pressure vs tps for power commander v

is this worth the effort ?
any tips and how to?
seems like pressure would be a much better control scheme, would look at all 3 cylinders too, I think

please

I think yes, for the very small throttle openings, i.e. 0-3% or so.
But once you get into big throttle %s, the throttle % is better.
It's like the pressure works better because you can have a wide range of pressures when the throttle barely moves at like 0-3% for example. And vice versa at the other end of the scale, i.e. pressure doesn't change all that much at 50-100% throttle.

That's my impression so far anyway, bear in mind I'm far far far from expert at tuning. It'd be nice if @Neville Lush could school us some on this kind of thing.
But since it's done this way from factory I can only assume it's the best way.

I made up a splicer mini harness to go between the MAP plug and the MAP sensor (connectors are 3 way Econoseal AMP), with the 0-5V signal wire piggybacked with an extra wire going back to the PCV analogue input.






And switched over to pressure based autotuning in the PCV map, using the same amount of columns as TuneECU has (makes life a lot easier if you want to eventually import all your PCV trims etc into TuneECU map and remove the PCV & AT)



Then used readings from TuneECU MAP sensor volts vs pressure to calibrate the 0-5V input on PCV.
(of course you have to convert the hPa numbers into psi first)

At idle



With engine off




Some small tweaks were necessary to get the "pressure" on the PCV screen to read 0.00 when the engine was off.
At this point the bike was autotuning based on MAP value.

N.B. when you changeover from TPS to pressure tuning (and vice versa) in PCV, it wipes the AFR table clear, so be aware of that.

You can of course import PCV trims into TuneECU, but bear in mind though, %TP based trims need to go into F tables only, and pressure based trims need to go into L tables only. They don't correspond cell position wise.
If you run the bike at idle and switch between throttle position based maps and pressure based maps, you'll see the live cell being referenced is highlighted, and that idle for example is around the left side of the throttle table whereas it's in the middle for the pressure table.

Anyway once i got good smooth fuelling at very small throttle %s (from tuning with pressure), switched back over to % throttle based mapping.

An odd time a manual intervention was required to smoothen out the maps. Having a POD 300 to log MAP, % throttle, rpm and AFR is a great tool for this.

R-III-R Turbo said:

I think yes, for the very small throttle openings, i.e. 0-3% or so.
But once you get into big throttle %s, the throttle % is better.
It's like the pressure works better because you can have a wide range of pressures when the throttle barely moves at like 0-3% for example. And vice versa at the other end of the scale, i.e. pressure doesn't change all that much at 50-100% throttle.

That's my impression so far anyway, bear in mind I'm far far far from expert at tuning. It'd be nice if @Neville Lush could school us some on this kind of thing.
But since it's done this way from factory I can only assume it's the best way.

I made up a splicer mini harness to go between the MAP plug and the MAP sensor (connectors are 3 way Econoseal AMP), with the 0-5V signal wire piggybacked with an extra wire going back to the PCV analogue input.






And switched over to pressure based autotuning in the PCV map, using the same amount of columns as TuneECU has (makes life a lot easier if you want to eventually import all your PCV trims etc into TuneECU map and remove the PCV & AT)



Then used readings from TuneECU MAP sensor volts vs pressure to calibrate the 0-5V input on PCV.
(of course you have to convert the hPa numbers into psi first)

At idle



With engine off




Some small tweaks were necessary to get the "pressure" on the PCV screen to read 0.00 when the engine was off.
At this point the bike was autotuning based on MAP value.

N.B. when you changeover from TPS to pressure tuning (and vice versa) in PCV, it wipes the AFR table clear, so be aware of that.

You can of course import PCV trims into TuneECU, but bear in mind though, %TP based trims need to go into F tables only, and pressure based trims need to go into L tables only. They don't correspond cell position wise.
If you run the bike at idle and switch between throttle position based maps and pressure based maps, you'll see the live cell being referenced is highlighted, and that idle for example is around the left side of the throttle table whereas it's in the middle for the pressure table.

