20” Unimog rims on a Mercedes 814 DA

bulya

Member
Load capacity for the MPT81s in the picture is 4240kg/axle which is enough. By flipping the rim in the rear there’s going to be pretty major wheel bearing stress increase however.
You would essentially going from ET 0 (the sum of offsets of duals, one being flipped) to -(125mm + thickness of flat mounting part of rim ~10mm).
What year is the 814DA? Does it have the OM364 or 904LA? If the 904, it might be possible to gain 41hp relatively easily through ECU reprogramming or replacement. Although I don’t have any idea on whether the turbos and injector nozzles (not too expensive) or actual unit injector pumps (expensive!!) are the same. The pumps are controlled by the ECU.
And you’d want to have an EGT gauge and observe it for weeks or months in hilly terrain to get a baseline before changing anything.

Why do you need EGT gauge? As I understand this to prevent engine overheating and further damage? If yes, why oil temperature gauge is not sufficient?
 

Iain_U1250

Explorer
Why do you need EGT gauge? As I understand this to prevent engine overheating and further damage? If yes, why oil temperature gauge is not sufficient?
EGT gauge shows when you may be melting the pistons, if it gets much over 700 Deg C ( before the turbo) it is likely you are damaging the engine. The main cause is unburnt fuel in a diesel, this carries on burning down through the turbo damaging that and the pistons. I know of people who have melted pistons on one long uphill climb and whilst the engine was running a bit hot, it was too late. The EGT gauge works almost instantly.
 

bulya

Member
Load capacity for the MPT81s in the picture is 4240kg/axle which is enough. By flipping the rim in the rear there’s going to be pretty major wheel bearing stress increase however.
You would essentially going from ET 0 (the sum of offsets of duals, one being flipped) to -(125mm + thickness of flat mounting part of rim ~10mm).
What year is the 814DA? Does it have the OM364 or 904LA? If the 904, it might be possible to gain 41hp relatively easily through ECU reprogramming or replacement. Although I don’t have any idea on whether the turbos and injector nozzles (not too expensive) or actual unit injector pumps (expensive!!) are the same. The pumps are controlled by the ECU.
And you’d want to have an EGT gauge and observe it for weeks or months in hilly terrain to get a baseline before changing anything.
EGT gauge shows when you may be melting the pistons, if it gets much over 700 Deg C ( before the turbo) it is likely you are damaging the engine. The main cause is unburnt fuel in a diesel, this carries on burning down through the turbo damaging that and the pistons. I know of people who have melted pistons on one long uphill climb and whilst the engine was running a bit hot, it was too late. The EGT gauge works almost instantly.


Any advice on EGT sensors/monitors brands?
 

Iain_U1250

Explorer
I've been using the Auber Instruments gauges and sensor for more than 12 years now. I've fond them very reliable - the first EGT I got back in 2010 in a Discovery TDi is still working great. I have five of them in my truck monitoring and controlling various things. https://fb.watch/e64ALmkSgi/


 

Tiktaalik

Supporting Sponsor
I have used Auber but my favorite is the Madman EMS 3 which monitors more than just your EGTs, including coolant level and temp, turbo boost, voltage, oil pressure and temp, etc



Any advice on EGT sensors/monitors brands?
 

bulya

Member
I've been using the Auber Instruments gauges and sensor for more than 12 years now. I've fond them very reliable - the first EGT I got back in 2010 in a Discovery TDi is still working great. I have five of them in my truck monitoring and controlling various things. https://fb.watch/e64ALmkSgi/


I have used Auber but my favorite is the Madman EMS 3 which monitors more than just your EGTs, including coolant level and temp, turbo boost, voltage, oil pressure and temp, etc



Ian, do you have OM366LA on your truck?

I have OM364LA. Does anyone have an idea of what is a normal operating Exhaust gas temperature and at what temperature would you consider the engine to be running too hot?

Also, do you install probe pre-turbo or after?

Thank you
 

Iain_U1250

Explorer
I have an OM352A ( turbo charged and with an intercooler) on mine, and on a pre-turbo EGT - try to stay around 580C - 620C maximum.
 

bulya

Member
I have an OM352A ( turbo charged and with an intercooler) on mine, and on a pre-turbo EGT - try to stay around 580C - 620C maximum.

Did you mount a separate sensor per each cylinder or do you use 1 sensor on one cylinder and it is good enough?
 

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