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Looks like you have a lot of information about these.
At the same time, every time an article comes out about them, it focuses on the diesels and on the last Wankel.
I believe there were 4 testbed generations of these. I never saw an article about generations 1 and 2. Not even close up pictures of that pure design.
Also, there could have been a different color for these, at one time. No word about that.
In the 70's the magazines were reporting about the progress Mercedes was making in developing the Wankel. These days, we all know the issues, thanks to .. Mazda.
How about a research brief, that would show at what point of the research, Mercedes closed the book on these?
I mean, if they were averaging in the 70's 11 Mpg, was that really a failure? Or what was it that they were averaging?
I believe that the 200 Mph at Nardo with the diesels was a matter of a ultra-high top gearing and waiting till it inched to top speed.
Not sure what issues you're referring to from Mazda. I think that's unfair and inaccurate to say.
The rotary has been very successful for Mazda, from the early RX vehicles and the Cosmo, to the RX-7. In fact, the RX-7's production went from 1978 - 2002. Most people don't realize that due to the halt on importing the 3rd gen RX7, thinking it was unsuccessful and was only produced for 3 years. This was due to a multitude of factors, none of which were issues with the rotary motor itself. These include:
- Poorly poorly trained factory mechanics in the US, unable to diagnose simple vacuum hose issues in the sequential twin turbo setup, leading to countless under-warranty replacements of perfectly good turbos
- Strict emissions standards that required the use of an incredibly restrictive catalytic converter, resulting in significant backpressure and heat, which are major enemies of the rotary engine. Incidentally, replacing the factory downpipe with a catless one is one of the first and best mods to a 3rd gen RX-7, yielding significant RWHP gains and making the car much more reliable (the restrictive cats inevitably clogged over time, hence the "Overhead Exh System" indicator).
- The 3rd generation came with an impressive 255hp in 1993, and was quite reliable in stock form. But in the hands of owners seeking more than double the factory output, aftermarket mods often resulted in lean conditions, which the rotary engine doesn't tolerate well, and breaking apex seals, resulting in compression loss and the need for an engine build. So it wasn't a Mazda or rotary problem; it was attempting to stress the motor beyond what it was build to handle. It wasn't a 2JZ...
In fact, the RX-7 made Car and Driver magazine's Ten Best list five times and more than 800,000 were manufactured over its lifetime. Also, in 1991, Mazda made racing history becoming the first Japanese automobile manufacturer to win the 24 hours of Le Mans, utilizing the 4-rotor 787B. Mazda was the only Japanese manufacturer to have won the prestigious 24-hour Le Mans race outright until Toyota’s win in 2018. Mazda is also the only manufacturer to win the 24 hours of Le Mans race using something other than a reciprocating piston engine. That's pretty impressive, seeing that Mazda is the only manfacturer to be involved in rotary engine R&D since the Oil Crisis of 1973.
Mazda began racing RX-7s in the IMSA GTU series in 1979. In its first year, RX-7s placed first and second at the 24 Hours of Daytona, and claimed the GTU series championship. The car continued winning, claiming the GTU championship seven years in a row. The RX-7 took the GTO championship ten years in a row from 1982. In fact, the RX-7 has won more IMSA races than any other car model.
If that's "issues" "thanks to .. Mazda" then yea, we should thank them for an impressive job.
The RX-8 was very successful in its own right as well. Produced in 2002 until 2012, it sold very well and kept the rotary alive and well. Unfortunately, the RX-8 was removed from the European market in 2010 after the car failed to meet emissions standards. Without the volume sales from Europe coupled with rising Yen prices, Mazda could not justify the continued sale of the RX-8 in other markets.
It's unfortunate that the Oil Crisis led to all other manufacturers abandoning R&D of the rotary engine except Mazda. But several manufacturers had rotary concept cars, such as the C111 above, and even the Corvette: http://www.thedrive.com/news/15334/d...otary-corvette.
Again, what Mazda did, singlehandedly, for four decades, deserves applause, not criticism.
That's my $0.02, and I'm sticking to it
Long time RX7 Owner
Do me a favor and don't single words out of my posting, in order to take them out of context.
This is the same as me saying:
"Poorly trained factory mechanics in the US", how do you know that all factory mechanics are poorly trained in the US? and what process was used to determine that all mechanics in the US are poorly trained?
Anyway, so because Mazda made this engine readily available, now we know its pros and cons, as developed by them.
But were these pros and cons the same as-developed-by-Mercedes, or was there a different set of pros and cons there?
Do me a favor and don't single words out of my posting, in order to take them out of context.
It wasn't done maliciously. I was merely trying to point out that I don't think the bad rap the rotary got was the doing of Mazda. A lot of it stemmed out of abuse and unreal expectations of the owners.
This is the same as me saying:
"Poorly trained factory mechanics in the US", how do you know that all factory mechanics are poorly trained in the US? and what process was used to determine that all mechanics in the US are poorly trained?
My point here was referring to the fact that countless turbos were actually replaced under warranty due to the Mazda techs/mechanics not being adequately trained in how to diagnose vacuum leaks from the sequential twin turbo system. Its a generalization, but it's accurate.
Anyway, so because Mazda made this engine readily available, now we know its pros and cons, as developed by them.
Absolutely. You're dealing with the pros and cons based on the extent to which their unilateral R&D reached. No one else was messing with the rotary after that.
But were these pros and cons the same as-developed-by-Mercedes, or was there a different set of pros and cons there?
Very good question. And unfortunately we may never know. I'd love to see other manufacturers look into this technology and what they can do with it. And there's definitely potential there. Mazda even developed a hydrogen rotary engine! http://www.mazda.com/en/innovation/technology/env/hre/
Originally Posted by MarcusDubya77
Two words for the 13B... Apex seals...
When abused, yes they're the weak point. But don't forget the tremendous endurance and reliability they've shown when naturally aspirated or even when turbocharged within the power and stress limits of the manufacturer. The 1st gen RX-7s run forever. And RX-7s have won numerous endurance races, as previously mentioned. So again, it's all about your perspective.
Unfortunately, these reliability issues spiked around the time of the 90s era sportscars in their prime, especially with huge engine powerhouses like the Supra, making double and even triple the factory hp on the factory motor. So the 3rd gen RX-7 underwent a LOT of abuse in its early days, which was probably the largest contributor to giving the RX-7 (and rotary) its reputation for poor reliability (when modified). Hence why the bad reliability reputation didn't follow the RX-8, which was very successful.
So, the person that wrote this article seems to be very knowledgeable and my question to this person was to the effect of sharing the particulars of the Mercedes research into these engines, to the extent that sharing is available, so that we can see these potential differences in the path that Mercedes was taking, vs what we know from Mazda.
11-06-2018, 04:51 PM
