therm8

I think it's something to do with unusable combustion occurring post power cycle, when fresh air is introduced. Or something... :D . I remember reading about it somewhere, but I can't seem to find the site. It was an aviation site I think. They also said that the missing heat from the lower EGT wasn't actually missing, it's just inside the engine and gets transferred to the coolant.

Regardless, Renesis EGT's are significantly lower than older tech rotary engines, and therefore old tech adages shouldn't always be applied to it.

auzoom

Someone show me a Hymee Exhaust shooting "glass marbles" and I will believe.

Interestingly fibreglass is being used to make fire proof clothing http://www.expresstextile.com/200503...rmance01.shtml from this link you can see that some fibreglass composites have melting points of up to 750°C, pure silicon having a melting point above 1800°C http://www.azom.com/details.asp?ArticleID=1114. What I am getting at is that "Fibreglass" is a generic term for a composite of silica (SiO2) and Plastic and is more appropriately know as Glass-reinforced plastic http://en.wikipedia.org/wiki/Glass-reinforced_plastic.

Fibreglass in its true term is pure silica http://en.wikipedia.org/wiki/Fibreglass (which I mentioned above has a melting points above 1800°C)

Hymee, is it possible to open up one of your exhausts without damaging it? or better yet get the composition of the "glass".

Andrew

PS happy Hymee customer for 6 months, 6000kms and 1 track day (not much I know :D)

Wildcard

I have the oldest Hymee exhaust in existence, and I've had no problems. My car has been driven hard plenty of times too.

Revolver

I've had a gutful of this CRAP.

Look, I'm not about to venture an opinion about this exhaust issue because I know my limitations with things mechanical (severe ) so excuse me if I just interject for a moment.

Dave, as I posted in your thread in the Aussie forum, I'm interested to see (and hear :D ) your turbo set-up and wish you all the best with it. However, please leave any attitude concerning other members who are attending the Nats north of the border. A lot of people have worked very hard to get this event up and running (including me) and the last thing I want to see is it being spoilt by the turbo v S/C war that seems to have developed.

The Nats is a place to exchange info in a friendly, non-threatening environment. Remember, a lot of us aren't technically gifted and this SHOULD be an opportunity to learn something, not witness an all-in because egos have been bruised by some particularly ill-thought posts (and I'm not just talking about Dave here).

So lets cool it and exchange differing views with some respect and maturity. In particular, let's leave the veiled threats at the door.

ASH8

I totally agree with Hymee's assessment of his Catback exhaust system and the materials used, if the muffler boxes were in the intermediate exhaust pipe section/closer to the engine, then perhaps there would be a problem with heat outcomes.
However, the dual muffler boxes are at the rear end where normal use and driving conditions will never create a relability/safety/performance issue.

I know that Hymee (Mark) thoroughly tests and evaluates the products he sells, indeed his own car is testament to the safety and advantages using the Hymee brand.

The Hymee grill protectors are the only brand that does not restrict air flow to the 8s radiator/oil coolers.

The Catback exhaust is also one of the best manufactured and finished aftermarket exhausts in the marketplace today.

sferrett

Perhaps it'd be worth pulling it off, cutting it open and taking a few pics. That should answer the question once and for all of exactly how glass perfoms in this particular implementation.

Hymee

iTrader: (1)

Planning on doing that real soon to mine. It is the second oldest in existance, and has done more km.

Cheers,
Hymee.

skc

Thank you Hymee for sacrificing your exhast in the interest of science and research.

I have the Hymee exhaust for over 1 year now with track day and regular sprited driving. It sounds awesome and it is provides an improved overall experience when I drive my 8.

The only change I have noticed is a lower exhaust note and less popping after my last service...this has been attributed to tha latest flash.

As far as technical stuff goes I am a novice and from what I have read I am comfortable in having the exhaust on.

skc

timbo

Well, the Nats will be an interesting place to be.

One of my general observations about technical issues and the Renesis is that people tend to revert to experience based on earlier rotaries. Nothing wrong with that, and I am not disagreeing with that at all. But we need to remember the old 'if we always do what we always did, we'll always get what we always had' adage. Innovation comes out of challenging hitherto accepted norms.

