Power Fc Vs Nistune

[GTSBoy]

Yep, you can place the rev and load points pretty much where you want.

[Ruff Ryda]

Even though the PFC has more cells to adjust the standard ECU calculates/interpolates better between them. I think the new HPI covered this subject come to think of it. The standard ECU takes TPS into the load calculation. Not sure if all PFC's do that? So if you got your cells as smooth as the PFC with the Nistune then is should calculate the load points better under dynamic conditions. In saying that I don't know if you can adjust the load points, ie if you can't what happens once you go above the standard redline?

That's pretty nifty.

Also interested to know what happens with NIStune chips in regards to exceeding redline and if there are load point adjustments...

[GTSBoy]

That's pretty nifty.

Also interested to know what happens with NIStune chips in regards to exceeding redline and if there are load point adjustments...

What do you mean "exceeding redline"? The standard maps in Nissan ECUs usually have the last cells that are mapped at revs that are well lower than redline. If you want to be able to tune to higher revs, the very first thing you do is rescale the rpm scale. And, if you expect to be making more power than standard, you do the same to the load scale. This has been said before in this thread. And, the exact position of each point on the load and rpm scales is completely arbitrary. You can bunch them up near peak torque or boost transition and spread them out elsewhere, or you can make them equally spaced. Up to you.

The redline is exactly that. A separate number that you can set at any rpm you like. That might be well below the top of the map, or it might be not far after the top of the map (sensible) or it might be well higher than the top of the map's rpm scale (which could be dumb). Whatever, the ECU just does the rev cut at that point, regardless of what the mapping look like.

Edited July 22, 2011 by GTSBoy

[paulr33]

im with GTSBOY

that redline statement makes no sense

you rescale according to your RPM range

[Guilt-Toy]

Lots of mis-information there ^^^^

^_^

[STATUS]

By what I've read, the MAP sensor doesn't rely on air flow but it functions via air pressure which can lead to better response and power output once tuned correctly. D-Jetro also has launch control, fuel / ignition cut, anti-lag, NOS, etc which are some features you may or may not use.

I was going to take this path, but I wasn't aiming for high power so based on my findings and having a NIStune setup, the NIStune is the best bang for buck. Hit up a few searches and this will also confirm what I've just typed.

Power FC is 20 x 20 and NIStune is a 16 x 16 resolution so if it's a high RPM revving monster then PFC should be considered.

I remember reading that NIStune is tuned cell by cell at 500 RPM intervals, think it was ns.com though so take that with a grain of salt.

again with the mis info.

Djetro does not have launch control or ignition cut.

Nistune scaling can be tuned via whatever scale you input.... from 50rpm to 5000rpm...

[paulr33]

and reading engine load by air pressure instead of hotwire airflow meter does not lead to better response or more power

hotwire airflow meter measures air directly passing through to give engine its load axis

manifold air pressure sensor measures pressure and guesses engine load based on pressure via a lookup table

when you reach target boost the manifold pressure sensor value remains fixed and you run 2d map from here on

when you reach target boost the airflow meter continues to increase and you run 3d map

[Rolls]

Yeah I always thought a MAF gave your far more information than a MAP + air temp sensor. MAF tells you how much air there is, MAP + air temp lets you guess how much air there is.

[GTSBoy]

Well, sort of. It is actually pretty easy to determine the relationship, for A GIVEN ENGINE, between MAP and air flow (with IAT correction). And it's not going to be much less accurate to calculate it like that than the error that a hotwire AFM will give anyway. Anyone who assumes that a hotwire is 100% accurate, even when brand new, is fooling themselves.

The problems with using MAP come when, for a given engine, you change things like cams or porting or exhaust, or anything that changes the way the engine breathes. This is why back in the day, with early EFI systems that only had MAP for a load reference, if you did any such mods the mixtures would all go to hell and you had to start tricking the system by putting in resistors on water temp sensors and so on. But with an AFM, if you make the same breathing mods, then the AFM just measures the air amount and the mixtures stay the same as original and it basically works OK.

But none of this matters a poop to anyone using a tunable ECU. Doesn't matter if you're using MAP, AFM or just TPS and revs as your load input. This is because even with MAP or TPS only, you don't actually want or need to calculate how much air is being ingested. You just change the multiplier (the value in the fuel map basically) to add or subtract fuel from what was there before to give the correct mixture and hey presto - it's tuned. On that basis, AFM and MAP are essentially equivalent in accuracy - and in reality, given that hot wires tend to get dirty and have their calibration drift over time whilst the basic breathing characteristic of the engine remains essentially the same, then MAP might even be more accurate over a longer period of time than AFM anyway. TPS and revs as load input sucks a bit by comparison, but we're not here to talk about that anyway.

Edited July 24, 2011 by GTSBoy

[STATUS]

Yeah I always thought a MAF gave your far more information than a MAP + air temp sensor. MAF tells you how much air there is, MAP + air temp lets you guess how much air there is.

another reason why its crazy not to run a AIT sensor with a map based ecu.... its seems nearly every microtech that comes in running like shit hasnt got one.... surely it should not be a an option when you buy one of these things... it should be included as std..

