It certainly makes no sense to use low compression rotors and either E85 or race fuel on a Renesis. It can achieve the max power potential on the OE rotors and good internal sealing with quality fuel, after which point trying to put more air through it will only accelerate the transition into hyper-boom ....

 

what is good internal sealing?
Where can you get quality gas 100% of the time?
What is the max power potential for the oem rotors?
Or has the conversation turned from talking about a DD car?
OD

 

I believe that with 300rwhp you'd still have a 30\35% margin of safe power increase with a stock, possibly built, engine.
I don't know what to say about quality gas, it looks like what you get there in the states simply sucks most of the time!

Good internal sealing to me is well chosen tolerances and well lubrified apexes so that you avoid blowby\blowback\pinging etc in the long run when the center of the seal doesn't longer seal that much.

 

Flat irons, smooth housings, apex seals with at least a 5mm height and no warping and tight, uniform side-seal clearances.

http://www.toptiergas.com/retailers.html

Choose the company with the smallest presence in your area, the least ethanol and only fill up there between deliveries

Close to infinite since they aren't a failure point.

 

Lol, i read "motor" before and replied accordingly.
Too much grappa on christmas eve's dinner for me!

 

Man--
OK what is a high reliable hp limit estimate for our engine with the 10/1 cr rotors and forced induction? 0?

 

In my humble opinion (and on my personal car), I am not going to exceed 44 lb/min of air.

For me that is too close to the edge for a street car, and I wouldn't use E85 for a street car, simply because I am too lazy for that.

If you are talking about a track car, I would think you could control variances well enough to hit 50 lb/min or more?

 

I would say that this is a very modest goal.

I put 52 pounds as the limit of what the Renesis will breathe on street fuel.

 

I agree it is modest, but then I can run one tune, from 20F all the way to 100F and fill up at the closest reputable gas station when driving around.

For me it really is about laziness (or lack of desire to treat a street car to excessive maintenence); and with that kind of power output I am perfectly happy driving on public roads with the occasional HPDE.

Though I will probably bump it up one day on the dyno just to see what it will do, curiosity did in fact kill the cat.

 

if you don't I may personally hobble over there and kick, or crutch, you in the nuts

 

what makes some of is laugh about this thread is that despite the theoretical compression ratio for the Renesis, the particular people going on about this (and probably a lot who went boom too) more than likely have a much lower real compression ratio due to sealing issues, likely lower than the target goal being discussed here ... so what does that tell you?

 

Lower compression due to poor sealing doesn't necessarily mean much. In that case the engine is failure prone due to the ignition\detonation issues you encounter for the gasses escaping in the next chamber, not because of the compression ratio per se.
Making assumptions with the starting point of weak engine makes no sense imho, we should always consider a properly working unit.

 

I agree that it's not the same thing, but many Renesis engines are poor sealing sieves to begin with. Many FI builds have been with a worn/used engine rather than a fresh build. It's a more applicable assumption than many want to admit ...

 

Just 'cause everybody jumps down a bridge...

 

I just read some racing beat Tech papers. One of which recommended that no more than 5psi of boost should be used on the higher compression rotors. RX8 rotors are included as defined by CR.
Interesting.
OD

 

Better not let any of the Honda guys know about that.
Or Nissan.
Or Toyota.
Or anyone else for that matter.

The Racing Beat (and stuff from similar sources) is decades old for the most part, anyway.

As I have noted elsewhere, the hard seals in the rotary motor have diminishing importance in effective compression ratio as the engine RPMs climb.

 

The math changed since the information was written?

 

5 psi of what? How much airflow, what charge temperature? What porting? How late are intake ports closed and resulting dynamic CR?

There is so much variables to point out such arbitrary figure

Decreasing CR would be silly idea since you lower expansion ratio and it will result in higher EGTs. In this way it will hit brick wall sooner than later.

 

read the paper 999miki. I didnt point it out, Racing Beat did. I dont think they do things off the cuff.
http://www.racingbeat.com/mazda/perf...rcharging.html

I dont think it is wise to compare fi recip engines with the fi rotary?
Different quench, sealing concerns,etc etc.
OD

 

No. Just the variables.

Better not tell Mazdatrix.

Seriously, though.
Once again, you guys are chasing your tails.

 

kinda hard to chase my tail when i am typing on this dang computer.

Too bad E85 is not more readily available. I do have a couple off stations in my hometown
but if I ever went anywhere--i could have a little hard time finding it. And the car would have --what? maybe a 200 mile range?
Sure would be a cheaper thing to do AND provide the cushion I am looking ofr--like Zoom suggested.
OD

 

I don't get why you're stressing on a lower CE and so many countermeasures for your "modest" goals Denny when all you might need is a balanced build with a good ignition system and a rock solid tune

 

Yet another place where the AccessPORT shines -

Two calibrations: One for regular gasoline and another for E85.
Just run the tank out between fills (easy enough with an alligator clip and an extension to the quick-release) and you are good to go.
Of course, on a turbo car, it is just one click on the boost controller to limit the manifold pressure for the gasoline tune.
The SC will require you to just keep your foot out of it, which can be difficult to do....

 

So, turbo/SC efficiency has improved since the Racing Beat study of forced induction RX8s, would this not make it a better idea to use more external compression with the more efficient compressor and use less engine compression for the same goal?

 

qft