Does ceramic coating increase EGT reading?

[PhilipA]

I spent yesterday installing my straightened , dewebbed and 1200C ceramic coated exhaust manifold,replacing studs with Wurth studs and copper nuts as well as turning up the boost 3 turns and removing the EGR on my 2002 EU3 TD5 auto. I also placed a turbo blanket on the turbo.

This allowed me to fit the sensors of my previously bought Boost Gauge and EGT gauge.

I have a stock tune, and still have my cat. The EGT gauge is fitted on the "dimple" just in front of the turbo, with the probe about 3/4 of the way into the manifold. Ie gently push in until it touches then draw back say 5-6MM. ( is this correct?) It certainly is very responsive.

I have read numerous old posts about EGTs and set the EGT alarm at 700C.

Trouble is that in a couple of short trips I have done I have reached 700C on just brisk acceleration up to say 60KMH at about 18 -19PSI boost. The car is going really well and i am pleased so far.

I don't think the blanket would figure in this as it is after the gauge, but any thoughts on whether the ceramic coated manifold is holding in most of the heat and making the gauge read higher than otherwise.

The bloke who did the ceramic reckons he got to virtually 100% of the interior as well as the exterior.
So what should my EGT alarm be set at?
Regards Philip A

[BathurstTom]

The wikipedia article implies that it does, but also says that it results in marginally better exhaust velocity.

Tom

[Blknight.aus]

yes, the ceramic coating increases the temperature in the exhaust by reducing the heat loss out of the manifold.

this keeps the exhaust gas at a higher temp leaving more energy to turn the turbine.

IT doesnt increase the temp inside the combustion chamber, but some people seem to think that the higher EGT temp from having the ceramic coating means the internal temps have risen.

It hasnt you;re just getting a truer reading of whats coming out than the rest of us. In theory this means you can hold a slightly higher EGT than someone without a ceramic coated manifold.

[justinc]

^^ 100% correct, it is only due to the lack of temp transfer from gasses through the manifold. One of the reasons people wrap their tubular manifolds is to increase gasflow by maintaining the heat energy in the gasses longer.

'Thermodynamic Dave' has hit it on the head😊

Jc

[sierrafery]

I have a stock tune, and still have my cat. ...

So what should my EGT alarm be set at?
Regards Philip A
IMO if you get rid of the CAT the EGT will drop a bit cos there will be less backpressure in the exhaust

if i was you i'd set the alarm to 800 without fear....i've ran about one year with mine with a generic remap chip which gave real guts to it without having and EGT gauge but after i fitted the gauge i was amazed to see up to 900 uphill and nothing happened to the engine/head in this time, since then i've got a proper remap, IMO the ECT is more dangerous if it stays above 105 for long than 800 EGT peaks so watch that carefully

[Jazzman]

I have an aftermarket remap, blanked off EGR to make it appear it is still there, removed CAT and centre muffler.

EURO 3 TD5 recently rebuilt with 020 oversize positions has done approx. 70,000Kms

I also have my probe mounted in the same spot in front of the turbo and frequently get to 800 degrees, but it flattens out at 800 like it does at 720 with a standard tune. Max I've had is about 920 pushing it real hard in the hot weather. My engine has had no side effects from it.

I'm running a standard turbo and exhaust manifold with not issues.

I could not find anywhere other than forum member opinion that 700 - 720 was the max temp. That is not to say it is wrong as it makes sense when compared to my findings running a standard tune.

However RAVE states under the turbo section that the turbo must be able to handle up to 1000 degrees C for a short time. So i figure a plateau of 800 degrees is fine.

[vnx205]

yes, the ceramic coating increases the temperature in the exhaust by reducing the heat loss out of the manifold.

this keeps the exhaust gas at a higher temp leaving more energy to turn the turbine.
... .... ..



Does that mean that the exhaust gas that reaches the turbo is hotter, so the turbo get hotter and the air that the turbo pumps gets hotter, so you either need a better intercooler or else the air getting to the intake is hotter?

If that is true, is it enough to make a difference?

[Blknight.aus]

short version,
Yes, true, No, it wont, but

longer version

it does transfer more heat to the turbo yes, but I would not have thought that it would have been sufficient to require additional intercooling on a stockish tune (other than more than a stockish tune needs better intercooling to deal with the extra fueling and the heat rise caused by the extra compressor loading) as the turbo has good airflow over the compressor housing, reasonable air flow over the cassette and a good oil excess to deal with the heat load from the turbine side of business.

For a given setup.

by preserving the heat (energy) reaching the turbo turbine side of businsesss you're not going to make more out of the turbo, you're just going to do it more efficiently. If you make something more efficient you can then make more out of it by piling more (fuel) into it until the losses are the same again. The problem with doing this is if you go far enough you then expose the next weak link which in the case of the TD5 will be the head, if not the manifold studs and gasket then in the head and its cooling ability.

[PhilipA]

Just a few more impressions.

The tip in and turbo lag are much better with the mods.

I don't know about absolute power as haven't done that yet ,as was a bit alarmed by the 700C.

It is obvious that the ceramic manifold has made quite a difference as I can also hear the turbo spooling which I couldn't before.

Oh and I think I have noticed that warm up seems slower without the EGR.

