Gomez

Good point...

Gomez.

AMG

Hymee...........christmas of which year??? :p :p

Seriously, haven't been on rx8club recently because of a lack of time and I stumbled on this thread. Well done with the foresight to take on this project.

Though it is still early days have u considered what kind of warranty will be provided?

Hymee

iTrader: (1)

Honest answer: Yes I have.

Cheers,
Hymee.

AMG

care to elaborate?

Hymee

iTrader: (1)

The Opcon Autorotor blower has a 12 month or 60,000 km manufacturers warranty, if that is any help. Other than that, I am thinking about that issue. I don't intend on putting something to the market with my name behind it if it is rubbish. Obviously, I can't warrant anything I haven't supplied. Lovely stuff to think about!

Cheers,
Hymee.

PS - Nice avatar change!

NT Rotor Head

Fantastic work Hymee, I'll be eagerly awaiting updates, and the completed project. Count on me for an order!

Turbine_pwr

Hymee,

As you already know, your plan is a good one. I thought, based on our earlier conversations, that you might be using the parts we had talked about. I think this will be a very successful project and look forward to following your progress. Good luck with your efforts.

arr ex eight

so will there be an AUTO application or just made for MT?

zyran

It should work for the AT but you may have to get higher performance auto transmission parts (torque converter).

shelleys_man_06

What do you think the stall speed should be changed to to support, at the most, 400 rwhp?

Hymee, what do you think about porting the engine along with the supercharger?

Hymee

iTrader: (1)

Since this is a "bolt on" I have not considered porting. And if I did, it would be pure speculation until some extensive experimentation was performed.

Cheers,
Hymee.

Racer X-8

I wonder what the new rpm barrier will be. Still limited by the coils?
Ref: my talk with CZ about this.

Hymee

iTrader: (1)

I'm not sure if I understand the question. I have not proposed to alter the rev-limiter.

Cheers,
Hymee.

Racer X-8

Ok, let me expound a little.
CZ suggested that perhaps the power drops off at high rpms due to the stock air flow limitations. Wouldn't a supercharger blow that limitation out of the water? Still there is the limitation of the coils being able to keep up. CZ also suggested that as a limitation. Then, there are others such as the eccentric shaft bearing support. But with higher rpm capability, wouldn't that completely take the engine to a new level? A highly modified engine could maybe get to 11,000 rpm. Now, I am not suggesting that a stock setup would go to 11,000 rpm redline with your setup, but couldn't it be the answer to its ability to breath up there? And perhaps a stock setup might could get to say 9,500 rpm without complications?

Hymee

iTrader: (1)

Yes - a supercharger should "blow that limitation out of the water" to a certain extent.

I am not suggesting we go any faster than the coils are already designed to run at.

I know race prepped RE's go at 11,500 quite regularly. And the modifications are not so much in the rotors or the bearings or the housings. It is in the porting/breathing, better seals etc. Initially I'm not trying to go there with this mod.

Perhaps the limitation on RPM (other than the PCM's RPM limiter), is the timing of the ports, hampering the breathing? In a FI application the postitive pressure will punch more in that what can get in under atmospheric. I have never seen a MAP graph showing if there is much of a restriction at high RPM. I do know with the MAF logging I have done, the air floww does start to ease up in the last 500-1000 RPM, and hence the ease off in power. (The power actually stays pretty flat right up top, from the dynos we have done). That is fairly typical of any engine really. Yes - it is all related to the intake restrictions and port timing.

Cheers,
Hymee.

robertdot

Others say that the stock engine starts to have harmonic imbalances at around 14K RPM. If that is true, 11K wouldn't be a problem in stock form.

Racer X-8

Ah! Yeah, it's that "punch" that I was getting at - good word for it.

Port timing. The time it takes for the flame to propagate / the burn to complete acceptably before the exhaust port is exposed. Can that be a major limitation with the side porting?

In any event, one step at a time. First, the supercharger, then, the 4mm apex seals, the modded porting, the center bearing... right?

oh, hey there robertdot, didn't see you there. Yeah, that's good news! Is that while actually combusting? Not, right? I'm thinking gurumotorsports eccentric shaft for a Renesis.

rotarygod

Power should always drop off a little before fuel cutoff. You want your peak horsepower to be within about 1000 rpm or so of what is considered the max usable rpm. This is based on tuning length of the intake manifold and overall flow limitations of the ports. Port timing also plays a role to a point. The reason you want power to be going back down at this point is so you get the maximum average amount of usable power that you can for the entire rpm range. You do not want to shift when your power is at it's max point.