So, in the case of the Renesis, we have a NA engine that is producing in emissions-legal, road friendly tune, output well ahead of single t/c 13Bs of just a few years ago, and close to those of the twin t/c RX-7s. The port design is quite different.

What does this all mean? I don't know, and I can also tell you, not a lot of the well-respected rotor tuners here in Australia know yet, either. Why? Simple! Not many of them have got their hands on them yet. The car is too young in the market.

However, at the Nats I am pleased we will have at least four well-respected people who have done just that. So we can expect to hear some facts, and have the benefit of experience brought to bear on solving problems and discovering attributes of the motor and all its peripherals. Only 19 days to go, too

Ciao

Thanx
I HAVE NEVER PERSONALLY ATTACKED ANYONE,,,BUT I HAVE BEEN ATTACKED !!!!..

Not that I care ...I want to see If these individuals are equally happy sayng these nasty comments to my face as they so heroically do on a keyboard. (wonder)

So As I say again Bring on the Nats

Ciao

Remember I never started this fiber exhaust thing ,,Just concerned about potential dangers

Dave

dracoMJB

I'm a little concerned with your claim of not attacking anyone. Yes you did not bring up the fibreglass muffler issue, but once it was raised you came out with:

Sounds like an attack on the Hymee Exhaust to me.

Then there was

Again, trying to say you aren't knocking Hymee's exhaust but then knocking him.

Then there was the abusive and name calling you made in a PM to me on the Australian RX-8 forum. Not attacking anyone, no of course not. Just casting aspersions on vendors products. I'm not a lawyer, but I would have thought that you should be careful not to suggest that a commercial product is poor or dangerous, because if that vendor loses business over it slander and libel laws can come into play. Then there is the hurling insults in private at someone, calling them a moron, an idiot and imbicile, nice. All I ask is for you to provide evidence that the RX-8 and a fibreglass packed muffler located towards the rear of the exhaust system is dangerous. So far you haven't done so. You've brought out anecdotal evidence from people that have worked on pre-Renesis rotary engines that have probably been developed and modified to produce as much power as possible and likely produce far higher temperatures than standard, un-modified RX-8s.

Ciao

I am over this

Evidence is there ..Do what you will .Dont care anymore

As for my PM..your ignorant post was the straw that broke this camels back

I never started the muffler issue .and Im not going to repeat myself again

I have concerns over this type of muffler packing .and for my Turbo project ,didnt want to take the risk!

Sharing my concern started this gang "lets bash up Dave " trip

End of discussion

My poor typing fingers can't take anymore

Dave

rpm_pwr

As someone who has obliterated a glasspack muffler on a rotary perhaps I can add a few misguided thoughts.

Yes it is possible to kill them, nothing is infallible. In my case, I had a ~350rwhp rx-7 that was initally setup to run very rich on high RPM decel. This combination generated the right conditions for long drawn out flames and the occasional ear-splitting backfire on fast changes. Not much can survive such treatment and it was no real surprise to hear the muffler totally pack it in one day.

Can / does this situation happen in an rx-8? No.
Is it possible for an otherwise standard rx-8 to generate sustained combustion in the muffler? No. They're specifically designed not to.
Do people even know what the exact material is in Hymee's mufflers? No.

In my experience you'll be replacing a torched read bumper well before the muffler says goodbye.

If in any doubt, look at someone who has already been down the same path as you and there seem to be heaps of rx-8 running glasspacks. If they can survive a trackday or ten they'll survive anything.

truemagellen

well said

I still think this thread should be closed though or deleted...it is just nasty

dracoMJB

Dave, I'm quite happy with your decision on what muffler to use. The problem is that when people started asking what was wrong with a fibreglass muffler you started attacking the Hymee Exhaust. No you didn't start it, but you sure have continued it, using RX-7 based evidence that has no relevance to the RX-8.

r0tor

iTrader: (1)

I'm not about to get in the middle of this.... but you should check out the flaming 8 exhaust vids and pics of those people replacing torched exhaust shrouds before saying otherwise....