Next mods could be maybe a decat pipe and flowmaster muffler.
Regards Philip A

[sierrafery]

Does that mean that the exhaust gas that reaches the turbo is hotter, so the turbo get hotter and the air that the turbo pumps gets hotter, so you either need a better intercooler or else the air getting to the intake is hotter?

What i can say is that after fitting the turbo blanket the IAT was not higher at all only the boost rose faster so as long as the OP has a turbo blanket IMO the effect of the hotter turbine on the boosted air is completely neglectable.

[PhilipA]

BTW, I bought the turbo blanket from Goldbys parts.

It was for a T25 as this seems to be the smallest available that I have seen on the web. Looks OK quality.

I had to cut out a large notch from the side to let the wastegate rod operate freely. They are held together by 2 springs which connect the centre of one side to the 2 sides of the other side by reinforced hooks.
It may not last as long from being butchered but there was little choice.
Regards Philip A

[Blknight.aus]

What i can say is that after fitting the turbo blanket the IAT was not higher at all only the boost rose faster so as long as the OP has a turbo blanket IMO the effect of the hotter turbine on the boosted air is completely neglectable.


Just a few more impressions.

The tip in and turbo lag are much better with the mods.

I don't know about absolute power as haven't done that yet ,as was a bit alarmed by the 700C.

It is obvious that the ceramic manifold has made quite a difference as I can also hear the turbo spooling which I couldn't before.

Oh and I think I have noticed that warm up seems slower without the EGR.

Next mods could be maybe a decat pipe and flowmaster muffler.
Regards Philip A

Thats all about what happens when you make the turbine more efficient by making sure hotter gasses reach it.

the other side is not only is the exhaust manifold not loosing as much heat, when you're off the noise its keeping warmer as well.

the reason that deleting the EGR slows down the warm up is because the air fuel ratio remains leaner. Diesels run cooler when there is excess air to the fuel available and run hot when you run more fuel than you hae air to burn.

by not displacing normal air with exhaust gasses there is more free O2 to limit the overall combustion temperature. However there is also more Nitrogen to produce more oxides of nitrogen.

The IAT in a TD5 wont show any change in temperature from anything you do with the turbo (excepting that when you do enough you raise the whole engine bay temp including the air in the airfilter) as the IAT sensor is pre turbo and is used in conjunction with the MAF (pre turbo) to work with the MAP (post turbo)so the total air going into the engine is known.

[sierrafery]

.....
The IAT in a TD5 wont show any change in temperature from anything you do with the turbo (excepting that when you do enough you raise the whole engine bay temp including the air in the airfilter) as the IAT sensor is pre turbo and is used in conjunction with the MAF (pre turbo) to work with the MAP (post turbo)so the total air going into the engine is known.
Re-think that please.... the IAT on a Td5 is together with the MAP on the inlet manifold, we call it simply MAP but in reality is 2 in 1 MAP/IAT....so it would have sensed hotter boost if it was the case that's why i mentioned it ...what you said is valid for Td4 and and 6 not 5

[Blknight.aus]

depends on which one you mean.....

td5's have 2 one in the air box as part of the AAP and one in the manifold as part of the MAP.

The one in the manifold works the total air volume going into the pots including the EGR gasses

the one up the front handles the total fresh air mass.

Which one are you reading from?

[sierrafery]

I was speaking about IAT(inlet air temp) exactly as it's named which is only one in MAP/IAT and all td5's have it, the AAT(ambient air temp) which is present only on Eu3 modells not on all td5s is part of AAP in the airbox and it has nothing to do with this discussion about boost temperature cos it's not even part of the addaptive strategy and used mostly as fine tuning for EGR controll

[PhilipA]

Oops, once it is hot it is going into a big miss under acceleration.

I assume it is boost cut, so I will wind back the wastegate a turn.

Turbo is now too efficient for its own good.LOL

Regards Philip A

[PhilipA]

OK I turned back the wastegate about 1MM and the boost cut is now not so evident.

I was wondering what was up as the Boost gauge was reading "10" plus a bit. I thought it cannot be only 10PSI.

Then I squinted and read the face and it reads "In Hg". So the boost is 14.7 +4.96 =19.66 PSI or just about up on boost cut still once the turbo is hot.

You wouldn't think the blanket and ceramic manifold would make such a difference but it seems to.
I will take another bit off the rod.
Regards Philip A

I had another look at the gauge and it says PSI on the boost side but In Hg on the vacuum side. The scale seems to be about right for PSI Vs vacuum in Hg but I cannot understand why it only shows "8" now. If that were PSI then I would have 14.7 +8 or 23 which cannot be right. It seems more likely to be 14.7 +about 4PSI =18PSI.
It cannot be 8PSI boost only as the car goes really well.
A mystery.

[sierrafery]

it's too hard for me to make each conversion from psi to HPa or bar...please tell me what's the MAP(manifold pressure) reading in inputs fuelling menu of nanocom(not instrument mode)

[PhilipA]

I have now done that as per the other post with the result of 0.6 .

Someone suggested that the wastegate flap could have become detached so that is the first thing I will look at. Adjusting it with the heat shield on may have caused the problem. If it is OK I will check the hoses etc.
Regards Philip A