Kawasaki ZX-10R Forum banner
1 - 12 of 12 Posts

·
Formerly CLCRACINGAaron
Joined
·
473 Posts
Discussion Starter · #1 ·
Ok guys here's the main topic: understanding how the ETV (Electronic Throttle Valve) is realized on a race track.

Disclaimer: this is mostly my personal opinion based on conclusions drawn from data collected with my AiM Solo DL. Don't take anything here as gospel and take responsibility for your own riding and/or adjustments made on your own bike. All I want to do here is start a conversation to see what can be understood from folks other than me, myself and I.






Dark Blue- GPS Speed
Light Blue- Throttle Input (ie what my hand is doing)
Light Green- TPS (ie what the bike is giving me)
Red- Lean Angle

These are images taken from my data for Turn 4 at Little Tally on my 2016 ZX10R. It's a full track bike and I'm using Pirelli SuperDiablo Slicks. Basic track mods everywhere else.

So with this bike, there is the ETV system that can limit power if the IMU parameters are within a certain range. On the exit of Turn 4 there is a little straight leading into a high speed left-hander. It's critical to get out of T4 as quickly as possible to start building speed for the back straight immediately following T5.

So, I was attempting to reach WOT (wide open throttle) as soon as possible without engaging the TC. So I am applying full throttle at the grip anywhere between 15-21 degree's of lean according to the data. The issue is that the bike is no matching my request and I'm spending a lot of time waiting for the bike to allow the TPS to go WOT.

To further support this, here is the next corner (Turn 5) where the bike is actually doing everything I'm asking.


Why is this happening? One thing that is fundamentally different is that my rolling speed is much higher exiting T5 then what it is from T4. This could mean that the IMU parameters are "ok" with allowing a (nearly) 1:1 throttle when I request it with the grip. I see the IMU's reduction of TPS as a preventative measure to counter act wheelies. I doubt it's for guarding against wheel spin (15-20 degrees lean aka fat part of the tire), so it must be a way to keep the front end down.

Based on this, I am planning on getting a Woolrich system to start adjusting the ETV. If I start getting too much wheelie, I'll make suspension tweak's and use the rear brake more, until the point where I need to pull back the ETV to help control it.

Thoughts? Comments? Concerns?
 
  • Like
Reactions: jd41

·
Registered
Joined
·
36 Posts
What do your wheel speeds look like in that area? Could it be possible that the ECU is seeing the rear wheel spin up?

And if you want to see a HUGE discrepancy in throttle traces, try the M power mode.... it's nuts.
 

·
Formerly CLCRACINGAaron
Joined
·
473 Posts
Discussion Starter · #3 ·
What do your wheel speeds look like in that area? Could it be possible that the ECU is seeing the rear wheel spin up?

And if you want to see a HUGE discrepancy in throttle traces, try the M power mode.... it's nuts.
It's not wheel spin, I'm only seeing 1-2% spin rate for that corner. There's more F/R deviation in the braking zone for Turn 5 hahaha....:badteeth:

I've never tried any other mode than Full. >:)
 

·
Formerly CLCRACINGAaron
Joined
·
473 Posts
Discussion Starter · #4 ·



Purple-Front Wheel Speed
Dark Red-Rear Wheel Speed
 

·
Formerly CLCRACINGAaron
Joined
·
473 Posts
Discussion Starter · #5 ·
You can see where I'm getting the rear to spin up (barely), then start to control it, however the ETV/IMU seem to step in and take away the fun... I want the rear to spin a little bit for steering the nose of the bike, but with these settings is really hard to get anything out of shape. I'm in TC 1 by the way.
 

·
Registered
Joined
·
197 Posts
What’s the rpm/gear when you are exiting those corners? At low rpm if the throttle is opened too quickly you actually lose power and that’s some of the reason that there’s not a 1:1 ratio at low rpm.

The traction control actually cuts fuel on the zx10 and doesn’t effect the TPS, the TPS is cut for wheelie control.

I run the race ecu so mapping is a lot different but I still don’t use a 1:1 ratio in lower gears.


Sent from my iPhone using Tapatalk
 

·
Formerly CLCRACINGAaron
Joined
·
473 Posts
Discussion Starter · #8 ·
What’s the rpm/gear when you are exiting those corners? At low rpm if the throttle is opened too quickly you actually lose power and that’s some of the reason that there’s not a 1:1 ratio at low rpm.

The traction control actually cuts fuel on the zx10 and doesn’t effect the TPS, the TPS is cut for wheelie control.

I run the race ecu so mapping is a lot different but I still don’t use a 1:1 ratio in lower gears.


