Vortech Supercharger

[uspspro]

Originally Posted by bakerr6

Completely inaccurate. Turbos force air into the motor that was previously hotter temps, but once going through the ic, in many cases it can actually be cooler than the air incoming from a sc. A sc is more restrictive, because the air being forced into the motor is solely reliant on the motor spinning the sc. I have a tc car already (tally is up to 3 now), and have had 2 SC cars. While I do enjoy both, passing along bad info. is not something I take lightly when looking at FI, which is what you and some of these other fanboys are doing.

Actually he is correct. See below:

Turbos force air into the motor that was previously hotter temps, but once going through the ic, in many cases it can actually be cooler than the air incoming from a sc.

Turbos compress air from the atmosphere in a compressor housing with a compressor wheel spun by a connected (via shaft) turbine that is driven by exhaust gasses. The act of compressing the air heats it up (see this -> http://en.wikipedia.org/wiki/Ideal_gas_law ). This is the same for any compressor, whether it be an SC or a turbo. An intercooler can be used on both applications SC or turbo.

A sc is more restrictive, because the air being forced into the motor is solely reliant on the motor spinning the sc.

Turbos and SCs both reliant on something. Exhaust gasses at 3000 rpm or at low throttle angles are not enough to get the turbo going full tilt.

Besides, the compressor (be it SC or turbo) is always going to be putting our more air than the engine could ingest as an NA in any performance situation (WOT, high RPM etc). So none of them are really a restriction on the intake side of things.

What Mandalay was getting at, is that turbos are essentially a huge restriction on the exhaust side. When you put a turbine into a fluid flow, you are converting energy from one form to another. In this case mechanical energy to spin the compressor and compress the intake charge. That costs energy. The exhaust flow is restricted and the exhaust gas pressure (and corresponding EGT) is much higher before the turbine. The heat will transfer to the combustion chamber and bring things closer to the knock threshold.

I'm definitely not bashing turbochargers here, just that so many do not truly understand them, nor do they understand superchargers.

I am waiting for a certain Rotrex based kit. I was going to develop one, until I found out my intended supplier is making a kit.

Anyway :happy0180:

[bakerr6]

Originally Posted by uspspro

Actually he is correct. See below:



Turbos compress air from the atmosphere in a compressor housing with a compressor wheel spun by a connected (via shaft) turbine that is driven by exhaust gasses. The act of compressing the air heats it up (see this -> http://en.wikipedia.org/wiki/Ideal_gas_law ). This is the same for any compressor, whether it be an SC or a turbo. An intercooler can be used on both applications SC or turbo.



Turbos and SCs both reliant on something. Exhaust gasses at 3000 rpm or at low throttle angles are not enough to get the turbo going full tilt.

Besides, the compressor (be it SC or turbo) is always going to be putting our more air than the engine could ingest as an NA in any performance situation (WOT, high RPM etc). So none of them are really a restriction on the intake side of things.

What Mandalay was getting at, is that turbos are essentially a huge restriction on the exhaust side. When you put a turbine into a fluid flow, you are converting energy from one form to another. In this case mechanical energy to spin the compressor and compress the intake charge. That costs energy. The exhaust flow is restricted and the exhaust gas pressure (and corresponding EGT) is much higher before the turbine. The heat will transfer to the combustion chamber and bring things closer to the knock threshold.

I'm definitely not bashing turbochargers here, just that so many do not truly understand them, nor do they understand superchargers.

I am waiting for a certain Rotrex based kit. I was going to develop one, until I found out my intended supplier is making a kit.

Anyway :happy0180:

using wiki as your source is hilarious. First off, you are correct that compressing air will increase the temp. However, the charged air goes through an IC, to cool the air before it enters the intake. There is also a difference between good heat and bad heat. Charge heat is considered to be bad heat, which is what intercoolers are designed to remove. Heat can also be a good thing, as engines turn thermal energy into mechanical energy, which is how engines make huge power numbers.

I can go into a full thermodynamics lesson, as to why the nominal difference in engine temps at the same boost levels would not be a deciding factor on this car with a properly sized IC.

[bakerr6]

I do agree with one thing though, that SCs are more efficient on a thermodynamics basis.

[uspspro]

Originally Posted by bakerr6

using wiki as your source is hilarious. First off, you are correct that compressing air will increase the temp. However, the charged air goes through an IC, to cool the air before it enters the intake. There is also a difference between good heat and bad heat. Charge heat is considered to be bad heat, which is what intercoolers are designed to remove. Heat can also be a good thing, as engines turn thermal energy into mechanical energy, which is how engines make huge power numbers.

