Smooth Throttle for UpRev

DIGItonium

Does it make much of a difference if you rev in neutral?

Here's a video I made to test throttle response. Skip to 50 sec. Details are there as well:


Basically I try to floor it around 1.5-2k RPM in 1st and 2nd from a roll. "Cool" means running test immediately after engine properly warms up. "Hot" means after at least 15-30 min. drive on a warm day in which oil temps are in the 180-200F range. This is an old video in which my car only has an exhaust.

Here's the turbo video (before and after). Skip to 2:05 mark.


For the 3rd gear pull, I keep it steady around 2-3k RPM (~50 mph) and floor it to redline. This is probably my best pull regardless of engine oil temp, but it does make a difference.

The remaining runs are 1st thru 3rd from a roll (freeway entrance), so I try to start at low revs in 1st (1.5-2k RPM).

The goal is to be under 3k RPM (preferably 2k) because it seems like revving past 2.5k typically yields consistent "more poweful" pulls regardless of temps. In other words, starting at low revs result in slower runs. Starting at higher revs result in faster runs. [shrugs]

__________________

Ron

Digi totally off topic but are you gonna get different springs for the BOVs to take care of that compressor surge?

Ron

You have Turbosmart BOVs right? In some models the spring pressure is adjustable from the top, no need to replace spring.

Ron

I think those are turbosmart BOVs but I don't see an adjustment bolt on the top. Yes, you would want to soften the spring just a little

Ron

Oops. I'm derailing this thread lol. We'll continue via pm.. Back on topic..throttle response..

Red__Zed

Props for cooking up a solution

I know a lot of people will get some good use outta this.

wstar

Red: Keep in mind I'm still experimenting. I'm still running the one I pasted up top as my main map for now, but I'm using 3 other maps to continue to explore and tweak, there may be more revisions to this table coming depending on results.

DIGI: To be honest I don't know if I can compare or comment really on your vids, since you've got TT and I'm NA. There are just a whole lot of variables in play between us because of that. It would be interesting to have an UpRev tuner (or get the license upgrade yourself if that's possible on your cable) pull out what your current throttle map looks like though. I wonder if GTM leaves it stock, or if they had to change the values wildly for TT.

__________________
7AT Track Car!
Journal thread / Car setup details

Jordo!

throttle response in N will be different -- motor is not under any real load.

__________________
Enjoy it. Destroy it.

wstar

Random notes from testing: the Throttle Position (as in butterfly) data in OBD-II may be faked, but it does track something roughly equivalent in VVEL if so. I did some logging on the curves while trying to roll through the throttle smoothly and consistently using different test maps. One was my standard smooth map to 3800, and the others were modified to smoothly reach 3200 and 4200. The funny thing is that in spite of the large change in the wide-open numbers, it was hard to detect any real difference in the graphs or the driving feel.

The 4200 map did tend to ramp out a bit quicker at the end (which just makes fine-grained control with the pedal more difficult), and the 3200 map did seem a little smoother at the top, but the differences were pretty trivial. It seems like the numeric maximums are largely irrelevant within reason. What causes throttle behavior changes is the shape of the curves (since they all started at the same low-end values, the 4200 map had a sharper slope than the 3200 map).

Also, based on testing, and based on reading some google search results of UpRev guys posting on other forums, reaching WOT at any RPM was never an issue on this car. Even on my stock throttle map, I can get the TPS output to peg when I stab the throttle from a stop in first gear. Apparently running a map like mine does remove some throttle latency in lower speeds/gears though.

What's left to test really is playing with the curvature. Right now I'm running linear (by percentage) from 18.8% to 96.9% on the table, and the TPS outputs still look fairly non-linear when rolling through the pedal smoothly. By that I mean, it goes relatively smooth for a while, but in the upper region it tends to just skyrocket relative to pedal position (i.e. more in the shape of an asymptotic graph), which I guess means I need to run the numbers up a little quicker near the bottom and flatten out the deltas in the upper-mid part. Going to try some other curves on the data and see what makes it smoother.

__________________
7AT Track Car!
Journal thread / Car setup details

DIGItonium

IIRC, Sam says he left the tables alone for safety reasons, so it's simply a tune. Therefore, throttle response is the same before and after the flash. The only difference is when boost kicks in, and it feels like an extra push.

What will probably mess things up for boost is when I'm pressing down on the pedal halfway, and the throttle ramps up slow enough boost won't even build up as if the physical throttles aren't opening up as much as expected.

I have this feeling there's no 1:1 correlation with the accelerator potentiometer position and actual throttle position (or VVEL response). One would think that 0-5V equates to a linear response in how a physical throttle would open up, right? There are times when 2.5V would feel like 50%, and other times 2.5V feels like 25% at the same engine speed. [shrugs]

I bet that'll throw a wrench in your throttle table(s) equation... It'll be nice to figure out how the tables are related to each other.

[EDIT] IIRC, from the UpRev forums, they say they're making progress with VVEL control.

__________________

wstar

Yeah, in general (not just our car, all modern drive-by-wire cars) the pedal is taken as "human intent" to the ECU, and the ECU controls throttle based on a wide variety of factors. The throttle map we have definitely does something, but obviously we lack full control without VVEL tables as well.

If you want to experiment, you can completely disable Electronic Throttle Control. At the bottom of the list of editable stuff in the UpRev Rom Editor, there's an "ETC: On/Off" setting. I've set it to off before, and when you do that the car very literally maps 1:1 between the gas pedal and the "throttle" (although still, I imagine it's more VVEL than the manifold butterfly).

Throttle response with ETC Off is awesome, the problem is it kills a lot of other functionality on the car too. You'll lose cruise control (who cares), you probably lose the (safer) Throttle Rev Limit, having to just rely on the fuel cut rev limit, and most importantly you lose Synchro-Rev-Match.

On a track 6MT car, for someone who disables SRM to heel-toe anyways, ETC Off might actually be a viable option. On my 7AT it's a no-go though, the transmission can't execute downshifts properly without its own equivalent of SRM.

__________________
7AT Track Car!
Journal thread / Car setup details

DIGItonium

No edit capability here... not without a license upgrade, but I don't know what I'm doing either.

Wow that's very interesting stuff. So there must be a lot going on with the throttle software... perhaps doing a bunch of SQL queries?

It's good to know about the response with ETC disabled, so it appears the VVEL actuators may have the mechanical capability to change position quickly.

True... in a sense "throttle position" is probably not relevant with our engines versus accelerator position. It's now VVEL actuator position... so what parameters are you able to log and monitor in real-time? Do you think you can record various parameters while making the video? Imagine overlaying the plots with your video. Someday I'll fetch a laptop and run Cipher to log stuff on the way to work and home.

Can't wait to see some videos! Be safe!

__________________

wstar

For these tests I'm just monitoring throttle position ong raphs generated by Torque on my phone while i drive. I could probably log that, pedal position, and some random VVEL parameters in Cipher alongside the usual rpm/speed info, but I'm not sure how I'd sync that with video.

__________________
7AT Track Car!
Journal thread / Car setup details

DIGItonium

I've only spent 5 minutes looking at Cipher. So I guess you can preselect up to 20 parameters to record. When you're ready to test, start recording on the camera, then start log recording. Stop recording on both when you're done with the test and before proceeding with the next test.

What I did was ghetto-rig my digital camera to the steering wheel with masking tape. In fact, my camera was upside down and I rotated it using the video editor (MS Movie Maker). I don't know how to overlay image over video with Movie Maker, though.

If you can't overlay the image and video, separate post is fine.

__________________

wheee!

updates?

__________________