should now some of the facts about the two ways of forced induction . Make you choice based on all the facts and make your decision from there .
 

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Discussion Starter · #2 ·
<b>AMEN CLINT!</b>

Not ONLY is it a "free" (re: frictionless) horsepower alternative, it's probably one of the most all-around cost-effective means of power production. Man, I miss my '85 ZXT. This '72 is gonna take forever!
 

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Discussion Starter · #3 ·
RE: Turbo vs supercharger

turbo-max hp at a limited rpm range ie. indy cars witch run flat out.
blowers-max torque over broad rpm range gives max acceleration. ie. any drag car.
turbo- change boost with popoff valve or impeller change
blower- change boost by changing pulley
 

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Discussion Starter · #4 ·
<b>RE: Turbo vs supercharger</b>

What the heck, you could always have BOTH... It's being without either that makes the world a scary place.
 

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Discussion Starter · #5 ·
<b>RE: Turbo vs supercharger</b>

Diesel trucks use turbocharger and they have only a 3000 rpm rev limit . This is false that a turbo won't make as much power as a supercharger at 2500 rpm and above it is just not true . Why drag racers use superchargers still is that a turbo will not make boost while the vehicle is revving at a standstill it needs load .The blower gives more holeshot power, engine gets boost while standing still . A guy by the name of BOOST visits here, he ran 12.5 sec on a $2500 motor . This is the price of a blower for a 5.0 liter Mustang which can only muster low 13's . I do very much like superchargers but they do have their limitations.
 

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Discussion Starter · #6 ·
Forced Induction 101

Can you set up a supercharger on a 1982 280ZX n/a? If so, what kind of modifications would have to be done and would the benefit outweigh the cost.
 

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RE: Turbo vs supercharger

In many classes of NHRA competition the turbo is FORBIDDEN to be used, hence the roots style blower. Now, lets throw this into the fray: The Lysholm-Screw Supercharger. These units using the 1967 Assymetric profile (and not the '57 Symetric profile) are EXTREMELY efficient, easily making 50 lbs boost! This style supercharger is also FORBIDDEN in many NHRA classes. Remember, the correct name is Turbo-Supercharger. The drive system determines the distinction. Case in point: Paxton Superchargers, Centrifugal dynamic compression of the intake air, rather than the positive displacement of the roots or lysholm screw, but because it's belt driven it's a supercharger, but has boost characteristics similar to turbo-superchargers, due to using the centrifugal compressor. All superchargers are not the same. The turbo's advantage is that after a certian point it begins to make way more air than it's recip motor can use, allowing for more fule, more power, etc. Like anything it can be engineered to work at any rpm range by changing trims on the wheels. The V8-71T Detroit Diesel uses a roots-style blower to scavenge the air at idle, and once underway and turbo boost is higher than roots-supplied boost, the engine has a valve that switches and runsthe engine solely off the turbo, allowing less parasitic loss from turning the blower, and more power, as the turbo continues to build boost as the rpms rise. I'm gonna quit, I could go on-n-on...
 

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RE: Well said, Tony

The way I see it the supercharger is much easier to retrofit to a car, especially if it is not fuel injected. The linear nature of the supercharger is why. The boost of a supercharger is directly related to rpm. 5 psi at 3000, 10 psi at 6000, etc. The turbo can make it's boost anywhere in the rpm band. Easier to get carbs to work in the linear flow pattern. Get an automatic and you can load the turbo against the tranny for some hellacious launches. Friend of mine leaves the line in his transbrake equipped GN at 20 PSI. Talk about a rocket launch. Putting a Paxton or Vortec on a Z is as easy as bolting it somewhere you can get a belt around it. Not so easy with a turbo.
greg
71 240z
 

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RE: Turbo vs supercharger

Besides issues of spool-up and lag, we need to take into account how the various forced air systems build pressure boost.
The so-called "turbomachines" (meaning not just turbochargers, but anything with a spinning impeller) all have the characteristic that boost pressure varies as the square of the rotating rpm; double the rpms, and you get, as a rule of thumb, four times the boost (this refers to turbo rpm, not engine rpm). On the other hand, the "positive displacement" devices, such as Roots blowers, are linear devices: double the rpm, and get double the boost.
 

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On-n-On-n-On

Mike hit my next point, and is correct. There's a bunch to be said for dynamic-vs-positive displacement compression.
 

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Discussion Starter · #11 ·
<b>Good Debate going</b>

Tony you seem quite knowledgable, on the different air pumps . I believe I saw a screw supercharger bieng first introduced to NHRA a couple of months ago . I define turbocharging anything that uses gases to turn a wheel which compresses air (turbbine) . It is true that centrifigal compressors offer much higher effeciency at a high boost . As for difficulty of turbo installation I thank my lucky stars NISSAN made a turbo L28. My inital point was Turbo gets the bummed wrap everytime .
 

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Discussion Starter · #12 ·
<b>RE: Good Debate going</b>

Guys, just two more humble points to make here:
1. Accessibility--you can get turbos just about everywhere, and unlike superchargers, you don't have to (but you can) spend a fortune on valves, springs, porting, etc. to insure your induction system can handle an unequal atmospheric balance in the combustion chamber.
2. I don't care how much you pay for a blower, or hybrid, it's not gonna make that groovy "shreeeeee-th-th-th-th-th" sound! YEAH, BABY... YEAH!
 

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You're right, Clint!

I'm not disagreeing with YOU, your initial point was correct. I know about compressors since I work on them on a daily basis--manufacturers rep for the original company holding the Lysholm Screw Patent. Turbos DO get a bum rap, and it's too bad. The Lysholm screw is really misunderstood, though. It is efficient over a wide range of speeds, but it's efficiency increases as it's rotors tip speed hit certian parameters. Similar to a turbine, the Lysholm can be throttled, and given the proper materials, can support a 5:1 compression ratio per stage. In automotive applications, using aluminum rotors and cases though, the CR is probably limited to below 3:1 (30psig). The efficiencies of the turbo-vs-blower come down to one thing in an engineering analysis: The cost of the power to drive a belt-driven blower is a direct, linear parasitic loss on the engine's output. The turbo is driven off WASTE energy, therby recovering the btu's normally thrown away in the exhaust--thereby resulting in a more efficient utilization of the fuel input to the powerplant. There is some HP loss due to a restricted exhaust, but it in no way compares to the power gained. Boy, I bet THIS opens a can of worms!!!
 

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RE: Good Debate going

Struck, you've never heard a full speed Lysholm get throttled back to zero and blowdown. Goes from a high-pitched cyclical WHEEEEEE-swhipp-WOOSHHHPPPPFFFTTHH!
My onomotopiea amazes me sometimes.
 

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is it the L28 or a turbo L28 with stock mulffer

when I slow down my car sounds like a big Diesel truck

I have a stock 280ZXT sounds sweet not like any other car I have been in

Jeff 280ZXT
 
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