Hello all.

I have an ongoing curiosity with what people think of the Ecotek CB-26P "Booster Valve" (I quote that as I dont know really what to call it).

I will admit up front that I own one and I am happy with my purchase. If it was its only benefit, the fuel economy I have experienced running it on my Mazda 323 SP20 is enough to justify the purchase. It has other features that I have only the "Butt Dyno" to prove. Again the main one of these being that the car was a lot smoother to drive.

Fuel economy is a hard thing to guage for me as I dont do a lot of long distance travelling. In the 1st 12 months of my SP20 I averaged about 400k per tank. 450 if I did a freeway trip or 2. After 12 months with the Ecotek I was up to a minimum of 450 a tank and easily 500 if I did a freeway trip or 2. I have had my 8 for just over month. I ran my 1st 2 tanks with the Ecotek and stretched the tanks to 300k. I then ran with the Ecotek for 2 tanks (before I took it off for my first 1000k service) and easily got 320k and 340k respectively. I have now put it back on and my 3rd tank (interupted as I did 30k without it on) I have done 280k and have a 1/4 tank left.

Again, nothing really noticably different to the drive (positive or negative).

The following is a previous conversation I started about it http://www.astinagt.com/forums/showthread.php?t=880

I am curious what you guys think.

Here is the products site http://www.ecotekplc.com/technical.htm

Regards


Andrew

 

It's probably a little too early to tell the impact on your '8. You've got a new engine... fuel economy will improve itself over time. 300k's a tank... you must be pushing the loud pedal pretty hard ;-)

If it is truly having an effect on the engine's performance it may also take some time for the PCM to learn the impact. I'd hazard a guess that the greatest impact if any would occur during closed loop where the PCM is "self-tuning" based on the O2 sensor readers rather than open loop where the PCM will be looking up a table of fuel injector duty cycles. By the sounds of your fuel economy, you're not doing much closed loop at the moment.

 

LOL...Damn! I've been found out...

Actually, I live 5 minutes from work...Kids school is 5 min from there so my morning is comprised of:

1. start car
2. warm up for 5min
3. crawl to school (10 min)
4. drop kids off
5. Take the 15min LONG way back to work

Most of this is done in at ~50/60ks in 3rd gear around 4-5k rpm (of course I have to get there first and the fact that it takes me about a second to get fom standing to 50 doesnt matter ;-)). Its also pretty hilly around here.

I actually got 340k's to this tank and put back 55ltrs (couldnt squeeze another drop in).

Is there any indication that you are in closed loop? I kind of wait until it drops the revs back to around 1k (ie the 5min warm up).

Andrew

 

Short trips kill fuel economy too - I live close to work too and the engine is jet getting warm as I pull into the driveway at work. With around 18,000kms on my speedo I'm getting 14-15L/100 around town on these short trips.

The only way to really tell whether your're in closed loop or not is with an OBD scan tool - you can read a data item called "Fuel System Status" which reports if you're in open or closed loop. But typically you're in closed loop when you're cruising and using gentle acceleration. Going WOT is a sure way to get you into open loop. Hymee has a good thread on this here: https://www.rx8club.com/showthread.p...ht=closed+loop

 

There are only 2 ways you can tell if it is in closed loop.

1st is with an O2 sensor. When the engine is in closed loop operation, the O2 sensor will indicate stochiometric (ideal) air:fuel ration (AFR). That is because closed loop is a continuous feeback loop, where the goal is to maintain ideal AFR. In open loop, it is obviously not in the "stoich" range.

2nd is with a scan tool (such as sCANalyser) to give live display of the O2 readings via ODBII as the RX-8 already has a wideband lambda (O2) sensor, but even better is displaying the "Fuel System Status" which shows you exactly what mode it is in.

Open loop is generally when you get on the gas. Typically, the engine will run richer - too rich actually. There is no feedback loop (hence it it "open") to adjust fueling based on exhaust gas (O2) readings. It will also go open loop on startup for a while, and then settle down into closed loop at idle. Light cruise is closed loop. Mild to heavy acceleration is "open", as is when you get off the gas and the engine is acting as a brake.

I hope that explains things a bit better for you!

Cheers,
Hymee.

 

auzoom, I can tell you when the car is exactly in open with the sCANalyser... so a drive on the Vic meet will be good.

