Vortech Supercharger

[sw20kosh]

Originally Posted by gmookher

more pressure equals cost, right? now I want a even bigger intercooler, an electronic controlled boost valve, must have exhaust work, hi flo cats, etc.

I'm certain your wish list, and mine, can be achieved at a higher than base tuner kit cost. they're telling you what that kit includes and its msrp

call it stage 1.5 with your add ons?

We get where you are coming from but what he is saying is not to increase boost pressure at all. Instead he is talking about installing a wastegate and a smaller pulley so that you can ramp up the boost faster and yet stay at low boost pressure all the way till redline (in the hypothetical boost graph below... red vs. gray)

Then end result is full boost by ~ 4k rpms rather than full boost by 7.5k. No extra fueling parts required. Just a wastegate with a 5, 6 or 7 psi spring.

[Tradewind]

Wastegate plan seems fine until you realise all the air (mass) you are dumping to atmosphere in order to regulate final manifold pressure has had to be pumped through the supercharger using a LOT of additional effort. Peak power in a regulated system is actually less than with a stock pulley. The chart above shows pressure, be a different story if it showed horsepower, the 18psi with WG shut would like awesome, the stock pulley would make a nice power number and the WG functional would have worst peak power figure of all of them due to the extra work being put into the SC for no gain

[MANDALAY]

Originally Posted by sw20kosh

We get where you are coming from but what he is saying is not to increase boost pressure at all. Instead he is talking about installing a wastegate and a smaller pulley so that you can ramp up the boost faster and yet stay at low boost pressure all the way till redline (in the hypothetical boost graph below... red vs. gray)

Then end result is full boost by ~ 4k rpms rather than full boost by 7.5k. No extra fueling parts required. Just a wastegate with a 5, 6 or 7 psi spring.

Yes , thats it exactly !

My point being that the kit really should be done this way if it is/was research properly. Done this way you will see an enormous improvement . You are just utilising the SC properly and not wasting it and with experience your first gear will get you so far in front that the turbo guys wont know what is happening while their turbos take time to spool up

[MANDALAY]

Originally Posted by Tradewind

Wastegate plan seems fine until you realize all the air (mass) you are dumping to atmosphere in order to regulate final manifold pressure has had to be pumped through the supercharger using a LOT of additional effort. Peak power in a regulated system is actually less than with a stock pulley. The chart above shows pressure, be a different story if it showed horsepower, the 18psi with WG shut would like awesome, the stock pulley would make a nice power number and the WG functional would have worst peak power figure of all of them due to the extra work being put into the SC for no gain

Sorry buddy but you are talking nonsense.

A SC is an air pump. If it pumps 8 psi at Red Line you will only have 3-4 at 4,000 rpm.
If the SC can pump 15 psi at red line at 4,000 it will be pumping 8 psi.
As you approach the 8 psi the WG opens and starts to relieve the pressure.

Thats what a WG does

Here is a WG control used for the ultimate traction, boost by gear


Uploaded with ImageShack.us

Additional effort ?
The bigger the SC the lower the gear ratio , more volume of air pumped less work
Have a look at SC specs > shaft spins less > lower temperatures/wear.
Stock pulley ? what stock pulley the one that the kit supplier wants you to use so as to lower the overall pressure or the stock pulley that is calculated by the manufacturer that will optimizes the pressure at your set red line.

Kits should always be done with collaboration with the FI manufacturer, ALWAYS.
If you were building a kit yourself YOU would.

[Calum]

Originally Posted by MANDALAY

Sorry buddy but you are talking nonsense.

A SC is an air pump. If it pumps 8 psi at Red Line you will only have 3-4 at 4,000 rpm.
If the SC can pump 15 psi at red line at 4,000 it will be pumping 8 psi.
As you approach the 8 psi the WG opens and starts to relieve the pressure.

Thats what a WG does

Here is a WG control used for the ultimate traction, boost by gear


Uploaded with ImageShack.us

Additional effort ?
The bigger the SC the lower the gear ratio , more volume of air pumped less work
Have a look at SC specs > shaft spins less > lower temperatures/wear.
Stock pulley ? what stock pulley the one that the kit supplier wants you to use so as to lower the overall pressure or the stock pulley that is calculated by the manufacturer that will optimizes the pressure at your set red line.

Kits should always be done with collaboration with the FI manufacturer, ALWAYS.
If you were building a kit yourself YOU would.

He's talking about the mechanical energy required to drive the SC. And I agree with him that the peak power will be lower with the small pulley and WG open vs large pulley and no WG, all else being equal. The energy required to blow all the air through the WG will be subtracted from the power at the wheels. That said, I'd gladly loose a couple peak horsepower for an extra 3000 rpm of power band.

[MANDALAY]

Except for one thing the bigger SC will be more efficient and spin les

[sw20kosh]

Originally Posted by Calum

That said, I'd gladly loose a couple peak horsepower for an extra 3000 rpm of power band.

This. Just look at those two boost curves and you will see which one is clearly better regardless of loosing some peak power at 6-8k rpms.

If you want a bit more peak power, just attach a boost controller to the WG and up the boost a pound or two.

:happy0180:

[Entroper]

Originally Posted by Calum

He's talking about the mechanical energy required to drive the SC. And I agree with him that the peak power will be lower with the small pulley and WG open vs large pulley and no WG, all else being equal. The energy required to blow all the air through the WG will be subtracted from the power at the wheels. That said, I'd gladly loose a couple peak horsepower for an extra 3000 rpm of power band.

Yes. Put another way, using a higher PSI pulley will add more parasitic load to the engine. The wastegate will relieve a lot of the additional load, but not all of it (it's easier to move air than it is to compress it).

[Calum]

Originally Posted by Entroper

Yes. Put another way, using a higher PSI pulley will add more parasitic load to the engine. The wastegate will relieve a lot of the additional load, but not all of it (it's easier to move air than it is to compress it).

Wow, did you blow the dust off this thread before you used the defibrillator?

All jokes aside, a big thumbs up for using the search function. Clearly you're researching something. Did you find what you were looking for?