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This is what i always wanted to clarify. What is the level of adaptation of the different obd ecus to changes like environmental ones or other parametres of the engine? To my little knowledge i believe that newer obd2a/b ecus can adapt easier to changes but are more resistant to tuning when we amend the intake or exhaust right?
As for my car i have seen great differences in performance according to environmental changes to such extent that it is annoying some times.
What about you? Does the obd1 conversion helps a bit in that?

saxophonias wrote:This is what i always wanted to clarify. What is the level of adaptation of the different obd ecus to changes like environmental ones or other parametres of the engine? To my little knowledge i believe that newer obd2a/b ecus can adapt easier to changes but are more resistant to tuning when we amend the intake or exhaust right?
As for my car i have seen great differences in performance according to environmental changes to such extent that it is annoying some times.
What about you? Does the obd1 conversion helps a bit in that?

Whats changes have you experienced? Changes in altitude is the only one I can think of but I dont know how badly it affects since england is relatively flat.

changes according to temperatures for sure, which are more visible at night, changes according to humidity, and when the altitude varies. But mostly, i can feel difference in performance from days to days. Some days it is sluggish and low and mid revs and some days not. When it feels torquey it performs really well throughout the powerband

I totally agree.
I think all depends from IAT sensor because we don't have sensor for humidity. And maybe from Oxygen sensor too but for this one I am not sure because in me ej9 the sensor has only one wire for reading I think only the emissions that are outside the permissibly confines, am I right? (feel free to correct me)
So when the outside air temperature are between 5-15 Celcious my ej9 have the best performance.
On the very cold days the car is nervous and at the very hot days is going like a donky

indeed the iat (intake air temperature) sensor but also the MAP (manifold absolute sensor) will cause this changes.The thing is how fast the ecu adapts to these changes.

Well my car is generally sluggish so I dont really notice a performance change, when I do I always put down as psychological . I always notice and prefer driving on warm days because the car warms up much faster which is good but your talking about performance so I cant say I've noticed a difference myself.

Here are my thoughts however:

The speed at which the ECU "changes" will be instant however it depends on the step size of change, for example, if the map only reads 5C temp changes the performance change will be expected to be quite large with temperature variations because when crossing the boundary on the next step size the performance will change abruptly, this is why having a small step size is better. Similarly if the map reads smaller increments then I wouldnt have thought it would be very noticeable on a normall day unless everything suddenly freezes or something.

If anyone has ever seen a base map for a D14 or other similarly equipped D series we could tell pretty easily the effects of these variables.

Comparing between a warm and a hot day is difficult though... Like I said I always put it down to psychological effects; for example sitting in a traffic jam in a hot car makes you feel like your car is sluggish... My car feels best on cool nights on empty streets however thats probably because I'm having fun

I can't put my finger on it as well.

What I do know:
Increments are small and cannot be noticed. Temperature is more a 0.1 deg increment than 5 deg. Though indeed humidity is not measured, I believe it is one of the largest influences on our cars performance which is not taken into account by either OBD1 or 2.

OBD2 has more environmental bullying. An example I know is this 2nd lambda sensor. Normally this 2nd sensor does not alter engine behaviour compared to OBD1. But what it does do is throwing error codes ones it detects the cat is broken. The trick is simple. Both lambdas are measured, the 2nd one should read slightly different compared to the 1st due to the cat. Once the cat is gone the lambda sensor will start to write exactly alike, which triggers error code. So OBD2 provides just more sensors to be plugged in to my opinion.

I guess the crankshaft speed sensors are also linked to OBD2... hmmm ice is getting thin here.

Ow on second notice, my OBD2 equipped EJ9 was always more sensitive to wheather than my current OBD1 setups. I actually forgot about that. But I also put only strictly one fuel in my car. BP Ultimate and nothing else. Nothing. Simply since most octanes are too low to my liking over here and most other fuel stations don't even bother getting '98 octane.

Opening up a D15B7 mini-me I builded having massive detonation also convinced me never to fuel anything else btw...