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contraption22
11-27-2007, 03:18 PM
I have my EGT probe in the "collector" area, just before the turbine inlet on my TU Hybrid header. It is ceramic coated. What effect do you think this would have on EGT readings?

johnl
11-27-2007, 04:11 PM
Don't know about the ceramic part but I got higher than typical readings, often 1600*F, with the probe in the same place - centered just before the flange. With appropriate fuel, played with ignition and cam timing to try to bring it down, never could.

contraption22
11-27-2007, 06:53 PM
I am having the same issue. Didn't think so much about the placement of the probe, but I guess that is a pretty hot spot!

A quick google search netted this article by a DSM guy:

http://www.stevetek.com/R-EGTprobeLocation.html

johnl
11-28-2007, 03:01 AM
I don't think ahead of the flange is wrong, just different from the "follow the crowd" idea that it should be in #4 or #3. Heck, ahead of the flange is almost #3 and close to #4.

So, you can do the 4 egt probes thing or you can send your injectors out to RC Engineering (or similar) for balancing, or you can measure their output yourself - all four at once - while hooked to your rail to ensure equal fuel.

Then you can explore the limits of "blended egt" - probably 1700ish* - that's where my last engine got tight. Regularly saw 1650. Got tight when I advanced timing to try to push the egt down.:banghead: cause everyone said 1600+ was too high:mad:

contraption22
11-28-2007, 07:40 AM
Actually on the TU header, the Turbine inlet is after 4. So it would be as close to sampling the average of all 4 cylinders. MY EGT only reads up to 1600... sure the needle goes past that, I THINK it's reading under 1700. My base timing is only at 10 degrees, so maybe I could advance it some.

Austrian Dodge
11-28-2007, 09:53 AM
try advancing the timing a bit.
i'm running 13 degrees base timing, and very progressive timing curves and the needle goes up to 1550° at WOT (at only 12PSI of boost)

cordes
11-28-2007, 09:22 PM
I have noticed that on my stock manifold with the probe between 2 and 3 in the boss that is there, my EGTs are consistently higher than what an engine should live at.

I really don't know what effect the coating would have on EGTs. I think that over a long enough time line (engine warmed up properly) there would not be significant reflection of heat enough to cause a difference.

Stratman
11-29-2007, 01:24 AM
I've run thermal coatings since 2004 on ported exhaust manifolds and seen it run from 1600 to 1750 with a manifold coated inside and out.
My terribly built slow spooling hybrid turbo in 2004 would cause EGT's to shoot to 1700 and up withing seconds of WOT at 15 psi boost.
With the Super 70/stock turbine turbo it called down a bit to 1550 or so until I installed the race ported head which caused the EGT's to go up by about 100 degrees with the .63 housing. Cruising on the highway at 3500 RPM/65 MPH I would be at 1375-1425 depending on how much throttle I give it.
When I started advancing the timing in areas to find more power with the new head my EGT's came back down around 100-150 degrees when about 3-6 degrees of timing were added in areas of the RPM band.
Now with the 112 gas, 26-30 psi boost, and far more agressive timing I believe it continues to stay around 1600 or a little more and has always seem to like it there with no problems from the heat.

I have also seen the EGT needle fly quickly past the last mark of 1600 and probably ended up hitting around 1800 when I wasn't feeding it enough fuel and the ecu was retarding the hell out of the ignition timing.

Sensor located very close to the flage driver's side of manifold near #4.

johnl
11-29-2007, 02:07 AM
Hey Mike, not sayin anything you don't know but be careful in advancing that timing. I mean the high EGTs haven't hurt anything yet, right?

