Thread: How to make your fuel and timing maps AKA "TP/LOAD" scales

UNISIA, I may have to disagree with your TP or 44-46 equaling 0 psi. Why?? Well, I did my own log to see how closely I can correlate the two, and quiet frankly, before scaling, 0psi corresponded to TP = 72 and after scaling and some advice from John, the new map 0psi corresponded to TP = 64............

As mentioned before, I have to agree with Ben and Vadim as using my first hand experience, you can NOT equate TP and MAF data to Pressure/IAT and MAP data. The two use completely different algorithms for measurements. Also, you need to use a correct sensor for the given properties. I just simply cannot wrap my head around the idea of correlating what readings you get from vacuum to actual boost pressure.

If you are measuring boost, at minimum, a 3 bar sensor is needed. Taking measurements using inaccurate equipment is a big no no in the real world...........

Do a log with a proper map sensor as well as a MAF hooked up and see what comes up

This method simply does NOT work however.........Sorry bud

We are not trying to step on toes here, just shed correct information. I fully grasp what both Vadim and Ben (as well as 5speed) are asking

You guys are truely blind if you dont see the relationship im presenting to you, does anybody see it? I know that tunning is like reading chinese especially if your brand new to it or old to it but been thaught wrong or your are theoretical book thumper to no end.

I have no issue with how you're setting up, or instructing others to set up their TP scale. In a round-about way you're getting a good scale, and that's fine. However, assuming that the rest of us don't know how to set one up seems a little presumptuous. That stuff was sorted out here a long while back.

The only issue I have is with the assumption that you can correlate TP with pressure, even when talking about a single setup in a single vehicle. I also do not see that correlation in your datalogs. I'm not surprised you see a correlation, because it would seem so when looking at your logs. However, like I've said before, your logs do not show a constant TP, nor a constant pressure (either would be fine) over a large range of RPM. Once you get a MAP sensor in there that can read boost, and you get your TPS sensor stuff fixed, and you do a log covering the entire torque range you'll see what I mean.

Treating 44-46 TP on your setup as atmospheric pressure (100 kPa) during all conditions is not something I would be prepared to do.



How would I set up a TP scale if I had to?

I would record the lowest TP value possible (hot day, warmed engine at idle conditions maybe) and then record the highest possible (a cold day with a very cold engine at torque peak likely) and I would use those as my extremes. I would add a little buffer (as you recommend) and I would likely space the values in some exponential/logarithmic fashion as to give greater resolution for the lower values than the higher values.

While tuning, I would never treat a TP column/row as a pressure/load reading. I would treat it like a fueling needs estimation (or torque estimation), because that's what it is.

oh my fucking god everybodys 0psi is going to be different mines happens to be 46 TP and you know how i fucking know this because I have a damn MAP sensor and logging capabiltys proof by my logs. Im not yelling at you guys just fustrated that you dont get it.


ARE ANY OF YOU LOGGING WITH A MAP SENSOR? ANY OF YOU? DIDNT THINK SO OR ELSE YOU ALL WOULD BE TELLING ME NO SHIT!

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I been doing this fo rmany years and you guys fail to read my post through and through like I said its a 1 bar map sensor and for the intended purposes of this discussion I dont need to have a 3 bar map sensor hell 1 bar of the 3 bar map is used for vaccuum so just pretend im using the vacuum part of a 3bar sensor jesus man.


You guys are lost re-read this 100 times if you have to so it sinks in, its simple. You guys are all guessing.


Ok look, for my setup and particular .bin my ZERO boost/vacuum is 46.

If I were to change my setup by like say changing the MAF sensor my ZERO boost/vacuum will change to lets throw a random number out there 74 TP

now it a change my MAF sensor again my ZERO vacuum/boost will change again to lets just through a random number out there again 112TP

IM NOT SAYING 46 TP IS ZERO BOOST/VACUUM FOR ANY OF YOU GUYS IT IS FOR ME EVERYBODYS TP IS GOING TO BE DIFFERENT AT ZERO VACUUM/BOOST DAMN IS THAT HARD TO GET THROUGH TO YOU GUYS.

Every god damn time i log 46TP im at god damn 0psi FUCK SHIT! LOL

The tea calling the kettle black...........

It seems you are NOT reading any of our posts either.........

Good luck! Thanks for the info and hopefully your write-up can be used for a MAP based system in the future

taken from: ecu.ztechz.net

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did they just relate TP to boost? :O

There is no direct correlation between TP and psi/kpa/ vacuum/ boost and i"ll show you why.

A Honda map (RPM x Vacuum ) is scaled different than Nissan ( RPM x TP). As others have to tried to point out to you, there is no correlation between vacuum/boost and what Nissan use as TP. Your own datalog showed this. The TP scale is merely the injector pulse width scale.

Let say we have an NA engine and want to upsize the injectors size from 300cc to 400cc.


On the Honda map/vacuum scale, the ecu would hit the same load column on the fuel and ignition map no matter what injector size you use because the vacuum/load is the same.

Now, on the Nissan TP scale, the ecu would hit a different TP column because you would have to change the K value in order to get the same AFR, more specifically, you would have to lessen the K value which equal a smaller injector pulse width. The smaller pulse width results in the ecu accessing the smaller TP column.

Here’s another example. Let say at low rpm, between 1000-3000 rpm, you give the engine full throttle. On the map/vacuum based scale, the ecu would go all the way to right of the map/ load scale. Not so on the TP based scale because the injector pulse width is still relatively low down on the rpm scale.

The only way you will get a close correlation between vacuum/boost and TP is to keep the throttle angle constant throughout the rpm range. This happens during wot, closed throttle down shift or idle, and cruise. And what a coincidence, Jecs has provided logs based on the same driving condition. Check out the tps column. There are no logs of real world driving condition like when you shift in out of gears and on/off throttle.

Final point: Jecs’s data logs are giving the impression there is direct correlation between the vacuum/boost reading and TP, they are masked because he still running with the MAF!! The MAF has already calculated the TP for him!! In a way, he is cheating. This has fooled some people like Boostlee into thinking Jecs got rid of the MAF. Jecs, try running without the MAF and use only the MAP. It’s not going to happen unless you change the whole Nissan fueling algorithm.

Btw, stating the numbers years you have Nistune don’t mean jack. Seem like you are still ignorant in how it works.