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-   -   Hard-Cut Rev Limiter? (https://www.ft86club.com/forums/showthread.php?t=150137)

FR-Saliba 06-18-2022 10:47 AM

Hard-Cut Rev Limiter?
 
Hey guys, so I just got my Stage 2+ tune on my car last week using Tactrix and Ecuflash, and I was wondering if someone here has any idea how to get a nice Rev Limiter Fuel Cut something close to hitting rev limiter while in NEUTRAL ( cool popping limiter ).

Already tried adjusting the Fuel Cut in RomRaider and made it 7400-7450 rpm, it feels sluggish when hitting the limiter.

Saw few 86/BRZ people on Instragram and youtube that have really cool and fast limiter that doesn't bug the car like the stock limiter.

:thanks:

tomm.brz 06-18-2022 12:28 PM

you need to reduce timing in base timing b at limiter to make it softer

Hysteresis at fuel cut of around 50rpm as you already have should be good enough though

FR-Saliba 06-18-2022 03:59 PM

Quote:

Originally Posted by tomm.brz (Post 3529942)
you need to reduce timing in base timing b at limiter to make it softer

Hysteresis at fuel cut of around 50rpm as you already have should be good enough though

Softer you mean like the one that comes standard in the oft tunes?
it was a hysteresis of 25rpm and feels like it only holds at 7600rpm, which is not what i want. Am seeking something like in the video link down below
Start at 2:15.

https://www.youtube.com/watch?v=dtSrWuQLeWY&t=303s

His limiter is really close to the limiter when in neutral.

I tried dropping it to 7450 with a hysteresis of 50rpm (shown in the picture below) cause i saw a difference in the base b table between the 7450 and 7600 values, but didn't change anything in the timing values cause am kinda new to this and i don't wanna mess up things.

should I turn it back up to 7600 with a 50 hysteresis and change dem timing values, how much should the values be? and at all loads or some of em...?

https://i.ibb.co/9Y8G7mK/image.png

tomm.brz 06-19-2022 04:35 AM

try drop more timing, like - 15 or - 20 in last row, and keep same hysteresis for ignition retard as for the fuel cut

FR-Saliba 06-19-2022 08:15 AM

Quote:

Originally Posted by tomm.brz (Post 3530030)
try drop more timing, like - 15 or - 20 in last row, and keep same hysteresis for ignition retard as for the fuel cut

okay, thanks man

I will try to tweak couple things as soon as possible, and will maybe post the results here and maybe try to logging for the 1st time too.

I will put the limiter back to 7550-7600
reduce timing line at 7600 to -15
maybe try some pops and bangs at load 0.15 too

tomm.brz 06-19-2022 11:01 AM

anyway in the video surely they have ecutek or Motec
Don t know why but I get smoother rev limiting with ecutek using custom maps than using the OEM fuel cut tables

FR-Saliba 06-19-2022 01:39 PM

Quote:

Originally Posted by tomm.brz (Post 3530051)
anyway in the video surely they have ecutek or Motec
Don t know why but I get smoother rev limiting with ecutek using custom maps than using the OEM fuel cut tables


yeah that guy in the youtube video is running Ecutek, but i think we can tweak a hard cut rev limiter out of the Ecuflash/RomRaider yet not being sluggish or dying off at limiter cause sometimes you need that limiter time mid-drift to go dem extra meters.


Do you have a clip or video to explain what you've done furthermore??

makinen 06-20-2022 02:15 AM

Quote:

Originally Posted by tomm.brz (Post 3529942)
you need to reduce timing in base timing b at limiter to make it softer

I think that this way is opposite of what OP wants.

tomm.brz 06-20-2022 02:38 AM

yes
but i m not sure we are using the correct terms anyway

stock limiter on gear is hard, meaning that it doesn t reduce timing and only cuts fuel abruptly and lets the engine drop 300rpm or more before injecting again with full torque, ence the "hard" cut

While in neutral hysteresis is smaller and trasmission is not engaged ence the "softer" feeling

I think what he wants it s still a soft limiter, but with more pops and bangs and a not so small hysteresis

He needs the ignition timing to be quite negative when it hits the limiter to get bangs but With too little hysteresis on the fuel cut, he would then get the rpm that stay too "fixed" at limiter, so i would try with something like 100-150 rpm of hysteresis, and more retard on the ignition timing side, and trying different X-axis values on the last 2 rows of base timing B, since he hasn t got any custom map to play with

makinen 06-20-2022 04:51 AM

But with retarded ignition timing, it can't stay there.

FR-Saliba 06-20-2022 06:57 AM

Quote:

Originally Posted by makinen (Post 3530150)
But with retarded ignition timing, it can't stay there.

Even with a small hysteresis (50 between fuel cut and resume)
it's gonna stay between 7550 and 7600 rpm but act differently with retarded ignition timing than just holding that rpm with no sound difference(popping limiter) like the basic OTS tunes ?

FR-Saliba 06-20-2022 07:11 AM

Quote:

Originally Posted by tomm.brz (Post 3530146)
yes
but i m not sure we are using the correct terms anyway

stock limiter on gear is hard, meaning that it doesn t reduce timing and only cuts fuel abruptly and lets the engine drop 300rpm or more before injecting again with full torque, ence the "hard" cut

While in neutral hysteresis is smaller and trasmission is not engaged ence the "softer" feeling

I think what he wants it s still a soft limiter, but with more pops and bangs and a not so small hysteresis

He needs the ignition timing to be quite negative when it hits the limiter to get bangs but With too little hysteresis on the fuel cut, he would then get the rpm that stay too "fixed" at limiter, so i would try with something like 100-150 rpm of hysteresis, and more retard on the ignition timing side, and trying different X-axis values on the last 2 rows of base timing B, since he hasn t got any custom map to play with


so should i be using a 100-150 rpm of hysteresis instead of just 50?
or is it just about timing
and should i be changing the last "2" rows not only the last one which is 7600 and that's where the fuel cut is
the row just before is 7450 so that's 150rpm away, so that should be the hysteresis ?

i'll upload a picture of the changes i currently made

https://i.ibb.co/jwg4db5/image.png

tomm.brz 06-20-2022 01:28 PM

make some trials
try fuel cut 7600/7500 and -20 on last raw timing advance, remember that there is also knock corr A being added to it

FR-Saliba 06-20-2022 03:10 PM

Quote:

Originally Posted by tomm.brz (Post 3530222)
make some trials
try fuel cut 7600/7500 and -20 on last raw timing advance, remember that there is also knock corr A being added to it

okay i'll try different values

but what should i do regarding the knock correction A ?


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