I know this idea has been lightly discussed in the past, but I have a few more thoughts on the subject.

I do know it's possible to use the 11psi pulley to attain higher boost at lower rpm's, then use a blow off valve to vent any unwanted excess boost above Xpsi. Well, what's the smallest pulley made for the Vortec or the Paxton Novi? I know there's a 14psi pulley for one of them.

Second thought. Sure you can increase the boost pressure with another smaller pulley. But what is the efficiency for the two superchargers. If higher boost takes these units out of their efficiency ranges, there is no use in raising their boost outputs. Any boost that is created outside of a compressors efficiency range just becomes overheated and the cooling requirements make it inefficient to go above those levels. This is why there are different compressors for turbos.

So I guess my question is are there any compressor maps for the compressors that are in the Vortec and the Paxton Novi? If so, what are their sweet spots and which has the biggest range? If one of them are efficient all the way to say 20psi, it would be more cost efficient to use a supercharger to get into that higher boost quick like a turbo does, then stay at that boost level by venting off excess boost.

Also, has anyone used an air/air intercooler with their supercharger? I know Yellowstreak uses a air/water intercooler in his engine bay, but I haven't seen anyone route their piping to an air/air front mount. Why not? It's cheaper, and lighter than an air/water. An air/water requires not only the intercooler, it requires the extra weight of the water, the radiator to cool the water, the hoses to circulate the water, the water resivoir, and the pump to circulate the water. An air/air just requires the extra tubing. And if you are seriously concerned about weight, you can get the tubing made of aluminum.

Any thoughts?

Ben

 

I've got an air/air intercooler.

 

I have the stock 7 psi pulley, 2 custom 9 psi pulleys, 2 custom 11 psi pulleys (one is on my car), and an 18 psi pulley.


I also have an AEM EMS, 785cc injectors, and an Exedy hyper single clutch.


With the 11 psi pulley, the car pulls like a raped ape!

 

How well does it perform? Does it give much of a pressure drop. If I'm not mistaken, air/air intercoolers are better also because of lower pressure drop across the intercooler. The main people that use water/air are competitive drag racers because they have larger resiviors to put ice and water in them and it actually chills the air instead of just cooling it.

have you thought of getting a smaller pulley and venting any excess boost like I mentioned? Whenever I buy a supercharger, I will probably do this if the compressor is efficient enough. Do you know of any compressor maps for the supercharger you have?

Thanks for any info. -Ben

 

It seems like using a high boost pulley with a BOV would just decrease the gain from the SC without reducing the load on the engine. Spinning an SC takes a lot of power.

 

Please correct me if I'm wrong (since I don't know much about FI), but doesn't a turbo build boost early, then stay at X PSI using effectively a variable "pulley" (wastegate?)? If so, wouldn't this mean that the load of the turbo is limitted to how much it actually needs to build the boost you are actually using?

 

[QUOTE]Originally posted by gernby
[B]Please correct me if I'm wrong (since I don't know much about FI), but doesn't a turbo build boost early, then stay at X PSI using effectively a variable "pulley" (wastegate?)?

 

I am going to be working with a local race shop that is going to plumb in a pop-off valve on the after-cooler discharge side. Vortech after coolers have blow-off valves arleady plumbed in to get rid of boost that is unused once the throttle body plate is closed.

The idea of the pop-off valve is to run a 14psi pulley and bleed out the excess boost over 7psi, so that I can theoretically have 7psi from 4500-9000. Full boost now is 7psi which is achieved at 9K right now.

I will have the crank balanced at this time along with a few other things, such as larger injectors & most likely AEM EMS. The shop owner/tuner is very well experienced with the AEM has been trained by AEM. I trust he will not have problems with tuning.

look between the charger and aftercooler the thing with the blue hat/cap is the blow off valve, on the opposite side is where I would like to have the pop-off valve plumbed in to bleed out excess boost.

 

btw, there is major difference between vortech sc and the comptech unit. Vortech uses a blower that is used on 25 other applications, it is gear drive unit that is good up to 30 PSI. The internals and flow properties are more superior than the Novi/Paxton unit. This is what I was told by a former vortech representative that was apart of all aspects of the kit developed for the S2000.

Additional comment. Last week it was 108 degrees Tuesday, I had thermal readings taken on the blower exit portion of the housing, reading 158 degrees and on the intake side close to the TB 101 degrees. The intake temps were reading below ambient that day. With results like this why would you want an AIR-AIR? I;d rather have the additional weight with more power added due to lower intake temps....

 

[QUOTE]Originally posted by CMiS2K
[B]Additional comment. Last week it was 108 degrees