Ok, have a seat cause this is going to be lengthy:

SC:

Overall, a great modification. Downside to them is the the heat soak effect they give to your intake air charge. Definitely would recommend an aftercooler or a water injection (a la Aquamist, AA, Spearco). If you dont address the cooling of the intake, the car can feel like a slug and sometimes perform less than when stock. The kit is simple enough for you to install if you have some technical know how, the only downside is that most (not all) SC tuners provide poor instructions. Another downside is that most of the providers of these kits don't have the software perfected; the hardware is of great quality, but without the proper software, the kit will not perform to expectation. On the track (eventhough I never tested mine), there are a few things you will have to address. One, being the afore mentioned intake cooling and the other would be an oil cooler. If I were to go with another SC kit it would probably be ERT or Dinan, but at the end I would probably end up ditching their software to have the car properly dyno tuned. At the end of the day, if you pay for the basic kit, you have a kit that does not perform consistently if you don't address the heat soaking.

Turbo:

To some, it may not be in their budget, but in retrospect, a properly designed SC kit will run you just about the same amount of money that the turbo kit would cost you. The power delivery of the turbo car is totally different than the SC'ed car (non-linear/semi-instantaneous -vs.- linear), but you will find this characteristic in every turbocharged car (the delivery can be dampened somewhat and you also have the variable vane turbo, but that is another matter). Overall, comparing the cars at the same boost level (trying to be fair, eventhough the turbo car had the upper hand since it did have the intercooler), the turbo car was WAY more fun. The turbo car was more repeatable with the amount of power it made back to back (negligible loss in power when compared to the SC). Again, with no experience on the track, the only thing I think I would recommend for the turbo car is an oil cooler (apart from most of the other track gear needed of course).

Maintenance cost for either kit:

It really depends on your driving style. Either can do damage to your drivetrain (clutch, shafts, diff, etc.) very easily. Oil changes on both kits are taken care of when you change the car's oil, only that you will have to change the oil at shorter intervals. The SC will have the added maintenance of the drive belt, but that is very negligible in cost. And then there is over boost, which will lead to detonation and the death of your engine if you are not careful.

Options that I would consider for either kit:

-Free flowing exhaust
-Water injection (far more for the SC than the Turbo)
-Aftercooler/Intercooler (SC not included, Turbo included)

If there is anything you want me to elaborate on further, post again, I think this may help a few others as I have seen a couple of threads asking questions about forced induction. Hope this helps.

PS. One last fact, which may be taken with a grain of salt. I have seen many people go from SC'ed cars to turbo'ed cars, never vice versa; sometimes from SC'ed back to naturally aspirated. Just something to think about.

PSS. You may want to take a look at this thread and do a search for turbo's and supercharger's: http://www.bimmerforums.com/forum/showthread.php?threadid=25190

good post!

my opinion is that most people would be better off with the SC as they tend to require less maintenance and last a little longer... and cost less. (agreed, heat soak sux)

Turbos are still the best way to get the biggest numbers though, always will be.

great way to start the forum and let the flames begin (no wait, did I say that??? :devillook )

may wanna add something about smog legality. IM having problems smogging now.

Dinan is CARB legal as well as Mechtech.

Great post indeed!

Also, with a turbo set up properly you can go with more psi and as a result bigger #'s all around. And it can get quite expensive, but you get what you pay for and my opinion was always if you decide to go turbo, go all out, make it worth it, go with a twin turbo set up, 14-15 psi and knock yourself out.

S/C's are little more "accessible" to the average joe, often can be bolted on by the owner with little fanfare, and can be less expensive, but overall are probably less "flexible" in terms of future modifications and top end power versus turbos.

The mods in my sig ran me about $8400 with insider connections and such, but I did have an extensive dyno tune elsewhere afterwards, so add another $1000 to that figure, and the average joe probably would have spent about $10K on my mods, so $10K plus $1K more = $11K, but I do have a proper tune, and my aftercooler is tuned so that I can use ice at the track for that dreaded heak soak problem. Where turbos can run $10-18K depending.

The only other thing I'm doing to my car is a 10 psi pulley and 30 lb injectors, so take on another $900-$1000 dollars for parts, installation, and an ECU remap, along with another extensive dyno tune.

I'll be very curious to see how my set up reacts when it gets warmer up here this summer.

