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The M275 Training document is inaccurate on many points, as many changes are made on a per vehicle basis,
Where are you reading this "official Mercedes published value". I am relaying my personal experience with this platform.
The boost spikes at 4k rpm, it is not mapped to spike .
I appreciate your experience as any information in this small community of owners benefits us all. I just want to add to this that my experience with the platform is different than yours-if that helps someone then great, if not then at least its in the community.
Yes, I agree that the training document is inaccurate on many points. I do not really use it for technical data though and I am not using it here. But some items are likely explainable actually. For example, the max boost that you mentioned that is listed for the m275 is 1.9 bar. As many know, if you measure pressure for these cars off the map pressure, you have to convert the map pressure to boost psi by subtracting 1 bar or 14.5 psi off the total . The resulting boost on m275 would be .9 bar or 13 psi which, according to what I remember, is the stock maximum boost for a m275 e55 600.
To reference how this works on the 65, this post also talks about the map reading https://mbworld.org/forums/m275-v12-...s-results.html
The map reading on his 65 was roughly 37psi which converted (minus 1 bar or 14.5psi) is 22.5psi. I know that car had a tune but just food for thought on the training document.
By published, I meant the figures contained in WIS and Xentry test programs. So my knowledge and experience is that a properly running 65 should have a Maximum boost pressure of the m275 e60 stock should be 1.5 bar at 2300 rpm. Your absolutely right that it is not mapped to spike. The spike is caused by a sizing issue with the small stock compressor wheel. By comparison, the sl65 black series is able to maintain that boost pressure through the rev range without taper like we have due to an increase in the size of the compressor wheel. It is a design element that increase low end torque and response at the expense of boost/hp at the top end.
I can verify tomorrow but I am almost positive this is all contained in WIS documents and repair/test procedures (which is official Mercedes) confirm 1.5 bar btw.
In fact, I have even run a Xentry test for boost pressure where you had to put the car in manual mode in 3rd gear at certain speed and accelerate fully. The test had a green zone which showed whether boost was in range. I hit 1.5 bar during that test. I was in cool weather for that test and had no tune.
I had many logs on the road and on the dyno, but a stock 65 never hit effective 1.5 bar.
Stock it is max. 1.2-1.25 bar and then tapers off with climbing revs. I know that MB is publishing 1.5 bar max. boost, but who knows for what reason.
Maybe xentry reads a different (short spike)?
And one question, should a tuned 65 also spike 1.5 bar with this theory?
Last edited by AMG-Driver; 02-07-2019 at 02:04 AM.
I had many logs on the road and on the dyno, but a stock 65 never hit effective 1.5 bar.
Stock it is max. 1.2-1.25 bar and then tapers off with climbing revs. I know that MB is publishing 1.5 bar max. boost, but who knows for what reason.
Maybe xentry reads a different (short spike)?
And one question, should a tuned 65 also spike 1.5 bar with this theory?
You need to use an analogue boost sensor to measure. Datalogging is too slow on this car.
You will hit 15psi max boost at 2300ish rpm, it will then climb to peak about 19ish at 4000, then start to taper off to redline at 12psi
A tuned car will climb to about 22psi. I have never seen a stock one hit 25psi, the document is "wrong".
You should do basic checks as well, like boost leak tests etc to ensure there are no leaks, there are many places that can leak. On R230's its common for the intake manifold plug at the back to leak (where a brake booster pipe would be on other cars).
You must also measure your ambient pressure, if its particularly low (high altitude) then you will have less boost.
Yes, I never had a problem with my boost - my car runs fine.
My point is, when MooksM275 reads 1,5 bar 22 PSI with xentry, why should the ouput rate of a obd2 port be fasterwith xentry than with Torque App etc?
Maybe it reads on a different point in the intake, but this makes no real sense to me, as obd is obd on these cars.
And you with analog sensor also only get 19PSI at 4.000 RPM it is still not 22 PSI?
I doubt that you hit effective 1.5 bar (22PSI) at any time with a stock car, this is my point.
Maybe MooksM275 had a tune on his car, he was not aware of? But I think he will know his car best... ;-)
Last edited by AMG-Driver; 02-07-2019 at 03:06 AM.
Yes, I never had a problem with my boost - my car runs fine.
My point is, when MooksM275 reads 1,5 bar 22 PSI with xentry, why should the ouput rate of a obd2 port be fasterwith xentry than with Torque App etc?
Maybe it reads on a different point in the intake, but this makes no real sense to me, as obd is obd on these cars.
And you with analog sensor also only get 19PSI at 4.000 RPM it is still not 22 PSI?
I doubt that you hit effective 1.5 bar (22PSI) at any time with a stock car, this is my point.
Maybe MooksM275 had a tune on his car, he was not aware of? But I think he will know his car best... ;-)
It isnt though, If the snapshot of data is taken at the right time, or if the engine is loaded on a very high gear, then it will be in that RPM range for long enough to see the value on xentry.
Also, W220/W215 has KWP which is much slower than later cars that use 11bit canbus, and therefore have faster sample rates
I know this is an old thread, but since it has been raised to the top of the forum, I just happened to be curious of what my IAT value was and read the value from the ECU. It was around 124°F/51°C on a 72° day, and this was under boost. The vehicle is a W221 S600 and right now is 100% stock but stock ECU maps, but I do have a tuned map I have thought about writing back to it (it is a tune Jerry from Eurocharged to write to it on the bench.). I was curious what the boost levels will be after the tune is written. The ECU sensed 12.7lbs stock.
I don't feel like I am experienced enough to "tune" an M275 that would cost some substantial $$$ to repair if I added too much boost and not enough fuel. But for the sake of curiosity, what are others that may be running tunes they wrote or from other vendors seeing on an M275 E55 for comparison. When I flash the ME2.7.2 and get a reading, I will post that value as well.
I don't have near the fuel supply to support that kind of boost levels. Is your car an E55 or E60 M275?
That is Absolute pressure 33.4psi - 14.7psi (*roughly) = 18.7 psi, which is about right for these. It probably spikes to more but you won't see it on a slow logger like that.
Pushed quite hard they will do 20-21psi quite consistently from 3800-4300rpm then they start dropping again.
That is Absolute pressure 33.4psi - 14.7psi (*roughly) = 18.7 psi, which is about right for these. It probably spikes to more but you won't see it on a slow logger like that.
Pushed quite hard they will do 20-21psi quite consistently from 3800-4300rpm then they start dropping again.
what I found is that adding water/meth is just the best mod ever
your V12 runs like cold morning or night full boost 100% all the time
but next engine will be done on dyno and bigger turbos for sure
06-20-2018, 02:36 AM
