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Posted by Simeon on July 02, 2001 at 15:51:39:

In Reply to: THIS MAY BE A STUPID QUESTION-SUPERCHRGR & TURBOS? posted by Chad Bleakney on June 30, 2001 at 11:31:06:

These are called "forced induction" systems. The differences are, power source, parasitic power loss, heat generation, overall boost gain, boost rpm range. Superchargers generally make less heat than turbos, generate their power more quickly but lack power at high rpm. At low rpm they may even rob the engine of low end power as they are crank driven. Turbos make more power, although later in the rpm range (turbo lag), and also they make more heat, which is not good for any motor. Turbos also require custom plumbing/welding which adds to their cost significantly.

The effective boost ceiling for the M62 motor is @ 6-7 psi. without modifications to the motor. (Forged pistons, compression reduction, ignition timing, intercooler, computer controlled variable rate fuel pressure, etc.) To go beyond 6-7 lbs. boost would require an intercooler to cool the air before it enters the motor. This is needed to prevent detonation, which would destroy your pistons in a matter of seconds, in an extreme instance.

To answer your question, there would be little benefit to spending the cash to do both systems, as either system could exceed the motor's capacity for "forced induction". I have been quoted between $30,000.00 to $40,000.00 just for twin turbos alone. A comparable supercharger comes in @ $6,000.00 with you doing the installation to the $14,000.00 Dinan (hopefully someday).

One thing I would recommend is an external oil cooler if you do a forced induction system to try and improve your motor's life.
In any case, the effect of such modifications is loss of warranty if your car is a CPO.

An important issue for any forced air system is the ECU re-mapping. A poor ECU set-up will make the gains from any boost system small. Many may deride me, but I would have a professional do the work, were I paying for all this, as each motor subsystem, depends upon the other subsystems in order to function properly.

Another concern is the transmission. I was quoted $3,500.00 for transmission mods, to ensure the increase in power does not destroy the automatic transmission. The other alternative is to convert to manual transmission which was quoted at $9,200.00 in parts, (excluding a custom drive shaft), and 3 days of labor @ $75.00/per hour.

I plan on a forced induction system at some point in the future. I am waiting to see who can do it right.


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