Thread: Tuning TP Scales

Disabling Front O2 Sensor

Are there any real side affects of disabling the Front O2 sensor? Calum does this on B13's already, but he has mentioned that B14's rely on it more.

I just got back from a test drive with O2 feedback disabled, and car seems to be driving pretty good, just shows up as in "Open Loop" all the time. The Map would need to be smoothed out a bit before it could be used safely for daily driving, but other then that it ran just fine.

Answer:
Set "E038 - Feedback Control Flags" to "D1"



Thanks dfddfd2!



Determining TP Scale
I've been reading some tuning guides to grasp how Nissan Tuning is done, here are the documents my question will follow the quote.

NisTune's Basic Tuning Guide and NisTune's Mapping Guide.



When I was out test driving, I set my TP to 100 from 69 (default DE+T one). I test drove the car, and it hit the final TP only when I really floored the car. This is great because that means I could possibly stay out of the boost map while simply daily driving.

With Nissan maps, if you roll over the map, it will keep on using the last column that it was on while still on the map. This is why you can get away with have 69TP as final column.

Now onto my question. If I say want my car to stay out of the last 3 columns unless I'm really flooring the car how would I go about the TP ranges?

For an instance, can I say do 0-30TP to be the way it is now, and then have the last 3 columns start with say 69-100TP?

Or would using the timing/fuel for 30 TP, be bad when in reality I would be at 50TP?

This is not for power reasons, you should be fine with leaving TP at 69 if your strictly looking for power, I'm just looking to stay out of the "gas hog" parts of the map unless I'm flooring the car.

It actually goes to about 112-120 tp. I did a mistake and it showed as that.



So like 60tp would be mid throttle so when I try to do that it won't go WOT and run pig rich?

Without O2 feedback you'll probably find that the A/F ratios at low rpm and low load vary quite a bit depending on intake air temps and coolant temps, and maybe the phase of the moon.


Every ECU I know will interpolate between data points. That means that if you have one TP column that is 30 and the next one is 70 and the air flow is actually at 50, the ECU will take the values in the map at 30 and 70 and do a weighted average to find out a good middle value to use. That should answer your question.

I drove to work today, last 3 columns had fairly high TP, 69, 85, 100.

I did not touch 100 TP unless I was flooring the car and was high enough in the RPM range, seems like around 4k rpm. I will post a map trace when I get it off my laptop.





I gotta expand my horizon to past 120 TP and see if I still stay on the map. I might be lower then you because I run less boost.

Note: I could be wrong on this, please correct me if I am
60 TP will be the same weather it is the last column or middle or even first.

This is why I'm a little afraid of modifying this too much. Because originally being at say 69 TP would mean I'm flooring the car. The ECU would keep on reading the 69 TP column because it's the last column it was on.

Thus I'm afraid if I have 69 TP and I put timing/fuel from the middle of the map into it, that might be too much timing for that much TP.

I'm thinking I will have a big gap, 40 TP would be the last of "descent gas mileage" then it would jump to 90-100 TP for the last 2 columns. I'm just worried about drivability



Ah, that makes sense, I guess I will now see how much IAT temps affect the A/F ratios



Ah good, I was worried that it might do what it does with RPM's. Which actually I think it could do in this case, but Map trace should give a better answer. What it does with RPM's is, if your at 3k rpm, it will put you in the 3200 RPM range because the one lowest before that is 2800.

Updated the top post with the map trace. With TP at 100 I was not in the last row unless I was really getting on it, which should help me in the gas mileage department.

I set my TP to 110 and 120, and it didn't touch those, so 100 seems to be best, 105 might work too.

Yeah thats true, you'll have to pretty much re-do the whole fuel/timing maps to get it to be right.

Simple, rescale the last three columns to 90,95,100 or just make the last three columns have big numbers. Then the ecu will only access them at full throttle. Not sure why you want to do this, you will lose resolution in some part of the map.

Same concept if you were to rescale the rpm. You can make last three rpm rows read 7.5k, 7.75K, 8K but lose resolution somewhere else.

Here is my test map, I will map trace and see how long I stay at 50 TP before switching over to 100 TP.

If I spent too much time at WOT at 50 TP, I will make 50 TPless aggressive and richer, and name set it to be 70.

You are losing a lot of resolution on the high load portion of the map. That's a big jump between 50 and 100 tp.

You need to smooth out the tp. Take 100 and divide by 16, since there are 16 columns. You will end up with 6.25, now start use 6.25 for the first column and add 6.25 to second and so on. Basically, you will have a 6.25 difference between the columns making the whole map smoother.

5speed, I see what you're recommending, and that's good for an N/A car, or a base to start from for a turbo car, but in reality once the throttle body is open, the volumetric efficiency of the engine doesn't change much at all and you tend to have very linear fuel and timing needs. Once you have linear needs, you can take care of them with two columns of data. The N/A section needs the most resolution. In boost you can take care of with 2 or three columns at the most (usually).