350 a tank a lot of fuel wasted though.... drive around the Yarra Bend will be able to see your driving habit and what the car is doing at the time.... right Hymee?

 

According to THIS post on the Ecotek forum on that website, one of the Ecotek guys, Barclay Lamont said they don't recommend using their product on rotary engines because of the engine design.

 

I also am getting around 300km on approx 50l of gas. I have 700k on the clock and mostly drive short trips at 50/60kph at around 3/4.2krpm.

I'm hoping after the 1000km service I'll start to get better fuel economy, but I knew what I was getting into when purchasing the 8 so no worries about it.

Someone mentioned that you can reset the ECU knowledge of your driving habits by stomping on the breaks 7times in quick succession???

I wonder what other "resets" you can do......

 

Normally I get close to 500km out of a tank. Normally a "tank" for me is between 58 and 62 litres.

It doesn't actually learn you driving habits. It maintains a short term fuel trim and a long term fuel trim. These are like caches in a computer, and are used to lookup adjustments. If you monitor both of these values with a scan tool such as sCANalyser, you can see them change. Even the LTFF (long term fuel trim) changes on a second by second basis. Therfore I contend that even "resetting" the ECU (which "zeros's" the trims) will not have of an effect accept for the first few seconds of driving. But this thread is no place to go into a explanation of the STFT and LTFT strategy.

I wonder how the air molecules and everything inside the intake tract of know that they are about to go into a 4 stroke engine that has the ports opened by rotary motion instead of "normal" valves, and that the mixture it is about to be squeezed up via a rotary compression cycle rather than an up-down piston? Must be smart air, or perhaps a rotory engine overcomes some problems perhaps only encountered on a shithousely designed piston engine. FFS - I have my doubts about this device. Like they said, it doesn't give any power gain. So why are we looking at it again?

Cheers,
Hymee.

 

Interesting thing is I have an email from Tim from Ecotek who said there is no reason not to run it on this specific engine.

I am more interested in the fuel economy thing. Also the claim about more efficient burn.

Taka, I will be there and you and the sCanalyser can bag my driving habbits :-)

Andrew

 

If your concern is fuel economy, then there's a simple way to address it: never use more than 3,250 RPM. It would be far cheaper than fitting this device........but very boring.

The economy you are getting is well within the normal range for the 8 on the type of driving you do.

....but you really didn't buy the 8 and then start thinking about economy, surely

 

Ha ha...Definately didnt, but it cost me 170AUD and the fact that I got an extra 50 K's per tank on my SP20 for 18 months I went through a tank each fortnight, saved roughly 13$ each time thats...$500 saved...paid for itself in my eyes.

For the critics, Once I was getting a stable minimum of 450k per tank (after about 3 months/6 tanks) I then switched it off for a month and it was instant loss of the 50k per tank.

I was VERY carefull to keep as constant a driving habbit as possible AND picked a period where I was traveling to and from the airport once a fortnight (both with and without the unit).

ANyway, I have it on now and am going to keep it. Going to see if the sCanalyser picks anything up on Sunday.

Andrew

 

Cruising down the freeway on the weekend in 6th at 110km/h, I found that everytime I commanded >25% throttle, I went into open loop. 25% throttle or less and it stayed in closed loop. I found that the best way to accelerate and remain in closed loop was to "blip" the cruise control. Even seemlingly mild depressions of the accelerator pedal sometimes pushed me over the threshold into open loop. Ditto if I "blipped" the cruise control 3 or 4 times in quick succession or held the "accel" button down.

So if you are dieing to absolutely maximise fuel economy on a long cruise by staying in closed loop, steady blips of the cruise control should keep you there. Or you could buy a 4 cylinder car....

I'm not sure if the closed loop / open loop thresholds are different for each gear, or what the determining factor in the changeover is, but that is what I saw under dual carriage-way hwy conditions.

 

We would need to do some logging to see what the "threshold" is. I guess it would be a combination of "demanded load" (basically throttle position and MAF) and RPM. It would make an interesting graph. Getting the data is the easy bit. Putting into a graphical representation would be the cool bit

Cheers,
Hymee.

 

throttle position is throttle relative or throttle absolute??

I can log all the data there is and send post 3 graphs up here for Hymee's analyse.

 

Taka,

Throttle Pct is the one that is the actual throttle position at the throttle body.

Cheers,
Hymee.

 

Got it...