It never seems to amaze me why people always want higher rpms. The faster then engine spins, the less reliable it is. This even applies to purpose built race engines. The older rotaries rev nice to 8000-8500 rpm and people want more. The Renesis can damn near hit 10,000 and people want more. This is entirely ignoring the fact that you are risking your very safety in the event that the flywheel explodes and sends shrapnel through the floor board. You'd at the very least need a scatter shield. The intake manifold can't flow enough air to supply a faster turning engine and make power. The port timing isn't optimized for this powerband. Your gearing isn't setup for this powerband. Your ignition coils can't handle it. They can barely handle what you got. Fuel consumption goes way down. If you get a power gain up top, you have to lose down low meaning your gas mileage will drop. The engine runs much hotter. It is much harder on the oil, etc, etc, etc... When are higher rpm's finally going to be enough. Yes it would be cool but time to come back to Earth and face reality. These aren't pure bred race cars with limited lifespans and millions in financial backing to fix them. These are street cars that have to do other things well and with a degree of reliability.

The stock powerband is great. Try finding ways to improve it before you try to get to a whole other rpm level. If you haven't maxed out the potential of a lower powerband (not one has!), you shouldn't be touching a higher powerband. This is learning how to run before you learn how to crawl and it doesn't work.

robertdot

I assume while combusting... otherwise, what is the point.

In the mean time, I always appreciate hearing rotarygod's insight, which seems like the absolute truth at this time. We need to get it right where we are, then talk about moving above our current threshold.

Racer X-8

Rotarygod, perhaps I should have started all this with "Don't try this at home!" Hehe. It's eventually where the Renesis might eventually go in the racing world. I'm not refering to a backyard weekend bolt-on do-it-yourself kit install project, where I can throw it in there & go terrorize all the ricers in downtown Columbia. Would be nice though
As usual, you are right on with everything you have said and I (we) appreciate your input immensely! Long road still ahead, huh?
Robertdot, just spinning a body into its resonant frequency (or multiple thereof) will setup harmonic vibration. Eventually, its amplitude of vibration will cause it, or the system that it's in, to crap-out. I thought maybe that's what that test was about. With all of the factors we've been mentioning, wouldn't it be quite difficult/impossible to run the actual functioning motor to 14krpm?

robertdot

Mayhap. But, I'm pretty sure Mazda did a lot of real R&D. If the rumors I hear are true, it seems like it would be really running. Obviously 9,500 was the top of the reasonable speed to run it at, but I don't doubt Mazda blew up a few engines finding that out.

But, the rumors could be false, and I wasn't there.

shelleys_man_06

I don't understand why you would want a street motor to run as high as 14,000 rpm. Like rotarygod said, the stock powerband is fine. In short, an engine with a higher rev tendency will have a lower thermal efficiency. You can apply the energy balance for rotating systems, and it will be clear the heat-energy part will much higher than the power produced. The point is to have a reasonable rpm range, especially for the street. In most cases, you're not going to see anything higher than 3500 rpm, or at least me. :o

If you want solid, street-able power, my suggestion is to increase the displacement. You'll get more torque on the low end, more power, but the trade-off is the limit of the maximum angular velocity; it will be lower than that of a smaller engine. Simple physics, right?

huhsler

So if I understand this right, Hymee's S/C will not change the RPM ranges that the engine will run at. It will severely bump up both the HP and Torque at those same levels, right? Have I lost me, yet?

Racer X-8

Hymee said about 13 hours ago "Initially I'm not trying to go there with this mod." I caught the key word "Initially". Wisely, he's focusing on the 0-9000 range. The land beyond 9000 has got to remain, for now, in the world of the future, but still it exists, and you have to wonder. I have yet to witness an F-1 team trade-in their engines for Harley's. They're all in that land and they're not looking back.

Hymee, sorry if all this has trashed-up your thread. Carry-on, you're doin' it man!!!!

rotarygod

Hymee's project is right on the money. Leave the stock powerband alone but increase the power within it. The twin screw supercharger is efficient at low rpms and high rpm's. Roots blowers aren't as good up high and centrifugal superchargers aren't good down low. I don't understand why centrifugal superchargers are even used in the automotive performance world. Hymee has probably the best and most realistic power upgrade for the real everyday, emissions passing, street driven crowd.