Renesis Must-Haves for Racing Use?

Let's say I want to pick up one of the many, many dead S1 RX8s I see for sale and rebuild the engine.  What does it need to be reliable in racing use?  I see that coils can be an issue so I'd plan to replace those.  Might as well delete the oil metering stuff and run premix too.  And add a big berkeleying radiator.  What else would be needed "while I'm in there" if I want it to survive lots of high rpm action?

an LSx?

In reply to bobzilla :

Let's assume class rules say I need to keep it a magical brapbrap triangle motor.

I'd like to know this too. I keep looking at the very cheap engine/trans combo from my local importer. Pretty sure I need a project with one of them in my life. 

¯\_(ツ)_/¯ said:

In reply to bobzilla :

Let's assume class rules say I need to keep it a magical brapbrap triangle motor.

an LSx under the Renesis engine cover? 

Sorry, I'm merely full of jokes this morning. No meaningful help available at this time. 

They seem to do well as long as you keep them cool and keep oil in them. Had a friend who ran one in TT and the harder he ran it the better it ran. They do seem to have a finite life, but that's years of racing at stock power levels. 

mazdeuce - Seth said:

They seem to do well as long as you keep them cool and keep oil in them. ... the harder he ran it the better it ran. 

This is what I want to hear.  The second coming of the 13B from my FC.

A spare on the shelf for when it inevitibly blows.

A masters degree in chasing failed sensors and weird/unique parts that are necessary to make them actually run.

Want one to start on?  I bought a thousand dollar '04 last summer and it's gone around the block a couple of times but no amount of wires/coils/plugs/tinkering makes it want to stay running.  Anything close to what I gave for it and it can be your headach......project.

There have been conversions on here before about the most reliable type of engine for crap can racing. if I recall, against most expectations, magic spinning Doritos were heralded as the thing to have. Surprisingly SBCs had a poor track record. I think stock rotaries love to be thrashed mercilessly.  

¯\_(ツ)_/¯ said:

mazdeuce - Seth said:

They seem to do well as long as you keep them cool and keep oil in them. ... the harder he ran it the better it ran. 

This is what I want to hear.  The second coming of the 13B from my FC.

They are. As stated, the difficult bits are electrical, but unless you try to push boost into them or otherwise think that they need to make all the wheels power, they are quite reliable on track. 

This is a really good question and I like where this is going. 

Can you just run pre-mix in a Renesis? I'm pretty convinced the reason my 12a is still running is because all of the owners for the past few decades have run nice healty pre-mix through a basically stock motor. 

As a former RX8 owner I've had to stop looking at cheap ones because they seem so tempting.  In a race environment I'm not sure there is anything magic about keeping the rotary alive, keep oil in it and keep it cool like any other track car.  If you're running pre-mix that solves the oil metering piece.  I never had issues with my wife's RX8 just kept an eye on oil and stop at every gas station because the tank was small and the motor was thirsty.

In reply to KyAllroad (Jeremy) :

Kind of, but you're a little far away for an impulse buy.  If I'm planning to be in the area though... yes?

Re-route the coolant overflow so it doesn't drain on top of the wiring harness/connectors for the electric power steering rack.

If you have the ability, I'd say rip out the electric power steering rack and replace it with something that doesn't fail over and over (I went through three of them in my RX-8).

I've wondered the same thing. Maybe I'm crazy, but I feel like it would be quite satisfying to do a rebuild on one of these and then be able to drive it. 

Brett_Murphy said:

If you have the ability, I'd say rip out the electric power steering rack and replace it with something that doesn't fail over and over (I went through three of them in my RX-8).

Not knowing much about these, I wonder if a de-powered miata rack would work. I do have one sitting around. 

AWSX1686 said:

I've wondered the same thing. Maybe I'm crazy, but I feel like it would be quite satisfying to do a rebuild on one of these and then be able to drive it. 

Either you're not crazy, or we're both crazy. Smart money on #2. 

LS2 coils and a clutch pedal reinforcement are common items.

I've heard of people premixing the S1 RX8 because the S1 motor didn't include an oil squirter (edit: misnomer. There are squinters but they system is very different in the S2 to address seal wear.)

Unfortunatley you can't just "delete" the oil metering pump and run premix. I bought mine with a mostly hosed engine that was stuck in limp mode due to a failed OMP sensor. The sensor isn't available, you have to buy the whole pump assembly. I cut the sensor open to see what failed. With 115k on the clock the wiper arm had worn right though the carbon track, not really fixable. There was some additional logic switches built into it as well so retrofitting a TPS sensor wasn't an option either.  You can keep the OMP functional and add premix on top of that of course.

I also think it's BS that mazda runs 5W20 in the renesis. The clearances are the same as the old 13B. 

The temp and oil pressure "gauges" are really analog idiot lights. I would run some real gauges. Along those lines I'd consider upgrading the oil cooling. The stock ones are nice but they are run in series with 10 miles of 1/2" line and hotter thermostat. I'd re-plumb them in paralell and either swap for a colder thermostat or ditch it for reliability. 

I've wondered if E85 wasn't a good idea (with tuning and proper syntetic premix oil). The Renesis runs premium anyway and lower EGTs should help keep the side seals alive. Water/meth injection?

i like where this thread is going. I know an RX-8 will never be a contender in Chaumpcar but we're looking for something with RWD and cheap to acquire (running is a separate expense). Another box is something that not everyone else has (E36/46, Miata, etc). 1st or 2nd Gen Odyssey is something else our team is looking at....but RX-8....yes let's continue. 

I came here to reinforce the clutch pedal reinforcement. That broke on my old  S1 RX8. Other irritating warning lights are coolant level sensor that is built into the coolant overflow tank, have to replace the tank to replace the sensor. Another one which may not be an issue for a race car is the HVAC temp selector, it's not a rheostat but a circuit card that crack the solders. Have heard about the LS coils but never tried it, that was never an issue on mine.

In reply to RXBeetle :

That seems like it's a question of what the ECU wants to see from that sensor then- I wonder if any aftermarket tuners have figured out how to spoof it.

In reply to ¯\_(ツ)_/¯ :

You should be able to turn off/ignore the sensor input with Versatuner.

Rotary Aviation also sells an adapter for the Renesis which gives you the ability to run uncut premix oil directly into the OMP at a 1:100 ratio. I was debating getting one for the RX-3's motor but it looks like they don't support the mechanical OMP any more.

The fuel pump can pull air at ~1/4 tank. You might want to consider a fuel cell. The fuel consumption is a bit of an issue for endurance racing, you definitely won't make it 2 hours.

They're great cars and have great controllability which would be useful for endurance racing. They have excellent factory brakes too, very useful for overtaking maneuvers.

As mentioned above, I would definitely run a thicker oil than speced from the factory.

I'm not sure that removing the OMP is all that necessary. I don't think they were a major point of failure like on the now very old RX-7s. Why not just add some premix for insurance and call it a day?