Acceptable EGT's?

I just installed an EGT guage in my car, but instead of drilling a hole and tapping it or installing a bung i have my EGR system deleted and on the block off plate that i have on the exhaust manifold i just drilled and tapped it there, normal highway driving it runs around 370 deg, mind you i no this location probably isn't the most ideal but i'm just looking for a figure so i know what it is actually doing. My question is at what exhaust temps am i looking at that will be unsafe for these engines as i have the EVRY mod on an on/off switch now, have bigger nozzles on the way and there's other things that i'm going to end up doing to it but this summer i plan on going to a track day or two and would like to know when i should back off a little. Any input would be appriciated even if it's just what mods you have and normal operating temps to your max temp you've seen is, thanks.

sorry moderators for the triple post, pages never loaded all of the way to show that it went through

is the probe long enough to reach in the middel of the exhaust stream?
if it's not propely placed the readings are not correct.

370fahrenheit = 290 cels a 70 mph its normal for a untuned tdi.
max egt is around 850-950 cels./1600-1750 fah. ( vnt 17-gtb turbo's)
keep the safe limit of 1600 fah. for a long life of the turbo at track days.

assuming you have a stock 02. It has a VNT-15 good for about 1562 F.

if its reading 370F, its not placed properly. 370C and it sounds about right for a moderate load at 70mph

Rough rule of thumb I use, on level ground at constant speed, is speedo X 10. Hence 60 mph gets me approximately 600 F. 70 mph gets me 700 F.

Going down hill is of course cooler and up hill is hotter.

And I have the TI located thru the EGR block plate like you do. Took me a few tries before I got the location right.

Below is the correct location to install a "TIT" probe for the VNT TDI. This places the probe directly and COMPLETELY in the incoming exhaust stream entering the turbine inlet (Turbine Inlet Temperature = TIT).



I have taken apart these turbos and the only reasonable location to measure all four exhaust streams is located in the picture above.

Measuring from the EGR port is a complete waste of time and WILL NOT provide accurate temperature data. The reason is that the probe will NOT be completely exposed to the exhaust.

If you are going to spend the time to install a probe, take the extra 20 minutes and install it correctly...otherwise don't waste your time.

Drivbiwire said:

Measuring from the EGR port is a complete waste of time and WILL NOT provide accurate temperature data. The reason is that the probe will NOT be completely exposed to the exhaust.
If you are going to spend the time to install a probe, take the extra 20 minutes and install it correctly...otherwise don't waste your time.

Click to expand...

complete waste of time? anywhere of the exhaust manifold you put the sensor, it will be exposed to exhaust...
putting sensor after the turbo, that's a waste of time.

Satiro said:

complete waste of time? anywhere of the exhaust manifold you put the sensor, it will be exposed to exhaust...
putting sensor after the turbo, that's a waste of time.

Click to expand...

Really?

If you are not reading the direct exhaust stream the circulation pattern (in the EGR area) will result is gross errors in actual temperature.



Look a the Flows in the manifold, then compare the flow patterns located in a stagnated EGR port (no flow) and then the primary flow regions of the Turbine inlet.

It's like comparing a Convection oven to a non-convection oven. The flows are what direct the energy, and this is what we are trying to measure with a TIT probe. The EGR has very low flow relative to the turbine inlet, worse yet with a capped off EGR in terms of total temperature error.

Just because it is in the exhaust manifold does not mean you are reading the temperature in the core of the flow leading into the turbine.

The EGR because of the 90 degree turn, results in a stagnant region of exhaust gas that does not reflect the temperature in the high velocity stream leading to the turbo.

So, tell us based on the above CFD analysis where you place the TIT/EGT probe?

Hint....

Drivbiwire: Great graphics!

What length probe is ideal for a cast manifold (B5.5) ? Any special prep required for mounting the prob in that location?

Thanks.

NHgranite - the EGR flange is much different on a B5.5 manifold. It might be ok to use a standard 2-4" probe in a block off plate.

Also note that there is a EGT port already in that manifold. If you are using it on a different application, other than a B5.5 TDI that uses the factory egt probe, you could utilize this hole and it is in the perfect location. My BV43 has a similar hole in it that I am using.

see pics of the AFN(similar) manifold here http://forums.tdiclub.com/showthread.php?t=298322
it shows how the EGR flange is oriented.

Drivbiwire said:

Really?

So, tell us based on the above CFD analysis where you place the TIT/EGT probe?

Hint....

Click to expand...

REALLY.
I tell you, i have probe in EGR hole, i have an AFN manifold and probe installed in EGR hole is directly in the exhaust way, so isn't a waste of time.

Satiro said:

REALLY.
I tell you, i have probe in EGR hole, i have an AFN manifold and probe installed in EGR hole is directly in the exhaust way, so isn't a waste of time.

Click to expand...

X2 - I made sure the TI Probe, located on the EGR block off plate, was long enough to reach the common area for all 4 exhaust ports in this manifold.

Total waste of time ? Not likely !!

Satiro said:

REALLY.
I tell you, i have probe in EGR hole, i have an AFN manifold and probe installed in EGR hole is directly in the exhaust way, so isn't a waste of time.

Click to expand...

You and the OP(and DBW) have completely different exhaust manifold setups.

here is where I have my EGT probe on a B5.5 manifold:

Perfect.

So on the bv43 there is an oem egt boss after the turbo on the exhaust housing. This must be good enough? As opposed to on the manifold?

It is in an excellent spot

G60ING said:

here is where I have my EGT probe on a B5.5 manifold:

Click to expand...