Stratman
11-29-2007, 02:13 AM
I found a good log. I remember having to add around 50 degrees to the log temp to be close to the guage reading. This is a log from my jacked up turbo. I can remember having to run pretty rich to keep detonation away at 18 psi of boost.
http://www.turbofreak.com/pics_files/egtlog1.jpg

Speedeuphoria
11-29-2007, 04:04 AM
Love that logworks:thumb: Good question about the ceramic coating, I know I've hit 1700 when trying to get the knock sensor to work, it pulled timing because of false knock. Also I'm kinda leary of 1600 deg gauges, not sure how acurate they are when there maxed out

contraption22
11-29-2007, 08:35 AM
Hey Mike, not sayin anything you don't know but be careful in advancing that timing. I mean the high EGTs haven't hurt anything yet, right?

You're right. They have not hurt anything yet. The A/F is safely rich and the plugs show no sign of trouble. But I'm wondering if the high EGT's could be a sign that more initial timing could be worth some more power.

Stratman
11-29-2007, 08:57 AM
You're right. They have not hurt anything yet. The A/F is safely rich and the plugs show no sign of trouble. But I'm wondering if the high EGT's could be a sign that more initial timing could be worth some more power.

In my case it was worth more power, but I had to start running the race fuel to really get into the power I wanted to get out of this engine without the detonation. Unfortunately I don't have the EGT's hooked up to the Aux Box anymore so I can't show you what it's doing after tuning in close to 16 deg adv timing over stock in some areas using 112 leaded fuel to get the power up among the RPM band.

Stratman
11-29-2007, 09:01 AM
Love that logworks:thumb: Good question about the ceramic coating, I know I've hit 1700 when trying to get the knock sensor to work, it pulled timing because of false knock. Also I'm kinda leary of 1600 deg gauges, not sure how acurate they are when there maxed out

I seriously don't think it matters. I've had a 1500 deg guage and a my 1600 deg guage in just for the reason of not trusting one and both guages would still end up at around 1600-1650.

contraption22
11-29-2007, 10:38 AM
In my case it was worth more power, but I had to start running the race fuel to really get into the power I wanted to get out of this engine without the detonation. Unfortunately I don't have the EGT's hooked up to the Aux Box anymore so I can't show you what it's doing after tuning in close to 16 deg adv timing over stock in some areas using 112 leaded fuel to get the power up among the RPM band.

I was using a fuel I don't normally use. They were outta c16 at the track, so I was using Q16... which is oxygenated. Maybe that's making a difference.

Dusty_Duster
11-29-2007, 11:47 AM
Let's see if I remember any physics from college...

I don't think ceramic coating would affect your EGTs much. It will keep the rest of your engine from getting as hot, though. I suppose if anything, it might actually make your EGTs read a tiny bit higher since more heat is trapped inside the actual manifold.

contraption22
11-29-2007, 01:11 PM
Well, I just read a tech bulliten about Q16 fuel. Looks to be some badass stuff. However when compared to C16, it requires 4-6% more fuel flow. So, perhaps thats where my high EGT's come in. It does say that the more efficient combustion should result in lower EGT's. So maybe I just need to add in some fuel when using this stuff. It also has a much higher resistance to detonation than C16, so I could get away with more timing.

Just sucks that I have to wait till spring to experiment with it.

Here is the tech info if anybody is interested. http://www.vpracingfuels.com/spec/Tech%20Bulletin--Q16.doc

Stratman
11-29-2007, 01:17 PM
Thanks for posting that Mike.

contraption22
11-29-2007, 04:47 PM
No, thank YOU and all for repyling to my question.

turbovanmanČ
12-02-2007, 02:43 AM
I am having the same issue. Didn't think so much about the placement of the probe, but I guess that is a pretty hot spot!

A quick google search netted this article by a DSM guy:

http://www.stevetek.com/R-EGTprobeLocation.html

Thats a good read. I am going to move my EGT probe.

mcsvt
12-02-2007, 04:17 PM
That's a good read Mike and seems logical.

That said, with a log manifold would we then want to put it down near #1?

johnl
12-21-2007, 08:58 PM
It's a good read, yes.

Empirically, it establishes what we all suspected - a reading taken in the collector will average the cylinder temps and will also heat soak/drift toward the highest cylinder's temperature. If the engine is rich, it may also show higher temps than in the exhaust port, as fuel continues to burn as it travels down the header.