Sent from my iPhone using Tapatalk
Interesting point. I looked at some later laps and found the session that I changed down to 2nd for that corner and this is what I am seeing. I appears a lower gear does allow for a more direct connection to the rear tire. I will make this note to myself whenever I feel the bike is holding me back. Thank you for pointing that out!



Hmmm... looks like it's time for TC0 then!
I rode a 2009 R1 (with no aids) but never got the hang of sliding the rear. I would get wheel-spin no problem but couldn't really get a decent slide going. Maybe this bike is different and maybe I'm a better pilot now? :badteeth:
 

·
Registered
Joined
·
36 Posts
Ha! I was kidding with the TC0 comment.
Newf brings up a good point about the throttle control no being used for TC. I've seen systems that use different strategies for TC, some with just ignition cut and some with both ignition cut and throttle control with varying amounts in different situations. Since the ignition cut can be sooo quick, it can respond to a slipping tire much faster..... if you've tried riding in TC4 or 5, you can hear the TC kicking in super easily.
Also, to further Newf's point, I haven't found pitch in the CAN messaging from the stock ECU even though the KRT ECU looks to have it. If you guys can find that in the CAN bus from the IMU, it would be worth looking at that value as well... it may provide better correlation to the throttle variation that you're seeing.
I haven't had much time to play with the CAN bus much recently, but I would also love to see some value for ignition cut if we can measure it for more precise tuning of the TC (I'm thinking KRT ECU or Woolich software)....
 

·
Formerly CLCRACINGAaron
Joined
·
473 Posts
Discussion Starter · #10 ·
Ha! I was kidding with the TC0 comment.
Newf brings up a good point about the throttle control no being used for TC. I've seen systems that use different strategies for TC, some with just ignition cut and some with both ignition cut and throttle control with varying amounts in different situations. Since the ignition cut can be sooo quick, it can respond to a slipping tire much faster..... if you've tried riding in TC4 or 5, you can hear the TC kicking in super easily.
Also, to further Newf's point, I haven't found pitch in the CAN messaging from the stock ECU even though the KRT ECU looks to have it. If you guys can find that in the CAN bus from the IMU, it would be worth looking at that value as well... it may provide better correlation to the throttle variation that you're seeing.
I haven't had much time to play with the CAN bus much recently, but I would also love to see some value for ignition cut if we can measure it for more precise tuning of the TC (I'm thinking KRT ECU or Woolich software)....
I see what you're saying about CAN bus protocols. There's no IGN channel from the stock ECU (and I doubt the KIT ECU), but the TC hasn't activated anyway. And the place I'm referencing on track the bike is very much up on the fat part of the tire, and the wheel speed sensors show that there's very little slip being measured.

This is more about the ETV settings and how I'm using the bike(as @Newf pointed out), the best way to use the gears in that corner exit, is to be lower into 2nd, not 3rd. (3rd felt to tall anyway). After I spend more time working on my riding, I'll go back to this and see what the data is showing regarding ETV. Then make adjustments from there. Fixing my riding it the top priority, that's where there's the most room for improvement.
 

·
Registered
Joined
·
64 Posts
How do you make Race Studio to show the TC, if any?
I have tried with Race Studio 3 beta but I didn't get to see anything meaningful.
I am using the race ecu + harness and the AIM MK10 dash.
 

·
Registered
2012 (Gen4) ZX-10R
Joined
·
1,092 Posts
With really big valves (for big power at high RPM) you lose intake air velocity at low RPM, this leads to less swirl of the incoming air/fuel charge and hence worse air-fuel mixing and reduced power.

So big valves and high lift cams can result in worse running at low rpm high throttle openings. ETV and STP’s resolve this but restricting a bit in this scenario, it actually can give you MORE power than WOT.

The electronics are trying to give you more power by not doing what you are asking for! ;)

Finally Kawasaki run a predictive wheel slip algorithm, and have done since the Gen4. They are one of the few companies that do this and is one of the reasons the Gen4’s traction control was so much smoother (less jerky) than the competition when it came out. Basically they try to preempt wheel slip and start to intervene BEFORE measureable wheel slip over an predicted level.

My understanding is this predictive part uses ETV, and the “oh shit it’s all going pear shaped” mode uses the much more aggressive ignition cut, i.e. once it senses wheel slip it moves onto “stage two” TC and starts to get more aggressive using ignition cut tactics.

Thats how I understand it at least.

Rob

Copy/Paste from Kawasaki docs for the GEN4 zx-10r…
448426
 
1 - 12 of 12 Posts
Top