Mazda 20 B engine in SL-C

[David]

It's more that you increase the chance of detonation with a higher charge temp (so you have to reduce power to avoid it going pop) plus a cooler charge is denser so while you might be right from a strict thermodynamics POV its not that simple in the really real world.

IIRC Rotaries really dislike detonation too, even more so than piston engines.

 

[Kyle D]

How about this... Apparently this YouTube guy lowered his rotary engines EGT's by 400 degrees Fahrenheit (204.4 degrees Celsius) just by offsetting his rotor faces and reducing the spark plug hole size in the rotor housing's combustion chamber! Sounds enticing, right?:

https://www.youtube.com/watch?v=m3pCLjHZmhM

Dave/Gary/rotary enthusiasts (like me...), what do you guys think? I think it's worth looking into, especially if you're wanting to reduce the possibility of detonation...

 

[Dave]

I would add that any intercooler can improve efficiency for the short term by spraying a liquid like water or alcohol on the air-cooled portion.

Water spray bars are rice. As for alcohol, the last thing I'd want to do is be spraying flammable liquid around my car. If you want lower than ambient charge temps, run an A2W IC with a reservoir and fill it with dry ice or regular ice.

I've even seen some intercoolers that are plumbed through the AC circuit so that the intercooler core actually sees cooling temps far below ambient, making it possible to send chilled water to the A2W potion of the cooler that is as much as 40 degrees below ambient.

I've heard of systems like that too but never actually seen one.

On the topic of AC, I just realized Gary emailed me a bit ago stating he does not plan on running A/C. That would free up the area on front of the radiator to run a heat exchanger for an A2W system. Unfortunately, I don't have this option as I will be running A/C, and stacking two heat exchangers in front of the radiator would tax the radiators efficiency too much, at least for track use.

How about this... Apparently this YouTube guy lowered his rotary engines EGT's by 400 degrees Fahrenheit (204.4 degrees Celsius) just by offsetting his rotor faces and reducing the spark plug hole size in the rotor housing's combustion chamber! Sounds enticing, right?:

https://www.youtube.com/watch?v=m3pCLjHZmhM

Dave/Gary/rotary enthusiasts (like me...), what do you guys think? I think it's worth looking into, especially if you're wanting to reduce the possibility of detonation...

That guys theories have long been discussed, even before that video. The video reignited the debate and there are a few threads on RX7club.com and others discussing it's merits and shortcomings.

The problem with the rotary is that up until very recently, and still to this day unless you have really deep pockets, is that all engines have been using stock parts with the exception of various after market apex seals, and having to deal with the OEM parts shortcomings. The gap is shrinking though.

There are several manufacturers who do billet side housings and billet rotors now. Instead of steel rotors, these shops are cnc'ing them out of aluminum and one guy working with Mazdatrix is even using titanium. I have held them in my hand and they are light as f~(k and a few prototypes had offset compression chambers. Titanium versions are not for sale yet but you have your choice of several different aluminum versions.

 

[Martin]

Friend of mine posted this pic on Facebook. Should get your rotors spinning

 

[Garry 20 B]

Looks like a plumbing challange

 

[Garry 20 B]

Here are some more pictures of my motor in the car, wiring harness made for the coil packs, and injectors. Going with water to air intercooler, that will be here tuesday along with the oil cooler, getting close to starting up, next couple weeks hopefully.

 

[Jack]

Me likes, waiting for some glorious noise!

 

[Bill]

How much does a fully functional 3 rotor motor weigh?

 

[marc]

That looks Glorious! Too bad most morons will look ask if its electric! LOL! Plus your going to need a muffler that is HUGE to have your neighbors not kill you.

 

[Garry 20 B]

Well, people tell me to run straight, the turbo quiets it down, so I will go with that for now.

The shipper bill was 385 lbs for the motor less the alternator/turbo/and manifold.

The tranny weights around 180 lbs. Another week or 2 and I should be ready to start it up, going to Summit today to get a radiator and fans and Lowes for some copper pipe for plumbing. Finished up my touch screen for starting the car with the Idec and next time I power it up Ill take some pics of that.

 

[Garry 20 B]

My exhaust end.

 

[Jimmy P]

Garry, Like Jack above I want the audio before I see the video....this thing will sound wicked and I like the nice detail at the rear. Well done!

 

[Keith]

Well, people tell me to run straight, the turbo quiets it down, so I will go with that for now.

It will be LOUD.

:thumbsup:

 

[Garry 20 B]

Here are a few of my touch screens to run the car, motor, lights etc.
There is a security screen, then after that is punched in, continues to the start screen and turning on ignition, fuel pump, water pump, fans, etc.

The PLC controlls the blinkers, brake lights, they flash 3 times then stay on, wipers, etc.

I'm thinking I might mount the touch screen in the steering wheel.

 

[Garry 20 B]

Turbo and intercooler plumbing, had to change a few things after I put the body on where I mounted the intercooler the first time, then putting the piece of the roll bar that mounts to the back, became another problem.

Its figured out, not to far out on starting it. Oil cooler mounted, intercooler cooler mounted, everything fits now inside the center section. The first picture shows how I mounted it till I put the body on, had to move it.

 

[Dave]

Coming along nicely. From the pics at least, it looks like you have adequately sized coolers for the IC system. My only concern would be the location of the oil cooler and heat exchanger and getting adequate airflow through them, in particular the heat exchanger, to prevent heat soak after anything more than a 1/4 mile pass. Since you are not running AC, why not mount the heat exchanger up front in the best airflow?

There is another builder who has located his primary and only radiator in that position. I'm sure I'm not the only one wondering how well it will work.

 

[Jon Thib]

THe tube from hte turbo outlet to the intoercooler looks a bit rough. I think a tube with almost a continuous radious would perform a bit better. The 90 on the LH side looks a bit tight. Easy for me to say from the pics as I don'y know about additional interferences. Great job of getting it together. Can't wait to hear the vid.

 

[Garry 20 B]

Well hopefully between the air duct on the side of the car and each cooler have fans on them, the inter cooler has 2, the oil has 1, I do have room to run another oil cooler if needed.

I didnt know that it mattered about the plumbing from the turbo on the 90 degree part, if it will be better for flow, I can make it a radius, or use a couple 45 degree rubber couplers, this is my first experience with a turbo, blowers are much more simpler.

Turned it over today, no leaks, oil pressure 60 psi cranking, all the electrics seem to be reading, TPS, air temp, water temp, oil pressure. Need to finish up the radiator and fuel pump and im ready to start it.

 

[Keith]

Box seat. :lurker:

:thumbsup:

 

[Garry 20 B]

Its running, fired up the motor Sunday, this morning the shop still smells of exhaust.

I dont know how to record the sound that you can actually tell what it is, any body know how to do this?

Have quite a bit of tuning to do, but it started.