I have a 2K1 with an auto tranny. Why will it hold a
SC and not a turbo?

 

it will hold a turbo. There are two 5th gens that have a turbo already. There were fitment issues before as the automatic transmission takes up more room.

 

You just gotta take more precautions with a auto.. Ex. getting a VB mod and tranny cooler is a must..

 

I strongly agree with him, you have to install these mods whether your going turbo or supercharger

 

turbo gives you a full boost at certain rpm. SC gives you a linear boost along the rpm, higher rpm, higher boost. turbo gives more stress to the engine and tranny.

 

What's with you and that face!?!

 

I keep on reading this that Turbo gives more stress to the engine. Is there any evidence of this or you guys are just saying that because it spools up very fast. From what I seen on Baggs Turbo he slams the gas hard and it gets there very fast he drives at ease is like is not there.

 

my sig?


or maybe my dyno story


you are right....I read this somewhere else. I think is when someone asked Mardigrasmax about turbo and SC.


oil report? guys? Kevin?

 

Your weird.


One would think that the turbo puts more stress on the engine then the super. Think about it, full boost spooling up at 3k rpm and pushing till redline vs. linear boost which builds and builds and builds. You'd think the extra shock of the boost hitting almost at once would stress the internals more. But I've heard that it doesn't. It doesn't make sense tho.

 

Quote:

One would think that the turbo puts more stress on the engine then the super. Think about it, full boost spooling up at 3k rpm and pushing till redline vs. linear boost which builds and builds and builds. You'd think the extra shock of the boost hitting almost at once would stress the internals more. But I've heard that it doesn't. It doesn't make sense tho.

what pulley will give you, say 7psi, @ 3000rpm?? even the 2.87 doesnt give me that much boost at 3000. we should ask the person with the smallest pulley in this forum.

 

I want that 2.5, but I have been informed it's beyond V2 s-trim spec

If anyone wants to experiment w/different blowers on my Maxima, I'm willing to be the test subject... just donate all of your paypal payments c/o Jer's email address...

 

Hey stand in line i get first dibsa on paypal payments!

 

2.87 is out of spec for V2 with the diameter of our crack pulley. If I remembered, it is above the spec after 5800 rpm. I got this from one of Kevin's thread.


hmmm, I wonder if other trim will fit onto our plate.

 

The 2.87 is at teh outmost limit of the stock V2...And the lowest pulley sold is a 2.62, 2.5 would have to be custom made...and the blower would have to be uped.

 

A turbo is exhaust driven. Boost is a function of pressure differential (exhaust pressure and intake charge pressure).

With a turbo system, if you're just cruising along the highway with the cruise control set, there is no boost. So under normal driving circumstances it's like the turbo isn't even there. The turbine and compressor wheels inside a turbo are just freewheeling. Think of a paper pinwheel that you stick out the window in a moving car: the air spins in at a certain speed, depending how fast you are going. If you open the throttle in a turbo car, the exhaust pressure increases. There is now a pressure differential. The intake pressure is low and the exhaust pressure is high. So the high exhaust pressure and low intake pressure causes the turbine to rapidly increase speed. Intake pressure starts to build until the equilibrium is reached; the turbine & compressor will level out. When you life your foot, the throttle body blade closes. Intake pressure will spike (and trigger the blow-off valve if there is one) and exhaust pressure will drop. Another pressure differential exists, and the turbine and compressor wheels will quickly reduce in speed until no pressure is present in the intake charge.

A supercharger is driven by a belt off the crank. Therefore there is that extra load on the crank whenever it is spinning. The supercharger is feeding compressed air into the intake charge even when cruising down the highway. The load is always there. The pinwheel in this case doesn't have anything to do with the air; it's connected directly to the engine. The advantage of this is instant throttle response. The disadvantage is it is consuming power, just like the other accessories (alternator, air conditoner, power steering, etc...). Quite a bit of power actually.

So if anything, a supercharger will put more wear and stress on an engine than a turbo. The boost of a supercharger is a function of the compressor speed, which is directly proportional to engine speed. The boost of a turbo is a funciton of pressure differential. So think of a turbo as a supercharger with a variable speed compressor.

Turbos are not generic (neither are superchargers). There are a number of factors associated with a turbo that defines how it operates. There are the turbine housing size, compressor housing size, the pitch on the blades. All of these factors affect how the turbo operates. And each turbo has a compressor map which can be used to match a turbo to a specific application.

Certain superchargers can also reach full boost at a certain RPM. Usually at a pretty low RPM in the case of a roots or screw-type.

Which is better? That's subjective. It depends on what your goals are. Superchargers are usually easier to install. If pure horsepower is your goal, the turbo is a better choice; the same engine at a certain RPM and certain level of boost will put out more power to the rear wheels with a turbo than a supercharger. But if you want instant throttle response, a supercharger would be a better choice. The Audi S4 with it's twin turbos has instant throttle response, but those turbos are very small and you can barely even hear them. Since they're so small their airflow is limited. So if you want to go beyond a certain power level you're going to need larger turbos.

One more thing: turbochargers are a subset of superchargers.

 

sure? I know my full boost comes in after 6000. since amount of boost is based on egine speed, higher engine speed will spin the SC faster and create more boost.

with a small pulley, SC will get a good boost at low rpm. but not full boost.

 

It depends on the supercharger type, size, etc. A centrifugal, like a Paxton, Vortech, ATI, etc... will probably not reach full boost at low RPM. A screw-type, like a Whipple, where boost is a funtion of throttle position and not compressor RPM, then full boost is reached at a lower RPM. I should have been more specific.

 

Are there lysholm/screw type SCs available without a kit?
IOW, why aren't screw-type SCs more popular?
It looks like they're all licensed from Europe. The patent can't be recent can it?

 

The twin screws are rather popular its just they are more popular for the "higher end" cars. And tend to be a bit more expensive. And real expensive in some kits such as teh clk kit that kit goes for around 25000 i think.

 

I don't know.

I guess it has to do with marketing and advertising. Also, the centrifugals hit the market first I believe. And I don't think that anybody with a Lysholm screw type could compete with the centrifugals at the drag strip. So the centrifugals got all the magazine coverage. Just some of my thoughts.

Yeah, the Whipple is from Sweden or something like that. Not sure.