Supercharging a 3.4 dohc

[zog09]

What would be the best twin screw supercharger to mod to bolt up to a 3.4 dohc (lq1) engine?

[timg]

Eurosport uses a 2.1L twin screw supercharger for their BMW M3 kits (I think they may have initially used a 1.6L). Active Autowerk used a 1.7L twin screw supercharger.

For a Lysholm supercharger, the LYS 1600 AX might be a little bit small, but would likely work well for a street car. The LYS 2300 AX is the next step up, but might be too big for a street car. Your choice between the two would depend on your ultimate goals.

If you want a Magnuson (not really a twin-screw, but similar), I would go for a MP1900. The 1900 is the latest generation and is fairly efficient. It's between the LYS 1600 AS and LYS 2300 AX in size.

http://www.magnusonproducts.com/mp19006thgen.htm

Tim

[zog09]

How much do LYS 1600 AX superchargers and LYS 2300 AX superchargers cost?

[pocket-rocket]

Google FTW?

[timg]

The biggest issue is that a screw-type supercharger won't fit the engine bay unless it's tiny or you cut the hood. You might be able to get one to fit where the stock battery and airbox were, but it would be a really tight fit. Centrifugal superchargers and turbos fit just fine.

Tim

[zog09]

The biggest issue is that a screw-type supercharger won't fit the engine bay unless it's tiny or you cut the hood. You might be able to get one to fit where the stock battery and airbox were, but it would be a really tight fit. Centrifugal superchargers and turbos fit just fine.

Tim

I was thinking about getting a hood scoop for my car anyways and make a ram intake that hooks to the scoop.

[Jimz24]

Depending on the height needed you might also be able to get away with raising the hood. By raising the side near the windshield you can gain a little bit of clearance.

By a little bit of cutting and height adjustment most custom supercharger setups can be fit in without needing to cut a hole in the hood.

[timg]

If you want to put it on top of the motor, making an adapter to mount to the lower intake manifold is the most common idea. I've done many CAD drawings of what such an adapter would look like. When I realized just how massive a hood scoop or hole in the hood would need to be, I abandoned the idea, went turbo, and wound up with more power. You're talking about a very wide, but not terribly deep hood scoop due to the transverse mounting of the engine.

The best mounting solutions I've seen were the old RSM centrifugal kit, the Magnacharger Grand Prix kit, and most turbo kits.

TIm

[zog09]

Can I just take off the whole manifold and make an adapter that would go between the SC and the top of the engine?

[pocket-rocket]

That depends on how much money you want to spend on custom machining and welding work. You will have to have flanges made that would be like your LIM head mating surfaces, weld some runners and a plenum area. Then you are going to have to ditch your power steering because your power steering pump and supercharger aren't going to like being mounted in the same spot. One of the things that made it easy for GM to supercharge the 3.8l is because of its wide V angle, 90 degrees vs our 60 degrees. That takes out a good amount of room between the heads that could be used.

[timg]

I'd recommend removing your upper intake manifold, mocking up a 2" spacer with a cardboard cutout the size of the supercharger you're looking at on top of it. You'll need a ton of room. You can replace the LIM, but it will cost a lot more $$, be a lot more complex, and maybe not even save you any space due to the narrow space between the two large cylinder heads. At one point, I even owned a M90 from a 3800 because I thought I was going to go that way until I began mocking it up.

Tim