Flat Foot Shifting Calculator & How To Set

[aaronc7]

OK here is a pretty useful tool when doing anything with LC and FFS. Left hand columns in this excel file show speed/gear/rpm relations. If you have another tire size...plug it into the right side and it will show your values. It's not off by much but if you like perfection, go for it (like me).

First let's clarify what this VSL (Vehicle Speed Limiter) table is. This is basically the breakpoint between LC and FFS operation. If your car is traveling below the set VSL, your car will be in "Launch Control" mode, and your car's rev limiter will be what is in your LC rev limiter table... period. If your car is traveling above the set VSL, your car will be in "FFS/normal" mode. Above VSL, with the clutch pressed down to the floor, the rev limiter will be what you set in the FFS table. If the clutch is let out, the rev limiter is the normal 6700 rpm (or whatever you set it to).

To set LC:
1.) Set desired LC rev limiter. This just takes practice and experimentation on your part to find what works for you/your car/road conditions, etc. etc.
2.) Set VSL. This depends on your LC rev limiter. You want this speed to be LOWER than what the speed of your car will be at your LC rev limiter in first gear. If it's set higher, then basically you will have a rev limiter of 3000 rpm (or whatever you set) in first gear and will not be able to go above that.

here's an example using a 3000rpm LC rev limiter:

At 3000RPM, in first gear, with 235/40/18 tires you will be traveling approx 16.26 mph. I rounded down to the nearest whole number, and then subtracted one...to get 14. That's what I used for VSL. Basically that just means my 3000 rev limiter is in effect until I hit 14 mph. I'm not sure if this is beneficial over setting it to a value such as 2, or 5 or something lower. The idea behind making it higher is so that it will help control wheelspin in a way by having a lower rev limit...but the vehicle speed that the ECU sees is based off of how fast the front tires are spinning, so I'm not even sure if this makes any difference or will help at all. I guess more testing is needed in this area!

Now onto FFS:

1.) Set FFS rev limiter. That's it. but now we get into the issue of "what is the ideal setting".

When I first approached this, I looked at "what RPM will the engine be dropping into after I shift into the next gear". I found that this varied by gear...and set it to some random value. In theory this makes sense, but I quickly found that in application, since you shift quickly, the rpms never have a chance to even begin to fall to that FFS rev limiter between shifts. The revs just seemed to hang in place, and then dropped back down after the shift. I shift at 6200 rpm (tach), I have set my FFS rev limit to both 3500 and 5500, and found no real significant, consistent difference between the two in regard to WOT shifting. With either setting, if you're shifting at 6000+, when you shift the engine will be cutting fuel (and whatever else it does) in this 'beyond rev limit' range. In my experience so far it has been that having this FFS value low....or fairly high makes no difference. Either case you are getting what you want in regards to FFS. The issue I had with the 3500 rev limit was rev matching when downshifting...it hit the rev limiter and was epic fail. SLS_MS3 says he has his 100rpm below his shift point, that is a good setting and also gives you little to no risk of hitting the rev limiter when doing a moderate downshift. The only drawback that I see with that is that you are limiting your shifting range. Let's say you short shift for whatever reason a few 100 RPMs early and FFS... the rpms will now rise between shifts and probably hit your FFS limiter before going into the next gear. Maybe that bothers you, maybe it doesn't, but that's the only "drawback" I see (not that it's a drawback, just what will happen). So, this one is kinda up to you....high enough so you will never have downshift issues and low enough to get the FFS results you want. I have mine set at 5300 right now and it seems to work great for me... I don't think I am going to be downshifting such that it puts me above 5300rpm.

A couple things to consider. Don't take this all as fact, just posting up my results and results of others. If you figure something out or find something to contradict my post..post it up!! We'll figure it out and I will update the thread as needed to reflect the most accurate information.

Also, ECU RPM does not equal tach RPM. you will see this, especially in the upper RPMs. I have found that in the lower (LC range), the tach reads about 150rpm high.... and anywhere from 200-300 in the upper range. This was just eye balling, nothing exact or scientific.

