Exhaust oddness..........

[batfink79]

Hi all,

A quick question which I thoought someone on here may be able to give me an explanation for..............

My MX5 has a twin exit exhaust, one either side, at the back. My car is currently stored in our garage whilst I sell a car we no longer need. This afternoon I started it up and backed it out of the garage to let it warm up. Whilst I was doing this I noticed that more exhaust gasses were exiting one pipe than the other, I have noticed this previously, but it was more apparent this avo due to the cold weather. I put my hand to the pipes, and noticed that on the R hand side the exhaust gasses were cold, and on the L hand side they were warm (This is the side with noticeably more exhaust gasses exiting).

Now I know its an odd question, but why would this be? any ideas anyone?


Thanks in advance,

A perplexed finkers!

[snotrag]

Well, the obvious answer is, that no matter how well its designed, one exit is going to have less back pressure than the other, and as such the gases will naturally run out of it that way.

A 'Proper' dual exhaust is found on V configured cars with a seperate exhaust running from each bank down each side of the propeshaft.

On a mazda its jsut a regular exhaust with a backbox with 2 exits.

I really wouldnt worry about it to be honest. Might be worth trying to temporarily block the freer flowing side with a rag and give it some revs, the other side might be a bit blocked up.

[batfink79]

snotrag said:

Well, the obvious answer is, that no matter how well its designed, one exit is going to have less back pressure than the other, and as such the gases will naturally run out of it that way.

A 'Proper' dual exhaust is found on V configured cars with a seperate exhaust running from each bank down each side of the propeshaft.

On a mazda its jsut a regular exhaust with a backbox with 2 exits.

I really wouldnt worry about it to be honest. Might be worth trying to temporarily block the freer flowing side with a rag and give it some revs, the other side might be a bit blocked up.

That may be the obvious answer, but its an obvious answer that I wasn't aware of. I'm not concerned about it by any means, merely curious. Why are the gasses that exit, different temps on each side though?


Cheers

[snotrag]

Presumably, its a longer, or harder 'route' for the gases to come out of the cooler side, as they must be passing through more material in the silencer, slowing the gasses down and also cooling them.

I imagine its a bit of a self perpetuating thing, IE when new, there will have been a side that was 'preffered' by the gases, and as such, more gases have flowed through this side over time and heat and flow will have affected it.

As I say, the only way I can think to change it is by temporarily blocking one side and letting the other side get hot and blow through, but realistically, I wouldnt bother.

[batfink79]

Ta snotrag.


It was purely idle curiosity that made me wonder how and why it had less exiting one side than the other. I have no overewhelming urge to start assing about with it, mainly because its of no real consequence.



finkers

Edited by batfink79 on Thursday 11th December 23:40

[MX-5 Lazza]

Yep, they all do that

[pmanson]

Ours does this as well.

[tybo]

Mine too

[franv8]

Thay all will, unless they give the exhaust gases an identical route our (i.e. split before entering two identical silencer boxes, or a single centre entry box with an outlet at either end)

My other car does run two seperate systems, and I can confirm that both smoke as much as one another - whish is some recompense for the amount of £5 notes in petrol that disappear while it does this...