Stillen GEN3 vs. K fuel Multiplier

flashgordon

hi,

Reading many logs, I found that after GEN3 the Max value of BFS was decreased from 20 to 18.

Since every maps refers to BFS to locate the correct value (es. VVEL or Camshaft Phase) I try to modify K fuel multiplier adding 2 click to the value...

The result is impressive!

Now (for who have the GEN3) the hole in power between 2000 and 3000 RPM disappears and at very high RPM the power is linear until the end!

Obviousilly AFR must be corrected...

rAiN

would like to jump on the discussion but i have no idea what you just said.

flashgordon

If you learn "Nissan Tuning Guide" by UPREV, you known that every map in the ECU has two axis:

Y = RPM (Rotation Per Minute)
X = BFS (Base Fuel Schedule)

BFS is calculated by MAF (Mass Air Flow) multiplyed by K Fuel Multiplier.

So, changing the Air Intake System (like GEN3), the MAF changes the readings and consequently the BFS changes as consequence.

The change of MAF reading, changes also the AFR (Air Fuel Ratio) of the mixture, but notoriously, the 370z has a rich mixture! So leaning it, would be an increase of power.
But! Every map in the ECU do not works on the entire range....
Low RPM suffer more....

flashgordon

...after a week I confirm my reasons....

At low RPM, between 2000 and 3000, the power is always delivered without holes!

N0SL3N

Can you explain how we can test this out in uprev?

__________________
| Akuma | Motordyne | Z1 | NST | CNT | Stillen | Avant Garde | RJM | Performix | Tint | LED | GTR | Nissan |

Jordo!

Veh beni! Gratzi!

... but are you determining this on a dyno or by feel alone?

On my old set up with various breather mods, I too ran a different k multiplier, which helped minimized the need for greater correction in the fuel compensation map, and made it easier to achieve desired targets.

Dynos, details, please?

__________________
Enjoy it. Destroy it.

flashgordon

If you have Uprev Tuner licence you can do it by yourself.

Simply open your ROM Editor with your MAP and modify K multiplier adding 2 tick.

After that, you must log and tune AFR. If you are not able, you can request an e-tune map.


How you can "diagnose" the issue that I posted a week ago:
If you have uprev before you have mounted your GEN3, you can compare an old log with a new one.

You can observe that the max MAF was decreased! But the new air intake ingests more air!

Decreasing MAF, also decrease the BFS, that controls the scale in every maps in the ECU!!

So at High RPM no problem: Timing, VVEL and camshaft phasing are defined.
At low RPM the critic zone is about 2000 and 3000 RPM where all angles moves.
If the scale is wrong, the progressive increase in power is not linear as stock!!

If you observe, Stillen provide graphics that starts at 2900 RPM!!

Obviousilly more air = more gas = more power = less MPG!
Many users says that MPG was decreased after GEN3: BAD!

This means that the car runs lean!!

K fuel multipler adjust the new environment of the MAF mounting.

flashgordon

Yes you are right!

At now only my body says WELL!

But:

I observed in a log with old K multiplier:
- RPM between 1200 and 2000 are linear
- RPM between 2000 and 2200 rise less quicly
- RPM between 2200 and 7200 maintains tha same slope as the 1200-2000

This regards that log, but when drive I could suffer this "hole" randomly between 2000 and 3000

After modified K the "hole" is more smoothly and is near linear

N0SL3N

I do have the tuner version so I have made minor adjustments but nothing major.

Can you tell me all of the relevant criteria I should select in cipher and if I should do any specific tests, i.e. 0-60

__________________
| Akuma | Motordyne | Z1 | NST | CNT | Stillen | Avant Garde | RJM | Performix | Tint | LED | GTR | Nissan |

flashgordon

You must log with Chiper MAF, RPM and BFS in 0-60 (Note: I have 6 gear Manual Transmission).

Before you must you compare an old log (before GEN3) with the new one, and if you note that Max values of BFS and MAF (in 6000-7500 RPM zone) are decreased (In my case BFS from 21.5 after GEN3 became 18.5!!) you can proceed

You can try to adjust K multiplier with Uprev ROM Editor. (I added only 2 click!)

After that, you must adjust AFR in compensation table.

At low RPM (2000-3000), in my engine, the power is more linear.
Last week I tried to reflash an older map, and the engine does not run well as now (at low RPM).

Of course the best test is dyno, but if you try and you notice an improvement , it's always a good thing!
To return to a previous MAP it's simple and economic!