Switching to an M62 would require a complete re-work of the setup. It is bigger in every measurement and the intake and discharge ports are shaped differently.
The pulley would fall in a different location, the intake spacers would have to be higher and the piping would need new flanges.

Also, that intercooler, while nicely packaged, will receive no airflow and will heat soak as soon as the car stops in traffic for 10 seconds.

 

Yeah. And what little airflow it gets will be fresh off the radiator. I ended-up insulating all the air ducting in my engine compartment with thermotec after I went turbo. The pipes were getting so hot they were almost too hot to touch, and a lot hotter than my IC outlet. The heat transfer from the engine was awful. I can imagine the same thing would happen to that IC.

 

I actually called the company and spoke with them for a bit, the unit you see is a prototype, the actual U.S. version will have a slightly larger and different blower unit.

Amazingly, and I'm taking there word for this (albeit skeptically), other than a fuel pressure regulator, they do not have any form of engine management alterations. No piggy back, standalone, refash nada.....according to them, at sucha low boost level, the stock computer runs rich enough so that the added air doesn't cause it to run to lean, and again, at such a low boost level, the high compression and ignitition advance isn't an issue and they aren't having pinging issues. They claim to drive the car around daily on pump 91oct, and said several folks at SEMA got to drive the car to prove it works (anyone on the board?). They claim that there are some other tweeks to the kit that allow for smoother operation sans management, but they wouldn't disclose those.

The U.S. kit may come with larger injectors also, but they are aiming to keep this as simple and reliable as possible. They aren't aiming for the crazy tuner guy, just the average person who wants some extra kick.

Take all this for what its worth, I'm not a fan of FI without engine management, but I'm open minded and curious to see how this plays out.

 

if the current managements maps are rich enough and then the management is just fine= but dotn go geting a reflash

 

^ I wonder if this was before or after the latest flash that came with the recall....

 

I'm guessing that its with the latest flash, at light throttle, the maps are pretty lean, but over 50% or more they are still rich by most peoples standards from what I saw on a standalone external wideband.

But that is a valid point about the reflashes, something to consider.

 

If they let people drive it it must have been after the show, it was inside the whole time.

 

Of course there's a chance that Mazda engineers made the stock fuel system capable of mapping for boost, you never know ... I know I don't have that answer. When I saw it I said to myself "wtf, no engine management" but it's possible that we don't even need it for low boost levels. It's not like it would be the first car ever that comes N/A and can handle low boost, and we know that they did engineer the RX-8 with more headroom in it's fuel system than in past rotaries.

 

I'm not sure about that. Just from a personal (bad) experience I had with the EManage that i had. When I first got my Greddy kit we installed it & were driving it on the street and it worked fine. We strapped it to the dyno and at medium to high revs (6500+) rpm it start detonating like crazy. We immediately shut it down, and called Greddy and they had told us it was a bad batch of EManage units that had gone out, and that essentially my car was running boost with the stock ECU mapping that is why we had gotten detonation. Needless to say i was more than a little pissed as I could have easily blown my engine with this. I pulled the EManage unit & sent it down to Greddy to get re-flashed, and when I we put it back in we got no more detonation. So I'm not sure if the stock ECU mapping can handle much boost (at least from a turbo experience), maybe PE found a difference.

 

Interesting.

Obviously the Greddy turbo pushes more air than this S/C, and I'm not sure how the pressure dynamtics are different between how a S/C would deliver boost and a turbo, other than the lag.

I wonder if the engine may deal with consistent low boost more happily than a turbo which spools up slower.

There are plenty of rotary turbo guru's, but few rotary S/C guru's. Anyone have any other thoughts on how or why no management could work at lower boost levels?

 

It won't. The factory ECU will keep the A/F at 14.7 or so even under boost - but this is too lean for safety.
As alluded to earlier in this thread, PE is using a fuel pressure regulator somewhere in the setup.

 

Yes, I do.

 

That's not really true ... under any sort of load it keeps things more like between 11-12 A/F's. A rising rate FPR could be all it takes to allow the stock ECU to do the same thing under low boost.

I'm sceptical of the setup, but wouldn't write it off that carelessly.

 

That is partially true - normally aspirated. As soon as the airflow passes N/A range, the mix goes straight to 14.5 or leaner and stays there pretty well through the rev range at low boost. That is what we are concerned with here.

Try it, you'll understand.

 

Not if you draw through. Then it doesn't know NA or FI does it??
You can run it up to whatever headroom Mazda built into it.
It just thinks you have a great factory engine somehow.

 

I do draw through.

Mazda just thinks that 14.5 or so is optimal regardless of airflow.
Go WOT under mild boost and you might see 13.5 at best.

There are only a few RPM ranges and load levels/load timings where the PCM forces 11:1 and those go away if the airflow exceeds normal N/A rates.

As I said, try it, you'll like it (not).

This is borne out of extensive testing, not speculation.

 

That ends that speculation. But brings up some possabilitys. How much will it keep reading too? If it's enough then the idea of using a reflash is very tempting.

 

Yes, a custom re-flash is the ULTIMATE solution. If I only had a brain that big, I would have worked it out by now.
The factory fuel delivery is good out to almost 300 HP. Getting it to spray at the right time and amount is the issue.
As far as I can tell, every aspect of the OEM FI is up to the task, including the AFM.

 

Veeerrrry interesting.

 

The factory AFM is a 5 volt model. It only puts out 4.1v at WOT and redline N/A.
Since the output is roughly exponential, that leaves a lot of airflow on the table.

 

Only 20% meaning a Pr of 1.2 or 3psi
Not enough.

 

Exponential.
The second volt is worth 1.75 times the first and the 3rd 1.75 times that, etc.
Sine function.
That gives you a flow equivalent of nearly 10 PSI of boost (at the same VE, which, of course, is not quite possible).

 

You're using linear math. MM says the voltage is proportional to some fractional exponent of airflow, meaning that you'll need a lot more than 20% more flow to use up the remaining 20% voltage. graph a square root function and you'll see what I mean.


EDIT: guess MM responded while I was typing!!

 

And on the seventh day, the Lord created the Weber.

 

I like the idea of no new engine management - in theory.

But on the RX-8, I think it is a pretty poor idea. All the RX-8's seem to have their own individual quirks/behaviours; not to mention there are a ton of ECU flashes out there - each slightly or significantly different from the last.

Two cars ago I had a Toyota with an TRD kit on it. The Denso ECU learned that I had FI (probably thought I was driving below sea level) and added more fuel accordingly over time. Simple linear fuel management.

The RX-8's ECU is highly non-linear and tries to do all sort of tricks based on a slew of volatile sensors.

I don't doubt that Power Enterprises has a kit that works on their RX-8 but will it work on my RX-8.

-Mr. Wigggles