What Supercharger should i use?

[gmorrell]

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[SuperchargedSHOguy]

Jessey needs to dyno his 91 and that will be another 400 whp-ft/lb vortech...

 

[somedude_001]

Atta boy!

Positive displacement. I've got an Eaton M90 on one of my 96 V8 SHO's. I LOVE the stoplight to stoplight action.

Full boost at low RPM's. Frankly, I can't "spool up" a centrifugal blower before the car in front of me becomes part of my bumper, so I can rarely enjoy the potential of my Centrifugally charged cars.

I have a lot more fun in real traffic with the roots blower car.

Busy making another one right now, this time with the full 03/04 Cobra blower setup.

If I were to ever do another boosted SHO There is no doubt it would be a PD blower. I wish my brother would have finished his M112 project on his 89. he had the manifold completely done. all he would have had to do it injectors maf, belt setup and tune. That would have been nasty.

 

[sbsho]

Hence an idea of mine. If I ran a smaller pulley like say 2.8 or 3.0. And using the BOV as a pop-off valve, like I am now, set at 9-10psi. The boost would start alot sooner and act more like a PD blower ( not as quick though). Would this work?? I already see 3-4 psi almost anytime I floor it. (sans 5th) It would be awesome to have 7-8 psi before 4k rpm. And then just hold 10psi to redline. Damn pistons!!! I mean if I'm limited to 10 psi, mine as well try to get it as fast a possible.

when i was running my centralfugal setup with an Albrex S/C i reached 9psi at 3800rpms, then about 12-14 psi from 6000rpms to redline. it was a fun car, i didnt do any welding for making the bracket, ran a lot of 3in piping,and a big frontmount. i plan on doing this or a turbo again in a couple of years, it all depends what i get a better deal on, or maybe try to pull off a custom roots blower, who knows. have fun when ya boost it.

 

[sperold]

Despite all that has been said, I would go for a supercharger. I have a problem with the heat of a turbo charger; and something doesn't feel right about interfering with the exhaust exiting the engine. Maybe the supercharger is not as elegant an enhancer because it consumes horsepower to generate the boost, but who cares, this isn't a science project. As far as the front main bearing, the bottom half of the bearing has been taking a beating from the power strokes of the engine, its about time the top half started pulling its weight. Nothing scientific about my choice. It just seems simpler.

 

[yamahaSHO]

The bearing wear on the top main bearing from running a tight belt is FAR worse than what the bottom half will see. When I took my motor apart at 90k miles, the top front bearing show much more wear than all the others combined, and it only had a supercharger for 8k miles.

Heat can be a problem, but it can be solved. I really don't understand your fear of interupting exhaust for a turbo. You can get away with running a smaller injector when making the same power and you don't have rev the crap out of it to get some go.

The only real argument for an SC is saving the transmission. If I were to do it again (it wouldn't be a SHO), I would turbo.

 

[Titanium89sho]

Jessey needs to dyno his 91 and that will be another 400 whp-ft/lb vortech...

The car is currently in my brothers hands. I did a sort of trade for his '08 Malibu since I started my masters and I drive over 100 km per day in traffic.

But we have some plans for it. We are going to re-do all of the IC piping and weld it all. The 90 mm MAF is going in and a tweecer RT. Then a smaller pulley from steeda so we can hit the 16-18 psi range. Then maybe we'll hit the dyno with NOS back on it.

And once I am done school, I am buying it back. Atleast it stays in the family. Once I have it back it will get a T-trim as well . Just give me a few years and it will be a beast.

 

[sperold]

The bearing wear on the top main bearing from running a tight belt is FAR worse than what the bottom half will see. When I took my motor apart at 90k miles, the top front bearing show much more wear than all the others combined, and it only had a supercharger for 8k miles.

Heat can be a problem, but it can be solved. I really don't understand your fear of interupting exhaust for a turbo. You can get away with running a smaller injector when making the same power and you don't have rev the crap out of it to get some go.

The only real argument for an SC is saving the transmission. If I were to do it again (it wouldn't be a SHO), I would turbo.

I must say your reasoned response has won me over, or at least got me thinking. I always attached some importance to scavaging (pulling the incoming charge into the cylinder by using the outgoing charge), but that is very theoretical and hard to imagine anyways. I am not using the top end of the rpm scale, so a turbo might be more my style. I have a hard time imagining the wear on the front main, but you have been there and know the truth. The exhaust modifications look difficult but maybe they are easier than they look. I am a changed man!

 

[gmail]

There are some over simplified explanations taking place here. Both systems generate compression heat in the intake charge air. Turbo systems add heat transfer through the body of the turbo, and also heat soak the exhaust manifold, producing radiant heat. This is why it is so rare to see an effective turbo system without intercooling. SC produces more consistent power, for mild applications, but for higher peak hp applications, a street supercharger must be turned at a very high rpm. This increases torque loads in the lower revs tremendously, and can lead to premature component failure. Turbos on the other hand, usually spool more gradually, as exhaust speed increases. They are slightly more likely to cause pre-detonation, if not intercooled properly, or if you use a poor quality, or sticky wastegate. To compensate for this, most people tune turbos rich in the higher revs, to cool the charge (strange but true/rich is cool). This means bad milage while boosting, but a somewhat large turbo that does not spool in the low revs, can run an essentially stock fuel curve, till the onset of boost, returning great mileage under low loads. Turbos use engine oil for lubricant and cooling, breaking it down more quickly. Superchargers put loads on the snout of the crank, that the engineers did not anticipate, and by lifting the snout, cause premature wear of the front upper main bearing, depending on boost and belt tension. Mechanically spinning the supercharger, consumes a small percent of the extra hp produced, increaling load, and reducing mileage. Turbos use the otherwise wasted energy of the expanding exhaust to produce their boost. Small turbo=throttle response, big turbo=peak power.

not to be rude but the extra fuel people add isnt for cooling the engine off or cooling anything for that matter the reason it prevents DET is because more fuel takes more time to burn and it retards the ignition event much like retarding timing.
it is however not a way to tune in properly, its like the old method of tuning by fuel only..
more power can be made from a properly tuned engine that is setup correctly
your just wasting fuel and power output by adding so much fuel.