Mr. Port & Polish

My case is a rare case. I wish to add no more to this thread.

thew

hehe are you with the CIA .. your very hush hush.. however I can understand your motives very well.. Thanks for the heads up. and good luck with your 8..

brillo

Mr. Port and Polish,

Please don't take the questioning or banter as an insult, forums like this are a great place to vet ideas and theories, your knowledge base is a valuable asset and I learned alot from this thread, it really forced me to get out my rotary manuals and study the design of the ports.

If I was to just polish rather than port the engine, what kinda of gains would that get..any idea? What does a P&P cost on average, minus the removing of the engine?

Speed Racer

Hey don't shoot the messenger! I'm just reporting what is listed in the manual.

cortc

There will always be engines that fail when you are producing them in large numbers, mistakes do happen... The fact is that anyone of our engines could have a flaw that will show its ugly head in the future; nothing we can do about that...

Is the rotary engine perfect? No, it is not; neither is any other internal combustion engine...

In the end it's all a compromise...

shelleys_man_06

That is fine.

Sorry if my question sounded too intrusive.

zoom44

hell i spent an hour 2 days ago looking for those specs! why didnt you post them up sooner it could have saved me some time

Speed Racer

I would have posted them sooner but I needed access to the scanner at work.

Landon_Starr

Hey everyone....

Just as a disclaimer of sorts, I'm not writing this up to create more "doomsday" claims, or create more flame-wars. I don't claim to be a rotary-expert, nor do I have anything to gain from a side-seal problem with the renesis.

That said, I'll provide some background to my issue.

After getting my vehicle, I dynoed it for the first time with about 10,000 miles on it. Unsure of beginning HP figures, as this was the first time I tested it.

The results were a bit disappointing. My vehicle dynoes 160 on its base run. We ran it again. 159.8. Then again. 160.4. I was not happy with the trend. Especially since a few other RX8s were dynoing mid 170s, and even a couple 180s on the SAME DYNO (mustang, by the way).

This, of course, was happening around the ECU richened due to catalytic converter life requirement hype/rumors were running rampant. So, naturally, I wrote it off as an ECU issue, which I could fix with the advent of a product to re-map my a/f ratios. Additionally, I had my vehicle flashed by Mazda to the "L" flash, and I was still dynoing less than other 8s (further confusing my amateur rotary mind). Blah blah blah, my vehicle is now at Mazda, getting a compression test. If the compression test is lower than normal, my dealer has already claimed that they'll tear the engine down to measure side-seal clearance, and if it's higher than the .016 in max spec, will replace the seal.

I'm sharing this info in hopes we'll be a bit more careful in assuming that this engine problem is only on a SINGLE engine. Although it's obviously not an issue on EVERY motor, I feel safe in saying a VERY small percentage of 8 owners have even dynoed their vehicles, or COULD be aware of an issue like this.

Let's keep our minds a little more open when issues like this arise. We'll all be better off.

That said, I'm very eager to hear some of our expert opinions on the topic.

Thanks!

--Landon

zoom44

160 on a mustang dyno is quite normal from my experience. 180 on a mustang would be high which could mean that car has a MAFS that has output voltages on the low side. not discounting you post at all, i am very interested in reading the results of your compression tests. please post them when you have them.

cortc

Yes, let us know the results...

shelleys_man_06

At least this problem is not universal. I believe the next step is to learn how to port this engine properly. Personally, I'm willing to go as far as a bridge, but not into a J or monster port. I'll do whatever it takes to make 380 rhwp.

Landon_Starr

Duly noted. As I stated, I was LOOKING for expert opinions, discredit it if you can, I think I'd feel better. =) . However, out of 5 RX-8 dyno tests, these were the results on this particular dyno:

188 (outlier, I'm sure)
178
174
178
160 (mine)

As you stated, Zoom, we've seen a HUGE disparity simply because of the variability of the mass air flow sensor, and the 188 outlier may lead us to believe that it could be accredited to MAFS issues, as you stated.

For newbies, the MAFS variability was discovered through the CANZOOMER piggyback initially (I think), and additional info can be found with a search.

Back to the topic at hand.....

Mean of 175.6 (calculated from the 5 dyno runs) shows the high outlier's absolute deviation from the mean at 12.4 hp, whereas mine is 15.6, not a huge difference in outliers.

BUT, here's the key that makes me think it's not due to the MAFS, the 188 outlier had HIS 8 re-flashed, and LOST 12 horsepower due to the re-flash, everything else remaining constant (except a few hundred extra miles on the engine, of course), leading me to believe his ECU came programmed more lean than the others, and that the outlier HP figures were not because of MAFS variability. Mine remained relatively the same after the flash.


--Landon

zoom44

good info. do you know what flash he went from/to?

Landon_Starr

I believe it was the "L". I don't think "M" was available at the time.

--Landon

Ajax

This could be anything though, from the Mass airflow sensor to different plugs, to bad plugs to anything. The MAF's are the most common issue as the deviation from spec is huge. I'd like to know if your car comes back from compression testing and has good compression. If it does, ask them to cherck the plugs and the MAF.

shelleys_man_06

Don't forget what type of dyno you're using. Each one gives different results. However, stick to the one you got your results from.

Landon_Starr

Plugs were replaced between the first & subsequent dynos. Negligible differences. I can understand a difference in hp due to plugs, say, if one wasn't firing, but that wasn't/isn't the case.

--Landon

Landon_Starr

That's precisely why I was keeping my comparison narrowly focused to the runs on the same dyno. I am well aware of the differences between the dynojet & mustang dynos. Remember, these comparison runs were ALL done on the same dyno, with all of the vehicles being "bone stock". No pun intended. =)

--Landon

Landon_Starr

Not sure about the "FROM" part, though. Sorry, Zoom.

--Landon

zoom44

its cool he woulda been on K then as they all came form the ports with K. i think k was definetly stonger than L. so if you were on L when he did his K run that could be enough to make the difference. then when he got to L and lost 12 hp the difference between your cars and his is close enough just to be in the " norm" from car to car and different dyno days.

Spazm

This free flow of information is incredibly beneficial to everyone. It's just too bad that some people get upset that their information isn't held to be inviolate and unquestionable. These topics help all of us, don't get upset with people questioning and probing.

JoeRX8ter

Has anybody recorded consecutive Dyno runs in the same car with different MAFs. It would be interesting to see the results. Especially if you had two cars with a substantial difference in HP and you switch MAFs to see if it helps the weaker car gain some power.

Landon_Starr

I'd say it would be equally intriguing to run the same car on the dyno between flashes, cuz I thought my "L" gave me MORE power than the previous map, very possibly in my head, though.

Unfortunately, dyno-time is often times more expensive than the answers are beneficial.

--Landon

Landon_Starr

According to PoLaK, all vehicles came from port with the "J" flash.

Flashes