Rotary Response and Racing



Ambient air temperature above 85 F   relative humidity less than 10%

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After working and racing the Rotary Engine since the early 70's most of which have been in extreme conditions there are a few things I have been that help give some reliability for these hot running engines.

We have unique driving conditions, very hot, "But its a dry heat!". Therein lies one of the problems, especially for any blown intake applications. No moisture means very low density altitudes. Another factor: higher altitudes, which means even a lower density altitude.

We have conditions when commercial aircraft can not take off. Because there is not enough air to produce power and the air isn't dense enough to produce lift. I am not going to go into all the physics, that you should all know already.

This page is really geared to the forced air applications for the rotary. We have one of the same problems as a commercial aircraft. We cannot get enough dense cool air into the hairdryers to return good safe HP. Pumping supercharged dry air produces a very lean condition, which as you all know is deadly for the rotary. I constantly get lack of power complaints during the summer. And I tell everyone wait till the temp gets below 85 and we get some moisture in the air. Don't drive the car hard during the day in the summer months, unless you want me to build an engine every year. It would actually be best to be able to disengage the turbos for summer driving. You still have 180Hp to play with and you probably add 20K miles to the life of the engine.

Some facts of life of driving in Arizona.   Surface street temps in front of the shop run around 170F. This is on a lightly traveled roadway. There are parts of the city where you might have noticed that the crossways paint is not a straight line, it takes over 200F to make asphalt do that. Under hood temps in normally aspirated rotaries run upwards of 300F, above 600F in the turbos. 0/5% humidity. Not good for round engines, which as you all know have a tendency to run hot anyway.  Just results of the physics of the design folks.

Recommendations for stock Rotaries out here:

1. Run straight purified RO water with Redline Water Wetter.

2. Change oil as soon as it starts to get any color, impurities.

3. Keep clean air and fuel filters.

4. Keep fins straight on oil coolers. Most have been bent from garbage hitting them.

Reasons for upgrades. I recommend the PFS system because it uses outside air for the intake, because of its design it also acts with a ram air effect. Taking air from in front of the car not from underneath or inside the engine compartment where under hood temps are much higher. Also, his design does not alter the airflow through the engine compartment that much from the original configuration. Because of the lean fire design of all new powerplants, round and reciprocating, engineering of airflow through the engine compartment has become one of the higher priorities of the design engineer. Getting air in and out of the engine compartment for cooling has become imperative. Many add on applications actually change this air flow so that dead air pockets are formed, resulting in higher temperatures. Think about that one for a moment.

PFS cool-charge air box and intercooler installed-

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click on image to enlarge

After seeing many different add-ons I have found that PFS has always performed better at keeping a cooler intake charge. I have had no complaints or problems with any of the PFS products. And all those that I have installed the clients have been very pleased. Reports are coming in of better fuel consumption with the complete FD3S upgrade and performance package.  Rotary Response has developed a Ram-cool-charge system using the stock airbox so the same benefits are gained at fraction of the cost. The original equipment replacement K&N filter works quite well. This system has proven itself in the Open Road race car, which did 165 with room to spare, a top side break out speed limit for the class holding it back.  

I use the PFS* computer because of it being a piggy back system that works in conjunction with the stock ECU. It is programmable and has 3 different boost control settings. It has shown to remove the 3k stumble completely. I use it in conjunction with the Bonez downpipe. Because of the very high chance of over boosting. These spool up really fast once you replace the precat with the downpipe. You can hit 20psi before you can say "Oh c...!" ping, rattle rattle.   I don't like having to do engines unnecessarily

*Since the PFS system is no longer available new and getting very hard to find used I have been forced to look at other options.  Apexi was going to be the replacement. Problems with it are that it is an ECU that is not engineered for US Fed Specification. So therefore will not pass emissions. Other problem is support.  A PFS replacement has been found though,  Greddy has come up with the eManagement system which is pretty much a PFS ECU that has been updated and improved. 20 year newer electronics and software refinement are the main reasons to go this route.  

A couple of notes on boost controllers: Problems I have with them, 1 they are a distraction in the driver compartment, if  you are looking at an LCD your eyes aren't on the road. And if you are so worried about what is on the screen that you are not doing what you should be doing. Enjoying the drive of  the car.   2nd and more importantly, they introduce many points of possible failure. All the vacuum lines that are compromised, added electronic components/wiring are all points that can fail. And if not installed properly, which is more often than not from what I have seen, they have a tendency to do.  

When the main cat goes I install the Bonez cat or factory mazda, which flows well and lasts if everything upstream is correct. 

Turbo upgrade - eFini 99 JSpec turbos are highly recommended, can't beat the price when everything is considered

All porting and engine assemble is done in-house.

Recommendations for upgrades:

1. Stage 1: PFS intercooler and cooler air intake and silencer. This is worth 12.2% I like his silencer because of the nice low note, rumble.

2. Stage 2: Bonez downpipe when the precat goes. PFS ECU or Greddy eManage

3. Mild ported engine and ported intake.

4. 99 JSpec eFini turbos

5. Fender/engine compartment modifications

6. R1 Oil cooler added, Oil cooler protector screens

7. Fluidyne or AWR radiator

Rotary Response & Racing rtrnabttn.gif (895 bytes) Rx for your 7

Tucson, Arizona 85716


27 December 2009 21:33 -0500

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