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Old 12th April 2013, 23:21   #1
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Default Maximum Temperature For Exhaust Gas

The car is a Skoda Laura 1.8 TSi
and has modifications - ECU remap from Kiirus, APR Carbonio, complete stage 2 carbon fibre intake system, forge aluminium blow off valve.
The remap was performed a couple of years ago, and the other modifications a year back.
After the remap the exhaust gas temperature has increased to 950 degree from 3700 RPM To 7000 RPM. The car has run 20,000 kms since the remap.
Recently some one told me that the exhaust gas temperature should not be above 800 degree or else it will melt your turbo housing. The car had no problems with the turbo or performance till date. I am unable to find any relevant data on the optimum or maximum exhaust gas temperature for the 1.8 TSi or in general for turbo charged petrol engines.

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Last edited by Rudra Sen : 13th April 2013 at 07:26.
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Old 13th April 2013, 00:15   #2
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by anarchy_99 View Post
...The Exhaust Gas Temperature Has Increased To 950 Degree From 3700 RPM To 7000 RPM.
Recently Some One Told Me That The Exhaust Gas Temperature Should Not Be Above 800 Degree Or Else It Will Melt Your Turbo Housing.
At which point of the exhaust is the EGT being measured? Before the turbo or after? How are you monitoring the temperature (instrumentation)?
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Old 13th April 2013, 00:22   #3
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by SS-Traveller View Post
At which point of the exhaust is the EGT being measured? Before the turbo or after? How are you monitoring the temperature (instrumentation)?
I Don't Know At Which Point The EGT Is Measured. Its Probably After The Turbo.
I Am Using The Ross-Tech VCDS To Measure The EGT.
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Old 13th April 2013, 07:32   #4
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Default Re: Maximum Temperature For Exhaust Gas

EGT should be measured before the turbo and not after. The sensor should be placed as close to the head as possible. High EGT is an indication that the engine is running lean and it needs more fuel in the AFR. 950 is too high. Generally 850 is considered the the higher limit for EGT.

Last edited by vikram_d : 13th April 2013 at 07:43.
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Old 13th April 2013, 07:40   #5
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by anarchy_99 View Post
The Car Is A Skoda Laura 1.8 TSi
And Has Modifications - ECU Remap From Kiirus, APR Carbonio Complete Stage 2 Carbon Fibre Intake System, Forge Aluminium Blow Off Valve.
The Remap Was Performed a Couple Of Years Ago, And The Other Modifications A Year Back.
After The Remap The Exhaust Gas Temperature Has Increased To 950 Degree From 3700 RPM To 7000 RPM. The Car Has Run 20,000 Kms Since The Remap.
Recently Some One Told Me That The Exhaust Gas Temperature Should Not Be Above 800 Degree Or Else It Will Melt Your Turbo Housing. The Car Had No Problems With The Turbo Or Performance Till Date. I Am Unable To Find Any Relevant Data On The Optimum Or Maximum Exhaust Gas Temperature For The 1.8 TSi Or In General For Turbo Charged Petrol Engines.
Is 950 C from 3700 to 7000 RPM the peak sustained EGT? Is it at WOT or is it while cruising? Is the EGT at the same range while cruising? Where is the sensor (OEM?) mounted in your car? If its post turbo the actual EGT the turbo is seeing will be higher than measured. EGT at 950 C isn't safe at all! If it were a short spike it might be okay but not for sustained driving. Sustained EGT above 800 C is generally considered high and above 900 its too high.

Is it possible for you to get the EGT of a stock 1.8TSI using RossTech?
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Old 13th April 2013, 08:12   #6
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Default Re: Maximum Temperature For Exhaust Gas

Would it be possible for you to check the AFR between 3700 and 7000 RPM?
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Old 13th April 2013, 16:42   #7
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by vikram_d View Post
EGT should be measured before the turbo and not after. The sensor should be placed as close to the head as possible. High EGT is an indication that the engine is running lean and it needs more fuel in the AFR. 950 is too high. Generally 850 is considered the the higher limit for EGT.
As per the factory repair manual, the lambda probe sensor (g39) which i used to measure the EGT is located after the turbo and before the CAT-CON.

Last edited by anarchy_99 : 13th April 2013 at 16:54.
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Old 13th April 2013, 16:53   #8
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by Sankar View Post
Is 950 C from 3700 to 7000 RPM the peak sustained EGT? Is it at WOT or is it while cruising? Is the EGT at the same range while cruising? Where is the sensor (OEM?) mounted in your car? If its post turbo the actual EGT the turbo is seeing will be higher than measured. EGT at 950 C isn't safe at all! If it were a short spike it might be okay but not for sustained driving. Sustained EGT above 800 C is generally considered high and above 900 its too high.

Is it possible for you to get the EGT of a stock 1.8TSI using RossTech?
1.) Yes the temperature is peak sustained, it is between 940 degree to 960 degree from 3700 RPM to 7000 RPM
2.) Yes it is WOT, i was measuring the power on the engine in 3rd gear to prepare a bhp and torque dyno graph, along with the torque values i also measured the EGT
3.) Never measured the EGT while Cruising
4.) The sensor is located between the turbo and Cat-Con
5.) i do not have the EGT values for stock car but i measured a tune o tronics mapped Laura vrs and the maximum temperature was 900 that to only between 6000 Rpm - 7000 Rpm
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Old 13th April 2013, 19:22   #9
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by anarchy_99 View Post
As per the factory repair manual, the lambda probe sensor (g39) which i used to measure the EGT is located after the turbo and before the CAT-CON.
If the O2 sensor is reading 950 EGT after the turbo, then your car is suffering from serious fuelling issues. It is running extremely lean between 3700 & 7000 RPM. The engine needs more fuel in this RPM range. Try and see if you can get the remap tuned. In my opinion EGT should not be more than 850 degrees under any load condition. The correct way to solve this would be to get EGT readings at various RPMS and then tune the map accordingly.

