Would you say your problems were with adding a turbo to the renesis or would you say the problems were more the greddy turbo kit (wastegates and all) and ecu problems. I guess what I'm getting at was it the turbo and engine as a whole that left a sour taste in your mouth or possibly just the components that left a sour taste?

Curious as to what your $6200 kit includes. I briefly looked at the website and saw just a garret upgrade kit and the accessport listed. What does the kit you have listed for the dyno stuff at 6200 include.

Also what exactly is the biggest holdback on the engine. I guess I'm more use to the 7's where its almost the sky's the limit (within reason) with turbo size, boost, etc. What exactly is holding the 8 back, is it the exhaust ports, or what. On the 7 its common to see 850cc primarys and 1600cc secondaries yet on the 8 it seems to be 5-600cc injectors. Are we speaking in general terms as a "easy" bolt on without major modifications and thats why leaving the option of new fuel system etc opening alot more doors or is it just the engine itself.

Thanks for chimming in on these posts too, its nice to get some good info for those that are interested.

To be honest, its a combination of things that turn me off from wanting to do the turbo renesis again. Cost, time, resources, frustration, etc

As a whole, I was pretty happy with the end result. The car had what the renesis was missing, which was a bottom end and STRONG mid range that pulled. The problem was it fell off at 7k, no matter what you do, that problem is in the hardware. I think with a different turbo and manifold setup, the renesis exhaust ports would easily support upwards of 10-13psi and make well over 300whp all day long reliably, but at what cost?

The biggest problem is the engine. I just dont see a configuration that will come online early enough and still maintain a high enough level of boost to make big numbers (500+) on the renesis. I hope someday I'm shown differently. I'd love to see a bolt on 500whp kit for the renesis...

Probably the biggest turn off is that I was/am a seven guy. You can get so much more for much less effort with an old style 13B.

I am still VERY happy with the NA 8s power though. Sure, my current 8 doesnt have the HP the last one did, but its still fun. I think with all the bolt ons and the soon to come out RB header - the NA renesis will make plenty of good power for a daily driver and weekend track day. After all, its still a 200+ hp NA 13B, thats good in any book.

My big HP goals will be achieved the old fashioned way - big port, big turbo, old car :)

^^^ isn't that like asking for a 400hp bolt-on kit for the NA FC? It seems a tad on the idealistic/dream side to want 500hp bolt-on for the NA 13B or am I not giving the Renesis due credit?

I believe that is his point, he would love to see it happen, but knows it won't happen ;)

The upgrade kit is $1800. That price is the upgrade kit plus the GReddy base kit plus the AccessPORT.

Its going to be interesting in making the attempt to bring people up-to-speed here. The last few posts above are almost perfect examples of the kind of thinking I was referring to in my previous post in this thread.
At least its not as bad as 7-Club. :icon_no2:

There is a LOT of old thinking out there that simply isn't in step with modern technology.

Really, I'd be happy just to see people stop using the word "boost" all the time when they are talking about FI. Its meaningless.

mazdamaniac, I'm guessing you are using stock maf system and using the stock ems to adjust?? Where as traditional "boost" uses map sensor bases system (in rotaries)... which I'm guessing is the difference... maybe i could be wrong as I have not done much renesis turbo systems or seen many until this thread...

By saying that, I know very little about the limitation of maf system. Last time I got in a conversation about it was about 5-6 years ago with a good friend SPOAutos. Im sure most of us here know very little as most of us never dealt with maf based system. Can you tell us what kind of issues or limitation (HP) it will handle before going with map based system??

Personally, I do like the idea that you use the stock EMS and maf (which I could be wrong). And since its maf based, maps could be interchangeable from car to car without the traditional idea about each cars needing specific tune etc... Please correct me if I'm way off... I would like to know and who knows, maybe renesis technology could be used on my FD or my duece. I do have a spare renesis at home:)

Also if you could tell us what kind of compensation the stock ecu does (ie air temp, coolant, etc)...

it got me thinking during my work morning...

I guess some of the down fall of maf system would be similar to what i had by using KN filter?? If your turbo's bad and oil in your intake, could cause MAF to be cleaned?? Or is their by pass to this??

Also, I'm also guessing there is some sort of limitation to maf?? ie volume of air (high boost/cfm) and turbo choices?? How would this maf would work for FD, low compression engine that you want to run 20lbs?? sequential?? Would sequential turbos cause problem as it transition from primary to both?? Just few things I was thinking..

I do however like the MAF idea (not thought about in years) and if it works, it will eliminate some tuners out there..

One more thing.. I remember.. I remember back when reading about BOV needing to recir. back to post MAF sensor?? Is this necessary if 8 would use MAF system??

There are several ways to figure out how much air is going into your motor. A MAF is the only method that actually measures it directly.
MAP-based systems need to compute the air mass by comparing pressure to temperature.

