Getting faster with time
#26
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Originally Posted by IkeWRX
Would hope that Mazda did their homework on the Renesis such as making sure it would pass emissions at port, making sure the oilpan was correct, making sure the HP was correct at 250, then at 247, then at 238, I could list more but I think you get the point...
#27
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Originally Posted by RX-Hachi
I don't disagree with your statement about Mazda doing their homework. However, for the record, Mazda Japan had stated that the high power Renesis was 250 ps, which is 247 hp. Mazda USA only "officially" down graded the advertised hp once (not twice as you imply), from 247 to 238.
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Originally Posted by IkeWRX
Actually initial reports were 280hp, then for a while it was 250hp, it was introduced at autoshows as having 250hp and that 250hp (not ps) number stuck until shortly before release I believe.
250 ps was "officially" announced in Japan, and remains their "official" figure. The US marketing folks blundered and may have published 250 hp (taking "ps" to equal "hp" too loosely ) in some early advertising before the car was "officially" released. This was a "marketing" error by Mazda USA, not an "engineering" one by the Hiroshima R&D team. However, once the car was "officially" released, all Mazda USA documents stated 247 hp (= 250 ps), until the figure was revised to 238 hp.
#29
VW coulda had it...
Ike sez: “So just passing off a potential problem as nonsense simply because you think Mazda did a lot of testing might not be a good idea. At this point the engine issue (or lack thereof) is really not worth debating further until more is known and more RX8s start to get up there in miles.”
Indeed! Mr. Port & Polish brings up some interesting points on his side seal thread, and undoubtedly has good familiarity with the internals of the rotary. Even Yamaguchi’s RX8 book has mention of early prototypes swallowing side seals, (solved by adopting a keystone seal cross-section) so we know issues caused by the large port area and/or shape have been looked at. I like to think (of course!) Mazda would have worked out major engine flaws before production. I mean look, these guys must know rotary engines inside-out, it’s what they do, and have done since the ‘60’s! And they wouldn’t want to alienate a whole community of rotor heads (or potential new owners) and ****-off Ford, would they?
There must be some good reason engineers arrived at this solution rather than re-shaping the port edge or adding a bridge. Perhaps all engines are supposed to have a chamfer on the port edge (a common two-stroke practice) but some don’t? The subject does concern me a bit, because I had hoped to drive the car at least 150,000 miles without noticeable power loss or excessive oil usage, given my kind of driving and maintenance, without having the internals of my engine examined to determine some engineering or assembly flaw.
At this point, I am going to just try to ignore the potential problem and enjoy driving the car as I have; if any problem should rear its ugly head, I’ll deal with it then. (hopefully, contestable, or under warranty!)
Indeed! Mr. Port & Polish brings up some interesting points on his side seal thread, and undoubtedly has good familiarity with the internals of the rotary. Even Yamaguchi’s RX8 book has mention of early prototypes swallowing side seals, (solved by adopting a keystone seal cross-section) so we know issues caused by the large port area and/or shape have been looked at. I like to think (of course!) Mazda would have worked out major engine flaws before production. I mean look, these guys must know rotary engines inside-out, it’s what they do, and have done since the ‘60’s! And they wouldn’t want to alienate a whole community of rotor heads (or potential new owners) and ****-off Ford, would they?
There must be some good reason engineers arrived at this solution rather than re-shaping the port edge or adding a bridge. Perhaps all engines are supposed to have a chamfer on the port edge (a common two-stroke practice) but some don’t? The subject does concern me a bit, because I had hoped to drive the car at least 150,000 miles without noticeable power loss or excessive oil usage, given my kind of driving and maintenance, without having the internals of my engine examined to determine some engineering or assembly flaw.
At this point, I am going to just try to ignore the potential problem and enjoy driving the car as I have; if any problem should rear its ugly head, I’ll deal with it then. (hopefully, contestable, or under warranty!)
#31
VW coulda had it...
My apologies to Frank Patrick and others for getting off topic!
Anyway, it is very possible your car is getting faster. I haven't noticed this in my case, but my oil consumption and fuel economy have improved. (at about 15,000 miles)
I would guess the seals get broken-in to the point where they seal more effectively.
Anyway, it is very possible your car is getting faster. I haven't noticed this in my case, but my oil consumption and fuel economy have improved. (at about 15,000 miles)
I would guess the seals get broken-in to the point where they seal more effectively.
#33
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Originally Posted by KKMmaniac
My apologies to Frank Patrick and others for getting off topic!
Anyway, it is very possible your car is getting faster. I haven't noticed this in my case, but my oil consumption and fuel economy have improved. (at about 15,000 miles)
I would guess the seals get broken-in to the point where they seal more effectively.
Anyway, it is very possible your car is getting faster. I haven't noticed this in my case, but my oil consumption and fuel economy have improved. (at about 15,000 miles)
I would guess the seals get broken-in to the point where they seal more effectively.
I agree - I'm around 13k miles now and my gas milage has steadily increased from about 18mpg in the beginning to 21.5mpg lately on my same home-work-home driving loop.
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Sorry to deviate a bit from the purpose of this tread, but the dreaded HP issue came up here as well and I wanted to give you my 2 cents worth. I read that the 8 was 247 HP and is still inside our engines. My understanding is that the reason for dropping the hp rating from 247 to 238 was because the US emmissions standard was raised and catalytic converters had to last 120k miles instead of the previous 80 K or something like that. And that change in emmissions law was right in the middle of production or the RX-8. Therefore as a result they had to quickly back peddle and find a way to meet this new standard and therefore changed the catalytic coverters and/or tuned down the engine. I guess they wanted to make the cat last longer or not heat up so quickly so they would burn up, because of the high heat rotaries produce. Makes sense I guess.
I have a copy of a staement I found on the web from Mazda explaining this. I think i got it from another thread here. In any event they make it sound like we never get to see all 238hp anyway for one reason or anotrher. Bummer.
The real concern is that if you found a way to max out your engine through the ECU, will you destroy the cat as well? Then what?
I have a copy of a staement I found on the web from Mazda explaining this. I think i got it from another thread here. In any event they make it sound like we never get to see all 238hp anyway for one reason or anotrher. Bummer.
The real concern is that if you found a way to max out your engine through the ECU, will you destroy the cat as well? Then what?
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