Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax Fumes under hard acceleration

Oh, and something did change - it was remapped by RTCC - my suspicion is that the cats may be overworked now.

Sorry, an old joke.

Link to a few BMW forums (thought these may be more relevant than Toyota etc.):

http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/99231-ammonia-smell-out-exhaust.html

http://forum.e46fanatics.com/showthread.php?t=301136

http://www.m3forum.net/m3forum/showthread.php?t=40302

Everything seems to point towards it not being uncommon and nothing to be worried about - seemingly they are post-filter fumes, something to do with the cats and various nitrogen doo-dads...

See also here:

http://www.wheels.ca/Article%20Category/article/31671

"BMW uses a particulate filter, right at the exhaust manifold, that traps the tiny soot particles in a complex honey-comb structure. When deemed necessary by the computing powers that be, the ECU adjusts various parameters of the fuel mixture and valve-timing to increase the exhaust temperature, and the particulates are burned off.

Now, about that pesky NOx. Just downstream from the particulate filter, liquid urea (a common organic compound made from ammonia and CO2) is injected into the exhaust stream. Here, it reverts back to ammonia and CO2, mixes with the NOx, and then the whole concoction is neutralized in the catalytic converter, emitting only nitrogen and oxygen. A small reservoir of urea is refilled at every service interval."

Jappo,


Should have asked earlier but whats the output now?

Sorry Jappo, I should have been more specific - no mechanical items have been changed (exhaust, airbox, cams, etc).

As a remap is simply a flash upgrade, my previous comments about the new map changing the exhaust gases, hence the effect on the cats, stands.

Would be inclined to agree with Simon.

Rotten eggs was a typical effect when the first tanks, sorry Volvos, had cats fitted and owners put leaded petrol in by mistake. Cats got mangled and needed work at frightening cost. Mind you it took the smug smile off their faces.

Amonia is a more pungent smell than the fouled cats and can make your eyes water so it might be valuable to gauge the difference.

Other options certainly include slipping clutch but also brakes. The S1 had smaller brakes than the S2 onwards if I understand correctly. If you are driving harder to test your new RAM chip then you might be pushing the brakes harder, ditto the clutch.

Get someone with a sensitive nose to go from point to point before, during and after to see if you can pin it down.

Also try the hood up and see if it is coming in, close the vents be hand and switch off the fan. Be careful of overdosing on fumes if you are catching exhaust gases. I had to put a second layer of foamy stuff around my airbox intake under the bonnet to quell gases coming in through my ventilation/fan system.

I would also be very interested to get your feedback on the chip upgrade, I had been thinking about it for some time as well.

Alistair

I don't drive my car hard but get this same smell. So don't think it could be brakes or clutch, assuming of course cause on Jappo's car is same as mine.

I will have to though note whether I can detect the smell with hood up (a not very common occurrence.

Cheers

Thanks for all the comments and help guys, I am suspecting that the remap and possibly a change in the breathing apparatus may be the culprits. I will contact RTCC to discuss.

In answer to a couple of other questions posed I am told the car is producing 325-330bhp although RTCC did not provide a dyno readout - certainly feels like it is however, the difference is very noticable, although it feels like a slight flat spot has been introduced between 3K and 4K rpm. It's almost like the fly by wire throttle has also been remapped a bit. Interestingly the car was freshly MOT'd by RTCC AFTER the service and ECU remap.

Car also has a four brtanch Librands exhaust system.

I will have the bonnet seals looked at as well.

Once again - many thanks for all your responses.

You sure they're not taking the piss?

(Sorry, medical joke)

I drive a thirteen year old +8 and my colleague a brandnew Roadster. Both produce ammonia smell under forced acceleartion. I am very much convinced it is the catalyst exclusively. My theory is (being a researcher in chemistry) that under hard acceleration a rather high amount of hydrocarbons are not burned to CO and CO2 and reach the catalyst surface which is composed from noble metal particles supported on rather ordinary metal oxides (iron oxide among them). The latter are actually catalysts (or precursors to them) for the conversion of nitrogen to ammonia (the industrial Haber-Bosch process for ammonia production relies on reacting nitrogen from the air with hydrogen produced from coal and water). It may very well be that this process is operative under excess conditions of hydrocarbons (fuel). There is not much one can do about it and it will not do any harm to the car. Best thing: Slow down and behave properly in civilzed aereas and accelerate in the country side where a little extra ammonia will not be noticed. I would keep the catalytic converters....