G-Power Supercharger - mild boost

[pokeybritches]

G-Power released a kit for the Z4 running very mild boost (4.3 psi) making a claimed +55 hp over stock. I crunched the numbers and this sounds very believable:

4.3/14.7 * 225 hp = 65.8 hp

The kit uses an ASA T3-313 centrifugal supercharger. Cost is 2500 EUR (~$3500). Anyone know details regarding tuning and vendors?

http://www.g-power.de/926.html?L=1&c...00&artgr=16001

http://www.zercustoms.com/news/G-Power-BMW-Z4-3.0i.html

[tarheel91]

Originally Posted by pokeybritches

G-Power released a kit for the Z4 running very mild boost (4.3 psi) making a claimed +55 hp over stock. I crunched the numbers and this sounds very believable:

4.3/14.7 * 225 hp = 65.8 hp

The kit uses an ASA T3-313 centrifugal supercharger. Cost is 2500 EUR (~$3500). Anyone know details regarding tuning and vendors?

http://www.g-power.de/926.html?L=1&c...00&artgr=16001

http://www.zercustoms.com/news/G-Power-BMW-Z4-3.0i.html

Don't they use a centrifugal supercharger? Never been a fan. Has the boost lag of a turbo and the parasitic losses of a positive displacement supercharger. 55hp sounds pretty idealized. You're going to have parasitic loss since it's a supercharger. Also realize intake temps will increase because of increased pressure, causing efficiency to drop even further.

[pokeybritches]

Yes, I realize that efficiency will drop because of parasitic losses and heat. However, 55 hp is believable when you bring a good tune into the equation since you will be starting with 230 or 235 hp instead of 225 hp. Tune aside, I don't think 4.3 psi robs more than 11 hp (20%). The non-intercooled centrifugal setup is easier to install and costs half as much as the ESS TS2. It's tempting for those that think the car has enough grunt around town but want more power on tap to keep up with some of the new turbo BMWs.

My 3.0i is about to have a 3.64 installed, so the addition of a low-boost supercharger would be welcome. Unless Active Autowerke comes out with a low-cost kit in the next few months, the G-Power kit is a definite consideration. I do have some concerns though. The M54 is said to have odd harmonics at high rpm, and many race teams experienced oil system failures from bolts backing out and shafts shearing; the only fix is either a dry sump system or the Motorsport oil system for $3000 plus install. With a centrifugal system, the car has to be wrung out because max boost is only available at redline (which generates lots of LEO attention too).

Long-term I would like to build up the car for an ESS TS3, but that would be years from now. I completely agree that a twin screw setup is far superior, but the initial cost is too great at the moment.

[johanness]

Originally Posted by tarheel91

Don't they use a centrifugal supercharger? Never been a fan. Has the boost lag of a turbo and the parasitic losses of a positive displacement supercharger. 55hp sounds pretty idealized. You're going to have parasitic loss since it's a supercharger. Also realize intake temps will increase because of increased pressure, causing efficiency to drop even further.

Think u've got it backwards. Centrifugal supercharges have greater thermal efficiency. Easier on the engine/drivetrain, and not as much lag as turbo (depends on system you're comparing it to).

I think the G-Power system looks great. Take a look at some of their other cars.

[tarheel91]

Originally Posted by johanness

Think u've got it backwards. Centrifugal supercharges have greater thermal efficiency. Easier on the engine/drivetrain, and not as much lag as turbo (depends on system you're comparing it to).

I think the G-Power system looks great. Take a look at some of their other cars.

I'm saying it has both lag and parasitic losses. The parasitic losses are a result of the compressor being hooked up to the crankshaft. Thermal efficiency has nothing to do with that, and is entirely dependent on the compressor itself.

Of course it's easier on the engine/drivetrain, it's not pushing as much air through the engine or making as much power!

I'm assuming you mean greater thermal efficiency than a positive displacement supercharger, in which case that's very dependent on on the RPM you're at, and the specific design you're using.

Regardless, the main benefits of a centrifugal supercharger is that they require less tuning since the power is made up top where volumetric efficiency is lower anyways, and they're cheaper. If you can afford a PD supercharger or turbo, I'd go with that.

P.S. There's an ESS TS1 and TS2. The TS1 is the cheaper model and still provides ~285whp in its most basic form. With a smaller pulley, you're looking at 320+.

[rabbit69]

cure to power loss by heat-> water meth!

[johanness]

Less tuning and easier on the engine/drivetrain is what I think people are after when they go for a system that is only 4.3lbs of boost like this one.