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MD,

I'm surprised you didn't reprimand me for not using a proper "goilet termination" device since I was planing to go with a non-goilet type of collector.

MD: I am a motorcycle mechanic and almost every racing bike muffler is made of alu. When i mentioned alu this was for the outer shell not for the inside tubing. Inside tubing is 20 guage 316stainless.

Jarle,

What kind of software do you use to estimate the header length, cam, compression etc ?

Jarle

If your exhaust system is going to be the same length as your motorcycle exhaust system then you won't have a problem. Since this is not likely, you WILL have a problem. The reason is that the gases in the motorcyle system do not reach a suffiently low dew point temperature before they pass out of the system. Therefore it's not an issue as you say.

In a car, the system is much longer and dewpoint is reached around the rear axle area typically. This is why traditionally the rear muffler usually corrodes out before the front one due to the acid attack being more aggressive there.

The reason why manufacturers chose to lag exhaust systems by cladding them is to maintain as high a temp as possible not only for the Cat. to work properly but to minimise the effect of dew point from temperature drops along the length of the system.

I would recommend you finish your excellent project with stainless instead of aluminium because the weight difference will be neglible but the you will have a lifetime system for your efforts.

At the end of the day, the value of this site is to teach each other what we know to spread the knowledge. What you do with that information, is up to you.

Hey Mr Zee

There are many things you can do with a goilet- just ask JK.

MD,
99.999% of the time there is no way the exhaust gasses will reach the dew point temperature. Corrosion may be a factor for other reasons but not that one.

Greg I am quite happy for you to disagree with me. I have provided rational explanations of why the case is what it is.

Now if you care to provide Jarle a similar rational ( or beter still a scientific ) explanation of why is it's not, the guy will have a balanced argument from which to make up his own mind.

I have known about the issue for over 30 years and I am reasonably happy with what I know to be the facts.

Here is the explanation of why the exhaust can't cool to the dew point temperature.

Dew point is the temperature to which air must be cooled to become saturated. It other words when the temperature drops to the dew point the moisture in the air becomes visable (ie rain, drizzle, fog, dew, etc.)

Now, the dew point is never below the ambient temperature. I have to write down all the weather data at least four times a day at my job, and I have never seen a dew point temp below ambient.

While I don't have an exhaust gas temp gauge near the end of my tail pipe, I am pretty sure the temperature of the exhaust comming out of the pipe is well above ambient. That pipe itself is certainly hotter, not colder than the surrounding air.

If the exhaust comming out of the tail pipe is warmer than ambient then it's not below the dew point.

If you can show exhaust temp data where the temp is below ambient, or a weather report where the dew point could be above the exhaust gas temp, I would love to see it. Heck, if you could show a weather report with a dew point above ambient, I would be pretty excited.

Hey MD, we do use the toilet here too...is this goilet an improved version (hence the spelling to differentiate)?? If you use it too, how do you mount them on trees?
Jim K.

JimGreek wrote:Hey MD, we do use the toilet here too...is this goilet an improved version (hence the spelling to differentiate)?? If you use it too, how do you mount them on trees?
Jim K.

Jim,The Aussies are a clever bunch..they invented the tiolet seat...It took the English 200 years to put the hole in it!!!!!!

You're probably right Barry, but I hear around where MD lives they're having a few problems as seen in the attached pic!
Has it occurred to them they should connect these things to a pipe or something?
Jim K.

The picture was removed to reduce the smell of fermenting fertilizer.

Ah,gross!!

Jim,

Your last post was full of shit.

LOL!

That's tacky.

Is the moisture thing more one of condensation? And that only the rear box gets rotted out having to do with that's where the moisture accumulates? or am i way off here?

Scott

Hey JK,

You're a scholar and a gentleman for removing the photos.

Mate, you can sling all the crap you can muster as usual but I just don't wanna see it in smellavision. Glad we go that sorted. Thank you.