Anyway once i got good smooth fuelling at very small throttle %s (from tuning with pressure), switched back over to % throttle based mapping.

An odd time a manual intervention was required to smoothen out the maps. Having a POD 300 to log MAP, % throttle, rpm and AFR is a great tool for this.

Click to expand...

thanks for the info

R-III-R Turbo said:

I think yes, for the very small throttle openings, i.e. 0-3% or so.
But once you get into big throttle %s, the throttle % is better.
It's like the pressure works better because you can have a wide range of pressures when the throttle barely moves at like 0-3% for example. And vice versa at the other end of the scale, i.e. pressure doesn't change all that much at 50-100% throttle.

That's my impression so far anyway, bear in mind I'm far far far from expert at tuning. It'd be nice if @Neville Lush could school us some on this kind of thing.
But since it's done this way from factory I can only assume it's the best way.

I made up a splicer mini harness to go between the MAP plug and the MAP sensor (connectors are 3 way Econoseal AMP), with the 0-5V signal wire piggybacked with an extra wire going back to the PCV analogue input.






And switched over to pressure based autotuning in the PCV map, using the same amount of columns as TuneECU has (makes life a lot easier if you want to eventually import all your PCV trims etc into TuneECU map and remove the PCV & AT)



Then used readings from TuneECU MAP sensor volts vs pressure to calibrate the 0-5V input on PCV.
(of course you have to convert the hPa numbers into psi first)

At idle



With engine off




Some small tweaks were necessary to get the "pressure" on the PCV screen to read 0.00 when the engine was off.
At this point the bike was autotuning based on MAP value.

N.B. when you changeover from TPS to pressure tuning (and vice versa) in PCV, it wipes the AFR table clear, so be aware of that.

You can of course import PCV trims into TuneECU, but bear in mind though, %TP based trims need to go into F tables only, and pressure based trims need to go into L tables only. They don't correspond cell position wise.
If you run the bike at idle and switch between throttle position based maps and pressure based maps, you'll see the live cell being referenced is highlighted, and that idle for example is around the left side of the throttle table whereas it's in the middle for the pressure table.

Anyway once i got good smooth fuelling at very small throttle %s (from tuning with pressure), switched back over to % throttle based mapping.

An odd time a manual intervention was required to smoothen out the maps. Having a POD 300 to log MAP, % throttle, rpm and AFR is a great tool for this.

Click to expand...

Thanks a lot for the detailed description - very helpful.

I do have an overall question about the TPS and pressure map. The bike runs on the pressure when on low throttle. Once you set to tune for pressure, how does the power commander make sure that while riding the bike is relying on the L-table and not on the F-table?

Do I have to adapt the F/L-switch table to 99%? Could you elaborate on this? I would highly appreciate your feedback.

rosenrot said:

Thanks a lot for the detailed description - very helpful.

I do have an overall question about the TPS and pressure map. The bike runs on the pressure when on low throttle. Once you set to tune for pressure, how does the power commander make sure that while riding the bike is relying on the L-table and not on the F-table?

Do I have to adapt the F/L-switch table to 99%? Could you elaborate on this? I would highly appreciate your feedback.

Click to expand...

Good question. Yes this is what I did, but I only raised the F/L switch to like 20% throttle or something, just for the duration of pressure based tuning, so my pressure table would be accurate well past the normal point of switchover in future when I set F/L back to standard and lock the map for good.

And vice versa then when %TP based tuning, lower F/L switchover so that the bike is running off the F table earlier than standard, so that my PCV trims will be accurate at a point lower than the standard F/L switch.

So at the end of the day I have an ample overlap breadth of F & L tables which are accurate well below & above the point of switchover (respectively).
The L tables are way off at the upper end, but that's OK because the ECU will never reference up there. It's gone to the F table loooong before there.

