OM642: Garrett GTB2365vk

[SaundersW203]

Do you think the stock inlet pipe is too restrictive?

In the high rpm's I gained over 15% more airflow. Compressor out temperatures also dropped significantly.
I had set up a vacuum gauge about 50mm from the intake on the compressor and I can't remember exactly but I had about a 25kPa depression. With the custom compressor in pipe, it was around 7 or8 kPa I think. I done this using a gauge so couldn't data log it unfortunately. So my numbers may be slightly out.

 

[No2fast]

I have seen, that you have the skills to help yourself on the ecu adaptions! I have the 4bar map sensor. i am wondering if you have/had the same ecactely the same turbocharger on your car.

 

[SaundersW203]

Hi,
i did not fit the turbocharger yet. But probabely next month. i had to replace the intercooler and all suspension parts on the car first. Which i did

updates

OM642 sprinter 906 manifold adaption (no flaps / no egr valve) autometer egt probe / exhaust manifold exhaust backpressure sensor mod / exhaust manifold egr cooler delete (mechanically) egr delete (mechanically)

34plus2.jimdofree.com

Where did you get your turbocharger?
Thanks for the warning. I will not add to much boost (max 2.1 bar).

TDi turbo's in the UK built mine.
I also had B14 Bilsteins, they made a massive difference.

 

[No2fast]

Very good information on the pipe..
I like Bilstein suspensions and shocks too. B12
I may need help on an initial tune for the beginning. But i have a remap on the dyno in my mind.
I will send you a message for the tune and pipe.
BTW I have a CDI4 ECU. I would guess you had a CDI3 or CDI4 as well on your car before? EDC16P31

 

[No2fast]

Hi SaundersW203,
unfortunately i am not allowed to send you a message here on the forum, i have less than 30 posts.
It would be nice, if you can contact me by message or mail. My contact details: Log in to Facebook or [email protected].
Thanks
Steven

 

[SaundersW203]

Very good information on the pipe..
I like Bilstein suspensions and shocks too. B12
I may need help on an initial tune for the beginning. But i have a remap on the dyno in my mind.
I will send you a message for the tune and pipe.
BTW I have a CDI4 ECU. I would guess you had a CDI3 or CDI4 as well on your car before? EDC16P31

I'm not sure I know the difference between CDI3 and CDI4 to be honest.

 

[SaundersW203]

If you get the file off your ECU I can have a quick look

 

[SaundersW203]

Hi SaundersW203,
unfortunately i am not allowed to send you a message here on the forum, i have less than 30 posts.
It would be nice, if you can contact me by message or mail. My contact details: Log in to Facebook or [email protected].
Thanks
Steven

Surely this is a good excuse to get those numbers up, haha.

 

[suty455]

When was the last time you logged EGT's on a diesel?
Please stop giving people on this forum incorrect information.
You are correct, more fuel is more heat, but 650°C isn't hot for diesel EGT's.
A lot of diesel cars will run over 800°C brand new out of the factory. The only reason they don't run them hotter is because of the increased emissions as you go above 800°C(ish).

Really ok well carry on then, but seeing as my Dad and his Brother run a fleet of HGVs pulling 50 tons plus and twin trailers from Capetown to Malawi every Day and have for the last 30 years I think I know a thing or two about EGTs, dont listen to this blithering fool anything continuous over 650 deg c is very bad for your Engine it WILL kill it the odd spike fine but sustained running will cause damage that is incremental, race engines can cope as they use exotic materials.
Please feel free to tell us which cars come from the factory and run 800c EGT? For the record Garrett posts that 720C is the limit for continuous running EGTs and they probably know a thing or two about Turbos, swirl cups and turbines can start to deform at 850 C and the jump from 650 to 850 really can be the blink of an eye if you tune to allow it.
Play safe stay under 650 and all will be good for many many miles not 10k or less

 

[ALFAitalia]

A very good way of damaging exhaust valves too.

 

[SaundersW203]

Really ok well carry on then, but seeing as my Dad and his Brother run a fleet of HGVs pulling 50 tons plus and twin trailers from Capetown to Malawi every Day and have for the last 30 years I think I know a thing or two about EGTs, dont listen to this blithering fool anything continuous over 650 deg c is very bad for your Engine it WILL kill it the odd spike fine but sustained running will cause damage that is incremental, race engines can cope as they use exotic materials.
Please feel free to tell us which cars come from the factory and run 800c EGT? For the record Garrett posts that 720C is the limit for continuous running EGTs and they probably know a thing or two about Turbos, swirl cups and turbines can start to deform at 850 C and the jump from 650 to 850 really can be the blink of an eye if you tune to allow it.
Play safe stay under 650 and all will be good for many many miles not 10k or less

So they run a fleet of HGV's, that is cool, they must be engineering experts.

