Flaming Tail Pipe

[griff4.0]

I've just driven back from the Triumph International show in Stafford (my other half owns a Spitfire). The Triumph bunch in the Manchester Area are a great crowd and we had a smashing though rather cold weekend.

The drive back was meant to be in convoy but it's difficult holding all those horses in check! and I ended up cutting across country in my '92 Griff 4.0 with my mate Phil in his Cerb. As we reached the roundabout where I go right and he heads left he pulled alongside me for what I thought was the usual thumbs up, smiles and see you soon but instead he shouted out "You've got flames coming out of your nearside exhaust!"

This may be desirable in some crazy show cars but not I fear in a Griff. Can anyone shed some light on what might be causing this?

[TeGriffic]

Most of the pre cats I know do that as does my own 4.3 - not sure why but I've noticed frequency changes depending on what fuel you have in there (at least, with mine it does. That doesn't answer your question of course.

[griff4.0]

It doesn't answer my question but it does mean I can sleep a little easier knowing that it isn't uncommon. I guess other people may have seen this but not had the opportunity to tell me about it as they disappeared into a small dot in my rear view mirror.

[TeGriffic]

www.pistonheads.com/gassing/topic.asp?t=6539&f=9&h=0&hw=flames+from+exhaust

[dougal]

Mine does it all the time. not unusual in Pre-cats, every one I've ever followed does it at some point during a drive. Mine pops and bangs with it.

[simpo two]

I wonder if you can get a decatted 500 to do it?

[shpub]

Yes

[simpo two]

shpub said:

Yes

But how about a normal decatted one that hasn't been 'shpubbed' with sintered grommet intakes etc?

[shpub]

To get flames... you need unburnt fuel in the exhaust that is hot enough to ignite it. The 520 is extremely good at doing it as the ECU finds it difficult to shut off the 12 litres a minute on full throttle that the engine demands. On lift off, the unburnt fuel goes through the exhaust and ignites.

The 500 does it occassionally mainly on track where I have wellied it, braked and floored it. The sudden accelerator changes causes the ECU to enrich the mixture to get pick up and whumpf.

The main key is the ECU programming and very sudden throttle changes.

[IPAddis]

shpub said:

To get flames... you need unburnt fuel in the exhaust that is hot enough to ignite it. The 520 is extremely good at doing it as the ECU finds it difficult to shut off the 12 litres a minute on full throttle that the engine demands. On lift off, the unburnt fuel goes through the exhaust and ignites. The 500 does it occassionally mainly on track where I have wellied it, braked and floored it. The sudden accelerator changes causes the ECU to enrich the mixture to get pick up and whumpf. The main key is the ECU programming and very sudden throttle changes.

And the lack of a cat. Well you do get it in cat cars, it's just that the flames & unburnt fuel get stopped by the cat.

[simpo two]

Thanks Steve, I'll have to practice my sudden throttle changes then!
Maybe some enterprising bod would like to market a small device that connects to to a dash button marked 'Flames'....? :heh:

[shpub]

You can buy them. Kit contains a spark plug and a fuel pump... Very Max Power though. Not like the real thing.

[griff4.0]

I'm new to Pistonheads & this was my first communication. I started off with a problem, which I now realise isn't anything to worry about but now I find that the discussion has moved to "how can we all get these flames coming out of our exhausts?"

I guess you're all mad - but thanks for your help

[burriana500]

griff4.0 said:

I guess you're all mad -

aah, another enlightened convert

[chim500nj]

burriana500 said:

griff4.0 said: I guess you're all mad - aah, another enlightened convert

Don't you mean another Lightened convert! (sorry)