But there is no point going very far past the factory switch point and MAP based tuning.
As I understand fueling by pressure reference rapidly becomes inaccurate (like exponentially) beyond low throttle positions, for NA engines (you hit the ceiling of atmospheric pressure and that's it)


Pinging @Neville Lush again to hopefully drop in and school us.

R-III-R Turbo said:

Good question. Yes this is what I did, but I only raised the F/L switch to like 20% throttle or something, just for the duration of pressure based tuning, so my pressure table would be accurate well past the normal point of switchover in future when I set F/L back to standard and lock the map for good.

And vice versa then when %TP based tuning, lower F/L switchover so that the bike is running off the F table earlier than standard, so that my PCV trims will be accurate at a point lower than the standard F/L switch.

So at the end of the day I have an ample overlap breadth of F & L tables which are accurate well below & above the point of switchover (respectively).
The L tables are way off at the upper end, but that's OK because the ECU will never reference up there. It's gone to the F table loooong before there.

But there is no point going very far past the factory switch point and MAP based tuning.
As I understand fueling by pressure reference rapidly becomes inaccurate (like exponentially) beyond low throttle positions, for NA engines (you hit the ceiling of atmospheric pressure and that's it)


Pinging @Neville Lush again to hopefully drop in and school us.

Click to expand...

Thanks for helping me out. I got a large cam and I see that below 2400 rpm my bike runs very much on the lean side. Idle is really rough as well. I know that in low revs air might pass and very lean measurements can happen, but I don't expect that effect for rpms higher than 1800. But I'm open to input here. At the moment I measure the AFR with a homemade muffler with an LSU and a datalogger (RPM,TPS,AFR). I see a high AFR >19 during idle/deceleration, I still have to figure out if the air is sucked in from the end or if the spikes I see are coming from the engine. Which I don't see as the 19+ AFR spikes are super sharp, I don't expect such spikes from air traveling all the way through the engine. I will prolong the AFR exhaust pipe from 40 to 80cm tomorrow - I will know more after that.

Independent of that, I plan to buy a PCV and autotune to get the L-table fixed so that idle and low revs will run nicely again. After that, I can play with the F-table as well. Beyond 2400 rpm the bike runs at 14.5 almost perfectly. Your strategy of shifting the F/L-switch table was what I thought of.

I just read somewhere that the ECU is also considering the L-table while deceleration or on a low-throttle cruise. Wouldn't a F/L-switch value of like 40% make sense during pressure tuning or would the inaccuracy you describe diminish any potential advantage?

On the other side, switching the F/L-switch to 0 is all needed to tune for rpm/tps right? No need to deactivate the o2 sensors with Tuneecu?

I thought about something else as well and maybe you have a thought about it. My current issue is that the bike is really lean in low revs. Can't I simply decrease the AFR table from 14.5 to 13.7 in the lower revs? Theoretically, that could be a quick fix, but the narrow band o2 sensors can't go that low. What happens if I set the AFR table that low? Does it simply prevent the bike from entering the closed loop?

The short version:
F/L to all zero is indeed, how you go pure Alpha-N (tps/rpm).
Changing AFR table does nothing to fix the issue you're having.
Big cam exacerbates the ITB issue, you'll want a low F/L switch if not zeroing the whole table.
It can be tuned to be very polite with big cam on F/L at all zeros.
On deceleration with throttle closed, Rocket 3 has fuel cut active.
Stock O2 sensor should be disabled and the bike needs to get put on a dyno and to be tuned. Leaving o2 enabled counteracts the changes you make in the fueling tables as the ECU trims back towards Lambda 1.0. You're literally fighting the ECU's trim function when tuning if the o2 is enabled.
PC-V Autotune is a trim function for a good base tune, it's not a good baseline tuning function, it can't cope with the acceleration enrichment or decel fuel cut the stock ECU always has active so will give you a fubar fuel table over time. If you absolutely have no dyno near you, grab a POD-300 and datalog with autotune disabled and make corrections manually in the fuel table.

