Foot to floor, but data sez big "accel pedal %" dropoff

[ZDan]

Originally Posted by 86league

Aftermarket tune? The stock tune has something like this as well?

I thought I remembered reading reports of the ECU cutting power with high temps, but a quick search didn't find what I remembered from years back.

Custom tune. Seems I've read that the factory tune might cut power around 300F? Not sure on that.

[timurrrr]

Originally Posted by ZDan

Forgot to update this! The tune was cutting back on throttle at 275F.

Well, that's an interesting data point, given the recent discussions on whether an oil cooler is needed.
Might as well explain why your oil never gets too hot

It's also interesting that your tune implements the "oh the engine is too hot" by faking the accelerator pedal position, rather than something else, such as altering the lookup in the drive-by-wire table.
If the accelerator pedal is pressed all the way, one could argue any data logging must show 100% accelerator pedal position.

Which OBD PID / CAN ID does your data logging system use for the "accelerator pedal position"?

[ZDan]

Originally Posted by timurrrr

Well, that's an interesting data point, given the recent discussions on whether an oil cooler is needed.
Might as well explain why your oil never gets too hot

I would consider 275F to be an absolute upper limit for 0w20, but low for good 5w30.
It seems like I've read that factory setting for calling things off is at 300F, for sure before the tune I never ran into any cutoff.

It's also interesting that your tune implements the "oh the engine is too hot" by faking the accelerator pedal position, rather than something else, such as altering the lookup in the drive-by-wire table.
If the accelerator pedal is pressed all the way, one could argue any data logging must show 100% accelerator pedal position.

Yeah, that data is sort of misnamed, should be "throttle commanded by ECU" and not "pedal position".

Which OBD PID / CAN ID does your data logging system use for the "accelerator pedal position"?

I don't know, but confirmed that it is *not* actual pedal position but rather what the ECU is dictating for throttle.

[timurrrr]

Originally Posted by ZDan

Yeah, that data is sort of misnamed, should be "throttle commanded by ECU" and not "pedal position".

...

I don't know, but confirmed that it is *not* actual pedal position but rather what the ECU is dictating for throttle.

Use CAN ID 320 (0x140 hex), first byte, divide by 2.55 to get 0...100 range.

[ZDan]

Originally Posted by timurrrr

Use CAN ID 320 (0x140 hex), first byte, divide by 2.55 to get 0...100 range.

I'm not much of a data jockey... I use the ECUtek software to view data, that's it. Again, it's been confirmed by the tuner that tune applies a multiplier to applied pedal at high oil temps and high rpm, so it's known to be controlled by the tune at that point and not actual pedal position.

[renfield90]

I wasn't aware there was a table for this - any idea what it's called?

[Shoebox]

Originally Posted by ZDan

Like I said!
Oil cooler setup is, nonexistent...
I'm not worried about 5w30 at 275F. Oil pressure should be about what it is for 0w20 at 250F. Or 5w30 at 250F with an oil cooler, at least according to this data:

https://www.ft86club.com/forums/showthread.php?t=91820

Yeah my oil almost never gets over 230F, with an oil cooler. It regularly got over 275F before an oil cooler. It’s cool if you want to drive around with limited power. And oil pressure at idle is irrelevant…..

[ZDan]

Originally Posted by Shoebox

Yeah my oil almost never gets over 230F, with an oil cooler. It regularly got over 275F before an oil cooler. It’s cool if you want to drive around with limited power. And oil pressure at idle is irrelevant…..

Who's talking about oil pressure at idle?

FWIW I had same max speeds at COMSCC Palmer event 1 this year vs. a car very similar to mine with slightly more peak power and slightly less midrange torque (he has 4-1 EL catless, I have 4-2-1 catless) and he has an oil cooler, so...

By "limited power" do you mean the factory tune cuts timing advance at some oil temperature? Dunno if my aftermarket tune does or not but in any case our max speeds were similar to when we were running full factory exhausts and tunes anyway...

[ZDan]

Watkins Glen event on Mon/Tue went GREAT (except for a couple of partially stripped wheel studs )!

