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:

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

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

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??

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

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

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 ?

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

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 ?

nothing, just meant that you could try more retarded timing on base timing B

So I changed the 7600 timing in the base timing B to -17
with a hysteresis of 50rpm
limiter still holds the limiter at 7600, zero bounces

with a 50 hysteresis with a -0.12 retard (as provided from oft) you hear a small pop once you hit limiter only and it sluggishly bounces without popping
(that one small pop is present when the car is fully stock, but the stock hysteresis is like 300 so the bounce is kinda slow.

Am thinking about 3 options:

1. advance some timing on 7600
2. same timing but bigger hysteresis than 50rpm only
3. same setup and same values for the last 2 base timing B rows
( -17 timing retardation at 7450 and 7600 ) with a hysteresis of 50

try bigger hysteresis also for fuel cut, 50 is very small and intended in fact to let rpm stay almost holding

The launch control has the same hysteresis as the fuel cut or nah?

i m not used to this feature in openflash/romraider, only ecutek sorry

oh okayy
i think we'll know if it changes on a bigger fuel cut hysteresis

you edit tunes in ecutek ?
is there ignition cut tables?

There in No ignition cut possible even in ecutek its all fuel cut,



to do ignition cut you would need additional hardware box like bee R rev limiter

This guy did it Bee R install





https://www.ft86club.com/forums/showthread.php?t=135466

update on the tune ( got a bit busy recently that's why it's a late reply )

so the limiter still holds at 7600 with a hysteresis of 100rpm and approx -17 of timing at 7600 in the base timing B
the rpm needle isn't even moving

i think i remember it used to sluggishly jump a bit with the default oft v4 stage2+ tune with a hysteresis of 50rpm and -0.12 timing at 7600rpm
and i think i was able to hear a one cut as soon as it hits 7600 ( similar to the stock tune cut but without dropping 300 rpm )

so i was wondering what would advancing some timing at 7600 above zero do to the limiter.

You have to keep advanced timing up to redline to make the rev up, not staying silently. Straight catless exhaust for popping, maybe.

my exhaust setup is kinda straight piped, only oem midpipe resonator left
my car is banging on 0.15 load with -15 ignition timing retard

my goal is to have a fast rev limiter ( similar to the rev limiter in neutral or to that guy in the video i linked in a previous post, will link it in this one as well )

it currently holds at 7600 with -16.29 on last row and a 100rpm hysteresis


start at 2:15

https://www.youtube.com/watch?v=dtSrWuQLeWY

I was talking to a guy with an NA brz on instagram, the shop tuned his car using ecutek achieving the same "popcorn" rev limiter like the boosted 86 in the youtube video linked above but at 6500 instead of rev limiting above 7000 (for safety as he mentioned)

So I think it doesn't have anything to do with being boosted

instagram post link below ( #6 in the album, onboard video )

https://www.instagram.com/p/CgTIwAzL..._web_copy_link

I've been playing around with some timing and rev limiter. I haven't tried it in the dry. However, it was raining for the last couple days. When I tested this out in first gear, I achieved what we are looking for. I was able to bounce off limiter.

base time map a: 7400rpm @ -12 degrees,
base time map b: 7400rpm @ -12 degrees; on the y-axis (RPM) I changed the value from 7450rpm to 7400rpm. and for the cells for 7600rpm are also -12.

*I noticed that the ecu likes to blend both maps A and B, so I make them similar for more consistent results.*

rev limit a (fuel cut): on = 7400rpm, off = 7300rpm
rev limit b: on = 7400rpm, off = 7300rpm