Swaps and Upgrades


How they work          diagnosing problems          porting and polishing          rebuilding nosedrives          Swaps and upgrades          Adding a boost gauge         

replacing needle bearings     adding a nosedrive drain          supercharger oil change          pulley size suggestions          links, references, and sources


There are various ideas here.  Upgrading a 92/93 Gen 2 blower to a 94/95 Gen 3 blower, adding a supercharger to a non-supercharged engine, etc.  We'll cover them one by one.  For more specific details, please visit www.pontiacbonnevilleclub.com (free to join) and post your question for our Gearheads.  You'll get a response almost immediately (depending on the time of day).

 

Upgrading a 91-93 Supercharged L67 to a 94/95 supercharger/throttle body

This particular swap isn't as simple as it appears.  While the nosedrives between the Gen2 M62 (91-93) and Gen3 M62 (94/95) are interchangeable, and while the L67 engine's lower intake manifold will accept either supercharger, there are other factors that come into play.  First off, a warning.  Do NOT use the larger 94/95 Throttle body on a 91-93 supercharger.  First off, it may actually hurt performance due to the restricted inlet of the Gen2 supercharger, and secondly, the possibility of a coolant leak to the INSIDE of the engine is very high.  This can cost you an engine through hydrolock.  In addition, swapping the smaller 91-93 throttle body onto the Gen3 supercharger carries the same warnings and risks.

The major differences between the Gen2 and Gen3 Eaton M62 superchargers are that the Gen3 has epoxy-coated rotors to improve efficiency, and also a larger inlet.  Minor differences are the quality of casting, specifically around the outlet area.  See my porting page for more details.  Other than that, the MAF sensor between the generations are different, and the stock pulley sizes are as well.  The difference in performance between the two generations is about 20hp and 15 ft/lbs of torque.  More than that can be gained by simply reducing pulley size, and there are difficulties with the swap you should be aware of before attempting it.

The biggest issue with the swap is trying to effectively run the Gen3 top end using the Gen2-programmed 91-93 PCM.  Air flow, fueling, and shift points will all be incorrect, and without getting a custom eprom burned for the project, you will never get the most out of the swap.  As these cars age, it's becoming less likely that very many owners would even consider this idea.  The parts required to do it correctly are the supercharger, throttle body, MAF sensor, and PCM (eprom) programming.

 

Upgrading a 91-95 L27 non-Supercharged 3800 with a supercharger and manifold from an L67

In simple terms, BAD IDEA.  Read here for why.  You're better off doing a full drivetrain swap.  This would be the engine, transmission, axles, PCM, and wiring from the donor car.  You will need factory service manuals for your year and the donor car's year.  You  may also need the VATS module, ignition cylinder, and other small parts.

 

Upgrading a 91-95 L67 Supercharged 3800 with a 96-2003 M90 supercharger

Not possible, at least not without VERY extensive fabrication and cost.  While both the M62 and M90 are well-suited for the 3800 displacement, the M90's dimensions prevent it's use on a Series 1 engine.  Nosedrive length forces a custom belt path, mounting flange of the supercharger doesn't line up with the LIM and covers fuel injector bosses, and several other problems.

 

 


How they work          diagnosing problems          porting and polishing          rebuilding nosedrives          Swaps and upgrades          Adding a boost gauge         

replacing needle bearings     adding a nosedrive drain          supercharger oil change          pulley size suggestions          links, references, and sources


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