You have it backwards, get your F table solid first, then introduce F/L switch above 0 and tune L tables. F table with zero F/L is significantly easier to tune than the L table with active F/L table.
Scenario Example: With F and L untuned, say your switching point is 20% in F/L at 1910 RPM. You're at 21% throttle, 755HPA, and running 15:1 AFR. What table do you adjust? It's not pure F. It's not pure L. There's a transition zone where it blends the two. Now add in that you can go to almost any map value at almost any RPM and within a very narrow throttle position range, it creates an incredibly narrow window for tuning L tables well.

40% is way too high F/L switch for cammed R3 imho, I don't expect you'll get very much resolution out of it.
For a while I ran F/L like this, it allowed me to tune idle using L table, and basically everything else using F table. It worked well for a big cam rocket 3.


My suggestion is ignore any and all tuning videos that are based on tuning cars that have a throttle body. While the general idea is correct, the nuance is completely lost when compared to a motorcycle with very large ITBs. I recently watched a video with one of the developers of the Haltech Elite series, he was asked what engines he hates tuning the most, his answer (and I'm paraphrasing)"Small displacement motors with large ITBS like Formula FSAE". His reason was the lack of MAP signal resolution due to huge proportional vacuum swings with low throttle opening. That is basically exactly, our engine

Claviger said:

The short version:
F/L to all zero is indeed, how you go pure Alpha-N (tps/rpm).
Changing AFR table does nothing to fix the issue you're having.
Big cam exacerbates the ITB issue, you'll want a low F/L switch if not zeroing the whole table.
It can be tuned to be very polite with big cam on F/L at all zeros.
On deceleration with throttle closed, Rocket 3 has fuel cut active.
Stock O2 sensor should be disabled and the bike needs to get put on a dyno and to be tuned. Leaving o2 enabled counteracts the changes you make in the fueling tables as the ECU trims back towards Lambda 1.0. You're literally fighting the ECU's trim function when tuning if the o2 is enabled.
PC-V Autotune is a trim function for a good base tune, it's not a good baseline tuning function, it can't cope with the acceleration enrichment or decel fuel cut the stock ECU always has active so will give you a fubar fuel table over time. If you absolutely have no dyno near you, grab a POD-300 and datalog with autotune disabled and make corrections manually in the fuel table.

You have it backwards, get your F table solid first, then introduce F/L switch above 0 and tune L tables. F table with zero F/L is significantly easier to tune than the L table with active F/L table.
Scenario Example: With F and L untuned, say your switching point is 20% in F/L at 1910 RPM. You're at 21% throttle, 755HPA, and running 15:1 AFR. What table do you adjust? It's not pure F. It's not pure L. There's a transition zone where it blends the two. Now add in that you can go to almost any map value at almost any RPM and within a very narrow throttle position range, it creates an incredibly narrow window for tuning L tables well.

40% is way too high F/L switch for cammed R3 imho, I don't expect you'll get very much resolution out of it.
For a while I ran F/L like this, it allowed me to tune idle using L table, and basically everything else using F table. It worked well for a big cam rocket 3.


My suggestion is ignore any and all tuning videos that are based on tuning cars that have a throttle body. While the general idea is correct, the nuance is completely lost when compared to a motorcycle with very large ITBs. I recently watched a video with one of the developers of the Haltech Elite series, he was asked what engines he hates tuning the most, his answer (and I'm paraphrasing)"Small displacement motors with large ITBS like Formula FSAE". His reason was the lack of MAP signal resolution due to huge proportional vacuum swings with low throttle opening. That is basically exactly, our engine

Click to expand...

I highly appreciate your first-hand insights. Yeah, I know that big cams are a headache but I kind of like to understand the entire topic better and give it a try. Everything you say makes sense to me and completes my picture of what I read and understood so far.

