Turbo on RX-8

[Herblenny]

Well, I have 2004 complete engine/transmission/harness/ems... I'm about to tear down the renesis to check it and rebuilt... But, if I could incorporate this system and as how mazdamaniac describes it, I might try to use the harness, sensors, etc to run REW with bigger MAF. Seems like this system once dialed in could work seemless in any condition.. At least thats the take I'm getting from reading mazdamaniac's post.

[Herblenny]

mazdamaniac, I'm glad you got on this forum... I'm learning something new and its firing my interest and thinking how this could apply on other levels.. I never thought about MAF nor 8 EMS and that kind of capabilities..

Question..

What's your take on this system in Low compression motor vs. high?? Maybe this is myth, but I've always heard problems with high is detonation is likely and needs to run richer to save engine..

[mazdamaniac]

Originally Posted by Herblenny

What's your take on this system in Low compression motor vs. high?? Maybe this is myth, but I've always heard problems with high is detonation is likely and needs to run richer to save engine..

Compression is compression.

If you don't have it static, you create it dynamically with the turbo.

a 10:1 motor on 9 PSI is the same thing as an 8.5:1 motor on 12 PSI.*

If you manage charge temps and fueling/ignition correctly, a high-compression motor with less boost will run circles around a low-compression motor with more boost at the same power levels because the off boost and throttle transition areas with be faster.

*(very, very, very rough and inaccurate exaggerated example, of course)

[Whizbang]

your site has more flash per square than another other mazda website in history.

that and i dig the Mx-3. I have been eyeing buying one from a local with 2.5

[mazdamaniac]

Originally Posted by Low Impedance

your site has more flash per square than another other mazda website in history.

Yeah. Sorry. A bit of Macromedia vanity, that. I wish I had more time to play with it.

Originally Posted by Low Impedance

that and i dig the Mx-3. I have been eyeing buying one from a local with 2.5

Mine was stupid. On a good launch, I'd practically torque-steer off of the track.
Then again, I am the suckiest drag racer on the planet.

Originally Posted by Low Impedance

You might be able to mimic the signals that the anti theft produces to fool the computer.

Well, its CAN bus, so its not "signals", per se.
The two systems talk to each other like PCs on a network.
If they don't give the secret handshake, you don't go anywhere.

[Phoenix7]

Originally Posted by mazdamaniac

What do you mean? My "public" dyno at 9 PSI on my nice, extremely streetable turbo is over 315 RWHP.
With meth and a bit more boost, I made 20% more over that.
If someone wanted a 400 HP RX-8 and wanted to deal with the street performance liabilites of that (just like the 400+ HP club of RX- owners do), they could go to a GT3571 or similar and be there all day.

The problem is, most people don't want a high-HP car - they just want to brag about owning one.
A 400+ HP turbo rotary is annoying at best in stop and go traffic. Add summer to the mix and the sacrifices you make in vehicle comfort to make use of that power and you have a car that no one wants to drive anywhere but straight down the 1/4 mile.
RX-8 owners like their DSC/TCS, A/C and power seats. Did I mention the cup holders and the Bose 9-speaker stereo?

On a road course, I destroy cars that are supposed to outclass me by a considerable margin.
Watch as this "500 HP", single-turbo 300 ZX desparately tries to catch me on the 1/2 mile straight at Firebird Raceway as I hit nearly 150 MPH.
Then watch as I out-brake him!
VIDEO
The Cobra and the Saleen did the same thing, only I watched them spin behind me in the second corner after that straight.
Very sad. I almost spilled my latte.

good post. Looks like I'm not giving the Renesis the credit is deserves. Thanks for patiently clearing things up.

Now regarding hi/lo comp:
I can understand how a high compression motor can match/outperform a low comp one at lower or the same boost levels. HP-wise the high comp motor wins but isn't the lower compression motor safer for boost application, like Herb said, for the safety of the motor? Or is this another misconception? I know that tuning plays a huge role in the safety and longevity of the motor but doesn't the high comp motor wear and tear at a higher rate?

Also, thanks for joining and taking the time to bear with some of us.

Also, What I meant by "yielding little power" was : yielding little HP per dollar spent (compared to the older rotaries).

[mazdamaniac]

Originally Posted by phoenix7

HP-wise the high comp motor wins but isn't the lower compression motor safer for boost application, like Herb said, for the safety of the motor? Or is this another misconception? I know that tuning plays a huge role in the safety and longevity of the motor but doesn't the high comp motor wear and tear at a higher rate?

Every motor has a finite number of puffs in it. The more powerful those puffs, the fewer it will make over its lifetime.

Tuning is everything. Period.
If a motor is properly built, tuning can extract power out of it right up to the point it breaks from load.
Almost no one ever gets that far before they make a mistake or get it too close to the edge of what available fuels and prevailing conditions allow.

Originally Posted by phoenix7

Also, What I meant by "yielding little power" was : yielding little HP per dollar spent (compared to the older rotaries).

