Thread: Anything you ever wanted to know about tuning and electrical systems...

Oh it doesn't stop there, then you have the wonderful OBDII to kick in and restrict you from anything Closed loop (O2 sensor sniffing).

This is why I'm pretty eager about the PNP solution



Yes, this is why I said hypothetically, TP is a mixture of Flow (MAF Valtage), Injector K value, etc. etc. TP will change with Injectors and if you modify the Injector K value. Hence you TP tune the last, this is also why a lot of generic tunes will have lower TP's like 64, etc.

A good guide that will cover this in greater detail can be found here.

i guess my example of 64 and 80 was too extreme for this scenario. i specifically said an all motor application since the timing/fuel in the last columns is not as drastic in change as a turbo application. from what i've seen if i recorded a max TP of 80, and i set my TP scale to 80, the only area used in column 80 is the top most cell. it seems like a waste if only one cell is used, that's why it seems logical to lower the TP scale to say 70 to gain resolution somewhere else. so again, what's the advantage of setting the TP scale to your max datalogged value in an all motor application. thanks guys.

The advantage is that you can properly tune your car. Unless you don't care about the ability to tune that cell.

Hey Dan, here is the info and calculations I have regarding the K-number for my Calum Basic tune to so I can throw an N60 MAF onto my NX.

Since you said you don't know much about tuning MAF's, it does involve modifying K-numbers, here is a quick version of how to calculate K-numbers: Old K# x (old injectors/new injectors) x (new MAF/old MAF). Injector numbers are rating by flow rate, and MAF's are calculated using maximum horsepower figures. For more reading on this stuff if you've never messed with it, check out this pretty informative PDF.

Now, onto my calculations. Since I am running a U13 Bluebird ECU, I also have the bluebird MAF (which is the same as the GTi-R). Maximum horsepower for the GTi-R MAF, as per this page, is about 290hp. The new N60 MAF has a max hp rating of around 325hp. I am not currently changing my injectors (and the Bluebirds came with 370's which I am currently running), so the equation we will be working with is Old K# x (new MAF/old MAF).

I am currently using just a stock U13 tune with the timing map tweaked for the 9.5:1CR. The stock K-number that comes on the U13 is 33107. Therefore, my equation should start out looking like this: 33107 x (325/290). If done correctly, my new K-number should be about 37103. This just seems a little high to me, and here is why...

If you start with a stock USDM B13 tune, your old K-number is 31206. Now, we need to change this to match 370's, and the N60. Don't forget the stock B13 MAF is good to about 250hp unless it has been bored out. So, the equation will be 31206 x (259/370) x (325/250) = 28397. And, going off of another tune I found for a US DE with 370's and a DE MAF, here is what I found by trying to just change it's MAF to the N60. 21475 x (325/250) = 27917.

These numbers seem to be all over the place. I would just like somebody to double check my work, and to ensure that I am doing this correctly. Also, if anybody has a .BIN for a USDE 370's & N60 at 3bar, that would also come in handy. But Dan, if you can figure this out I will greatly appreciate it. Also, I would like to tweak my fuel map a bit after I get this all straightened out. I am running 7-8lbs boost on a T28 on my USDE. If you have any recommendations, tips, or any fuel maps set up for something similar to this I would love to discuss them with you. Unfortunately, a wideband is something I don't have yet, but will be one of my purchases in the next month or two.

Nathan, Dan is on the road and after that we're going to do some test runs of my car and another. He'll likely get back to you later on in the day.

I've looked over the numbers and assuming the ECUs work the way I think they do and using my memory of how the K value is used in the fueling calculation I'd trust your result of 37103 and go with it at least initially. I see why you're worried it is too high, but I think the U13 tune is just that way.

Great, thanks for the fast response Ben. As soon as I can find an air filter adapter for the N60 it will be going on.

What does TP stand for?

When i change from MAF to map/iat, where should i put them?

in the intake plenum or in the charge piping before TB?

I would drive down but the only part of my tune that is spot on is WOT at 11.5 on my wideband It bucks horrendously when cold and also when cruising freeway speeds it cuts in and out. How about if I data log cruising speeds and a WOT pull and you guys see if you can clean it up for me so I can drive down there?!!?

I'm gunna make an assist here Dan.

TP stands for Theoretical Pulse width. It is a value calculated using the input from many sensors, some other variables a look-out table and possibly a constant or two. It is supposed to represent how much fuel the engine needs at any particular moment. I believe if you logged the TP readings as you did a pull on the dyno the TP values would closely match the HP curve.
If you want to read more about it Vadim likes to give poeple this link: http://www.plmsdevelopments.com/files/nissan_ecu_tuning_basics.pdf

I also like this one: ECU Tuning

Our forum member dfddfd2 is also intimately familiar with the calculations of the TP value and how it is used in the ECU.