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How hot is diesel soot flame?


discomikey
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Hi all,

the other day i took my mate out for a spin as he was interested in a TDi, long story short i found out my engine is literally a fire (amber burning soot?) breathing monster.

The engine wasnt particularly hot, it had been warmed up on a 4 or 5 mile normal speed drive, sat idling for about 5 mins and then i took him for a blast up the road.

my truck started producing glowing exhaust gases within less than a minute of hard driving, literally first, second, third, glowing.

my question is surely i cant have got it to above the EGT safe limit in that short a time? so what temperature does diesel soot start to burn off at?

here's the video (sorry non facebook users, my youtube is currently not working)

P.S. EGT gauge ordered within 5 mins of finding out! :hysterical:

Also, whats better, Intercooler or water to air charge cooler?

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I've been going steady on it since, but it's still boosting as hard as before, i actually turned it down a bit the other week. It had been running another 5psi before that.

Maybe it's time for a water cooled vnt!

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My brother in laws 110 does this on a regular basis with so far no ill effects and mines done it in the past with about 8 or 10 inches of flame out the exhaust and again It's all fine they both boost to about 16psi and there both 200tdi's.

Water cooled turbos only exist to stop the oil coking after you switch the engine off, the waterways in them actually move the water around to cool them.

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The general consensus is that the maximum turbo temperature should not exceed 750*C - above that the titanium vanes can distort. The exhaust flames in your video would be around 950*C so I'd be looking at your fuelling settings if I were you, that and your timing and you could well have a burnt out exhaust valve(s).

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Re intercooler types, water/air are more efficient on cooling the air flowing through them than air/air - the downside is that to have a totally efficient water/air intercooler (or air charge cooler for those that don't like the term intercooler) to install one correctly you really need a separate radiator, electric radiator cooling fan and electric circulating pump rather than using coolant from the radiator which would commonly be around 80*C, whereas a correctly sized separate electric fan cooled intercooler radiator wouldn't go much above 40*C with an air delivery temperature of around 58*C.

I looked at it for my Disco and it's a very, very expensive option, I was saved the expense as there wasn't anywhere I could install the radiator and the large water cooled intercooler, pump and pipework so I just got an upgraded intercooler core ^_^.

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I have a corsa cooling rad and electric fan that I was thinking of utilising to cool the water, which I would put in a seperate circuit like you mentioned.

I think for the cost I would have to shell out for a custom intercooler, I could probably set up a charge cool system.

Are there any rule of thumbs to consider for specifying the charge air cooling side of it? I can work out radiator size requirements and I have a suspicion a corsa rad is over specced for that haha

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Didn't know it was illegal for flames to be emanating from an exhaust....

Seen them out of the back of an ultima, and I think they are designed (if that's the term) out of the rear of a McLaren (YouTube link required), but there won't be anyone standing behind if under deceleration or throttle lift off...

(Ultima at night is impressive with a nice blue flame from twin exhausts .... Err when you're trying to keep up with it when it's just overtaken you on an A road)

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I think it's noticeable because you have a short free flowing exhaust, yours doesn't black smoke as much as my 90 but by the time the unburnt smokey fuel has got to the back of my 90 it's cooled and isn't reacting with the comparatively oxygen rich atmosphere that yours is IMHO.

What size exhaust do you have and what boost are you running?

Will.

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Presumably the exhaust is very short and free flowing?

Apparently my V8 M5 used to produce four flames out the back when it hit the rev limiter even with a standard exhaust!

Nighttime video of you landy would be nice to see captured from a following car?

Marc

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Currently running around 18psi although before it was basically permanently shut and off the gauge at 24+psi been like that for 4 years reliably.

Just been to South Wales and back still pulling like a train and no loss of mpg. I think I'll put it down to the short ~3 foot long exhaust and for an EGT gauge to keep an eye on things

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If you install the EGT probe in the plate normally used for the EGR return then the temperature indicated on your EGT gauge will be about 40-50*C higher than the actual temperature at the turbo vanes. If you are fastidious and want an accurate temperature reading then you will need to remove the exhaust manifold and drill and tap the front face of the manifold so that the EGT probe is all but touching the vanes and on the turbo centre line - in my opinion hardly worth the effort. Depending on the make of probe and the pyro casing and the minimum radius the pyro can be bent It could also be very close to the alternator so, before you attempt it, check the available distances first.

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any idea how thick it is? all my bits are really sharp, if i know how thick then i can stop just before i break through to remove all swarf, then reapply grease to the bit for the last bit

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