I have professional experience running, calibrating and developing engines in the automotive, motorcycle and motorsport industries. I am by no means a valve expert either, but I have a good idea of what goes on. Valve spring rate, exhaust temperature, camshaft ramps, exhaust back pressure are all very important. Also, I have run production automotive engines for very long durations, at temps way above your 650°C limit.

Garret may state that for one of their turbo's, but turbo housings, vnt's and turbine wheels are made of different materials allowing for different working limits.

 

[SaundersW203]

Really ok well carry on then, but seeing as my Dad and his Brother run a fleet of HGVs pulling 50 tons plus and twin trailers from Capetown to Malawi every Day and have for the last 30 years I think I know a thing or two about EGTs, dont listen to this blithering fool anything continuous over 650 deg c is very bad for your Engine it WILL kill it the odd spike fine but sustained running will cause damage that is incremental, race engines can cope as they use exotic materials.
Please feel free to tell us which cars come from the factory and run 800c EGT? For the record Garrett posts that 720C is the limit for continuous running EGTs and they probably know a thing or two about Turbos, swirl cups and turbines can start to deform at 850 C and the jump from 650 to 850 really can be the blink of an eye if you tune to allow it.
Play safe stay under 650 and all will be good for many many miles not 10k or less

I have never had any involvement with HGV's. So wouldn't like to comment on safe EGT's for one of those.

 

[suty455]

I have never had any involvement with HGV's. So wouldn't like to comment on safe EGT's for one of those.

And the standard spec engine that has 800C EGTs?
A Diesel Engine is a Diesel engine be it 1 cylinder or 8, 2hp or 560hp the EGTs work the same except of course non turbos are not that critical downstream. EGTs on HGVs pulling weights are ultra critical, the road from Cape to Malawi is actually an average climb all the way so the engine is under constant load a rogue EGT can blow a 25k engine in seconds and a constant high one will slowly degrade its lifespan which on a HGV is critical commercially, each trip is 4100km each way and the trucks tend to run for 500000 miles before major maintenance is considered, the biggest warning lights on the Trucks from the manufacturer is Air, Oil and EGT, I should mention that the HGV limits we have in the UK dont apply they tend to run 130 kph fully loaded on good roads (SA and Botswana) and only 90kph in poor roads (Zambia and Malawi) and ambients can hit 45C in October to December and of course much higher with bounce back from the Road.
Sometimes it depends where your taking the pyrometer reads is it pre or post Turbo I have seen Turbos in my own tuned road cars glow in the dark from heat but never a TD, Petrol has a higher external temp than Diesel but the internal temp at the piston on a TD is much higher hence the need to maintain a very close watch on EGTs, and as I said exotic materials apart standard Turbos and housings will begin to deform at 850C once that starts its game over

 

[Willo54]

@suty455, actually saunders is right about turbo max temperature for car (don't know about trucks). Working on car engine test bench at the moment, I asked the question about the turbo max temperature at two co-workers that are really experienced on the diesel calibration (worked for car manufacturer diesel development and calibration). 800°C are really common on OEM diesel, but it's about the safe limit. Run higher temperature can cause variable nozzles damage, and it's the reason why gasoline engines don't have VN turbo (except a few engines from Porsche for example), because of the temperature that ruin the nozzles.


@SaundersW203, can you bring us more informations about your W203 ? I read that you tune it about 120mm3 of fuel, and in the last tune even 2,6 bar of boost (3,6 absolute pressure), with 1800 bar rail pressure is that correct ? What about the exhaust back pressure you ran, exhaust temperature, measured lambda ? How much did you modify your SOI ? I'm really curious about that, because I'm concerned about the cylinder pressure that OM642 first generation can hold. On the OM642 datasheet, Mercedes said that they achieved 180 bar of cylinder pressure. With your tune, I suppose that you should exceed 200 bar, that is really huge. The material resistance isn't linear, and approach 200 bar on OEM pistons can't be safe for a long-term vision. Some co-workers confirmed me that where I work. 170-180 bar are still common for recent diesel, and for example, Audi said in the datasheet of the 3L Bitdi that they worked about 185 bar ... and the engine develops 320 horse power with 3,2 bar absolute boost pressure. (it depends of the engine, MB engines are made to a power peak at 3800 rpm, while Audi and BMW produced less torque at low revs, but work at 4500 rpm)

Boost pressure and rail pressure are the most important parameters on cylinder pressure, and we know that piston heads of OM642 can crack. It's not really uncommon, according to some case report about that.

