Throttle lag and filtering?

[Drifter X]

Originally Posted by Turdinator

These add additional layer of filtering before the ECU even receives the signal from the throttle pedal. There is no way they can increase response, all they will be doing is sending a signal to the ECU that makes it look like you wanted more throttle initially.

A tune helps with throttle response and I've read people claiming in these boards that doing the pedal dance improves throttle response. Personally I think it is just something we have to live with on this car with its electronic throttle. I am not even sure the stock ECU will be able to work if you put a cable throttle on the motor.

I agree. It’s something I have learned to live with. I’m not even bothered by It.


Sent from my iPhone using Tapatalk

[freerunner]

I'd try to check with an external wideband if the O2 sensor is off and the engine is running lean without any sign in the log.
Could also be nailed with fooling the calibration of the O2 sensor a tad into the lean area around stoich to force running a slightly richer mixture in closed loop.

[ermax]

The answer really is in the TIR (Transient Ignition Retard) tables. These threads have some good info:
https://www.ft86club.com/forums/showthread.php?t=50088

https://www.ft86club.com/forums/showthread.php?t=118629

“transient” is when there are big fluctuations in the RPMs, for example blips or shifts. In the early days there was an issue with detonation on shifts at redline which was eating injector seals. The cause was that the original roms had the TIR table zeroed out so it wasn’t pulling timing on shifts. Shortly after the release of the car they filled in the TIR table which fixed the injector seal issue but also impacted blips a little. In 2017 they got WAY more aggressive with the TIR table which fixed some knocking on fast shifts but really killed blips.

It’s a trade off between throttle response or knock when it comes to the TIR table. I run the 2013 TIR table but don’t get the knock because I’m on E85. I think if you have a lot of time to play in RomRaider you could come up with a perfect table that will avoid the knock on high RPM shifts without killing blips.

[DiscoQuinn]

So for some updates to this very old post:

I tried a few different 'hardware' solutions.

Chinese Pedal Commander: $26CAD




Results? Only changed how fast the throttle goes to 100%. It didn't change the throttle hang when letting off the pedal, and it didn't improve the input filtering. You can still hit the pedal 40 times quickly, but the throttle wont respond unless you hold an input.

Decided to try the bad idea as well. I knew it wasn't going to work, but had to try. Had the spare parts to test the theory.






What was most interesting is the firewall, carpet, and pedal all had pre-made notches or holes specifically to fit a throttle cable. They all line up perfectly.





The motor would rev up if I matched the pedal position to the throttle plate position, but otherwise would choke and throw limp mode at me. Worth the shot, but man I fucking hate the throttle feel in this car. I am creating a drift kit, but I don't want to force people to buy aftermarket ECU's just to open the idea of throttle control during drifts. Like, you can't 'pedal' these cars. You could if the throttle pedal and throttle plate were actually working together.

[Drifter X]

Wow thanks for taking the plunge and testing. I hope someone comes up with something.


Sent from my iPhone using Tapatalk

[ermax]

I attempted similar stuff on my IS300 but if the input doesn’t match what the ECU expects it freaks out. You say you don’t like the DBW in the Twins, you should see how bad it is in the IS300 or the Z/G3X or Porsche. The Twins have by far the best DBW of any modern cars I’ve driven.

So, I guess you still haven’t played with the TIR tables.

[tomm.brz]

just try modify the tables of DBW, also if you have ecutek you have an extra table to modify it's sensitivity

[Capt Spaulding]

I've seen a number of videos discussing Ayrton Senna's throttle technique. He rapidly cycled the throttle in corners from apex to exit. These DBW systems would have made his driving style impossible.

[DiscoQuinn]

Originally Posted by ermax

I attempted similar stuff on my IS300 but if the input doesn’t match what the ECU expects it freaks out. You say you don’t like the DBW in the Twins, you should see how bad it is in the IS300 or the Z/G3X or Porsche. The Twins have by far the best DBW of any modern cars I’ve driven.

So, I guess you still haven’t played with the TIR tables.

I've spent about 30-40 hours of seat time in around 15-20 different IS200s. Maybe the 1GFE is different than the NA 2JZ, but the throttle control of those cars was far more direct than the BRZ/FRS.



I've also got somewhere in the 300ish? hours in a Caymen on circuit, but the porsche I can completely confirm is similar to the twins, where you are required to keep it planted to get any sort of torque delivery.




