275 RS Monitor and engine power reading Is it accurate?

Discussion in 'Mechanical - Engine, Gearbox, Exhaust etc' started by 3vo, Jun 2, 2020.

  1. 3vo


    Hi Guys,

    I have Mk3 275 trophy. The power reading from the RS monitor? is this at the crank or wheel?

    I have noticed going from the RS monitor, max power reads out at 256 BHP, this is in sport mode? Normal mode I am seeing 242bhp? This was all from 3rd gear pull. Turbo pressure reading, I am seeing between 900 and 1000mbars which is about 0.9-1.0 bars of pressure? I have come across many forum users stating pressure should be around 1.2 and 1.5bars?

    Little bit worried something isn't right? It's around 20bhp loss? The car pulls fine and all but just not sure how accurate the RS Monitor is?

    Any help at all would be truly appreciated.
  2. manugtt

    manugtt RSM Club Member

    To be honest, I don´t have the car much time ago to give an answer, but I think it isn´t very accurate. Anyway, I don´t use to see that parameters, only oil and intake temperatures. Sincerely, I thought the RS monitor was more useful. For what is need the throttle position? Or brake press? Or G-forces? The only good thing for me is that you can chose the gas sense in sport mode as you prefer, and the temperature parameters. Just my opinion!:wink:
  3. 3vo


    Hi Manugtt,

    Thanks, sounds like the RS monitor shouldn't be really relied on?

    I know the RS monitor is a bit of a gimmick thing onboard but, just thought given the RS monitor is receiving data from ecu the numbers would reflect some truth?

    I have felt the car do some kind of correction with the boost? Like error correction trying to achieve boost target based on engine load?

    I took the car for another spin and boost went from 900mbars to 1250 and back down to 1000mbars. Power 263bhp.

    Maybe looking too much into it.Just concerned car isn't making correct power due to some underlying issue or something.
  4. D_K


    For boost pressure it should be accurate I would have thought as its coming from the ECU. Keep in mind boost will taper off towards higher RPM , so your max boost will be seen lower in the rev range .

    Oil temperature seems to be a predetermined calculation and not direct from a sensor , there isn't any in the sump so would not rely on it to convey oil temperatures accurately (the temperature does rise very quickly compared to a proper sensor in the sump)

    The power figure is going to be as accurate as the ECU can judge it to be but obviously not 100% . If its using the MAF g/s readings it will come pretty close to the actual output (gram per second /0.8)
  5. manugtt

    manugtt RSM Club Member

    D_K, in my experience, in the sump the oil temp. is at least 10ºC less than the block. So, don´t think the Renault engineers fit a sensor in the oil pan, just don´t think! I have seen worst things!:grin::grin:
  6. 3vo


    Hi D_K

    Thanks chiming in.

    I am seeing 1000-1250mbars between 3500-5000 before or after the mid-range it's around 900-950mbars. I think the only reason I am thinking about boost is if, there could be an issue related to boost which is whyRS monitor is showing a lower engine power reading.

    I will try using an OBD tool and see what is recorded via that method.
  7. D_K


    Yes 10 degress at least of a difference depending on location due to heating . A temperature from the sump for me is favourable as it gives an indication of oil conditions entering the oil pickup and ultimately bearing surfaces . From what I believe there is no individual or combined oil temperature sensor on this engine contributing to the RS Monitor , can anybody else confirm that ? I have started a journey from 5degree celsius conditions were the car was left cold overnight , after 3 km oil temperature reading was at 50c and climbing almost as fast as the coolant temperature once that hit 70c and began to show . For me this is not a good indicator and I continue for at least 15mins of continuous driving before beginning to use the car more spiritedly..

    Yes would be nice to confirm OBD and RS Monitor are both showing the same data , I would be surprised if not . I have not seen a factory boost graph but from general experience that seems like a normal Megane RS to me . Its an interesting topic and good for clarity.
    manugtt likes this.
  8. The Magane engine is fitted with an oil cooler, that is fitted behind the oil filter, this also acts as a oil warmer as it uses the coolant to heat the oil up, but then cools the oil once it goes above the engine coolant temp
  9. manugtt

    manugtt RSM Club Member

    Very interesting thread! About the oil temp. sender, I remember some car where the oil temp. and level was the same sender. In that case, maybe our Megs works the same way. I had been with the car just now, shame I don´t realize to count the wires of the level sensor. If it have 3, would be the temp. sender too.
  10. 99.9% sure its two wires
  11. manugtt

