G8rboy

Not sure if this info has been brought up- I don't remember seeing it in the thread so far. In the Jack Yamaguchi book I mentioned earlier they mention that the in the Renesis' early development, due to the much larger intake and exhaust ports, the engineers frequently experienced the "swallowing" of the side seals as it passed over the ports. I'm assuming they meant it was passing over unsupported at some point. They go on to discuss this is why the developed the new side seals that are 1/2mm taller and 1/2mm wider (than the 13BREW) and with a trapezoidal or keystone cross section, to be stong enough to pass over the larger ports.

I also found similar supporting info in this article:
https://www.rx8club.com/showthread.p...=keystone+seal

"Previously the side seal was arched and rectangular-sectioned piece w/ a thickness of .03 in. The new engine’s side port configuration allowed significant enlargement of both intake and exhaust port opening areas. Earlier in the development stage, Mazda engineers experienced frequent breakage and “swallowing” of side seals when they traversed over the ports. A new keystone seal, .05 in thick at the top is adopted to solve this problem.
The keystone seal has a trapezoidal section, thicker at the top and tapering down at 4.5 degrees in its .14 in height."

So Mazda definitely knew that there was a potential side seal issue very early on, and they believe that the thicker, stronger side seals have sufficiently addressed this in the stock NA state. So the only question for me that remains is if the seals are strong enough to withstand boost of any kind, and if so how much.

Thoughts...?

zoom44

well there were the oft repeated claims by Mazda people around the time of Launch that the renesis was built to take boost.

G8rboy

That's good to know... I'm really interested in seeing Petit's long term results with their supercharged renesis. I know 6PSI isn't exactly breaking any records for boost, but it should establish some level of comfort for boosting our 8's.

devious12

I definatly think the engine was made to market more of a daily driver, but I do agree that the engine can take boost. Someone just needs to set it up the right way and tune the car correctly. The engine has more potential than alot of people are given it. It is just going to take time, and when it does reach the point that tunning and power of the engine is perfected, I think we will have access to a monster that was once underestimated.

neit_jnf

bump... where's the "subscribe to this thread" button?

Rob Tomlin

Look under "Thread Tools" near the top of the page.

globi

I haven't read the entire thread, so I'm not sure whether this has been asked before: But just assuming there is indeed a wear issue. Could this be from that extra soot that is produced during the combustion process? (Due to the fact that the engine runs richer than originally intended?)

zoom44

if by "root" you meant soot then no i dont believe so.

globi

Yep, soot (corrected it)

Hymee

iTrader: (1)

Glad you corrected it, otherwise this thread might be sooted.

(a humorous play on words, meaning probably lost with most Americans. But I'm all for a bit of cultural edumacation.)

Cheers,
Hymee.

Richard Paul

iTrader: (5)

Teach me. "edumacation" is that the Ausie humor???
You know I'm a little slow on that English humor stuff, I can't sit through their movies.
And aren't you guys the rebels, not really fond of the UK because they threw you out of the jails??
Edumacate me.

rotarygod

"edumacation"??? We all know it's actually spelled "edupacation" or it's more phoenetically correct form of "edupacashun". Sheesh you Aussies are weird.

globi

Well, living next to the 4X brewery is not always a good thing or is it?

Talking about soot again: What if you had some carbon depositions and they somehow end up on the housing sides and then get milled by the rotors, wouldn't this cause some extra wear? (On the other hand graphite is also used as a lubricant. So considering this it might not be an issue.)

rotarygod

Carbon depositions? You mean carbon deposits.

Carbon is pretty soft. Some race engines use carbon apex seals. When they break they usually don't damage the interior of the engine. Carbon inside the engine does this all the time. This isn't something you typically worry about.

Richard Paul

iTrader: (5)

Now he's a communist?? Not that I don't agree, have to think about it awhile.
Well somewhere i bet there were some Carbon depositions, just need to go look it up in some law library

rotarygod

I'm going to keep changing my title often. That's what he would do!

Richard Paul

iTrader: (5)

Flip-Floper

RotoRocket

iTrader: (1)

Whatever became of this issue?

Sorry to revive it (not really sorry), but many people have passed the magic 25k mark, and the only ones who seem to be having problems are those with ATs who live in extremely hot climates.

MazdaManiac

iTrader: (3)

Good question. I'd like to see this discussed more as well.

mysql101

I thought it was dismissed:

https://www.rx8club.com/showpost.php...&postcount=101

MazdaManiac

iTrader: (3)

Ito dismissing a subject is as worthless as his addressing one in the first place.

I guess GuitarJunkie would have a better answer since he ports these things.

r0tor

iTrader: (1)

all the doom and gloom and almost 2 years later my car is still as moderatly quick as it was back then -shrug-

therm8

My 4 port has 63k on it, driving exclusively in FL, GA and SC. Summertime on the streets, temps can hit 110+ rather often (and it's always very humid). Still spins like a top. But then I rarely use the AC. Car runs too hot when I do (based on continued fan operation after shutdown).

RotoRocket

iTrader: (1)

You rarely use your AC and it regularly hits 110+ there?

You're a glutton for punishment.

Nice to know your at 63k problem free, though.

My fan runs after shutdown in Michigan, too, but I've never been bothered by that. It's just doing its job.

Have you run a compression test?

therm8

No compression test. Never felt the need. The car pulls strongly all the way to redline. I'll probably get one before getting a supercharger (though the car may have 200k on it by then ), just to be sure.

I've become used to no AC. On the highway, windows down works enough for me. In stop and go at 110F, the AC is worthless anyway, so I just sweat . The reported temp doesn't actually get that high, but with all the heat coming off the pavement, the in-car and various bank thermometers get up there regularly in July and August.

My fans will sometimes run for 5-10minutes after shutdown, even after babying the car with the AC on. I don't like having the coolant temp skyrocket with no forced flow through the radiator, so I try to take it easy on her in the summer. The fans rarely run, and never for more than 30 seconds, as I drive it now. A cool rotary is a happy one in my book .