I can go into a full thermodynamics lesson, as to why the nominal difference in engine temps at the same boost levels would not be a deciding factor on this car with a properly sized IC.

Wiki is plenty good enough to explain a simple law of thermodynamics to the general public....

[Alienate]

USPSPRO, can you elaborate on who and when?

"I am waiting for a certain Rotrex based kit. I was going to develop one, until I found out my intended supplier is making a kit."




I find the above sentence intriguing.

[bakerr6]

Originally Posted by uspspro

Wiki is plenty good enough to explain a simple law of thermodynamics to the general public....

The reference in there is good, but whenever I source anything, I make sure that is the last place I reference.

If you don't mind me asking, why did you choose a rotrex kit? I've never had a car with a rotrex, only one with a centi and one with a roots.

[catharsis]

I don't even understand what is being argued here. a SC at 8 psi will make the car feel much smoother and linear than a TC'd car running at 8psi. The only reason to ever choose turbo over sc is for more power.

[SkullWorks]

OMG


I hate this stuff.

8psi is not 8psi, 8psi @ 120degrees is alot less air than 8psi at 90degrees....for starters....more TC engines have intercoolers than their SC bretheren, this is because alot of SC are Eaton roots style positive displacement and they are less friendly for air to air intercooler packaging, centrifugal SC's on the other hand can be plumbed just like a TC as far as intercooling is concerned.

8psi on a SC engine at the same temp as 8psi on a TC is close to the same thing but the SC will be down several % due to belt driven pulley losses. this is the advantage of a TC, all you lose is exhaust gas temperature at the tailpipe.

as far as turbos being a restriction...a well designed system doesn't increase exhaust manifold pressure until well after there is a gain in intake flow, this is why real R&D pays attention to exhaust vs intake manifold pressure, to help determine and maintain engine scavaging and cross flow...and lets not forget that increased pressure in the exhaust manifold...translates into torque applied to the compressor wheel....translates into more compressed air...

I have yet to see a SC motor match or better a turbo all the way across a map. there are advantages to both (except centrifugal...those are a waste of recycled beer cans...only good for people that don't want to properly design a FI system.)

for a motor this size with this rev range turbo makes more sense...until someone wins the race to CVT driven SC's...

[Turbowned]

When did this become an S/C vs. turbo thread? Jeez...

I do wish someone would develop a roots-style supercharger for this kit. We already know it fits, so someone doooo eeeet! Both my MR2 S/C and Audi S4 used roots blowers and they had THE best powerbands of any cars I've owned; my N/A and turbo cars couldn't touch 'em for responsiveness and power delivery.

Basically, if someone can recreate a dyno plot like this with an S/C, I will be drooling. We're down a liter of displacement and up a point-and-a-half on compression, but who knows?

[DRACHENV6]

^I dont know much about the different SC types, but I agree. Maximize that throttle response and powerband using the best technology available. I'm sure any company going the SC route will try to maximize appeal and push their advantages.

[uspspro]

I got this out of a Rotrex from the lowly 1zzfe that originally made 125 rwhp/ 125 tq. This is a DD setup on CA 91-octane piss gas.



The throttle response (not shown on a dyno) was excellent, and the feel was soooo damn smooth.

Felt like a giant superbike.

[Coheed]

A roots style SC with a proper A/W setup can work really well and make good power. A well designed turbo setup will make more power, with arguably more complexity.

What people often overlook is pressures. This is an NA engine, and cam profiles are designed as such. Get the backpressure to boost ratio right, with proper cam timing, and it will (and does) make huge power. Dial the overlap to keep pressures just right and you can get great results.

With superchargers you don't have to worry too much about pressures, until you start getting boost blow-thru during overlap. Which should easily be tuned out with the cam actuators.

There's a lot that goes into tuning. Not everyone is going to be pleased with every setup. But thats why its great to have options. If you can make 300whp with a roots on this platform it will be intense.

[gmookher]

you will all be very happy with what you will find out at sema
mums the word till then

[Shiny]

TC or SC, in my opinion it all goes back to the individual. Bothe have Pros & Cons. Bothe can be fitted with IC, Air To Air or Air To Water.
It all depends on the design of the system. I say see the dyno chart and decide if it is ok for you or not.
I say the man 2 design is Posited Vs Centrifugal. Positive will deliver a fixed amount of volume pear revolution, and centrifugal will double the speed and the volume quadruple.
I believe on centrifugal SC or TC using the same compressor and housing, the dyno chart should be extremely similar and close.
For me When I can afford a 86 (not in the near future), I would want something like the Edelbrock E-Force system. A TVS Eaton charger with Air to Water cooler.
At the end to each his one.