2GR Camry sensitive accel pedal - MR2 Owners Club Message Board
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post #1 of 69 (permalink) Old November 3rd, 2018, 16:42 Thread Starter
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2GR Camry sensitive accel pedal

Does anyone else not like the pedal sensitivity? My car is about 1000 lbs lighter than a MR2 so that might play into it but it is so hard to be gentle with it at light throttle. I know the Tundra guys complain about their sensitivity and Toyota has an updated PN (04000-0440C) for them that seems to be better. I pulled the Toyota shim fix out and replaced the small spring with a heavier one but I am waiting on a few parts to test drive again. Anyone know if the Tundra pedal will electronically work?

Here is a list of pedal part numbers.

http://media.fixed-ops.com/Toy_Campa...Supplement.pdf
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post #2 of 69 (permalink) Old November 3rd, 2018, 17:04
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Your car weighs 1700 lbs?
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post #3 of 69 (permalink) Old November 3rd, 2018, 18:47 Thread Starter
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1690 lbs. It's a Lotus Europa. Stock is 1550 lbs.
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post #4 of 69 (permalink) Old November 3rd, 2018, 18:54
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Wow just by coincidence there is one of these for sale near me.

https://honolulu.craigslist.org/oah/...705858465.html
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post #5 of 69 (permalink) Old November 3rd, 2018, 20:38
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Hey so maybe more topically relevant, I had a number of things going on with my car that made it feel very trigger happy on normal traffic take-off. Combination of lightweight flywheel, highly grabby clutch, and of course, the pedal itself. So two things that helped me to deal with it. A. Sensitivity training for my left foot - learning the clutch engagement point and how to work it delicately, this coming after a lifetime of driving manual transmission where all I had to do was plop the thing out and go. And B. The clutch wore in eventually - this took months - so it became more forgiving. I didn't do anything with the accelerator pedal.
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post #6 of 69 (permalink) Old November 5th, 2018, 07:53
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I initially found it to be pretty sensitive as well. Actually, when I first drove a 2GR swapped car (probably 5-6 years before doing the swap myself), I found it to be VERY sensitive, but that car also had a very grabby puck clutch in it if I remember right. But I found I got used to it pretty quickly and it doesn't bother me any more. That said, in a perfect world I would have it a little less sensitive. But it's really not bad enough for me to want to go to much effort to change it.


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post #7 of 69 (permalink) Old November 5th, 2018, 09:06
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Anyone try one of these? Mine is pretty sensitive as well.
https://www.pedalcommander.com
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post #8 of 69 (permalink) Old November 5th, 2018, 12:16
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Anyone try one of these? Mine is pretty sensitive as well.
https://www.pedalcommander.com
Interesting. As seems all to common, they seem to be focused on making it MORE sensitive (better throttle response don-cha-know), so I wonder if it can actually go the other way. It's also a little spendy in my opinion (330 bucks).

I wonder... since the output from the pedal is just a voltage signal (I am logging it with my data logger for throttle position), one might be able to reduce the output from the pedal a little at all positions by adding resistance. I have data logs that show a small dead zone at the top of the pedal travel where the throttle is already at 100% but the pedal has another 15% or so to go, so maybe a little resistance could reduce that? Might be worth a little investigation.


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post #9 of 69 (permalink) Old November 5th, 2018, 12:53
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This is revisiting a previous discussion. As Marc has discovered and shared with this forum, the pedal position is not a direct input to the throttle position. First the ECU transforms the pedal position to a "TORQUE REQUEST." Then the torque request is transformed to a throttle position that is commanded to the throttle body. This is done with two separate tables. These tables are featured in a number of other threads (linked below). So the proper way to modify the throttle response is to tune the throttle control maps, which is do-able now that the ECU can be flashed. It may be enough to just change the break points in the pedal position table and this should have a "damping" effect.



Source: https://www.mr2oc.com/6633945-post528.html

Interestingly in these tables there is no time rate of change dependency, as you would see for example in an acceleration enrichment table. Something tells me this might not be the full story.

PS> Another thing that occurs to me is that different ECU's have different calibrations tuned to the specifics of the vehicle. One example that comes to mind is the MAF calibration, which varies by intake. So who's to say that the throttle calibrations are all the same, and what effect the differences might have when you mix-and-match ECUs and throttle pedals.

Last edited by merryfrankster; November 5th, 2018 at 12:57.
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post #10 of 69 (permalink) Old November 5th, 2018, 13:00 Thread Starter
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I don't have a problem shifting. My problem is creeping along at slow speeds, say under 15 and giving a little throttle, any small input seems extreme. I'll test my pedal next week and see if my changes helped at all, I might try a stiffer spring on the large OD one.

I emailed the pedal company asking them how much sensitivity can be taken out. It is pricey but might be my only option. They have an Eco mode too.

https://www.pedalcommander.com/insta...v=7516fd43adaa
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post #11 of 69 (permalink) Old November 5th, 2018, 13:53
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How did you change the spring? I think I'd be happy with a stiffer spring providing more resistance.

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I don't have a problem shifting. My problem is creeping along at slow speeds, say under 15 and giving a little throttle, any small input seems extreme. I'll test my pedal next week and see if my changes helped at all, I might try a stiffer spring on the large OD one.