Sadly, I just don't know how to tune ROMs. I've got a KESS V2 at my disposal to move tunes to and from the ECU, but that's about the extent of my knowledge. I'd rather just some VW down drafts and lock the cams in place. I really don't care about power, I just want predictability.

[DiscoQuinn]

I MUST BUMP THIS THREAD:

This update is in anger. I spent some seat time in an ZZT230 Celica today. My work car is DBW, and my BRZ is DBW. Driving the Celica today was a huge reminder about the feeling I'm talking about.

The 'torque dip' really isn't the major problem. It's the fucking throttle input filtering.

I'm desperate to drive an FA20 car with a completely aftermarket ECU with a map made from scratch. I can't fucking stand the throttle plate doing things that I'm not telling it to.

In moments of oversteer in the celica today, I was able to subtly control throttle inputs there was no delay or negotiation of the wheel speed I needed at the moment. Immediately after I drove the BRZ in the same course to only have it constantly arguing with my inputs, and the delays themselves changed depending on some mystery maps and circumstances.



I really don't have the ability to know what others have done, but I'm so done with the FA20. I can't think of another N/A 2L I've driven that feels this disconnected from throttle control. The dip, and filtering teamwork to create random wheel speed control unless you hold it on the floor and hope. From 1%-99% you have no idea what the throttle plate is doing, and even sometimes when you hold or maintain a position the plate may change resulting in destruction on the art of throttle control. I need to find a solution that doesn't require me buying a new ECU and spending hours and hours trying to tell a dyno technician what I mean by throttle linearity, as I've not met one of those guys yet that gets it.

--End rant.

[ermax]

I assume you are doing the long hold on the TC button. Have you also tried the pedal dance? I’ve just not noticed the levels of filtering and lag you speak of. I have no problem at the razor edge of traction. Can’t say the same for other DBW cars I’ve driven. Nothing will fully replace a cable though.

[churchx]

Originally Posted by Capt Spaulding

I've seen a number of videos discussing Ayrton Senna's throttle technique. He rapidly cycled the throttle in corners from apex to exit. These DBW systems would have made his driving style impossible.

IIRC he also was the only F1 driver to use that technique, rest did normal "smooth is fast". That technique may have roots from Senna's childhood karting history and not sure it's that usable in modern F1 cars either.

[churchx]

Originally Posted by DiscoQuinn

... I really don't have the ability to know what others have done, but I'm so done with the FA20. I can't think of another N/A 2L I've driven that feels this disconnected from throttle control. The dip, and filtering teamwork to create random wheel speed control unless you hold it on the floor and hope. From 1%-99% you have no idea what the throttle plate is doing, and even sometimes when you hold or maintain a position the plate may change resulting in destruction on the art of throttle control. I need to find a solution that doesn't require me buying a new ECU and spending hours and hours trying to tell a dyno technician what I mean by throttle linearity, as I've not met one of those guys yet that gets it.
--End rant.

AFAIK throttle mapping linearity can be easily done. It had been done in OFT tunes, so assuming that competent ecutek tuners can do it too.
As for throttle dip .. if you want to keep engine in powerband you'll be above it anyway, and in normal easy driving along the traffic most of the time i'm below it. Until i first read about existence of such, i didn't even consciously noticed it myself. End it's not that car doesn't accelerate in dip, just does it slower. But ocasions, when i need to accelerate from 2Krpms to 5? Rarely happens. When i need quick acceleration i just row down few gears anyway.
Now for general throttle lag .. if it is left as only issue .. to me it certainly is not of that high priority, especially to think of engine replacement "to fix". Nice to have it improved, but can live without.

[Capt Spaulding]

Originally Posted by ermax

I assume you are doing the long hold on the TC button. Have you also tried the pedal dance? I’ve just not noticed the levels of filtering and lag you speak of. I have no problem at the razor edge of traction. Can’t say the same for other DBW cars I’ve driven. Nothing will fully replace a cable though.

It is entirely possible that I am out of my mind, but I am convinced that the throttle mapping on my '15 changes when I do the long (double) press on the nanny buttons. I usually do that as the engine is warming up, but on occasion I forget. When I do I find myself being irritated that my shifts seem clumsier and the throttle blips less predictable, Eventually, I'll notice the absence of lights on the panel and fix it at the next light.