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      10-19-2021, 04:39 PM   #1
tanzaniteM4
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Incorrect EGT values on E85

Hi everyone,

I recently made the switch to beets (not corn here in France) to feed my M4.

Right now the tune is very soft, just want to get E85 perfectly working on stock power levels then I will push it further.

The car is running good but I realized that the burbles (overrun) usually works one or two minutes after starting the car and then are disabled by the DME. I dived into that issue and I saw that they were disabled by reading too high EGT..

I know that EGT value is modeled and not from a sensor, my car is reading EGT higher that 2000F frequently. So, my question is there is a way to calibrate the model that EGT are reading good while using E85 because for now they are totally useless..

Here is a log showing extreme EGT on very soft driving: https://www.bootmod3.net/log?id=616f...729b197d4d673d

The car currently has the following mods:
  • Full akrapovic exhaust including downpipes
  • Hybrid turbos similar to Pure Stage 2 (not plus)
  • F8S Ethanol Spark Plugs
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      11-16-2021, 07:54 PM   #2
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Which BM3 tune are you running?
Hybrid turbos usually take the 2H maps but there's no E85 version. Neither FlexFuel map is 2H…

When I looked at your link no log data showed up, just a blank log. Maybe check the link.
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      11-17-2021, 03:20 AM   #3
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No data on that link but with a setup like that I'd have to assume you have a custom tune. Have your tuner fix that for you.
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      11-19-2021, 11:02 AM   #4
tanzaniteM4
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Hi, that datalog was deleted by error.

This is a custom tune, not an OTS, everything works fine (except burbles the first time, so I had to increase to EGT values on burble tables.)

Here is a working log showing that hight EGT: https://www.bootmod3.net/log?id=617d...90c66e747d4ca9
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      11-19-2021, 01:30 PM   #5
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Quote:
Originally Posted by tanzaniteM4 View Post
Hi, that datalog was deleted by error.

This is a custom tune, not an OTS, everything works fine (except burbles the first time, so I had to increase to EGT values on burble tables.)

Here is a working log showing that hight EGT: https://www.bootmod3.net/log?id=617d...90c66e747d4ca9
The EGTs are "modeled" so the numbers are based on some table or scaling factor. Since this is a custom flash your tuner should take care of that for you.

Are you self-tuning on BM3, or who is your Tuner?
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      11-23-2021, 07:40 AM   #6
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Quote:
Originally Posted by TopJimmy View Post
The EGTs are "modeled" so the numbers are based on some table or scaling factor. Since this is a custom flash your tuner should take care of that for you.

Are you self-tuning on BM3, or who is your Tuner?
I am self tuning, just being really conservative I am not pushing anything until I know how all tables work and react together.

Ps: This is not the first time I am tuning, I have a VW group tuning background (Audi, Porsche)
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      11-23-2021, 07:54 AM   #7
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Quote:
Originally Posted by tanzaniteM4 View Post
Quote:
Originally Posted by TopJimmy View Post
The EGTs are "modeled" so the numbers are based on some table or scaling factor. Since this is a custom flash your tuner should take care of that for you.

Are you self-tuning on BM3, or who is your Tuner?
I am self tuning, just being really conservative I am not pushing anything until I know how all tables work and react together.

Ps: This is not the first time I am tuning, I have a VW group tuning background (Audi, Porsche)
Sorry, I don't know how to custom tune. You need to ask the professional tuners about those details.
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      12-02-2021, 05:10 PM   #8
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I had the same problems. I don't know of a better way other than to raise the limits. If you find one, please let me know! I am self tuning as well. The EGTs are a modeled value and are not real values. Don't forget to raise the EGT limits for Component Protection as well. I spent a lot of time figuring that one out lol.

You'll notice if you advance ignition timing the EGTs will go down, presumably because it's assuming more combustion occurs inside the cylinder.
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