986 3.4L Supercharged coming soon!
 

We are in the process of installing a supercharger on a 986 with a 3.4L 996 engine. I know that it is a risk supercharging a 986/996 engine but I think it is worth it :).

The supercharger is being installed next to the AC compressor on the left upper side of the engine using also an open filter (that will get a heat shield).
New injectors have been installed that can flow up to about 460 HP.
A recirculating blow-off valve is also being installed.

Hopefully the engine will start again today and coming Tuesday it will be strapped on the dyno for further tuning. My aim is 400 HP at the crank (at about 4 PSI Boost).

Now let’s pray together that it all ends well :D

Hello, Edreamsz.

My Boxster S is stock, but my Mazda Miata is supercharged at about 6 psi. I'm sure you've done some research and are aware of the issues involved in boosting a motor that was not designed for it. The two things I suggest you take special care about are engine cooling and ignition timing. The denser fuel/air mixture will require some spark advance, which will follow a curve based on RPMs. I've found that a programmable, and real-time adjustable, digital ignition control box is useful.

Cooling of the cylinder heads and the exhaust stream is trickier. The Boxster's exhaust path is short. You could actually melt the catalytic converter's guts if you're not careful. Or, just use a non-cat system. A high-flow water pump should be enough to keep the heads cool, but maybe not. Do the thermal calcs to see if the radiators will be able to shed enough heat.

Good luck with the project. It will be fast and fun. Do it right and it will last longer.

Cheers,

Dave

Following!!!

Please share some pictures of your setup. I removed the AC compressor from my car and I've been wondering if a supercharger could take its place.

Hi Dave,

Thanks for your reply and suggestions.

The correct air/fuel ratio will be achieved bij reprogramming the DME and the cooling has been increased by installing a 3rd (center) radiator. I also installed 550cc injectors and a new fuel pressure regulator.

I will make some pictures one we clean the engine bay :)

371 HP / 420 NM at the crank @ around 4 PSI Boost! I was aiming for 400 HP but this is a very nice first step. In the future I would like to increase the boost to about 4.5 and install larger 380 CC injectors (the 550cc where sadly to big). That will bring it to about 390/400 HP I hope

The stock injectors cannot go further than the above stated numbers. I am at work right now prohibiting me to drive to the Porsche tuner and pick te car up! Can't wait to drive the car again :dance:

I will upload some photo's soon!

Is this a kit or something you designed yourself. I have a 3.4 too and would be interested in more info. Congrats and thank you. - J

It is a custom design. We used a Raptor V supercharger (Australian brand) a recirculating dump valve, custom fuel rail for the left fuel rail, etc. I still have to do some fine tuning.

• The 550cc fuel injectors are too big so we are using the factory ones (around 290cc) but they are being pushed to their limit. (5 bar fuel pressure and max 90% duty cycle). I really don't like that so we are going to install 440cc injectors instead.
• The air intake/filter is in the engine compartment right now and it's not to my liking, so we will have to think about another way to position the air filter so that it gets colder air.
• And the boost pressure drops after 6250RPM. We think that it has something to do with the dump valve.

Pictures and videos please. :D ;)

Regards, Markus

+1 +1 +1, hell +1,000! lol. Please and thank you :cheers:

Sorry guys for the late reply. I am on vacation and will be back home in about 2 weeks. After that I will continue working on the car and make pictures! (Promise)

I still have to figure out how and where to move the airfilter. Right now its an open filter in the engine compartment. I think that i'm actually losing HP because of the heat in the engine compartment.

I read about a company called VF superchargers based out of california. (No affiliation) I figure if JAAY has the 996 3.4s and the ecu to go with it, you may be able to use the supercharger kit for the 996.


@ Edreamsz I think it is awesome you are supercharging the beast! Can't wait for pics either.

Thanks for your comment. I'm enjoying a vacation here in the South of France but cant wait to work on the car again.

Things to do:

Replace th fuel injectors with 420cc matched injectors
Redesign the connector where the dump valve and AOS/Catch can connect just before the Supercharger.
Find a place to get fresh to the intake filter: Right now the airfilter is in the engine compartment and the supercharger sits just in front of the air inlet for the original airbox. Any wild ideas in how I can get fresh air to the filter? (Air intake from inside my rear luggage bin?) :)

How do you arrive at your HP figure, is the engine out of the car?

Install a 987 air filter box & MAF tube & 75mm throttle body along with the 996 DME program for that MAF tube. Search this forum for install instructions.

How are you getting on with this.? Been over a month now dude.
Need pics...!!! :D

How is this coming along? Would love to know more about it