ALSO!!!!! If you want your units in MPH.... go to edit->configure options (Control + F), and check 'standard units'.

If you don't feel like reading all this and want a good starting point.... try this:

FFS Rev Limit: 5300
LC Rev limit: 2800
VSL: 10 (mph)

[Haltech]

I dont use the Lanuch Control, but the Flat Foot Shifting i have is set to 5200 rpm and works just fine.

[SLS MS3]

Setting FFS @ 100 rpms below my shift point has worked best for me. Anything lower than that takes too long for the engine to drop to that rpm.

[aaronc7]

OP updated. btw i did not proof read anything i just wrote, so if something doesn't make sense let me know

[cbusby]

Thanks for the info, can't wait to try this out.

[SLS MS3]

Originally Posted by aaronc7 At 3000RPM, in first gear, with 235/40/18 tires you will be traveling approx 16.26 mph. I rounded down to the nearest whole number, and then subtracted one...to get 14. That's what I used for VSL. Basically that just means my 3000 rev limiter is in effect until I hit 14 mph. I'm not sure if this is beneficial over setting it to a value such as 2, or 5 or something lower. The idea behind making it higher is so that it will help control wheelspin in a way by having a lower rev limit...but the vehicle speed that the ECU sees is based off of how fast the front tires are spinning, so I'm not even sure if this makes any difference or will help at all. I guess more testing is needed in this area!

Setting your VSL in that manner definitely helps to limit wheelspin, that's the "control" part of LC. Using your example, until you actual travel faster than 14mph you can experience a controlled launch. As soon as the tires start spinning, the LC rev limiter is hit and power is cut briefly. That process is repeated until you get above the VSL. A problem I've noticed with some people's settings is that they set the Hysteresis too high, I'm using 2. That makes the power cut long enough for the tires to regain traction, but it's small enough to make the power cuts brief. I might post some vids tomorrow of it in action.

Right now, we can't get the most out of LC the way it's implemented now. Ideally, there would be two seperate LC rev limits you could set to make it totally effective. The first rpm that you actually launch at, then a 2nd rpm/speed to disable LC and switch to FFS. We have to set the rpm relatively low for the launch, but all hell breaks loose when you pass that rpm/speed and full power is enabled.

Originally Posted by aaronc7 When I first approached this, I looked at "what RPM will the engine be dropping into after I shift into the next gear". I found that this varied by gear...and set it to some random value. In theory this makes sense, but I quickly found that in application, since you shift quickly, the rpms never have a chance to even begin to fall to that FFS rev limiter between shifts. The revs just seemed to hang in place, and then dropped back down after the shift. I shift at 6200 rpm (tach), I have set my FFS rev limit to both 3500 and 5500, and found no real significant, consistent difference between the two in regard to WOT shifting. With either setting, if you're shifting at 6000+, when you shift the engine will be cutting fuel (and whatever else it does) in this 'beyond rev limit' range. In my experience so far it has been that having this FFS value low....or fairly high makes no difference. Either case you are getting what you want in regards to FFS. The issue I had with the 3500 rev limit was rev matching when downshifting...it hit the rev limiter and was epic fail. SLS_MS3 says he has his 100rpm below his shift point, that is a good setting and also gives you little to no risk of hitting the rev limiter when doing a moderate downshift. The only drawback that I see with that is that you are limiting your shifting range. Let's say you short shift for whatever reason a few 100 RPMs early and FFS... the rpms will now rise between shifts and probably hit your FFS limiter before going into the next gear. Maybe that bothers you, maybe it doesn't, but that's the only "drawback" I see (not that it's a drawback, just what will happen).

What you see as the "drawback" is what I see as the whole point. If you aren't hitting the FFS limiter, you might as well be granny shifting. You want to hit the limiter, that keeps load on the motor during shifts and keeps boost up. If you aren't hitting the limiter, power is cut during the entire shift and all boost is lost.