I don't have a dyno near me so what I would consider doing, as you suggest, setting the F/L to zero and collecting AFR data for the different TPS/RPM pairs while riding. With this information, I can then incrementally tune the F-table. What is your overall suggestion on how to collect this data? Should this be done on a "lonely street" by running through the TPS/RPM pairs, meaning, gear 3, RPM 1500, then turn to target TPS, e.g., 20, and run through the RPMs? Repeat several times for all target TPS? Or simply collect data while riding in a non-city area? In this scenario the different de-/acceleration cycles do negatively impact the data, right? I would love to hear your thoughts on this.

After tuning the F-table it might still be that I have less optimal AFR values during different kind of acceleration, at least I believe so. How do smooth them out? Is it that I have to collect data during these events and then play with the TPS/RPM values related to the time these actions happened?

Then back to the L-table You busted the myth that changing the AFR table would provide me with a quick fix. Considering that I'm fighting the ECU trim function, I thought to set the AFR table to a lower value - not that low that it runs in open loop all the time - and increase the L-table values until I reach a point where I get my target AFR. For example. The AFR during idle is set to 14.5, I could decrease it to 14.1 and increase the L-table until I see an AFR of 13.8. This way the closed loop would still be intact but especially in the lower revs where the ITB hits, I let the ECU trims run into its limits. My belief is that the closed loop, even though it can't deal with my low revs, is still valuable, and at least I can try to keep it on. Or would you say: "Don't go down that road, don't overcomplicate it, and just turn it off"? From what I understood you played a bit with it as well so you had a certain opinion before you knew what you know today.

Looking forward to hearing your thoughts.

The ECU O2 is a narrow band, it alternates back forth across the set point the ECU is calibrated for, which is somewhere near Stoic, or 1.0 lambda. It has no ability to tune to any AFR other than stoic. That one should be off, on newer ECUs they can trim to target like you want it to do, but this ECU cannot.

My rough in process if you can ride it, is to baby it to a an empty/uphill(hill helps slow the ramp rate of RPM while datalogging, I drag the rear brake at times too to slow it even more) street if possible. While datalogging in 2ndgear to start, as to not put too much load on the engine I climb the street at a set throttle position, holding position as it sweeps up a good bit of RPM, 3500-4000 or so. I coast back down the hill and climb it a few times in various throttle positions, something like 5/10/25.

Stop and do the adjustments in the Powercommander, roughly 1 number in PC-V table is 1% up to somewhere around 20% +/- fuel.
Repeat as necessary until you have a AFRs consistently between 12.5 and 14.5 through the RPM sweep.

Then I move to 3rd gear and do the same, remember speed creeps up quick

Once 3rd is done to 4500 or so, I start using the freeway when it's not busy and I do all my base cruising area/city riding tuning in 5th gear. It has the highest load and slowest movement out of given cells in the table so you get the best log data. I refine as much of the map as possible at reasonable speeds like this, often doing sweeps from 2000 to 4000 or so.

Once that's done, you can take the fuel map in the PC-V and move it over to TuneECU. I do not use the provided function in TuneECU, I've not had good luck with it. I manually move then PC-V trims into the TuneECU map +1% e.g. +12% in in PC-V I would put +13% in the TuneECU map area that corresponds. Interpolate areas as required. Then zero out the PC-V trim table.

From there I just datalog while I'm out riding and correct when I get home directly in TuneECU, leaving a zero map in PC-V.

When you're satisfied with that part of the table comes the hard/risky part... larger openings. I look at the general shape of the map I've build using the curve visualizer in TuneECU like this:

Then I shape the curve so that each RPM row, provides a similar shape but with higher values as RPMs climb. The exceptions are understanding where peak torque is, there will be a non-linear increase as you cross peak torque where it wants more fuel, then it will slowly taper the rate of increase from peak torque to peak horsepower, but each subsequent row will still still use more fuel than the last. Say my peak torque is at 5200, from 4400 to 4800 I may add 5%, then from 4800 to 5200 8%, then from 5200 to 5600 back to 6%, the rate of gain slows.