Was your W203 daily drive ? How much kilometer have you driven on it since the turbo modification ?

One solution to increase torque without too increase cylinder pressure is to stay really safe on SOI and spread the combustion to avoid a pressure pic. But it's compromise as always, spreading the combustion is made by delay the start of injection, that increase exhaust temperature and can cause smoke.


@No2fast, thanks for sharing. Please keep us informed about the project.


OM642 peak pressure



Audi Bitdi peak pressure

 

[suty455]

Ok well you try running one in the real world like that and see what happens, it also depends on where exactly the sensor is fitted, Garrett Gasoline Variable valve turbos are said by garrett to be capable of 1020 deg C, what you need to consider is the differing burn characteristics of the two fuels, diesel burns slowly and more completely than petrol so the heat is in fact built up within the engine not within the exhaust, what you see in the exhaust is actually cooler than further upstream, whereas a petrol engine is in many cases still burning as it leaves the cylinder so the heat is actually concentrated downstream.
Diesel fuel is denser than petrol and the actual combustion temp is far higher in a diesel than a petrol hence the observation if the EGT is 650c it is way higher within the engine and damage will occur, perhaps advances in modern materials will allow higher temps but this would be new right now, your OM642 is from 2008 on and was designed earlier with the material limitations of the time

 

[Bellow]

, what you need to consider is the differing burn characteristics of the two fuels, diesel burns slowly and more completely

Not so. If diesel combustion was as complete as you suggest there would be no issues with soot in the exhaust. Soot in the exhaust is the limit for fuelling even when overall the AFR is below stoichiometric.
Diesel in a CI engine burns as fast as it can find oxygen. That is a function of the combustion system - not the fuel. Diesel mixed homogenously with air will burn very fast. It just doesn't readily atomise to create a homogenous mixture and even if it did, it's octane rating is so low as to create uncontrollable combustion.

diesel burns slowly and more completely

than petrol so the heat is in fact built up within the engine not within the exhaust, what you see in the exhaust is actually cooler than further upstream, whereas a petrol engine is in many cases still burning as it leaves the cylinder so the heat is actually concentrated downstream.

The reasons exhaust temps in diesels is lower than petrols is due to:
A) the compression ratio - more accurately the expansion ratio. At close to double the petrols the cooling effect of expansion (of a gas) is much greater.
B) Due to excess air in the cylinder the mean cylinder temp during combustion in the diesel is lower than with a petrol. Thus, expansion begins from a lower temp.

Diesel fuel is denser than petrol and the actual combustion temp is far higher in a diesel than a petrol

Not so. Combustion temperature at stoichiometric is the same (within very narrow variation) for all hydrocarbon fuels.

hence the observation if the EGT is 650c it is way higher within the engine

It is erroneous to deduce temperature in the combustion chamber from EGT. As an example of how misleading it can be consider what happens when in the early stages of detonation in a 2-stroke. The heat build up in the cylinder of a detonating 2-stroke will melt the piston very rapidly but the EGT actually drops during that occurrence (due to the heat being absorbed by the piston and not reaching the exhaust to be measurable as EGT). Going in the other direction, retarded timing (injection or spark) will increase EGT but during combustion the temp in the cylinder will be lower than it would have been due to a decrease in peak pressure.

 

[suty455]

Lots of armchair "experts" who frankly have no clues ok a single paragraph from the ACEA who I think you have to agree know a thing or two about fuels and engines after that am done with this thread do what you will, and the last time I looked we were not talking 2 strokes

Science says

"
By virtue of the combustion process and the overall engine concept, a diesel engine can be up to 40% more efficient than a spark-ignited petrol engine with the same power output, ceteris paribus, particularly with new ‘low’ compression diesels.