[aaronc7]

Originally Posted by SLS MS3 Setting your VSL in that manner definitely helps to limit wheelspin, that's the "control" part of LC. Using your example, until you actual travel faster than 14mph you can experience a controlled launch. As soon as the tires start spinning, the LC rev limiter is hit and power is cut briefly. That process is repeated until you get above the VSL. A problem I've noticed with some people's settings is that they set the Hysteresis too high, I'm using 2. That makes the power cut long enough for the tires to regain traction, but it's small enough to make the power cuts brief. I might post some vids tomorrow of it in action. Right now, we can't get the most out of LC the way it's implemented now. Ideally, there would be two seperate LC rev limits you could set to make it totally effective. The first rpm that you actually launch at, then a 2nd rpm/speed to disable LC and switch to FFS. We have to set the rpm relatively low for the launch, but all hell breaks loose when you pass that rpm/speed and full power is enabled. What you see as the "drawback" is what I see as the whole point. If you aren't hitting the FFS limiter, you might as well be granny shifting. You want to hit the limiter, that keeps load on the motor during shifts and keeps boost up. If you aren't hitting the limiter, power is cut during the entire shift and all boost is lost.

Assuming your VSL is set low enough so you don't have a permanent rev limiter in first gear...the issue I see with the launching is the ECU knows no difference between speed of the front tires and actual car speed. As soon as the tires spin, you say you hit the LC rev limit... I have not encountered this. Wheelspin = rpms and speedometer shoot up, when the RPMs hit my LC rev limit rpm...the ECU thinks I am moving because the tires are spinning. I guess you could get around this by slipping the clutch a whole lot, but I'm not really a fan of that. If the ECU could somehow know the actual speed of the car and not the front wheels, this would be pretty useful I think.

Post up some vids of what you are talking about when you can

Whether the FFS limiter is set to 3000 or 5800, aren't you hitting the limiter either way? since you are above it at the shift point. I will play around more with FFS... I'm slowly moving it up I'll have to see if i notice anything different or improvements.

[SLS MS3]

Originally Posted by aaronc7 Assuming your VSL is set low enough so you don't have a permanent rev limiter in first gear...the issue I see with the launching is the ECU knows no difference between speed of the front tires and actual car speed. As soon as the tires spin, you say you hit the LC rev limit... I have not encountered this. Wheelspin = rpms and speedometer shoot up, when the RPMs hit my LC rev limit rpm...the ECU thinks I am moving because the tires are spinning. I guess you could get around this by slipping the clutch a whole lot, but I'm not really a fan of that. If the ECU could somehow know the actual speed of the car and not the front wheels, this would be pretty useful I think. Post up some vids of what you are talking about when you can

Yeah, if you get massive wheelspin then the ECU will think you're going faster than the VSL and switch to the FFS rev limit. But if you don't pop the clutch too fast, the LC is able to tame the wheelspin somewhat until you really do get about the VSL. Whenever I get out of jury duty, I'll go film some launches.

Originally Posted by aaronc7 Whether the FFS limiter is set to 3000 or 5800, aren't you hitting the limiter either way? since you are above it at the shift point. I will play around more with FFS... I'm slowly moving it up I'll have to see if i notice anything different or improvements.

No, you aren't hitting the limiter. FFS isn't so much a limit per se, it's a target RPM you want to stay at. If you are above the target rpm, then power is cut until you are at or below the target rpm. Maybe that's why you keep saying all you see is the rpms kinda hang during your FFS shifts. You have your FFS rev limit set so low that you never actual activate it during shifts.

[Fobio]

man...I wanna ride shotgun with SLS or aaron to see how you guys are adapting your driving to get the most out of this. Thanks for all the info so far guys....keep it coming!

Please and thank you's...

[bast525]

Just FYI - my tach reads HIGHER than my actual RPM. dunno if it is the same for everyone. At 6000 RPM it shows about 200-300 RPM higher.