There's also an inflection point, at least on my setup, for me it's at 15%. From 15% to 20% there's a very non-linear increase in airflow, thus, the big jump in fueling. Your inflection point will be higher than 15%, it's because of my bored throttlebodies. As I remember, stock, it's around 25%, you can see it in the stock maps too.

I lean towards too rich vs too lean.

After that is done I go datalog some progressively increasing throttle 3rd gear pulls 40/50/60 etc, backing out of it the moment I see 15:1 on the gauge. or feel anything odd. Check logs, adjust, repeat. This part takes a long time, and its loud, and its fast, and its illegal AF- be cautious. When 3rd is tuned reasonably well I do some 4th and 5th, but ... there's no safe way to do high RPM 4th/5th on the street so I don't do it a lot.

This point is when I call the shop and schedule a dyno. I've routinely been about 10% down on power vs the fully dyno tune, but the dyno tune feels 100x better, and its because of something else you asked: Acceleration Enrichment. Will post in separate section.

Disclaimer.. I'm not quite sober so if this makes no sense speak up hah.

The short and lazy version - shoot for 13: 1 everywhere and ignore the 1 second of data in the log after significant throttle openings during acceleration enrichment period. Grab a tune file that's from a bike that has the same mods or as close as possible if you can that was done on a dyno by a pro, it can save a lot of work.

Acceleration Enrichment is tricky because we don't have access the AccelE table in TuneECU, but you can tune it still somewhat. This part is much harder to do on the street because it's time intensive and a dyno can load these areas with more stability. This will differ but generally this is how I've found the map to contribute to various riding events:

PS: Dont use these values for anything, I have a completely non-stock fueling setup.
The areas blend together somewhat depending on how fast you open the throttle/gear etc as the ramp rate changes. Not all areas want the same AFRs, so don't chase 13:1 in accel area, or unused area go by feel, did 12 feel better? If so, try 11 did it feel better? If not, try 13.5:1. Your butt will know when it's correct.

This will absolutely vary from rider to rider/bike to bike based on engine build/torque curve and riding habits. For example if you go to 100% from 20% at 3000, you'll go through a specific set of cells during transition, those indicate the acceleration enrichment area. For a given built bike there will be a different set of cells as the rate of torque gain differs, for a given rider the cells will differ based on how quickly you normally go through that area (not the deliberate, 20-100 as fast as you can forced action, but day to day riding).

0% to 2% should have no jerk/hiccup as they do stock (most stock bikes do). You smooth this by adding fuel, it doesn't matter if that split second when it opens is super rich, if you can pick up the throttle from closed to cracked without a jerk/bump mid corner it's right imho.

Steady state should be tuned so mid-corner steady part throttle doesn't hunt/jerk/cough, whatever AFR that is. It should smoothly roll through, predictably responding to slight adjustment without non-linear output changes.

Cruising I used to shoot for 14ish to 1, but I gave up on that economy bologna a while back and shoot for feel, which, for me, was around 13.4:1 in the cruise area. Still get 40+MPG commuting if there's no traffic.

Moderate Acceleration I recommend shooting for a solid 13:1 for street tune. The consumer grade WB sensors are fairly accurate but 13 gives you a good feel and the 4 WBs I've tested have all been within +/-0.5 point in this area, so it's a safe guess.

Lets GOOOO area... how much do you trust your WB sensor? I don't trust my engine to LSU sensors so it gets a 12.5:1 target on street tuning and is only ever leaned out for best torque on the dyno using a much better sensor (this is why it picks up power after a dyno tune). Remember power is a plateau not a peak, as graphed below. The graph is slightly deceiving, as it looks parabolic(ish), in reality power falls off slower on the leaner side of mean best torque usually (and the Rocket 3 has a quite wide plateau). Without a dyno, there's no good way to test for what AFR works best at a given RPM, so shoot for a stable AFR.