The 4-rotor 26b engine overview, facts and information by Defined Autoworks.

[@TheRotarded]

That center cooling is really smart.

[@earldouthwright8548]

Impressive work Logan! The 13B you built for 10:21 me years ago was still running perfect. Money well spent. Thank you

[@GTORx7]

Thanks Earl, I'm happy to hear that!

[@christianmaldonado3367]

Thanks for the content, love learning as much as I could about these rotary engines

[@Raczoon]

Pretty! All that advanced work you do, and here in SC I can't even find a tuner that works on rotaries.

[@danunk]

Awesome Christmas present! I really love this type of video, very interesting. Thanks for sharing your knowledge!

[@RGHTBrainDesignDrive]

Superb video, Logan!

[@TwinChargedRX7]

Thanks for sharing. Great video!

[@dragbeast]

What did mazda do that was different 30 years ago to make so much power on the Le Mans 26b engine in the 787b?

[@GTORx7]

They figured out the ideal port timing, intake design, used ceramic apex seals with cermet coated side housings. I've exceeded Mazdas horsepower, but it took a good effort to get there.

[@dragbeast]

@@GTORx7 You exceeded them on N/A horsepower? How much does your car make? I am a supporter of yours by the way, thanks for the info on this vid !

[@GTORx7]

@@dragbeast Yes they made 690hp at the crank, Im doing 662hp to the wheels which is 785-790hp range at the crank. 662 is going to be a old number, aiming to make a good amount more. I appreciate the support!

[@jnmason6283]

I've been looking at the evolution of Defined Autoworks for the last 10 years or so, always impressed by the creative solutions developped for engine and chassis tech. Props on the work Logan! By wanting to emulate the R26B, were there any plans on creating a variable length intake trumpet system to extend the torque curve? What do you think of Judd's twin roller barrel throttle bodies on their V10 race engines vs the slide throttle? I've read it can be "easier" to get decent drivability from them and less chance of sticking, although they are a bit heavier than slides or butterflies. And I've always wondered if exhaust power valves (like on modern 2-stroke sleds) would be beneficial on a rotary... Arctic Cat's latest 858 C-TEC2 has an ingenious servo-actuated power valve system. The idea would be to somewhat control the amount of overlap on a full PP rotary to get more torque and response on the low-end and make it a bit more streetable (might be useless for a racecar, but curious nonetheless). Might make for an overly complex exhaust sleeve, but I haven't seen anything like this tried on a rotary through 60 years of patents. Cheers mate!

[@GTORx7]

Thanks a lot! With any luck at all I hope to release videos and changes I've done over the years but never have shared. In short there is already a variable intake on my car at the moment. The controls for it are being refined so I trust its operation on the race track. So far on the dyno its been incredible. Twin roller intakes are awesome, but weight and space are too large for me to use.

[@galognu]

Awesome Logan.

[@njs461]

At 6:42 you said “the problem with the 4 rotor” and go on to describe the limitation of side port motors, confused. There’s no side port 4 rotor is there? Just 20b I thought.

[@andrewable2634]

Thoughts on Dahm's (or really the Curran Brother's) custom irons that utilize a tungsten coating on the face of the iron? He seemed to have success with it, just wanted your thoughts. Wonderful video.

[@jnmason6283]

I'd say the hardness of the side and corner seals have to match the hardness of the coating, otherwise the seals will be short lived consumables. Lots of patents dating back to the 60's testing out different seal and cermet type coating materials. Some with good results, but the bean counters always have the last word.

[@GTORx7]

I know Rob pretty well and we have gone back and forth on coating types and their composition. I even sent a racingbeat aluminum side housing to him for analysis on a special scanner. The jury is still out, but so far the tungsten coating seem to generate accelerated wear on the oil control rings. Racingbeat used more of a cermet coating and that has been inside my race engine for over 10 years with no abnormal wear of the seals. Keep in mind Mazda on the R26b also used cermet type coatings on every surface. So the science is there.

[@brianfordham4167]

Fantastic info. Out of curisoty do you prefer the single or the two piece ceramic seals?

[@GTORx7]

2 piece for sure. Best compression.

[@ChErRyaVe20pK]

Why does scoots 4 rotor have that smooth high rpm 787b sound while yours sounds similar but kinda raspier like a v8 f1? is this only to do with the exhaust?

[@fourtysevennn]

I hope he answers this too! i am really interested what is the difference between Yukis Kamakuras 4 rotor by scoot & defined autoworks

[@GTORx7]

Definitely the exhaust is unique on my Rx7 compared to all the others. It's a 4-2-1 system, while the 4 to 1 collection is everyone else. 4-2-1 has proven to make the most power, but uses more fuel. This is why the 787b did not go with this setup.

[@wrighty338]

I like the V-band exhaust and love the slide throttle. Im surprised that such a small dry sump works but it is a small motor overall. Do you have figures on the coolant temp differences between your system and lets say a "stock" 4 rotor coolant system?

[@GTORx7]

I have never placed a "stock" 4 rotor on a dyno with temperature probes in each housing to see what the difference would be. Possibly in the future I can test this out and give actual number value. I do know that a single temp sensor on the outlet of the waterpump will not show the problems. The rear rotor will start to steam and cavitate, but quickly cools down on its return path to the outlet and factory positioned sensor.

[@alexkyriakidis6580]

If you use a 12a intermedia iron you can solve the intake side port problem?

[@GTORx7]

No, still not the same size as the secondary runners. Additionally the coolant seals are not in the irons.

[@Subar_Sama]

Everyone talks about power, but.. how much torque could a 26B engine make?

[@jnmason6283]

This engine makes 662 wheel hp at 9200 rpm, that means it's making 378 lb-ft at 9200 at the wheels. I'm guessing the peak torque would be around 6000-6500ish rpm, probably around 430-450 lb-ft at the wheels. Really depends on the application. A 4-rotor built for 10,000 rpm like this one won't be making as much torque as one built for 7500 rpm with much longer runners and port areas designed for low-prm intake velocity.

[@GTORx7]

Mazda made 450ft-lbs at the crank which is roughly 382tq to the wheels. Mine is right at 400tq to the wheels, or 470ft-lbs at the crank.

[@luimedina5542]

Why are short crank 3 rotors not good for boost but 4 rotors can handle boost? they both have a intermediate plate machined for stationary gears

[@Vipurs]

Good stuff

[@breakupgoogle]

Good tech info

[@bobdavis2807]

Why did you not do the whole engine out of billet would the middle stationary gears crack easier because they are cast

[@dongarrett9735]

What about a Six Rotor?

[@GTORx7]

What question exactly do you have about a 6 rotor?

[@dongarrett9735]

@@GTORx7 Can one be built?

[@GTORx7]

@@dongarrett9735 Definitely I can build a 6 rotor anytime.