CSF Radiator on N54 135i

[bbnks2]

Originally Posted by davidwarren

Felix, have you reprogrammed the coolant set points? MHD allows that. Maybe you mentioned, but what coolant are you using?

I’m running distilled and water wetter, no a/c, a hood vent, and the “sport” MHD setting. My coolant temps top out at 103C on track.

You might be seeing no change because the ECUbis still targeting 230f/110c

Exactly. Need to re-do all this testing with MHD forcing the thermostat open to take the DME logic out of the equation. The data is showing the stock logic at play.

[fe1rx]

Originally Posted by bbnks2

Exactly. Need to re-do all this testing with MHD forcing the thermostat open to take the DME logic out of the equation. The data is showing the stock logic at play.

Only the green area will be affected by the thermostat logic. The thermostat is wide open under any conditions of interest to me. Earlier thermostat opening may delay reaching peak temperature under continuous maximum power conditions, but it won't affect the final steady state temperature, which is estabished by the heat rejection capacity of the cooling system, up to the point that the ECU starts pulling power to protect the engine.

But someone feel free to prove me wrong with logged data ...

[bbnks2]

Originally Posted by fe1rx

Only the green area will be affected by the thermostat logic. The thermostat is wide open under any conditions of interest to me. Earlier thermostat opening may delay reaching peak temperature under continuous maximum power conditions, but it won't affect the final steady state temperature, which is estabished by the heat rejection capacity of the cooling system, up to the point that the ECU starts pulling power to protect the engine.

But someone feel free to prove me wrong with logged data ...

You're looking purely at PEAK temps and completely ignoring the area "under the curve." This was already mentioned in previous posts, but, with MHD settings you can be at a significantly lower coolant temp floor in less intense area of the track. Then when you get to the straight away you have significantly more overhead available before you approach power reduction. This can help turn "trouble spots," like the straight away, in the data into minor blips. Maybe coolant temps will still trend upwards overall across a 20minute session. Maybe not. You've never tried.

I completely get your point, the coolant temp rise is still there. capacity is being exceeded. I mentioned this years ago in regard to oil temps. Go WOT on the street for a 4th gear pull and coolant temps will drop but oil temps will rise. That pointed to the need for the 26row oil cooler I now run. But just how tight of a control on temps can I really get? I'm still going to get a several degree rise while blasting down the straight-away no matter how big of an oil cooler I put on the car... Same concept as Coolant.

Will you ever truly be able to get your car to ride dme setpoint of 222.8f coolant temps in "normal" mode? Highly doubtful that the pid response is even responsive enough to keep such a tight control over temps... drop dme ambient threshold of 98.6f down to 76f like MHD does and enjoy the greater overhead available before limp...

All this being said, I am glad to be N55 because I havn't had any of these issue for years. Now with a PS1. E85 400whp tune, straight water, and 26 row oil cooler. I rarely see PEAK temps above 22xf coolant and 26xf oil even on 90f+ days. Everythign else is stock. With MHD race settings I am going on track with 210f oil and 180f coolant. No low temp thermostats needed. Might be doing a CSF rad soon. That should have me sitting pretty golden.