    manugtt RSM Club Member

    Well, now I´m thinking, maybe the sensor take negative through the same block? In that case, those 2 wires would be signal for level and temp. Damn electricity! Never understand it!
  12. could try and unplug it, then see if it reads a temperature
    manugtt likes this.
  13. manugtt

    manugtt RSM Club Member

    Good point Ian, sometimes the best test is the easy one!
  14. it will prove it one way or the other :laughing::laughing:
  15. My 250 hits 1.15bar so i think you might have a boostleak, although i'm sure things like altitude and ambient temp plays a part aswell.

    Thats the number i hit with a small boostleak too (sure in my case it affects spool mostly). Gonna try and get it fixed soon.

    Also my power level reads 250 everytime so i think its just some number that corresponds to whatever revs you are on, probably a load value in there somewhere too.

    Someone else probably knows better tho.

    Logged the boost via odb like a year ago looking for a fault, and rs monitor seemed to read that fairly accuratley. Not sure if it was reading same as MAP or intake pressure sensor tho, was one of them anyway. Update frequency was just a tad slower and obviously it did some rounding up and down.
  16. Guys, I have also an 275 Trophy and my experiences are pretty identically. First, to my opinion the R-Link will never show the real engine Performance. The display is Gimmick, and it doesn´t anything else as to read the rpm and throttle load and Displays the standard power curve whats the engine is rated from Renault. Full throttle and 5500 rpm means 273 hp. If this figure should be measured, you would have installed a dyno inside the car, isn´t possible. The only physically possibility to measure the engines real power would be to have a engine combustion pressure sensor ( what has no car at all) even then you don´t know the friction the engine has. It´s some engineering knowledge involved, so lets state that the displayed power ist only from the Standard Renault diagram. I´m pretty sure that if you have some engine mods, the display will never show -let say 320 hp. >It shows always stock output.

    The oil temp is right, it´s a display with an algoritm what calculates the water temp, time of operation gradients which are heating the engine, ambient temp, engine loads and rpm what heats the engine. I think the oil temp is 99% realistic. It heats very quick, thanks to the oil heat exchanger with the water cooler. Oil and water temp equals out to similar figures, normally maybe 85°C.

    About the boost pressures: My car shows very similar figures, with full throttle in 3. or 4. gear it won´t reach more than 1000 mbars, some guys with 275 are telling about 1350 -1400 mbars. Strangely, sometimes it goes up im 2. gear in race mode to About 1300 mbars, but it´s different and not basically repetable. Anyway, I´ve not the feeling that the car is low on power, but I think there are big influences from ambient temp and water temp with boost, the ECU will sense the knock figures and corrects spark advances and boost. I have replaced the timing belt at Easter and replaced as well the Thermostat because my car didn´t exceed 70° water + oil temp that time (was cold outside). With the new stat, water temp raised up by About 15 °, now it will be usually 85°, but in Germany it´s currently very hot (mostly 25-28°). Inj the meantime, I suppose that the old stat might be a modified low temp stat for a modified engine and I`m thinking about to reuse it again in summer ( have to provide a new one, I`m an idiot and have scrapped it). With the current one, temp is very quick in the 90-100° region whats not good for max power.....the ECU will down-regulate the engine I think About installing an stand alone boost sensor….
  17. I have an Obd reader and on Autobahn, with several tests pulling the gears, the values given by both RS Monitor and Obd, were very similar(both read the Ecu info).
    but I think it's all "invented" because the values are calculated in relation to the throttle position/ rpms / temperatures, etc.
    It's not a real time values,just calculations.
  18. I would be interested in finding an offical Renault chart what shows the boost pressure over the rpm and torque figures at full throttle. Just for knowing whats about boost pressures what are displayed on the R-link, nobody seems to know stock ratings from Renault. It´s not helpful to see 950mbar anywhere on the rpm range and I don´t know what boost curve is according to stock condition. 100 mbars missing or not?

    Not even the Renault dealers knows stock conditions, at least mine doesn´t. Maybe Renault doesn´t state boost figures to avoid complaining customers...
  19. I don't have R-link, just the RS Monitor. But my car it's remaped and shows the full line in the boost pressure, so I assume that makes more than the original values. I think that full original makes 900-1200 mbars approximately.

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