Last edited by vikram_d : 13th April 2013 at 19:26.
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Old 13th April 2013, 19:24   #10
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by anarchy_99 View Post
As per the factory repair manual, the lambda probe sensor (g39) which i used to measure the EGT is located after the turbo and before the CAT-CON.
Buddy i'm a little confused here... how do you measure EGT using lambda sensor? I looked up on the G39 lambda probe, its a heated sensor how can it read EGT?
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Old 13th April 2013, 19:43   #11
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by anarchy_99 View Post
1.) Yes the temperature is peak sustained, it is between 940 degree to 960 degree from 3700 RPM to 7000 RPM
2.) Yes it is WOT, i was measuring the power on the engine in 3rd gear to prepare a bhp and torque dyno graph, along with the torque values i also measured the EGT
3.) Never measured the EGT while Cruising
4.) The sensor is located between the turbo and Cat-Con
5.) i do not have the EGT values for stock car but i measured a tune o tronics mapped Laura vrs and the maximum temperature was 900 that to only between 6000 Rpm - 7000 Rpm
Hope this helps, its from VWvortex. From the post below 900 seems OK for heavily boosted cars (hows the boost after remap?) but its not OK beyond that.

Quote:
Channel 34: Exhaust Gas Temperatures (EGT)
...most of our cars don't have EGT probes built in...

Pretty straight forward here and a great channel to use to give you the heads up that other things are going wrong. This monitors the exhaust gas temperatures of the car. You want to see what the limits are here and it will take some beating on the car to find it. When the car is still warming up, your readings may not accurately reflect just how high these temps can get. Take your car out for some spirited full boost runs, then start logging in the normal 3rd gear WOT manner. Exhaust gas temperatures at 900 degrees Celsius and below are common for our engines when heavily boosted. This sensor appears to be only accurate up to 999 degrees Celsius or so. If you see readings creeping up this high, you have a great indicator that something is not right on your car and your engine is not happy with you. Running too high of temps for too long will spell disaster.
http://forums.vwvortex.com/showthrea...ips-and-Tricks

I'm interested to know whether your car have an EGt probe, because the quoted post says not all 1.8TSI have them. You're saying that the EGT is being read by a heated O2 sensor, i'd like to know how that works.
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Old 13th April 2013, 21:38   #12
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Default Re: Maximum Temperature For Exhaust Gas

Hi,
Like some others, am very interested in knowing how ex temp is actually being measured in this case. Esp. whether it is being measured, or computed.

My (very outdated info) says 950 C sustained AFTER turbo = toasted engine. Somehow, I doubt this reading.

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Old 14th April 2013, 01:54   #13
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by Sankar View Post
Buddy i'm a little confused here... how do you measure EGT using lambda sensor? I looked up on the G39 lambda probe, its a heated sensor how can it read EGT?
Screenshot source :- http://www.vaglinks.com/OBDII/Vag-co...d_Graphing.pdf

I referred this pdf file and assumed that the o2 sensor is used to measure the EGT. Please correct me if i am wrong. the measuring block that i use to measure the EGT in VCDS is Block 112. After referring the factory repair manual, i found out the location for the O2 sensor between turbo and cat-con.

Also i am posting the new logs which i took today. the car has got all four ignition coil replaced last week and also got engine oil changed.
one log is while cruising and the other one is WOT in 3rd gear.
i have logged all the relevant fields as requested.
Attached Thumbnails
Maximum Temperature For Exhaust Gas-screen-shot-20130414-1.45.06-am.png  

Attached Files
File Type: xls Laura.xls (30.5 KB, 183 views)
File Type: xls Laura Cruising.xls (171.5 KB, 322 views)

Last edited by anarchy_99 : 14th April 2013 at 02:12.
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Old 14th April 2013, 10:09   #14
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Default Re: Maximum Temperature For Exhaust Gas

Quote:
Originally Posted by anarchy_99 View Post
Screenshot source :- http://www.vaglinks.com/OBDII/Vag-co...d_Graphing.pdf

I referred this pdf file and assumed that the o2 sensor is used to measure the EGT. Please correct me if i am wrong. the measuring block that i use to measure the EGT in VCDS is Block 112. After referring the factory repair manual, i found out the location for the O2 sensor between turbo and cat-con.
The EGT reading in the log file is the projected EGT, its not the actual measured EGT. The EGT is calculated based on O2 sensor input and some other parameters. A further reading up on this topic i came across people in VW and Audi forums mentioning this projected EGT is not accurate for a chipped vehicle, and an EGT probe is recommended if true EGT is to be measured.

Since your car is a remapped vehicle this EGT readings may not be true at all and if your car had an EGT sensor (G235/G236) the readings will be from that sensor instead of the G39 lambda probe. I think you should get in touch with Rosstech/Tuner and ask them what they think of this reading and how its calculated and whether you should be concerned. This is the best you can do, or install an EGT probe if you are really worried about the EGT and engine health.

Last edited by Sankar : 14th April 2013 at 10:13.
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Old 14th April 2013, 20:54   #15
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Default Re: Maximum Temperature For Exhaust Gas

Projected, ie computed value. Not actually measured.

In a modified car, computed values can be totally off. Computation is done based on a mathematical model. Which is painstakingly refined and validated. Modifying the engine can throw the model wildly off.

Regards
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