Thread: Beginners Guide to Chipped ECU Tuning

Front page shows all of your tuning options. Use a Sentra or P10 ecu and chip it.

Thanks! One more thing...would a B14-to-P10 adapter harness help me in that case? (Apexi Neo AFC)
Sorry, this is way over my head but hopefully since I'll be doing part of the work during the swap I'll gain a better understanding and be able to help other in the future as you do.

(I'm KH3 P11 also by the way, our cars look a lot alike.)

@Vadim, can you also please post/update 'old' k-values for Z32 MAF? By using your formula and the k-value of 399 on most of the 370@ 4 bar (427cc) tunes I could find, it appears stock k-value on z32 maf is 657(399/(259/427)). I've found, however, that this kind of conflicts with other k values on other tunes. In other words, what the k-value 'should' be based on this formula, it isn't or it's pretty far from it in some cases (one I saw off by 40).

-G

There is no such thing as stock K value for Z32 maf for our cars. There is a K value for 300zx, but since it's a different engine with different injectors that number is irrelevant. Your best bet would be to find a 259cc z32 maf tune (good luck!)

I'm just saying your numbers of 298 are for 259cc injectors and stock MAF. I believe 259cc injectors with Z32 MAF k-value would be 657 based off your formula and reversing it for what I believe is the most popular tune (370@4 bar, z32 maf). Because we can't use your 298 figure if we have a Z32 MAF.

Just as an example..

259cc z32 maf = 657
upgrade to 370@4 bar(427cc)

(259/427) * 657 = 399 k-value (What I saw on all the tunes)

Another example with 740cc injectors..

(259/740) * 657 = 230 k-value

The 657 value seems to get within 10-20 for most of the other tunes I saw with upgraded injectors on a z32 maf tune when I used the formula, so it's probably a solid figure to use.

You got it, I personally don't spend too much time calculating the K value, since I can edit it while I drive and see AFR's in real time. Now also that's not my formula, that's the one I found on lots of forum posts.

Now the reason I said there is no such thing, no one really runs a 500whp maf on stock 259cc injectors .

Also as a rule of thumb, when you upgrade MAF you have to increase K value to give more fuel. I think this is because higher HP MAF's stay in the lower volts a lot more thus the VQ number is going to be smaller, thus you have to compensate with higher K value.

When you upgrade injectors you decrease the K value, bigger CC injectors are able to flow more fuel at the same amount of time/pulsewidths, thus you need to reduce the overall fueling by adjusting the K value.

I think that's exactly right. I think it has to do with calculating the TP value which includes VQ number in the calculation. 4v on a b14/b13 maf flows a lot less air than a z32 maf @ 4v.

TP= ((VQ*K/(RPM*256/50))/Cylinders

^ Using the above value, you could theoretically calculate TP value as long as you're logging MAF voltage(covert using VQ table formula) and RPM. Just make a formula conversion in excel.

As an example with 740cc injectors with k-value of 230, RPM of 5000rpm, and maf voltage @ 4.00:

TP = ((29324*230)/(5000*256/50))/4= 65.86

Could be a poor man's map trace

-G

^^ Man I don't miss tuning my Calum ECU because of these manual calculations. Nistune handles this so much better, and that will be because of the tuning software. The only time Calum ECU is as good as Nistune in logging department is with TunerCode (which is no longer sold as stand alone firmware). Calum ECU with TunerCode trumps Nistune in the tuning department, but not as good as NEMU RT. NEMU RT beats everything in tuning and in logging department.

Calum's values for the TP and RPM scales on the b14 are correct, but reversed in his post. In other words, where you see 'TP' put RPM and visa-versa.

@Vadim: Can you please fix this?

Wrong:

B14 SE-R 95-97 (G20 94-97) Map Trace Values:

RPM MSB - 3472
RPM LSB - 3471
TP - 314E

Timing map - ED00
RPM Scale (timing) - E480
TP Scale (timing) - E490

Fuel map - E100
RPM Scale (fuel) - E0E0
TP Scale (fuel) - E0F0


Right:

B14 SE-R 95-97 (G20 94-97) Map Trace Values:

RPM MSB - 3472
RPM LSB - 3471
TP - 314E

Timing map - ED00
RPM Scale (timing) - E490
TP Scale (timing) - E480

Fuel map - E100
RPM Scale (fuel) - E0F0
TP Scale (fuel) - E0E0

Updated, I remember seeing that myself, guess I forgot it by the time I made this thread.