That location looks great but those crimped on spade connectors might completely screw up the readings depending on the type of sensor that is.

That's correct. On a "k-type" sensor you should use the well known yellow "mini plug" only to connect it....

Auber gauge and their EGT sensor and their connectors for their gauge.

G60ING said:

Auber gauge and their EGT sensor and their connectors for their gauge.

Click to expand...

I honestly don't know the company so I"m not going to knock them, however i just went to their site and it says that is a normal k-type sensor.. Which means that type of connector should never be used.

It appears to be the exact same sensor that Percy's sells but with spades crimped on. I"ve used many of those sensors and they do not output the same if you use a connector like that. I wouldn't trust it unless they give me a damn good reason why its ok. The only reason that type of sensor even works is the junction between the dissimilar materials which you have not thrown off with those connections.

I would just like so say that i realize that where i have my probe is not the ideal place for it but i didn't have the time to drill into the manifold, but i would like to argue the statement that its is completely worthless. does it give me a number? yes, do understand that it may have a lag to temp. spike and less than the actual temp., but if i take the number it gives me and we'll say that modestly it's 500 deg F below the actual number (and the numbers i gave were F not C) then if i take the maximum suggested value and subtract 500 from that then i still have a number tokeepaneye out for and not exceed, do i not?

The "pocket" of air that the probe is sitting in does not allow for such a linear relationship to the flowing gases as you're suggesting. Not trying to knock you, here. It IS a number, *but* it will never give you any data reasonably close to what you need. I speak from experience on this one. When I upgraded my turbo, I took the opportunity to drill and tap a hole for the probe. The difference was astonishing! It went from lagging to read 700˚, at most, to very responsively reading peaks of 1200˚+ You took the time to route the wires and install the gage, so take the time to make that work justified. No point having a gage that presents you data that you can't use.

The reason it is worthless is that you could be burning up the turbo and not know it. This is why you need an EGT probe. My previous tune, I was running 1700+F and didn't know it because I didn't have an EGT probe. I still wouldn't know it if it was placed incorrectly.

tyrone shoelaces said:

I would just like so say that i realize that where i have my probe is not the ideal place for it but i didn't have the time to drill into the manifold, but i would like to argue the statement that its is completely worthless. does it give me a number? yes, do understand that it may have a lag to temp. spike and less than the actual temp., but if i take the number it gives me and we'll say that modestly it's 500 deg F below the actual number (and the numbers i gave were F not C) then if i take the maximum suggested value and subtract 500 from that then i still have a number tokeepaneye out for and not exceed, do i not?

Click to expand...

There is NO SUCH THING as a "Linear" relationship to temperature when it comes to high energy gasses. You can't just "Add 500" or whatever you think. What you fail to understand is by the time that exhaust gas travels from the combustion bowl at TDC and until it arrives at the Turbine Inlet, the temperature at it's maximum will have already dropped 2750F to a nice comfortable range of around 1650F (your maximum safe turbine temp). This distance is approx 12" factoring in piston travel and exhaust manifold length. There is so much energy in this system that you can vaporize titanium if you are not careful, a WAG is just asking for trouble when dealing with this level of temperature in the system.

As a comparison, It's like measuring the EGT post turbo, Just add 300? WRONG! The temperature drop will vary depending on the amount of boost being generated, more boost the GREATER the post turbine temperature drop but the temperature will be far HIGHER in the incoming exhaust gas stream (TIT)...but hey you added 300 but the TIT was actually 500F higher (re-read what JFettig posted about the difference in actual from detected).

Just because you have a probe that is jammed (incorrectly) into an exhaust manifold DOES NOT mean you are reading anywhere near the correct temperature, NO WHERE CLOSE! AND NO it is NOT something you can just add 500F degrees for...isnt the point of having the probe to know the exact temperature?

Since you don't seem to have any comprehension of turbines, Temperatures, pressure, energy transfer (simplistic way of putting it), and the difference of a melted turbine (or not) is 5 degrees for a few seconds so what's that 500F wag gonna do for you...NOTHING and it is truly meaningless AND a waste of time.

Actual TDI turbine wheel, guy was pushing 1600F on a 1550F rated turbine (1Z TDI with retarded timing - Below the red line in Basic Settings)



Do it right or don't do it at all.

OLd thread I know but why would a gauge specialist like auberins put the wrong spade connectors on their k type probes?
THese must be ok?

It's possible that the spade connectors are the same type of material that the wire is made of? I don't know since I haven't used one of their gauge setups..

I shortened my EGT lead a LOT, but I didn't use any kind of connectors to splice the wires together.. I twisted them up in a tight knot, then held them together with heat shrink tubing.. The gauge seems to read just as it did before..

So how does 625C max sound for a 110bhp PASSAT chipped to 130bhp ish at WOT in 4th? Running too much boost for the fuel at 20psi due to 3bar map sensor
Or difficult to say?

Sounds low . I've pushed a VNT17/VNT20 hybrid up to 950C regularly and I've seen even 970-980C a few times and it was perfectly fine till something went through the hot side and kind of broke it. And this is on AFN manifold with EGT mount in the EGR port (but going deep enough to be in the main flow).

Some says that this turbos (VNT15/VNT17) are rated at 850C and the GTB turbos (GTB1756VK, GTB2056VK and GTB2260VK) are rated to 950C. It seems that they can survive a few degree more if something like 100C is considered as few .

And yes - in your case it seems like you are running too much boost. Or too much advance. Either of these will results in less power.