Hymee

iTrader: (1)

I thought that was what he was saying: the torched exhausts shrouds would need replacing before the muffler??

CarlRX8

There are heaps of links showing RX8's with flaming exhausts .But People will believe what they wish .
This dead horse has been flogged to death !!

Go to the Canzoomer site and see his RX8 shooting 4foot flames . out the back

I saw it ages ago .I think about two years .Most of you would surely have remembered that?

Fiberglass is acceptable if you really have to have it , and youll probably have to change it every couple of years ,or so,
There has been some proven dangers,but like someone said ,if it is far enough back it MAY not pose a threat .
My arguement is for the extra dollars , a stainless steel packed exhaust has no dissadvantages whatsoever and will give you trouble free motoring for years.

NO attacks please

Carl

Hymee

iTrader: (1)

Carl,

Thanks for your comments. It made me realise something, as it put a different light on things...

All my comments have never been aimed at denegrating or questioning a stainless packed muffler. My comments have been defending the glass-fibre/wool packed mufflers from the critisims and FUD laid at them. At this point in time, some 18 months down the track, we don't seem to have any issues. And there has been track work as well.

But I dont argue against stainless wrapped/glass packed mufflers. I hope my comments were not read as they were.

And I hope you can see this post is not an attack :D

Cheers,
Hymee.

BTW - Perhaps I can close this one off now?

Revolver

Hey Carl

Firstly, hopefully we've gotten past the personal attack business. I'm more interested in learning something.

I disagree that this debate has been done to death. From my perspective there's been a lot of heat but not a whole lot of light (no pun intended ).

With respect to the evidence you refer to of RX8's with flaming exhausts could you answer some questions:

1. Were those cars stock or FI cars?

2. What were the driving conditions (i.e. normal use or racing/dragging)?

I've not heard of a stock RX8 emitting flames after normal or even track day use (with limited time sessions).

Could it be that those instances where extreme heat and flames have been demonstrated have resulted from heavily modified cars being used in extreme ways?

The reason I ask this is because many people are buying these products for relatively standard cars that are not FI and are not going to be raced or dragged. Do you really believe that such people are going to experience the kind of heat problems you refer to?

Obviously time will tell but the experience of those who have bought these kind of products to date suggests to me that your concerns have no empirical support with the RX8 and its Renesis engine.

CarlRX8

Thankyou Hymee . Im not offended
Even though I may not buy one of your exhausts ,you have sooo many other fantazmic products on offer that I definetly will buy
Scan tool , short shifter etc etc

Carl

CarlRX8

Revolver,The flaming exhaust link I was refering to was an ever popular one about two years ago( if you want me to find it it may take time)
It was a red one filmed on a snow laden night with huge flames comming out the back
I assume the car was stock but If you really want ill check or on the other hand do a search on this forum ( thats where i saw it )

Carl

Revolver

Hymee, our posts crossed as it were. :o

I'm okay if you want to close it off but assuming we've gotten past the personal nonsense I think it is a good idea to thrash the rest of this out.

People are referring to various evidence without context or supporting information. That does not assist people to work out what is the true position and I think such evidence should be tested so people can work out whether the various claims that have been made hold water for their intended use.

Those planning FI mods and/or racing/dragging will no doubt satisfy themselves what equipment is appropriate.

The rest of us who simply plan to do mild mods and use the car on the street and at the odd track day (no doubt the vast majority) could probably do with any nagging doubts being addressed by those making the claims.

I am not suggesting you need to continue to defend the product. You have made your position clear in a compelling fashion. However, those who keep referring to evidence of flames, etc should tell the rest of us a bit more about the circumstances in which such flames occurred so we can work out whether it is an isolated extreme case or something we should be concerned about.

Draco attempted to ask these type of questions and was met with hostility. I'm simply suggesting that we lose the hostility and see if those making these claims are prepared to back them up. If they do not, we can make our own judgments about their veracity.

Revolver

Carl,

Thanks. As you can see, I want to get past the assumption stage and see what has been proved.

Dave

BTW - welcome to the forum. Sorry it's been such a baptism of fire!!! :D