Now, that is a different question completely.
The people that have figured out how to make power with this motor are charging what the market will bear. Wouldn't you?
Do it yourself and the material investment is no different than any other motor.

As the charts I posted indicate, +300 HP is reachable for about the same cost as it would be on any motor that only made 190 or so to begin with.

[Whizbang]

hmm...maybe you can bring the anti theft system onboard and then fool THAT into thinking everything is peachy keen

[mazdamaniac]

Originally Posted by Low Impedance

hmm...maybe you can bring the anti theft system onboard and then fool THAT into thinking everything is peachy keen

That is exactly what I do with the Grand Am cars.
Just wire-tie it up under the dash board and tape an ignition key fob to it.

[Herblenny]

Why?

I'm kind of thinking in terms of the market.. maybe for you..

If you could get this system to work for stock turbos and extract as much power potential as you claim (close to 400WRHP), just by the swap, stock FD set up without changing the turbo, you'll hit the market! Especially, you work out the maps and sending it to people... people no longer need so called tuners tuning cars. Like how you are doing with the 8 owners. It would be simple solution to quite a lot older turbo car users..

[Phoenix7]

well, I don't know if I'd agree with the last line about costing the same as a 190hp car. The TII is 160-170whp and with ~1200 bux you can make 300HP (BNR turbo, accompanying fuel and electronics). You can add another 1200 if you want to use a standalone. LIke you said, we're talking older technology, maybe that's what makes the differences in prices.

As far as sequentials:
I thought it might help with the top end. I see that the Greddy upgrade in your charts has great low end that tapers off after 6K RPMs in one graph and 7.5K RPMs in the other. Wouldn't a second turbo maintain linear power all the way through the powerband? Similar to the FD setup?

[mazdamaniac]

Originally Posted by phoenix7

The TII is 160-170whp and with ~1200 bux you can make 300HP

Its already a turbo car. Doesn't count for this comparison. Try making that power that cheaply on the GTU.

Originally Posted by phoenix7

As far as sequentials:
I thought it might help with the top end. I see that the Greddy upgrade in your charts has great low end that tapers off after 6K RPMs in one graph and 7.5K RPMs in the other. Wouldn't a second turbo maintain linear power all the way through the powerband? Similar to the FD setup?

Power tapers in the high-end of the Renesis because of the flow restriction of the exhaust ports.
The Renesis has a very wide power band, but it isn't going to be all at the top like a peripheral port 13b.
Once the gas velocities get really high, the right-angle turn of the exhaust ports becomes a restriction.
The high power output Renesis applications you will see in the future will make their peak tq at 6200 and hp at 7200 max.

Originally Posted by Herblenny

If you could get this system to work for stock turbos and extract as much power potential as you claim (close to 400WRHP), just by the swap, stock FD set up without changing the turbo, you'll hit the market!

The problem with the FD turbos are they don't flow enough air.
You can tune all day, if the air is hot coming out of the turbos (low mass) the power won't happen.

[Herblenny]

Originally Posted by mazdamaniac

The problem with the FD turbos are they don't flow enough air.
You can tune all day, if the air is hot coming out of the turbos (low mass) the power won't happen.

People have made upwards 380ish RWHP sequential via MAP system on stock twins.

99 sequential turbos also made around that HP with quicker spool.

BNR's have made over 400RWHP sequential in MAP system.

So, Are you saying that its the temperature of the air that might cause problem of tuning MAF based system?? Again, I'm not an expert in MAF tuning.. but doesn't air temp gets measured by MAF sensor?? or is there another sensor after TB?? And when running EtOH/Water inj. Do you shoot before MAF or after??

[Phoenix7]

Originally Posted by mazdamaniac

Its already a turbo car. Doesn't count for this comparison. Try making that power that cheaply on the GTU.

you got me there. You're right.

Power tapers in the high-end of the Renesis because of the flow restriction of the exhaust ports.
The Renesis has a very wide power band, but it isn't going to be all at the top like a peripheral port 13b.
Once the gas velocities get really high, the right-angle turn of the exhaust ports becomes a restriction.
The high power output Renesis applications you will see in the future will make their peak tq at 6200 and hp at 7200 max.

Makes sense, what exhaust manifold does the MM turbo use?

The problem with the FD turbos are they don't flow enough air.
You can tune all day, if the air is hot coming out of the turbos (low mass) the power won't happen.

[mazdamaniac]

Originally Posted by phoenix7

Makes sense, what exhaust manifold does the MM turbo use?

Its the GReddy cast iron manifold.
Pretty decent piece - the flow cross-section is about equal to the port area.
I've been thinking about an Extrude-Hone to increase flow a bit.

Originally Posted by Low Impedance

i think the problem is the turbos are getting out of their efficiency range when you start getting up there.

Exactly.
Even though the pressure is rising, the mass is holding because the heat is going up.