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86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

22re supercharger

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Old May 16, 2008 | 05:33 PM
  #21  
abecedarian's Avatar
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From: Temecula Valley, CA
They're expensive because:
a) there isn't a great demand for them
b) they can't use an existing design / part: keep in mind that most of the roots type blowers for GM products come off of Detroit Diesel engines (built by GM).
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Old May 16, 2008 | 05:35 PM
  #22  
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because very few of them get sold...
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Old May 16, 2008 | 06:27 PM
  #23  
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Originally Posted by abecedarian
Roots type superchargers are crankshaft driven positive displacement pumps. That means that the amount of air increases linearly with engine RPMs.
Turbochargers are exhaust driven centrifugal pumps and the amount of air increases exponentially with the exhaust gas velocity.
Superchargers generally make power as soon as the throttle opens, and turbochargers need exhaust gasses to spin up so they require the engine to spin faster before they start making power- hence the phrase "turbo-lag".

Superchargers generally peter out at mid-range RPM's when compared to turbos, since the turbo can take advantage of the increased exhaust gas velocity and spin up even higher. Also, the higher air temps created by supercharges limit the amount of horsepower a given combination can make.

The trick setup would be a hybrid super/turbo charger setup where the supercharger was governed by a clutch that would disengage the supercharger once the turbocharger made more boost than the supercharger did.

Also, another downside of superchargers is that 'most' superchargers are connected directly to the intake plenum. That means it's difficult to incorporate an intercooler in the system and thus lower the intake charge temperature / increase the intake charge density. Paxton superchargers are remote mounted and operate much the same as a turbo and can use an inter(after)cooler.
Wow, thanks for the post. So, how hard would it be to actually turbo my truck? Not actually put a turbo on in the condition it is...cuz that would be dumb But I am considering rebuilding it and putting a turbo/SC on. I'm not sure which one sounds better...but they both sounds pretty good...can't you hear a turbo???
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Old May 16, 2008 | 06:29 PM
  #24  
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From: DFW TEXAS BABY!
It depends on what you do with your truck. If you wheel it a SC will be MUCH more usefull then a turbo.

You can hear a SC too, it just sounds differnt and don't have a blow-off valve.
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Old May 16, 2008 | 06:35 PM
  #25  
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From: Temecula Valley, CA
Basically, a turbo is best when you're looking for high RPM horsepower and a supercharger is best when you're looking for low RPM torque.
Acceleration takes torque- the twisting force to get it moving.
Speed takes horsepower- keeping it moving.
Yeah, there's a relationship between torque and horsepower- to get more of one you sacrifice the other unless you force more air and fuel into the engine. One of the reasons the 22RE is not a cheap engine to add power to. It's already pretty well maxed out on the balance between torque and horsepower from the factory. Oh, that and the engine design lends itself more towards torque than HP.
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Old May 16, 2008 | 06:38 PM
  #26  
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From: Aurora, CO
Originally Posted by 91Toyota
So, how hard would it be to actually turbo my truck?
Depends on how far you want to take it. If you buy all the parts, takes a day to install. If you fab most of the parts, it can take a long time. I would recommend buing the turbo and turbo manifold, and fabbing up some piping, if you have access to a welder. You can just buy sections of prebent tubing and cut and weld where needed.


Now, a turbo would be fairly useless offroad. You don't spend enough time in the upper RPMs to make it worth it. Having said that, the Got Propane guy has a turbo on his, and it supposedly does really well. You can hear a turbo, and it will make your exhaust quieter, as the turbo acts as a muffler.


Hope that helps.


IMHO, supercharger FTW.
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Old May 16, 2008 | 10:23 PM
  #27  
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From: Temecula Valley, CA
Originally Posted by Hayes
<misc. snippage>
Now, a turbo would be fairly useless offroad. You don't spend enough time in the upper RPMs to make it worth it.
However, with dual transfer cases and low 3rd gears, it's not unreasonable to find an engine revvin around 3-4k is it?

and a small turbo say one designed for a 500cc engine, would spool up quite quickly behind a 2400cc engine, but would be severely limited for total boost... hmm... maybes my cx500-tc has a purpose after all.

Last edited by abecedarian; May 16, 2008 at 10:27 PM.
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Old May 16, 2008 | 10:33 PM
  #28  
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From: Salem, OR
This sounds pretty cool. Although my truck is pretty much street only, so I'm not sure if I SC is a need. If I want high boost...what do I do to the internals? Like do I need dish pistons (I think thats what they are called) and can it handle it?
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Old May 16, 2008 | 11:10 PM
  #29  
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From: Temecula Valley, CA
forged pistons, around 7.5-8.5:1 compression ratio (depending on total boost)
custom fuel management and ignition controls

reports are that a stock 22RTE can survive 17+ lbs of boost.

Oh and if you want to supercharge it more than 5-8 lbs boost, you'll need to do the same mods as if you were turbocharging it.
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