So, are you going to go to the expense and complication and risk of 4 sensors, or just one? And if one, then where? And if 4 sensors, what about heat soak/rich rise at #3 and #4 locations - almost the same as in the collector - assuming a log header.

A sensor at #1 will tell you about #1 while a sensor at #4 (in TU header) will tell you about the same thing as one in the collector. Since #1 and #4 supposedly are the hottest, maybe that leaves #1?

Guess we're back to old school plug chops to double check what EGT on a single cylinder is saying.

My96z
12-28-2007, 12:07 PM
It was a good read but my thoughts...

Do we care how hot it gets in the exhaust manifold or any further down the stream? I monitor my EGTs for the saftey of my pistons and head and state of tune. The cast iron manifold will take the heat as well should the turbine. It just seems to me that the best place to get a idea of the temp of the combustion (where it counts) is in the runner.

Jeff

contraption22
12-29-2007, 12:40 AM
It was a good read but my thoughts...

Do we care how hot it gets in the exhaust manifold or any further down the stream? I monitor my EGTs for the saftey of my pistons and head and state of tune. The cast iron manifold will take the heat as well should the turbine. It just seems to me that the best place to get a idea of the temp of the combustion (where it counts) is in the runner.

Jeff


I think we all agree what you are saying. The point of the thread was to see what could be the cause of high readings, that do not seem to jive with other conditions.

slasky
12-29-2007, 01:14 AM
, I know I've hit 1700 when trying to get the knock sensor to work, it pulled timing because of false knock. Also I'm kinda leary of 1600 deg gauges, not sure how acurate they are when there maxed out

Mine wrapped around and started it's second trip when it was too sensitive to knock. It hat to be over 2k.

johnl
12-29-2007, 02:22 AM
Mine wrapped around and started it's second trip when it was too sensitive to knock. It hat to be over 2k.

Now there's a new idea, at least to me.

Detonation, or some kind of noise, causes the puter to pull timing, and that retardation results in unburnt fuel dumping into the exhaust manifold and that pushes the EGT above 1600*

Then, someone says/thinks, "gosh, I got high EGTs and that means I'm too retarded on the timing, or I've got too much fuel, and they advance the timing, or pull some fuel, and . . . . it's all wrong.

slasky
12-29-2007, 06:22 AM
Now there's a new idea, at least to me.

Detonation, or some kind of noise, causes the puter to pull timing, and that retardation results in unburnt fuel dumping into the exhaust manifold and that pushes the EGT above 1600*

Then, someone says/thinks, "gosh, I got high EGTs and that means I'm too retarded on the timing, or I've got too much fuel, and they advance the timing, or pull some fuel, and . . . . it's all wrong.
It took me a while to figure that one out.

moparzrule
12-31-2007, 09:41 PM
Thats why you need a cal with the CEL flashing on knock enabled! Works wonders!

contraption22
01-02-2008, 06:58 PM
Thats why you need a cal with the CEL flashing on knock enabled! Works wonders!

Indeed!

johnl
01-02-2008, 11:40 PM
Well . . . . where I can get one one of those? I need a decent cal.

cordes
01-02-2008, 11:47 PM
Well . . . . where I can get one one of those? I need a decent cal.

In the code repository on this site, or on moparchem.com

johnl
01-08-2008, 06:45 AM
In the code repository on this site, or on moparchem.com

Sheesh, ya mean I gotta spend a hundred hours gettin up to speed on that stuff?

moparzrule
01-08-2008, 07:26 AM
Is your cal for logic module or SMEC? There's a few people that do cal's.

johnl
01-08-2008, 02:25 PM
Is your cal for logic module or SMEC? There's a few people that do cal's.

87 CSX 3 bar LM

moparzrule
01-08-2008, 04:28 PM
Talk to ''Aries Turbo''

johnl
01-08-2008, 07:02 PM
Talk to ''Aries Turbo''

Thanks, will do.