[STATUS]

Well, sort of. It is actually pretty easy to determine the relationship, for A GIVEN ENGINE, between MAP and air flow (with IAT correction). And it's not going to be much less accurate to calculate it like that than the error that a hotwire AFM will give anyway. Anyone who assumes that a hotwire is 100% accurate, even when brand new, is fooling themselves.

The problems with using MAP come when, for a given engine, you change things like cams or porting or exhaust, or anything that changes the way the engine breathes. This is why back in the day, with early EFI systems that only had MAP for a load reference, if you did any such mods the mixtures would all go to hell and you had to start tricking the system by putting in resistors on water temp sensors and so on. But with an AFM, if you make the same breathing mods, then the AFM just measures the air amount and the mixtures stay the same as original and it basically works OK.

But none of this matters a poop to anyone using a tunable ECU. Doesn't matter if you're using MAP, AFM or just TPS and revs as your load input. This is because even with MAP or TPS only, you don't actually want or need to calculate how much air is being ingested. You just change the multiplier (the value in the fuel map basically) to add or subtract fuel from what was there before to give the correct mixture and hey presto - it's tuned. On that basis, AFM and MAP are essentially equivalent in accuracy - and in reality, given that hot wires tend to get dirty and have their calibration drift over time whilst the basic breathing characteristic of the engine remains essentially the same, then MAP might even be more accurate over a longer period of time than AFM anyway. TPS and revs as load input sucks a bit by comparison, but we're not here to talk about that anyway.

One fatal flaw in your theory.... on why map is better... have a think about what you've written.

[Rolls]

on a turbo car air temp just sounds like such a useful sensor to have even with a MAF, no idea how people try and tune a microleb without one.

[The Mafia]

Microtech are just shot anyway. Old and poorly laid out.

Anything is better.

Oh, and if I could run a map, maf, and AIT all together with some awesome calculation to make it work, I would.

[GTSBoy]

on a turbo car air temp just sounds like such a useful sensor to have even with a MAF, no idea how people try and tune a microleb without one.

RB20 ECU does not have IAT correction. One of the reasons it sucks a little bit.

[GTSBoy]

One fatal flaw in your theory.... on why map is better... have a think about what you've written.

And?

[Rolls]

RB20 ECU does not have IAT correction. One of the reasons it sucks a little bit.

Do the 33 and 34 ecus ? I didn't know that.

[Ruff Ryda]

Yeah just checked Google and NS. I can confirm I had fail searches! Thanks for the clear up.

PFC Pro only has launch control.

But I have some points I'd like to clear up too, perhaps STATUS can shed some light on this too:

@ PaulR33 - Your stating that MAP won't produce better results as oppossed with a MAF.

@ PaulR33, Rolls, GTSBoy - If a MAP sensor is based on a table with direct input then wouldn't you be able to tune it finer without having inaccuracies unlike the MAF? If MAP wasn't as good for performance then why is it incorporated with the the PFC D-Jetro (higher end) ECU package?

Sorry if it's starting to sway off-topic, but I believe the nitty gritty bits of information is important before laying cash out for either a PFC or NIStune.

[Rolls]

Air pressure does not directly correlate to how much air you have, you need air temperature as well and you need to know load. That is why I believe it can be less accurate, obviously the maf sensor isn't perfect though and only has a certain range that it works in.

Basically Im under the impression that there is more guessing with a MAP + IAT to get a table that can plot load vs rpm in a way that will be correct in all situations. Someone feel free to correct me though, that was just my understanding.

[rob82]

By what I've read, the MAP sensor doesn't rely on air flow but it functions via air pressure which can lead to better response and power output once tuned correctly. D-Jetro also has launch control, fuel / ignition cut, anti-lag, NOS, etc which are some features you may or may not use.

I was going to take this path, but I wasn't aiming for high power so based on my findings and having a NIStune setup, the NIStune is the best bang for buck. Hit up a few searches and this will also confirm what I've just typed.

Power FC is 20 x 20 and NIStune is a 16 x 16 resolution so if it's a high RPM revving monster then PFC should be considered.

I remember reading that NIStune is tuned cell by cell at 500 RPM intervals, think it was ns.com though so take that with a grain of salt.

Tuning resolution has very little to do with the accuracy of a tune. Dont ever let tuning resolution sway your judgement on what ecu to use.

The BA-FG V8 engine is speed density based and only uses 2 1x14 lookup tables to map the entire engine operation. And it still gets through euro3/4 emmissions compliance.

[GTSBoy]

Air pressure does not directly correlate to how much air you have, you need air temperature as well and you need to know load. That is why I believe it can be less accurate, obviously the maf sensor isn't perfect though and only has a certain range that it works in.

Absolutely and not absolutely. Correct about needing air temp - but that's just so you can get the density of the air right. The MAP signal (+ correction via IAT and any other little corrections that may be applied) effectively multiplied by rpm and with a factor for volumetric efficiency vs rpm IS your load signal.

Basically Im under the impression that there is more guessing with a MAP + IAT to get a table that can plot load vs rpm in a way that will be correct in all situations. Someone feel free to correct me though, that was just my understanding.

There's no guessing. It is a calculation to turn MAP into "air quantity". That calculation is actually reasonably simple to implement, and as I said a few posts up, if you get the absolute answer of the calc a bit wrong (assuming we're talking about what happens with a modified engine), you just trim it out in the fuel map.