amp

anyone know what temp ranges the exhaust port side surrounding the sleeve are generating..

Lynn E. Hanover

Send me in coach, I know that one.



With a bridge ported 12A with two 38MM chokes and timing at 27 degrees BTDC, and the probes sitting 3 inches outside the ports, we are looking for 1575 to 1600

degrees at top RPM around 9,600. This is well rich of peak EGT that could be above 1800 degrees.



Important pieces start to get soft at 1800 degrees.



The stainless liners are too small to leave in the port on a 12A, but the 13B has much bigger liners, and nearly all tuners leave them in the port to help insulate the rotor housing.



More is better. In this case more fuel is better. A bit lower flame temp. Lower front velocity. If you mix oil and fuel, more oil. If you have a choice between 1,550 degrees and 1,650, 1,550 will be better for long life.



Best power is just rich of peak EGT. Maybe 75 to 100 degrees rich of peak.



But best power is just real close to too much temp for the apex seals. And each setup has a different max EGT. You have to lean past max EGT just to determine what the max is, so you are in violation just gathering the data.



This is only a factor for those who use the engine to the limit and for extended periods. Short periods in violation of the prime directive are seldom punished.



Everything affects everything, so the EGT is changed by anything else that changes. Fuel octane. Ignition timing. Engine RPM. Load. Inlet air temp. Boost. Plug heat range. Back pressure. Lubrication. And on and on.



Is that what you were looking for?



Lynn E. Hanover

hazard80

WOW That is great info LEH, do you get all your knowledge from racing experience and practice etc. or have you done some sort of formal rotary education? Who teaches stuff like that? (Sorry to thread jack here, I'm just curious as to your background

mazdaspeed7

Id like to add though, that the housings never get that hot. I have had no adverse affects from not running the sleeves on my SP 6 port. I havent had any cooling issues at all, even in 80+ degree weather sitting in stop and go traffic for 30 min.



Lynn, that is very good info. One thing I should mention though. Tuning via EGT's is something where you *really* need to know what youre doing to not kill the engine. Its slower to react, and much harder to read. There are more things that affect EGT than the a/f ratio, which you mentioned. If you dont really know what youre doing, youre shooting in the dark. If you guess wrong, it could be the end of the engine.

RETed

I agree with Mazdaspeed7 - I think the fact that the housings are being cooled by the coolant flow, so the EGT probe is seeing 1600F in the center of the exhaust gas flow but the sleeve would probably be more like 1000F.





-Ted

Lynn E. Hanover

There is a special little dash board on the passenger side of the cockpit that has a tach, oil temp water pressure and two EGT gages. When the car is on the track there is a video camera trained on that little dash. It is zoomed in so that the gages are easy to read.



The EGTs are not slow at all, but go up and down like a tachometer. The engine builder wanted to always use WOT in 4th at 9,000 RPM as the base line for all tuning. So it is required that we pause the tape as the tach hits 9,000 and read the EGTs. There is no way the driver could get that reading done even once in a session. The needles are moving way too fast. It is just not possible. But it is easy with the video machine.



The rotor housing with the liner runs cooler than without. The liner acts as an insulator. But it has been ages since they ran just a hole in the aluminum. The liner reduces housing temperature and keeps the EGT higher. At first to make the big cast iron reactor hotter and working better. And later to keep the monolith at operating temperature for better emissions readings.



In the 12A when the liner is removed, a replica of the outer part of the ring is installed so as to avoid the big step in the runner where the liner has been removed. The liners are harder than the hinges of hell, and very difficult to port, so most builders discard them and install the aluminum replica and match that up to the rest of the runner. The 13B liners are so big that in nearly any application you can leave in the liner and it will work just fine.



I have been thrashing on rotaries since 1980. With good luck and lots of fun. I just got tired of breaking connecting rods.



I took apart a 12A this morning that had been serviced by a major builder. Found and old wire corner seal spring amongst the new style. I found a rotor bearing installed out of index and the resultant bearing damage. I found a main bearing installed with the tab out of index and damaged. This thing had less than one hour on it and the bearings are trash.



Look at the rotor bearings. There is no reason for this bearing to be indexed in any particular position. Grind of the tab completely before you press it in. You cannot go wrong. And there will be no damage caused by out of index installation.

The same thing goes for a racing rear main bearing. It has three windows in the center groove. There is a groove in the stationary gear below these windows.



Not so the stock bearing. If you press a racing bearing into a stock stationary gear (without the oil groove) be sure to check that the oil passage is not closed of by the bearing. But the racing bearing still has the indexing tab and there is just no reason for it. Grind it off and save yourself some grief. I also radius the three windows in a new bearing. It probably has no affect at all, but it makes me feel good.



Some front main bearings have oil windows that mismatch the oil passage a good bit. Get out the die grinder and open up that new bearing to match the whole gallery opening.



This engine was not built by a pro. In fact I evened up some of the port lines once we had it apart. I am helping the owner who left water in the block over the winter and popped out some core support plugs.



Also keep in mind that a big shop has many people who are assembling engines. I will show some pictures to the builder when next we meet. Even so, you have to get the basics right.



If I can get this picture to load, you can see the extra dash.



Lynn E. Hanover

vosko

that is a MEAN race car !

93 R1

Hell yeah. Thats sweet

White_FC

Soo....... that FD race car runs a 12A?



Class rules obviously?

Lynn E. Hanover

Thank you for asking.



No formal training. Just a car, engines, airplanes, and anything mechanical nut for



about 55 years.



I have a web page that my daughter put together for me years ago.



http://www.members.aol.com/lehanover/



I have been building race cars since the 70s and rotaries since 1980.



This RX-2 was built for drivers school. Then ran in IMSA as Racing Stock class car.



No bridge ports were allowed, so some clever folks came up with a finger port.



Think about that for a while.



Then into SCCA enduro races. Then SCCA GT-3 class racing. The picture is from one of the three years of Columbus 500 races. Note the parking meters behind the fence.



The small cars did an hour long race and the big cars did 500 miles. Through the streets of down town Columbus. All on television. That was in the early 80s.



Lynn E. Hanover