The OE PCM is very powerful. It has a different fuel map for each pair of gears and compensation tables for every possible operating condition.
It compensates for intake temp, coolant temp, throttle position, barometric pressure and vehicle speed. It even has compensation for time at a particular load!
It has different latency tables for each bank of injectors (to answer an earlier question, the Renesis has 3 injectors per rotor, instead of the old 2 injector setup; many of us are running the equivalent of a 500/1200 setup by splitting the secondaries into two staged groups for very fine fuel control in boost) and a progressive ignition dwell table that resolves down to .001ms.
There are separate throttle control tables for each gear to adjust throttle sensitivity independent of pedal position and "acceleration" tables that not only compensate for throttle opening rate, but can adjust for engine RPM delta.
There are tables to adjust when to be in open or closed loop for each gear and load level and trim for closed loop at different load levels.

Ignition control is equally dense with completely independent tables for the leading and trailing ignition, idle control matrices with inputs for temp, RPM, gear, vehicle speed, throttle position and delta and engine load.

The best part is that the PCM takes all of the operating condition data and compiles it into a single value - calculated load - that is then applied to the engine RPM to compute the target injector duration based on commanded target lambda.
You don't need to know how much duty cycle you need at a given RPM and boost level, you just tell it you want 11.5:1 at 6500 RPM and it does the rest.

If a Power FC is a knife and a Haltech or Motec is a scalpel, the OE PCM is a laser.

The MAF on the RX-8 is sitting in a 3.375" i.d. tube and driven on a 5v circuit. It has enough resolution to see .001 g/sec variations at idle (~6 g/sec) and still measure out to ~360 g/sec at full load.
For those doing their due diligence, that is about 47 pounds of air or 450 HP.
Realistically, I'd say the OE MAF is pegged at 420 crank HP.
Of course, you could just put it in a slightly bigger housing and rescale it.
Or, you could replace it with the MAF from a Cobra.

On a draw-through application, a boosted motor is going to vent after the MAF, so metered air is allowed out of the system and an over-rich condition may happen between shifts, etc.
In practice, this is negligible with proper tuning, but it can be completely negated by recirculating the BOV.

i would have to say i am impressed with what the stock computer can do!

I've only touched on a fraction of it.

I've tuned Microtech, Motech, Haltech, Electromotive, Apexi, GReddy, HKS and a few others - many of those on rotary motors and nothing comes close to the PCM in the RX-8.

Now, it would be nice to have some more AUX channels (you can use the VFAD, for instance, to trigger water injection), but that isn't really a legit complaint.
If I needed to control more aux channels, I'd throw a $60 used GReddy e-Manage blue on there just for that.

Great info maniac. I enjoy this MAF info.

how adaptable could the computer be, with the proper tunning abilities? Could you use it on an earlier 13B engine with proper controls and related adapted and adjust everything accordingly?

I don't see why not.
You would have to address the wiring harness in a serious way and have to adapt a few important sub-systems from the 8 (the anti-theft system is particularly invasive).
It should work, though.

I'd enjoy that challenge, actually.

I've contemplated putting an REW in the RX-8.

so, the electronics are capable of reaching high HP goals. How about the motor itself? Why are the turbo applications yielding such little hp?

Thanks Mazdamania!

Now its making my head turn:)

Hmm.. I tought about MAF based few years back and never thought about doing it as I didn't see any aftermarket computer I saw.

So, what you are saying is its possible to run REW with RX8 harness and EMS, with larger MAF to run higher boost (or push more air)?? I'm already thinking about getting 4 secondary LIM and using this system.. What do you think?? How about 3 rotor?? Any MAF EMS that might be able to run that??

Sorry about all these questions.. Obviously I know too little to get myself in trouble... And far as tuning, Is it that easy, just putting in n value?

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

But generally speaking, with some knowledge of systems, it might be cheaper than buying a standalone, albeit not easy.

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.

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.

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..

You could do that.
The tuning is ALWAYS as simple as putting in a value.
The trick is knowing that value.
You do have to get the calibration for the MAF and other sensors right, also.

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

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

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.


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.

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)

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.

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).

how about sequential system?? Do you see any problem running it?? or solution to it??

I feel like now I'm just picking your brain... SO, I apologize if its wasting your time..

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.

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.

You mean sequential turbo?
First, why?
Second, air is air. The motor doesn't care how it got there.

These days, the water-cooled, ball-bearing turbos are so fast and so powerful, there is no good reason for multiple turbos on a tiny motor like the rotary.
Now, a 7 liter V8 is a different story, but they do fine with a big BB turbo as well.

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..

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? :dunno:

I see VNT technology being good for this application

yeah, I think its the difference in time.. I mean, I remember when PFCs were 1500+.. Now its only 700.

I'm beginning to like the idea of this and makes more sense. I guess i totally forgot about the whole maf system and been involved too much in tuning map based system.

I'm very intrigued to learn more about this as this could work for older generation turbo systems.. I think its bit more complex compare to map, but I do see the advantage over it.

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

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.

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??

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

you got me there. You're right.



:icon_tup: 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.

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