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Re: Supercharging-Turbocharging Questions (Long) (archive)

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Posted by Osh Minelian on October 04, 1998 at 20:37:40:

In Reply to: Supercharging-Turbocharging Questions (Long) posted by Lester on October 04, 1998 at 12:41:47:

>: I have been looking to add more power to the ///M Roadster that I have on order. Can someone help me with the
following questions about turbocharging and supercharging?

: 1. The ///M Roadster has a large engine in a small space. This causes increased heat in the engine bay. That is why
BMW redesigned the front end and took off the fog lights, to allow more airflow into the engine bay. It seems to me that
more horsepower may mean more heat under the hood. Does anyone know if the motor runs hotter when connected to a
turbocharger or supercharger? Is this a problem? If it runs hotter, what modifications should I make to the type of oil
used in the motor?

The engine bay may appear smaller than the M3 but it is not really. The front corners of the engine bay are trimmed away
to accommodate the shape of the Roadsters nose section and that gives the impression that it is smaller. The firewall,
interior air intake, master cylinder and all accessories that are found on the firewall of the M3 are located further back, increasing engine bay area. Also there is no insulation under the hood of the M Roadster, further
decreasing engine bay temperatures. For a turbocharger, the turbo does get quite hot and the grade of motor oil used should
be turbo specific. Oil change inervals will also be more frequent. Supercharging will have very little affect on oil
temperature. All the M50 and M52 cars I have supercharged, show little or no increase in oil temp. never the less it's
always within safe limits. Use the manufacturers recommended (or higher) grade of oil.

: 2. Most turbocharger or supercharger changes also include a new computer chip and larger fuel injectors. What is the
effect of these after market changes on the scheduled maintenance I'm suppose to received from my local BMW dealer?

I would stay away from turbo charging for now as there is no software systems in place that will provide proper fueling.
Turbo boost comes on very rapidly and the adaptive computers ( all new BMW cars have) can not enrich the fuel mixture
rapidly enough. One turbo kit manufacturer has done considerable testing and has stopped selling there kits for the 96-98
BMW cars. This (adaptive engine management) is one of the reasons that supercharging has become so popular among the tuners. Centrifugal superchargers (Vortech, Paxton, Powerdyne, etc.) provide a linear boost curve. The engine management responds well to centrifugal superchargers. Routine maintenance will remain the same.

: 3. What is the effect of adding an after market turbocharger or supercharger on the new car warranties from BMW? One
maker of a turbocharger and supercharger posted a web sight note that indicated that it does not void your warranty. I
would rather avoid the legal arguments with my dealer and BMW. What I'm looking for is this, how has BMW actually
treated a warranty problem with major after market modifications to their motor?

Good News , Bad News.

Bad news, Your drive train warranty is now void.
Unless your married to the Dealers daughter, although that in it's self may void your warranty.

Good News.
Your motor and drive train can take allot more punishment than any low boost supercharger can put it through. After-market warranties are offered. I personally think they're a waste of money.

: 4. Dose anyone have any thoughts on whether a turbocharger or a supercharger would work best in an ///M Roadster?
A recommendation on the brand would also be helpful?

Supercharger, Hands down.. We use a Vortech supercharger in our M Roadster kit. We think It's the best for this
application. But let's not turn this into an infomercial :-)

: 5. Should I wait until the motor has a few miles on it before I install a turbocharger or a supercharger? By this I mean,
should I wait until after the break-in period is over or until I have about 10,000 miles on a well broken-in motor? I should
note that my Nissan 300z turbo came with the car, and I have had no problems with it in a little under 100,000 miles.

Wait 3500 miles. The motor can handle it from day one but it's best to drive the car in case there are any drive train problems
during break in. It there are any , they should appear by 3500 miles.

: 6. I note that Dinan sells a Supercharger System for $6,995.00, says it takes about 21 hours to install, and makes 338
horses with 281 ft/lbs. of torque. Dinan also offers a Supplemental Warranty for $2,500.00. Turner Motersports sells a
Supercharger System for $5,995.00, says it takes 7 hours to install, and makes 356 horses with 302 ft/lbs. of torque.
Does anyone have any experience with either one of these systems and do you have any recommendations? Why is a
Supplemental Warranty needed anyway?

Sorry, conflict of interest :-)
I hope this info helps.

: I'm sorry if this post got a bit long, but I thought that before I make another major investment that I would come to the
experts for some advice.

: Lester, with a Boston Green/Black/Black ///M Roadster on order.

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