I was able to run extended sessions, no problemo
Did a 2:14.870 on day 1 and 2:15.335 on day 2 (headwinds, everybody was slower) and TT'd 2:15.688 which was enough to take the win in T50 by 2+ seconds vs. Miata I've been going back and forth with this year
https://www.comscc.org/events/result...?id=2021-09-14

Having the oil temp trigger reset to 285F resulted in never running into the tune cutting back on commanded throttle. Oil temp on the factory gauge remained at the same normal level of just over 270F indicated.

Sweeet...

Originally Posted by ZDan

Forgot to update this! The tune was cutting back on throttle at 275F. Had the trigger bumped up 10 degrees to 285. See how it goes at Watkins Glen in a week!

[CSG Mike]

Originally Posted by ZDan

Watkins Glen event on Mon/Tue went GREAT (except for a couple of partially stripped wheel studs )!

I was able to run extended sessions, no problemo
Did a 2:14.870 on day 1 and 2:15.335 on day 2 (headwinds, everybody was slower) and TT'd 2:15.688 which was enough to take the win in T50 by 2+ seconds vs. Miata I've been going back and forth with this year
https://www.comscc.org/events/result...?id=2021-09-14

Having the oil temp trigger reset to 285F resulted in never running into the tune cutting back on commanded throttle. Oil temp on the factory gauge remained at the same normal level of just over 270F indicated.

Sweeet...

Time for some proper studs and open ended lugs! Which I suppose is annoying given your road salt and stuff...

[ZDan]

Originally Posted by CSG Mike

Time for some proper studs and open ended lugs! Which I suppose is annoying given your road salt and stuff...

I have the shorty ARP studs so I can run closed-ended lug nuts on the street.

I got some purty rainbow-colored Muteki lug nuts for track for this year for max disco. Before going to the Glen I noticed one of them hanging up a smidge while changing wheels/tires for the trip. Ran down one of my street lugs on that stud by hand, no problemo, so I "cleaned up" the Muteki lug nut with a tap and then it installed fine by hand. *At that moment I should have removed all the Muteki lug nuts*.

At the track while removing the left front wheel on day 1, one of the Muteki lugs was dragging, and then halfway through removing it, it totally siezed up. Took a big-daddy impact to remove it. Cleaned off the outer half of the ARP stud but the inner threads were fine and I was able to get a few good turns on it. Took max torque with my street lug nuts no prob.
Day 2, exact same thing happened on the right rear.

TL/DR: Muteki lug nuts are *shite*. WAY worse than off-the-shelf "tuner" lug nuts from Pep Boys (the "street" lug nuts I've been using street and track for a few years now).

[FR-S2GT86]

Originally Posted by ZDan

Watkins Glen event on Mon/Tue went GREAT (except for a couple of partially stripped wheel studs )!

I was able to run extended sessions, no problemo
Did a 2:14.870 on day 1 and 2:15.335 on day 2 (headwinds, everybody was slower) and TT'd 2:15.688 which was enough to take the win in T50 by 2+ seconds vs. Miata I've been going back and forth with this year
https://www.comscc.org/events/result...?id=2021-09-14

Having the oil temp trigger reset to 285F resulted in never running into the tune cutting back on commanded throttle. Oil temp on the factory gauge remained at the same normal level of just over 270F indicated.

Sweeet...

So in your situation, what do you think would be the better fix out of these two examples?

1) Increase the thermal safety limit so that the ECU can't limit the power output of the engine when the oil reaches the original temperature setpoint,

or

2) Install an oil cooler so that the oil temperature doesn't reach the original thermal limit in the first place.

[gcranston]

Originally Posted by FR-S2GT86

So in your situation, what do you think would be the better fix out of these two examples?

1) Increase the thermal safety limit so that the ECU can't limit the power output of the engine when the oil reaches the original temperature setpoint,

or

2) Install an oil cooler so that the oil temperature doesn't reach the original thermal limit in the first place.

But that's not what actually happened. The original temperature setpoint was _lowered_ by the custom tune on the ECU. So as I see it, the question should be "which of the following is the most effective for engine longevity":

1. No action - factory oil temperature setpoint and 5W30
2. custom tune to lower temperature setpoint
3. oil cooler to reduce oil temperature well below setpoint

[Kelse92]

I'll admit I've glossed over this thread... But why Not buy an oil cooler? regardless of the oil's thermal capacity itself it literally is cheap insurance for a motor seeing track use.