I emailed the pedal company asking them how much sensitivity can be taken out. It is pricey but might be my only option. They have an Eco mode too.

https://www.pedalcommander.com/insta...v=7516fd43adaa
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post #12 of 69 (permalink) Old November 5th, 2018, 14:29
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I don't have a problem shifting. My problem is creeping along at slow speeds, say under 15 and giving a little throttle, any small input seems extreme.
Oh yeah this problem. I forgot about that. I had this only when creeping in 1st gear. Shift into second when creeping and all fine for me. This seems to give enough drivetrain resistance to keep the engine under control.
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post #13 of 69 (permalink) Old November 6th, 2018, 05:11 Thread Starter
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Pop the silver covers off the side and press the pin out. It takes some manipulating to get it apart. The small spring is 1.735" long x .435" wide x .050" wire diameter. I used a spring 1.800" long x .485" wide x .070" wire diameter. I had to use a bench grinder on the end of the OD on the large spring. On one end of the pedal the spring seats on the ID the other end is held by the OD, it just need a little fitting. If you have the Toyota shim fix, I would remove that too. It is easy to pop back in later. This video explains the shim.




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How did you change the spring? I think I'd be happy with a stiffer spring providing more resistance.
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post #14 of 69 (permalink) Old November 6th, 2018, 09:28
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Originally Posted by merryfrankster View Post
...Interestingly in these tables there is no time rate of change dependency, as you would see for example in an acceleration enrichment table...
I am not surprised by this. The throttle itself will have no history as long as the throttle motor is fast enough, which I imagine that an electromagnetic actuator can easily be. The acceleration enrichment has to do with the complex dynamics of air rushing into the plenum and fuel vaporization. Maybe it is just the response time of the MAF, which is a thermal device after all.
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post #15 of 69 (permalink) Old November 7th, 2018, 09:51
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Quote:
Originally Posted by merryfrankster View Post
This is revisiting a previous discussion. As Marc has discovered and shared with this forum, the pedal position is not a direct input to the throttle position. First the ECU transforms the pedal position to a "TORQUE REQUEST." Then the torque request is transformed to a throttle position that is commanded to the throttle body. This is done with two separate tables. These tables are featured in a number of other threads (linked below). So the proper way to modify the throttle response is to tune the throttle control maps, which is do-able now that the ECU can be flashed. It may be enough to just change the break points in the pedal position table and this should have a "damping" effect.



Source: https://www.mr2oc.com/6633945-post528.html

Interestingly in these tables there is no time rate of change dependency, as you would see for example in an acceleration enrichment table. Something tells me this might not be the full story.

PS> Another thing that occurs to me is that different ECU's have different calibrations tuned to the specifics of the vehicle. One example that comes to mind is the MAF calibration, which varies by intake. So who's to say that the throttle calibrations are all the same, and what effect the differences might have when you mix-and-match ECUs and throttle pedals.
Marc and I have talked about this a little. Part of the problem is, as you said, there are probably other tables that feed into this stuff, and it's a complicated enough subject that he has said he doesn't want to mess with it without understanding it better.

And my data logging of the subject shows that this is true. For example, I setup my race capture pro to log actual throttle blade position (using one of the TPS outputs from the throttle body), as well as pedal position (was already logging this). A pedal sweep with the engine off shows a pretty linear relationship, other than the top 15% of the pedal not doing anything, because the throttle was fully open at about 85% pedal.

But, if we look at those two charts, one would expect a sweep using the 400rpm row to never exceed about 42% throttle, since we would need a torque demand value of 6400 to jump into the 73.9% throttle position cell, and torque demand on the pedal position map never exceeds 6080. Yet when you log the pedal position vs actual throttle position, this is not the case. So clearly we don't know the whole story.

In fact, it probably would be much easier to drive if it behaved as those charts would indicate it should, but for some reason it doesn't.


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post #16 of 69 (permalink) Old November 9th, 2018, 06:42
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Yeah, these 2GRs have an enormous amount of torque at the bottom. As long as you undo the pedal recall so you have friction in your pedal you'll quickly get to where you can drive it. I do agree that it could use a bit of a softened low end on the pedal though but as Alex just mentioned It isn't just those tables and i don't fully understand the interactions to be able to modify it intelligently and safely.
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post #17 of 69 (permalink) Old November 21st, 2018, 18:06 Thread Starter
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I got a chance to drive it. It is so much better. I can actually control it at part throttle. Comparison of the small spring I swapped out. This is also with pulling the shim out.

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Last edited by Clifton; November 21st, 2018 at 18:09.
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post #18 of 69 (permalink) Old November 23rd, 2018, 12:34
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How much of a spring rate increase is the new spring?
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post #19 of 69 (permalink) Old November 23rd, 2018, 13:55 Thread Starter
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How much of a spring rate increase is the new spring?
According to an online spring rate calculator the original spring is 12 lbs/in, the new one is 46 lbs/in

https://www.thespringstore.com/sprin...alculator.html
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post #20 of 69 (permalink) Old December 11th, 2018, 22:42
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Bummed that there's not a ECU mapping change for this. The throttle is a little touchy at times when heel/toeing the thing. Just a word of caution, it's not a bad idea to keep an extra throttle pedal handy, we had a pedal die on track, started out intermittently being dead for brief instants until it finally died completely. I have a feeling it's from side flex on the pedal causing one or both of the hall effect sensors to read incorrectly (relative to the other) or fail outright. Obviously it depends on how much you abuse the equipment and mine is on the extreme end being used as and endurance race car.

I'm hoping to setup a circuit to support auto-blip and throttle cut for a paddle shifter, maybe I'll adjust the throttle output under normal operation at the same time.
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