Another interesting note about s/c's, on the BMWs the ones I have seen have all been centrifugal s/c's, which are nice, cuz basically under normal driving conditions, your car remains as docile and smooth as stock. But given a choice, I'd love to have a roots-type blower, like an Eaton, get that instaneous low end torque. Makes launching at the track tougher, but makes everyday driving more of a kick. Could also eat into your mpg some, but the Eaton roots type blowers with a conservative 6-8 psi, are among some of the most reliable s/c's around, that's why manufacturers seem to love 'em, (Ford, Mercedes, Pontiac, Chrysler now, etc...)

Great post guys, keep it coming!

Originally posted by psk145
may wanna add something about smog legality. IM having problems smogging now.

Dinan is CARB legal as well as Mechtech.

Yes, please add any other comments you may have to this thread that way newbies that are trying to learn/purchase any form of FI will be well informed when making their decision.

About the smog legality. I know some AA kits that have passed tests in Cali. Maybe Jon Caldito can fill us in on this. I am lucky enough that here in FL I don't have to go through smog checks.

Here is what Jon posted on another forum on some of his results on his car in Cali. :

Doesnt care about emissions?

Lets see, I just passed my tail pipe emissions test on my M3.
Here are the results;

15mph @ 1786rpms
CO2 = 15%
O2 = 0.1%
HC (PPM) = measured at 26, Average is 12 and max allowed is 54
CO% = measured at 0.05, average is 0.05 and max allowed is 0.50
NO (PPM) = measured at 17, average is 74 and max allowed is 992

25mph @ 1890 rpms
CO2 = 15%
O2 = 0.1%
HC (PPM) = measured at 30, average is 5, max allowed is 37
CO% measured at 0.06, average is 0.02, max allowed is 0.47
NO (PPM) measured at 25, average is 78, max allowed is 852

Mind you all that my catalytic converters were only hot and NOT extremly HOT. At least this kit thats on my M3 does NOT burn holes in pistons or blow headgaskets nor do I have to use race fuel, octane boosters or some sort of industrial chemcial to keep it from detonating at WOT (7.5psi).

You really have to ride, look (under and on top), touch, smell, know how the systems work (fuel, boost, ignition etc.) what parts are involved, and drive an Active Autowerke turbocharged M3 before anyone can bash about the kit or their work.

well, I know a properly tuned system will pass the sniffer tests fine. But Im having a hard time with visual now :(

Passing a tail pipe sniff is not enough in CA. If it's not CARB'ed and you pass you either got lucky, live in some farming county, or paid the tech handsomely to overlook the engine bay.

I just don't get paying $10k+ for a turbo system, esp. if it's not CARB'ed. Shortly after picking up my M3 I started this thread at DTM - gives some stuff to think about if you may consider the DIY route.

http://forum.dtmpower.net/showthread.php?s=&threadid=5521&highlight=forced+community

- Beau

You need to get yourself a CARB compliance sticker.

Originally posted by jsp98m3
You need to get yourself a CARB compliance sticker.

and how does an individual go about getting one of those? Or can I not get one?

Originally posted by Beau
Passing a tail pipe sniff is not enough in CA. If it's not CARB'ed and you pass you either got lucky, live in some farming county, or paid the tech handsomely to overlook the engine bay.

I just don't get paying $10k+ for a turbo system, esp. if it's not CARB'ed. Shortly after picking up my M3 I started this thread at DTM - gives some stuff to think about if you may consider the DIY route.

http://forum.dtmpower.net/showthread.php?s=&threadid=5521&highlight=forced+community

- Beau

I live in Miami, far and away from a farming county, we just have a governor that revoked the necessity for them:buttrock :buttrock.

Originally posted by psk145
and how does an individual go about getting one of those? Or can I not get one?

Buy a Dinan intake and peel the sticker off:devillook :evil2 :devillook :evil2

You don't have any label companies doing business near you?

I got a label maker at work. Thats about it. I printed some info off CA's website that has CARB #'s listed along with their respective systems. Im gonna try to go in and pretend mine is a Dinan system

Originally posted by psk145
I got a label maker at work. Thats about it. I printed some info off CA's website that has CARB #'s listed along with their respective systems. Im gonna try to go in and pretend mine is a Dinan system


I like the way you think :devillook :evil2 :devillook :evil2

"It says RMS, but thats who made the bracket. Its really a Dinan kit!!" Hope that works!!! Half these morons cant tell the diffrence between a 3 series and 5 series.