AC Schnitzer Compressor

[Genie]

Anyone using or have experience with this compressor ?

http://www.acschnitzer.com/englisch/produkte/pdf/Motoren_E46_englisch.pdf


i have been offered a 330i step 2003 with this engine modification. It put out 295 whp and 380 tourqe. it is fitted with a custom carbon intake, and ACS exchaust.

do anyone know what type of compressor they are using. have anyone any experience with this modification ?

it looks like something "nice to have" since this particular car has been tuned AT ACS witch must be a plus :) .. this car is almost a "collectors item" since they only do a limitied modified cars pr. year.

i have planned to bore up my 323i and add a ASA charger. but this car has most of it allready ;)

[BMWintoxication]

super charged step 330 with how many miles??..

i hope the tranny can handle all that power...

got pix of the car?...

and.. i'd like to know which SC did ACS pick to put on their logo..

[vmwerks]

"Because of the excellent efficiency of the supercharger, no extra intercooler is required."

:bs: It doesn't matter how efficient the S/C unit is. Compress any gas and it gets hot... technically the more efficient charger, more pressure, the hotter the intake charge will be.

[Mr Paddle.Shift]

Now that you mention....the E46 C30 AC Schnitzer supercharger was featured in BMWCAR Magazine Aug 2002 and Feb 2003. The latter issue was more interesting when they compared it to an Alpina B3S. Funny thing is both articles didn't mention what brand of compressor is used.

I have no doubts about ACS products. I believe they are well-engineered. Surprisingly however, this ACS supercharger kit didn't take off very well. It did get a few press reviews but I have yet to come across a single third-party review. When it first debut in UK, the kit can be installed through any BMW dealership and is covered under regular warranty. But soon after, BMW GB withdrew their distributorship of the supercharger kits. No one really knows why.

[Mr Paddle.Shift]

"Because of the excellent efficiency of the supercharger, no extra intercooler is required."

:bs: It doesn't matter how efficient the S/C unit is. Compress any gas and it gets hot... technically the more efficient charger, more pressure, the hotter the intake charge will be.

Actually they are right if they are referring to adiabatic efficiency, in which "adiabatic" means a process in which no heat is gained or loss. Another term for "adiabatic" is "isentropic".

An ideal compressor of 100% adiabatic efficiency means it can compress all the inlet air to a desired pressure at the outlet WITHOUT gaining or losing heat. This we know is not attainable in the real world.

The more efficient the compressor the cooler the outlet charged air. I know it's difficult to visualize this but it's true. So in comparing two compressors that are driven to produce 6psi of boost, the compressor with a higher adiabatic efficiency will produce a cooler charged air.

[MarvelPhx]

Just FYI, I am sure the 380 is Nm, so that is 280lb-ft.

[vmwerks]

Actually they are right if they are referring to adiabatic efficiency, in which "adiabatic" means a process in which no heat is gained or loss. Another term for "adiabatic" is "isentropic".

An ideal compressor of 100% adiabatic efficiency means it can compress all the inlet air to a desired pressure at the outlet WITHOUT gaining or losing heat. This we know is not attainable in the real world.

The more efficient the compressor the cooler the outlet charged air. I know it's difficult to visualize this but it's true. So in comparing two compressors that are driven to produce 6psi of boost, the compressor with a higher adiabatic efficiency will produce a cooler charged air.

Good point but pressure is still pressure . How much of a difference in overall intake temperature would an efficient compressor make over a less efficient one? Is it enough to make any difference bearing in mind that the car is probably going to be making more than 1 full throttle pass?

[lee330sport]

Theres a few Acs ones in the UK but they dont produce 295rwhp more like 250ish.

[BayerischeMW]

ACS' claims is 295 at the crank, not at the wheels. it costs a fortune as well

[db-330Ci]

btw. AC-Schnitzer took their supercharger kit out of the programm for 2006!

Greetings from Germany

Daniel

[RichP]

I remember hearing a quote from CEC when this kit was released, and I want to say it was like 15-18K. That in itself explains why it never took off, regardless of how pretty that CF engine cover is!

[GBX330ci]

I remember hearing a quote from CEC when this kit was released, and I want to say it was like 15-18K. That in itself explains why it never took off, regardless of how pretty that CF engine cover is!

that CF cover was damn pretty :drool:

didn't someone who posted here from germany have the ACS blower? This was at least a year ago (probably more like 2-3), but i think i remember something.

[Mr Paddle.Shift]

Good point but pressure is still pressure . How much of a difference in overall intake temperature would an efficient compressor make over a less efficient one? Is it enough to make any difference bearing in mind that the car is probably going to be making more than 1 full throttle pass?

Hey Walter,

I base those off the top of my head from my college turbomachinery and thermodynamics classes. I know I can be nerdy about this.

I was concentrating just on the compressor itself. Once IAT is brought into the picture, you have to look at the entire system. In answering your first question, it depends on the rest of the design. not just the compressor. I would love to compare some real world data. But it seems like no one else really logs any data.

Now, in looking at the entire system, assuming that the company that makes the compressor with a lower adiabatic efficiency has already found the best path on the compressor map (more later). But they realized through laboratory testing that the charged air is way too hot. The engineers could find a way to cool the higher temperature charged air by designing a different pipe routing, materials, IC, AC etc for the overall FI system. However, compensating the shortcomings of the source by optimizing the design of everything else isn't going change much. At the end of the day, the design is STILL limited by the source.

The other way to think about this is that a more efficient compressor is capable of boosting a little higher. So, in a controlled environment, a more efficient compressor can say run at 8psi yet produces about the same charged air temp to that of a less efficient compressor running at 6psi. I am making this statement with a word of caution because there is another side that you need to look into, which is the compressor map. Very little is discussed here. I wanted so bad to post a technical thead but what the heck...who's going to read anyway. The compressor map is the single most important property of the compressor. If you look at a compressor map you will notice that peak adiabatic efficiency occurs at a certain region of the map. You want the compressor to do work along a path that stays in or relatively close to the peak efficiency contour.

All that being said, the common question still boils down to how much of these are really applicable in the real world. Well, first and foremost, there will always be theory and the governing mathematics. I did a quick computation and came out with these numbers:

Suppose the inlet to the compressor has a temperature of 58.2F and 14.5psi (atm). The compressor peaks at 22.5 psi. What are the respective outlet temperatures if the compressor is 80% and 60% efficient?

80.6F and 89.6F respectively. Assuming constant specific heats for air.

So 9.6F. No that big of a deal probably. Frankly, it won't matter to Tom, Dick or Harry who just drives the car on the streets or round the grocery corner or screeching the tires for a 1/4mile street race. But it matters to me given the nature of how I push my car. IMO, one has to look at the steady-state of the system to really appreciate the details. This is the other reason why I am so addicted to track events.;)

Hope I answered your questions. :P