The calorific value of diesel fuel is roughly 45.5 MJ/kg (megajoules per kilogram), slightly lower than petrol which is 45.8 MJ/kg. However, diesel fuel is denser than petrol and contains about 15% more energy by volume (roughly 36.9 MJ/litre compared to 33.7 MJ/litre). Accounting for the difference in energy density, the overall efficiency of the diesel engine is still some 20% greater than the petrol engine, despite the diesel engine also being heavier."

and you say
Not so. If diesel combustion was as complete as you suggest there would be no issues with soot in the exhaust. Soot in the exhaust is the limit for fuelling even when overall the AFR is below stoichiometric.
Diesel in a CI engine burns as fast as it can find oxygen. That is a function of the combustion system - not the fuel. Diesel mixed homogenously with air will burn very fast. It just doesn't readily atomise to create a homogenous mixture and even if it did, it's octane rating is so low as to create uncontrollable combustion.

Yes soot is a by product but its not due to less efficiency but because its a heavier and denser fuel, combustion temps within a diesel engine are higher, within a petrol engine its lower because yes the fuel cools it on the way in, in fact it needs to or you get pre ignition which does your engine no favours, exhaust temps on a petrol are higher, no you should not use the EGT as a measure of internal engine temps thats why its called an EGT but it is absolutly indicative of whats happening 30 cm away in the cylinder higher EGTs in a diesel can indicate over fueling and potential damage.

Done

 

[Bellow]

Lots of armchair "experts" who frankly have no clues ok a single paragraph from the ACEA who I think you have to agree know a thing or two about fuels and engines

I take my info from Sir Harry Ricardo...

after that am done with this thread do what you will, and the last time I looked we were not talking 2 strokes

In the combustion chamber it matters not one jot whether 2 or 4 stroke.

Science says

"
By virtue of the combustion process and the overall engine concept, a diesel engine can be up to 40% more efficient than a spark-ignited petrol engine with the same power output, ceteris paribus, particularly with new ‘low’ compression diesels.

Defining by volume (as above) isn't the accepted metric.

The calorific value of diesel fuel is roughly 45.5 MJ/kg (megajoules per kilogram), slightly lower than petrol which is 45.8 MJ/kg. However, diesel fuel is denser than petrol and contains about 15% more energy by volume (roughly 36.9 MJ/litre compared to 33.7 MJ/litre). Accounting for the difference in energy density, the overall efficiency of the diesel engine is still some 20% greater than the petrol engine, despite the diesel engine also being heavier."

But they got there in the end (kg/kW.hr).

and you say
Not so. If diesel combustion was as complete as you suggest there would be no issues with soot in the exhaust. Soot in the exhaust is the limit for fuelling even when overall the AFR is below stoichiometric.
Diesel in a CI engine burns as fast as it can find oxygen. That is a function of the combustion system - not the fuel. Diesel mixed homogenously with air will burn very fast. It just doesn't readily atomise to create a homogenous mixture and even if it did, it's octane rating is so low as to create uncontrollable combustion.

Yes soot is a by product but its not due to less efficiency but because its a heavier and denser fuel,

Nonsense. Soot is formed when the diesel cannot find sufficient oxygen to combust cleanly with which is a function of the efficacy of the combustion system.

combustion temps within a diesel engine are higher,

Localised they are higher than the mean but the mean temp is lower in a diesel than in a petrol. The diesel heats a larger quantity of air to a lower temp than does a petrol engine - it is a 'lean burn' combustion system. That lower overall temp reduces heat lost to the coolant and is one of the principle reasons why a diesel is more fuel efficient - and why they take so much longer to warm up.

within a petrol engine its lower because yes the fuel cools it on the way in,

By volume, the petrol as a vapour is 4% of the total cylinder contents. The cooling effect isn't significant relative to combustion temp.

in fact it needs to or you get pre ignition which does your engine no favours,

Detonation is the limiting factor (not pre-ignition) with SI engines - which sets the HUCR (Highest Usable Compression Ratio) for a given fuel octane and thus its expansion ratio.

exhaust temps on a petrol are higher,

Due to lower expansion and a higher initial mean cylinder temp - and not much else.

no you should not use the EGT as a measure of internal engine temps thats why its called an EGT but it is absolutly indicative of whats happening 30 cm away in the cylinder

Monitor EGT for the benefit of components in the exhaust system but it takes very careful reading (ie context) for EGT to be an accurate reflection of in-cylinder events.

higher EGTs in a diesel can indicate over fueling and potential damage.

Can, but the old industry standard the VSL (visible smoke limit) would have detected the over-fuelling in the form of soot.