IT Rotary Engines

[Andy Bettencourt]

Steve,

They are asking for dimensions. Templates won't tell them any hp increases but at least it's a good step 1 in a protest to see if anything externally has been monkied with.

Just like a piston motor, like I said a ton of posts ago, you are going to have to take them both apart and go the extra mile.

If you think there is an issue, have your stock rotor housings ready and in the wrapper. Heck, pay for them and have them shipped to your chielf of tech for him to 'stock'.

[GKR_17]

Is it safe to assume that material usually isn't added when port work is done? If so, would it be possible to spec a volume, and use a similar process as would be used when checking compression? Or is there too much variation to be useful?

[Andy Bettencourt]

Porting for performance like Steve said is done internally to the intake ports.

I still get weirded out when I see missing fins in the exhaust ports.

[seckerich]

You don't get it andy. Anything short of a cad drawing will not even get you close to port shape. Have you ever even looked at one of Nicks motors? The only part of a rotay motor that gets machined at the factory is the first .050 in the cast iron face inside the motor. That is nothing you or anyone else have the tools or expertise to check at the track. A flat template is a perfect tool. Matches perfect, it is legal.

Grafton the only way to add material is with JB weld or similar. Housings are cast iron and then gas nitrided for wear from the factory. It is removal of material that cheats them up. Look at it as adding 20 degrees duration to a cam if you move the wall of the port. It leaves the intake open longer and has a little more volume. The runners are cast and vary so no port volume will tell you anything. Besides, flow is not always better on the bigger ports. It is really not this hard guys.

[MMiskoe]

At the risk of a thread derailment, I am curious to hear the opinion of the rotory guys who are here & appear to be pretty smart on it all.

Long ago I was told by a guy who'd built a few Wankels that if a 13B motor won't idle at 1000rpm w/o loping, its had some port work done. Is there any truth to this?

Although it hasn't happened in a while, there used to be a time when there was at least 1 RX7 on the ITS grid that either idled at 2500rpm or sounded as smooth as a Harley Davidson.

Matt

[Andy Bettencourt]

A flat template is a perfect tool. Matches perfect, it is legal.

This is what I have been suggesting the whole thread Steve.

Matt,

Massaging the ports is like changing the cams on a piston motor if you had to make a comparision, so yes, a loping idle is usually indicitive of some porting.

[lateapex911]

Not always.

My loping 12A has been thought to be ported, but the guy who did the carb insists that the carb setup he recommends is fastest, and it results in a loping idle. I can change carbs in 5 minutes, and have done so for doubters. With the race carb, it idles and runs like crap down low. Then I put the stock carb on and it idles great, purrs, but has no power. (Working on a best of both worlds combo).

My understanding of the 13B isn't as deep as my 12A knowledge, and that's not all that great as is, so I'll leave it at that.

[xr4racer]

You guys are thinking that this is going to happen and be done right are dreaming. The tech shed at the runoffs last year could not even measure a cam and valve lift in a Ford V8 AS engine. SCCA started a whole committee to investigate why everything was so messed up and this was in our premier national championship event. I for one hope all of the cheaters are ran off, but I doubt it will happen.

matt

[lateapex911]

Matt, as guy who's been on the wrong side of a screwed up protest for reasons similar to that, I hear you.
BUT, Ron and Jeff and Steve P are trying to work within the system to make it better. If the system isn't used, it will rust, and never work. But by USING the system, kinks and bugs get fixed. While I might be coming off as a detractor in this thread, (I hope not, but...) I'd prefer to think of myself as a devils advocate, ...but no matter what, I applaud the efforts, want to see them continue, and hope that success comes their way.

[Andy Bettencourt]

I think the main goal here is simple:

Give some guys who race against these cars some templates and basic dimesions and illustrations so that IF they protest, they have something to reference upon initial teardown.

To me, you then decide if you want to have the pieces shipped off to Topeka for the official decision based on what you see inside.

Jake: Hence the words 'usually indicitive'.

[JeffYoung]

That actually sums it up nicely Andy.

[Ron Earp]

That actually sums it up nicely Andy.

I agree.

And, I apologize if anyone on the thread has felt that I've posted misinformation about the topic. I don't know these engines well but thought the situation was important enough to start a discussion over.

Incidentally, I've always been interested in the wankel engines. My father used to write for model airplane magazines in the mid-70s when I was around nine or ten years old. Companies would send him products to test and I remember him getting model airplane engines to test out, a wankel engine and a radial engine. Both were obscenely expensive and produced by a German company (I think, don't know the name). Anyhow, he had a test bed airplane he used for this sort of thing and tried them both out. The wankel was just about impossible to get started and always was trouble but made a hell of a noise when running. Once I learned the engines were also in cars I always wanted a RX7 but never did manage to own one.

[lateapex911]

The wankel was just about impossible to get started and always was trouble but made a hell of a noise when running.

Sounds about right, LOL. They DO like things a certain way!

Once I learned the engines were also in cars I always wanted a RX7 but never did manage to own one.

No, you didn't, you think they're shitboxes!

[Ron Earp]

No, you didn't, you think they're shitboxes!

No no no. RX7s are race cars. Front engine, rear wheel drive. The natural way of things.

Now, if it was a FWD car, particularly of the hatchback variety, four door or two door, then yes it is a shitbox. And of course I'm not 100% serious. A bit serious, but but 100%

[lateapex911]

I hear ya, LOL. You're only 99.8% serious.

Didn't Mustangs come with hatchbacks and 4 cyl engines for a while? Was it the sophisticated suspension that kept them from being shitboxes?

[Ron Earp]

Didn't Mustangs come with hatchbacks and 4 cyl engines for a while? Was it the sophisticated suspension that kept them from being shitboxes?

Nah, RWD keeps them out of the sheetbox category. As for those four banger pinto motored stangs, I had one that made a bit over 300hp, at the wheels. In the 90s that was some pretty serious street fun, although nowadays not so much.

[JeffYoung]

The defining line between shitbox and piece of shit is definitely FWD/RWD.

Ratty ass old GTi? Shitbox.

Ratty ass old straight six Camaro? POS.

I'll lick a lollipop to that!

[C. Ludwig]

Long ago I was told by a guy who'd built a few Wankels that if a 13B motor won't idle at 1000rpm w/o loping, its had some port work done. Is there any truth to this?

Matt

This is just not true. We build and tune mostly fast street cars which are mostly all "street" ported. With good tuning you can get a pretty aggressive street port to idle smoothly at 800 rpm. Now that programmable fuel injection is legal it would be easy for someone that knows what they're doing to pass off a street port in terms of idle characteristics.

If idle characteristics are the factor used to judge, more people will be indicted on the basis of poor tuning skills that actually cheating.

There is porting that will cause a loping idle, but I can't believe anyone would think they'd ever slide such an engine passed anyone in terms of tech.

[ddewhurst]

I have read only patrs of this thread. With the subject at hand, has anyone talked to Topeka/Jesse Prather/Dave Lemon. It is my understanding that Jesse & Dave had gone through this whole deal & forwarded a plan to Topeka several years ago.

[seckerich]

I have read only patrs of this thread. With the subject at hand, has anyone talked to Topeka/Jesse Prather/Dave Lemon. It is my understanding that Jesse & Dave had gone through this whole deal & forwarded a plan to Topeka several years ago.

That was for the definition of "street porting" in EP and they have pictures and guidelines on the Mazdatrix site as well as SCCA links. Stock is stock, no need to define it.