We are going to FI territory now? Different can of worms - outside the thread topic. OP was talking about bolt-on modifications. I don't care about your silly turbo EJ subies (OK - I guess I do, I have a 2013 WRX hatch, but again we are off topic).

And who said anything about temperature compensations? I made no claims with regards to that. Emanage does have temperature compensation tables, though

I can tune as well as the next hack on this car. My original post said nothing other than MAP (speed density) being able to take into account altitude changes and hence it is better than TPS tuning in the case of a piggyback unit - especially considering our stock computer uses MAP as the load variable. You cannot argue that WOT will hit different load points at different altitudes and therefore will better be able to track with different atmospheric conditions.

You are welcome to throw all the Honda compensations in the OEM ECU out the window and do the same thing in a standalone if you want to. I for one, have found the OEM ECU does an excellent job of this.

 

No, not specifically. You can drastically change a motor in NA forms as well. The reason I mentioned the Subaru ROM as it is free to download both the software and the strategy.

I did. I was further expanding on how compensations play a large roll in how the engine operates under all conditions. I know E-manage will allow you to adjust based off water and air temp (with little resolution), however, I was giving several examples.

Both sohc_mshue and I fully understood what you said about the MAP, however, we both understand that the MAP is not the the entire part of the equation. We all agree that working off VE tables will be much better than TPS, but it doesn't specifically take into account altitude changes. The stock ECU does use MAP to take into account, along with other tables in the ECU that a piggyback does not give us access to, but it is not solely responsible for how the car behaves at varying altitudes/atmospheric conditions.

As far as the bolded part: It will read pressure as it normally would, in the manifold. However, that is not the full story (as already explained) and not the end of final fuel calculation. If you get a chance to look at an OEM ECU running SD, you will see the tables that account for this. In some of Cobb's advanced tuning guides for AccessTuner Race and SD tunes, they explain how altitude has an effect even though the MAP is seeing changing pressures. If you had the ability to go in the stock ECU and zero out the additional changes, you'd would notice a change in the tune when changing considerable altitudes.

Have you tuned many OEM ECU's (not piggybacks)? I really don't have to explain this part as there is plenty of information out there. OEM ECU's across different makes isn't too dissimilar in how things are calculated, so it doesn't have to be specifically found for a Honda or S2000.

This passage tells me you missed the point I was making. It was stated that the OEM ECU is the one accounting for altitude changes. It was further explained that the E-manage is not the one doing it and why. That pretty much sums up everything above. A little explanation can go a long way in helping someone understand what they are trying to achieve and what product would work best for them.


Summed up again... With a piggyback tuner, you will utilize OEM compensations for VE changes due to atmospheric changes when considering lower/higher pressure at the end of the exhaust. The Greddy will allow you to manipulate input/outputs for MAP and fueling to achieve desired results.

 

At this point all I can say is I'm not sure what we are debating. MAP is not the whole equation, correct, but due to the fact that the OEM ECU still provides the other parts (baro/IAT/Coolant Temp) you do not need to do all the speed density calculations and corrections within the piggyback. I stand by my statement that MAP-based tuning will be sufficient and better than TPS in the OP's scenario, and will get you a perfectly functioning tune at whatever altitudes necessary.

The original poster was talking about bolt-ons, we aren't talking about an exotic FI or ITB setup. Obviously, as things go further away from the OEM configuration the stock ECU is less able to correct.

Obviously a full speed density calculation requires more variables than MAP pressure, but those variables are accounted for quite well by the stock ECU. If you're going to standalone, you sure as heck better make sure the other variables are tuned for.

 

This is what it comes down to and I agree with you, the rest of the "debate" though worthy, is basically just jerkin off.

Hell ive been more then content correcting just off of TPS in NA config for sake of simplicity, but I rarely change altitude, and I think even then the tune may not be optimum there, but it will be safe.