I agree with Aaron after experimenting a bit that I didnt see much difference when I changed the FFS RPM. Initially I aimed for 4700 as I shift at 6000 and that is the average RPM I would drop to. Then I followed suggestions here and set it higher, and really didnt notice a diffference.

LC.... doesnt do anything for me. I suck at launching as it is, and LC didnt improve it at all. It helps me get off the line, but as soon as the VSL is hit, the tires start spinning, even worse than when I just launch the old fashioned way. Building boost while stopped is NOT helping!

[aaronc7]

same for me bast...around 6k the tach reads about 250-300 higher than what the DH/AP show. around 3k...the tach is around 150 high.

[Lymerock]

damn LC and FFS are fun, but I dont think either will extend the life of the car.


only way LC worked for me was to slip the clutch, but when done right, the car is much faster off the line than without it.

FFS doesnt seem to work on some shifts, but im guessin its due to the massively huge flywheel not letting the rpms drop fast enough, on some other shifts I definately noticed it... had it set at 4850 and when short shifted 2-3 it hung right at 5k on the tach

thanks cobb!

[Trader]

If the ecu is limiting fuel to keep the rpm's down for LC & FFS, is that harmful to the engine in any way??

[sleeping]

Ok so I encountered a problem setting up my lc/ffs. the car was stuck in lc mode in any gear in any speed, and my thought is that I should have changed vehicle speed limiter which was initially set at 200 on my 104 map, (and I left it there) and not changed my vehicle speed speed hysteresis which was originally set to 4 and I bumped to 14.

What is the speed hysteresis? and is the vehicle speed limiter the number I was supposed to change?

[SLS MS3]

Originally Posted by sleeping What is the speed hysteresis?

Once you reach the speed limiter, the throttle will close until your speed has been reduced by the value in this table.
Ex: You set the Speed Limiter to 200kph and the Speed Limiter Hysteresis to 14kph. If you ever get to 200kph, the throttle will close until the car has slowed down to 186kph.

While you're at it, you really need to switch to standard units. Click the EDIT menu, select "Configure Options" then check the "Standard Units" box.

Originally Posted by sleeping Ok so I encountered a problem setting up my lc/ffs. the car was stuck in lc mode in any gear in any speed, and my thought is that I should have changed vehicle speed limiter which was initially set at 200 on my 104 map, (and I left it there) and not changed my vehicle speed speed hysteresis which was originally set to 4 and I bumped to 14.

Was the first post really that hard to read? VSL means vehicle speed limit.

Originally Posted by aaronc7 To set LC: 1.) Set desired LC rev limiter. This just takes practice and experimentation on your part to find what works for you/your car/road conditions, etc. etc. 2.) Set VSL. This depends on your LC rev limiter. You want this speed to be LOWER than what the speed of your car will be at your LC rev limiter in first gear. If it's set higher, then basically you will have a rev limiter of 3000 rpm (or whatever you set) in first gear and will not be able to go above that.

[sleeping]

Well yeah kind of, if you look in atr under vehicle speed hysteresis it has a label under the value box that says vehicle speed limit, and it is the first box you come across, and it's closer to the value you would expect for the lc/ffs switch. The second vehicle speed limiter box with it's higher value looked much more like a top speed governor than anything else. Anyway thanks for the clarification, Is there a way to change your top speed limit?

[SLS MS3]

Originally Posted by sleeping Is there a way to change your top speed limit?

Only if you don't use LC.

[sleeping]

ok so does that mean it's stuck at 155 or is it just nothing?

[Fobio]

I did some late night tweaking last night and flashed a LC/FFS map this morning.

Left the gargae and I have a 2800rpm redline...wtf, must have been the bleary eyes messing with me last night...w/e, flashed to a tweaked 1.04 map w/ default LC/FFS values on the side of the road...continue to work.

so when I get home, I loaded up ATR and had a look...thinking I must have adjusted the Normal Rev Limiter rather than the LC Rev Limiter.

BUT NO...

