Conventional wisdom tells me to never run any type of forced induction with out some form of intercooler, be it turbo or supercharged. That said, I do see alot of low boost OEM supers running without an intercooler.

So my question is, if we assume that the FI for the 8 is going to be some form of supercharging, and the idea is to go for a mild 4-6lb of boost, would you have to have an intercooler?

For that matter, has anyone ever actually supercharged a rotary engine? I've never read of a case, but then again, mazda did most of the hardwork by offering several RX7's with factory FI

 

A lot of second gen rx-7's use superchargers. Reason being that the non-turbo set up's were totally different in that they had 6 ports so you couldn't just go buy a turbo off a TII. The superchargers for those are like $3K. SunFlower motorsports makes a BADASS supercharger for the RX-8. Looks like a Vortec for a Honda Civic. Nice chrome housing. 100 HP bolt on. Comes with an aftercooler I believe (don't quote me) To answer your question about the intercooler, you really NEED to run an intercooler with any forced air setup on a rotary for the simple fact that they just run so damn hot. For the life of your engine use the intercooler.

 

Don't be worried about words like aftercooler and intercooler. As far as I'm concerned, the two are analagous. Using an intercooler is case-dependent. In an ideal world, an intercooler would just lower the temperature without lowering the pressure. This is a good thing. Unfortunately, we don't live in the real world, and since the intake charge has a transient effect, there is also going to be a significant drop in pressure. The size of the intercooler can be a culprit for pressure loss. Too large of an intercooler will lower the temperature a great deal, but the trade-off is a large pressure drop across the intercooler. Too small of an intercooler would have a lower pressure drop, but also a lower temperature drop. In addition, too small an intercooler can lead to heat soak, turning it into an inter-heater.

For something around 4-6 psi, I don't believe an intercooler is absolutely necessary. A good method though is to pick the right size intercooler for the application.

Some cars, such as the Mazdaspeed Protege have a factory intercooler that comes with it. But, from what I hear, this tiny intercooler is prone to heat soak, making it an inter-heater during hard use. Reheat for car engines is bad. The design is not a bad one, but it is not a good one for hard driving.

Companies like HKS make turbo kits that do not come with intercoolers, simply because they don't make sufficient boost to actually heat up the charge too much.

 

Brillo:

All I can say at this time is that there is a Supercharged 8 out in final testing stage and it does have an intercooler. In fact the car I am alluding to is in the hands of one of the car magazines for testing and more info will be available in several weeks. I drove the car during the ECU mods and under power it was a great improvement.

Stay tuned for more from South Florida.

 

Drool.

 

Where in So. Fla.???

 

All I will say is that I live just west of West Palm Beach and there is locally a Rotary speciality shop. Start foaming at the mouth, it's for real this time and a major improvement over stock. :D Their car has a lightened flywheel, midpipe change and I think a borla cat back system, plus numerious suspension upgrades.