My LC Rev Limiter is at 2800 and my Normal Rev Limiter is @ 6700...WTF?!

I'm not going to just switch them around for trying...but I'm at a loss.

[aaronc7]

read the first post...the VSL is your issue

[Fobio]

thank you...late night tuning isn't the best idea. I swear I had it set to 13 last night.

[Nliiitend1]

Good to see you guys realized that the FFS limit should be set higher...

I made this suggestion right after the feature was released (in this thread: http://www.mazdaspeedforums.org/foru...tml#post277060) and was met with a little bit of resistance to the idea...

I still haven't even gotten around to activating LC or FFS on mine yet...but it's good to know I have a decent understanding of things beforehand.

Keep up the good work!

[tunersteve]

Definitely some good info here. When I first set up FFS, I thought the rpm setting was the enabling point in which the FFS works. After reading this and looking up more info, its definitely not the case.

I originally had my FFS set at 4500, which seemed to work pretty well, then I dropped it to 4000 and haven't driven it yet. I guess we'll see how it works for the particular application.

[barcainho]

so i got my ap i think at the perfect time. when the best map is out. im loving my ffs and lc.
ffs limiter:4600
lc speed:5
lc rpm:300 but haven't launched it yet
normal limiter:6700
VSL:4
it works perfectly

[ljudgeii]

Originally Posted by barcainho so i got my ap i think at the perfect time. when the best map is out. im loving my ffs and lc. ffs limiter:4600 lc speed:5 lc rpm:300 but haven't launched it yet normal limiter:6700 VSL:4 it works perfectly

Wait a Tick....are you sure you LC is at 300rpms or 3000rpms

[barcainho]

3000rpm i meant but i changed it this morning to 2800 i think it will better

[DaleNixon]

Thanks to this thread, my car now sounds like a boat

[dougefresh_]

With the exception of no wheelspin on the MS6, a couple of fellow MS6 people gave me good values for FFS on our cars. I also heard that FFS helps combat the slight bogging you can get with fast WOT shifts. It's nothing wrong with the car per se, just an quirk of the MS6. I was curious to know if you MS3 guys get the slight bogging during WOT shifts, and if FFS (when set up properly) eliminated this problem?

Thank you!

[aaronc7]

I find FFS shifting to be much much smoother, no bogging at all.

I have my FFS set to 5000 and I usually shift around 6200-6500rpm

[IndianOutlaw]

Where do you actually set up the parameters for the LC and FFS?
I've opened up the ATR but can't find it.

[grantmm]

Originally Posted by IndianOutlaw Where do you actually set up the parameters for the LC and FFS? I've opened up the ATR but can't find it.

I know it's late to respond to this, but I just started playing with LC too so this thread is new to me. You find the parameters under the Limiter Tables.

For my car's setup (245/45/17 Dunlop Direzza Star Specs) the settings in this thread wouldn't give me enough wheel spin on launch. Here's what's working best for me:
ffs limiter:5300
lc speed:17
lc rpm:3500
normal limiter:6700
VSL:2

3500 RPM launch keeps me right on the edge of traction all the way through first, while letting the wheels spin up enough to get me off the line fast.

Thank you to everyone who put forward their advice/experience. It was very helpful to read everybody's posts when trying to figure out what will work best for my goals.

[Zak]

Someone could tell me what is the stock value of ffs limiter please?

I'm not using ATR to tune my car, but I've also "limiters RPM" tables.

thanks

[JacksonMS30]

Originally Posted by Zak Someone could tell me what is the stock value of ffs limiter please? I'm not using ATR to tune my car, but I've also "limiters RPM" tables. thanks

I'm not exactly sure what you are trying to say but there is no stock value for ffs because ffs is not a factory option.
You can only get ffs if you get the cobb ap and set it up in your limiter tables with atr.
Or you could get the wot box but I've heard some bad things about that and cats...

[bigmike]

Hate to revive an old thread, but is it just me or is the link not working to download the file...?