Yeah, basically. I just want to get a better understanding of what this "throttle" table really does, and what we can do with it in practice. Probably the answer is "not much without access to VVEL, except smoothing things out".

I'm not messing with the MAF table or timing or fueling, just leaving those where they were set on the dyno. Lacking a dyno and the know-how, I don't really trust myself to play with that stuff and not cause myself a big problem . At least, for now. :)

I'm not sure what the numbers mean tbh. They could just be a fictional scaling value, or the product of some other units that make more sense. The highest points on the stock table on my car are in the 3600's somewhere, and I got "3800" from the fact that my tuner filled in a few upper columns with that value when he tweaked my throttle table. In any case I'm pretty sure they're Nissan's values, not UpRev's. UpRev just relocates the factory tables to RAM so they can be map-switched.

I may have related my story above backwards by the way, it may have been the lower-value crazy table that caused the butterflies to try to open earlier, not the one full of 3800s, and I got confused about which map was which. I'll check again tomorrow.

Well, some of that is simply lack of low-end torque. Nothing will fix the engine being a bit slower under 3K if it just can't do any better against the physical load. That aside though, I'm sure everything else is in software. My throttle map experiments were kind of crazy. For a brief instant when it hit the crazy part of the table, the engine responded like it never does under normal mappings. I'm quite sure it's mechanically capable, but a lot of this stuff may require access to VVEL tables.

just to chime in here, most of the time the throttle plate is fully open, VVEL is controlling air flow and sending a simulated TPS signal back to the ecu. Charles at CJM (Phunk) confirmed this and had tuning issues using a return kit with a FPR. He basically said he had to disconnect the vacuum source as the cruising/off throttle vacuum was not correct/consistent since the throttle plates where not actually closing entirely.

Also, there still are no fuel tip-in maps as far as I know, but they are working on them.

That sucks. Once those can be accessed you should be able to really get great throttle response without screwing too much with the scaling of things.

Most ECU's pull timing on tip in (can be especially aggressive on autos), so if you add timing back in and a little extra fuel (sudden change will make AF ratios skew lean -- might not matter too much if Nissan did a good job tuning that) you can achieve instantaneous response and really smooth transitions from low to high load.

Does it feel like it has a light flywheel at some point? I'm still not entirely convinced it's lack of torque because even a Corolla has a sharper throttle tip in which can overwhelm the front tires (simply because I wasn't used to it). When I drove the '08 350Z, I barely tap the throttle and the revs rip to 2k in no time as if it has a lightened flywheel. I even broke loose the tires tapping the throttle in 1st. With our cars, it just has a progressive ramp to 3k as if it is in tire saver mode lol.

Ah! I hadn't considered the idea that the "Throttle Position" feedback coming over OBD-II was faked. In that case, it does explain a lot of my misunderstanding, and it also means that this "throttle map" is really more about some aspect of VVEL's operation rather than the butterflies. I'm almost tempted to put a bullet camera in my intake tubes so I can watch the real throttle and confirm it myself.

Anyways, I like my smoothed version to drive on still, even if it's just based on math and a total lack of understanding :)

Since we have 5 maps to switch from, are you able to put this table on one of the maps and retain the original table for say... winter driving?

Oh I see you have 7AT... I wonder what the tables for 6MT and 7AT are like.

BTW... since I only have the cable that came with the GTM kit, do I still have to buy the s/w separately to log and view this stuff? I didn't hear anything from UpRev.

Good question. If you have an UpRev cable, it probably has some sort of license attached to it, the question is which kind. If you go to UpRev - Engine Management, you can download their software there. Either Cipher or Osiris Standard (one of the two, probably Cipher) comes with a License tool that will tell you what your cable is licensed for.

The smoothed map isn't incompatible with winter, at least not on my car. It's just... smoother, while still reaching those 3800 values that my tuner seems to think allow easier WOT at all RPMs. The main thing I need to figure out now is whether I'm being robbed of raw acceleration in exchange for this smoothness because he's got the idea behind these table numbers totally backwards :)

I got some support via email from UpRev today on this. Basically they confirmed that setting the 3800 values up high is about what they normally do to get better WOT capability on Z/G cars in general. They also confirmed that nobody really knows how this table works, it's just trial and error. To quote from their Nissan tuning guide PDF:

Anyways, I'm going to continue trying out various refinements to how my table is set up, in case my current smooth map at the top of the thread can be improved.

Thanks! Got it. Everything's disabled except Cipher. It appears I am also able to flash the ECU, but not dump it.

It'll be nice to "open source" the throttle control project. Pretty soon flashing our cars is like Android flashing our phones. :)

It's probably a "Standard" license then. You can probably upgrade it to Tuner, but you should send them a License Report from that cable firmware tool first to be sure.

Unfortunately modding our ECU (or any car ECU really) is never quite as open a process as I'd like. I'm an open source developer myself, but the ECU world is all about trade secrets and warranties and whatever.

Nissan doesn't tell anyone how the ECU works. UpRev reverse engineers it to tease out whatever maps they can, but the deep details they produce (which allow them to make their roms and tools), they keep to themselves so they can run a profitable business, as it takes a lot of money to do the reverse engineering of this stuff.

I plan to continue posting whatever I can about whatever I can learn from playing with the tables in the Tuner edition of UpRev, but I don't think that will lead to anything resembling an open source ECU for our cars. Mostly it's just to reduce duplication of effort figuring **** out.

The quote from the Nissan tuning guide fits my earlier comment. Basically, you are balancing fuel, spark, actual measured air mass and theoretical VE derived from forumulas based on the known displacement of the engine, RPM, and thottle position (really, VVEL).

There's probably limits to how great those values can be before they are not doing a good job of modeling the physical reality of acutal air mass ingested at a given RPM and VVEL position(s).

Modeling airflow is a real PITA, and yeah, a lot of it is trial and error, especially if the values you can record/ adjust aren't intuitve.

I guess you can try datalogging VVEL and MAF g/sec (assuming you can get this data from either upRev or from an OBDII scan tool) and try to figure out more precisely what the range of values ought to be.

Actually -- let me recommend a really good text that may be helpful as you learn how to tune it --> Amazon.com: Engine Management: Advanced Tuning (9781932494426): Greg Banish: Books

I found that book to be incredibly valuable in figuring things out when I used to tune my previous car.

Oh yes... that thought completely slipped my mind. I guess being able to truly open up at 100% is a good start, but I don't know if mine is doing that until I start logging data with Cipher. That's the sense I get every once in awhile as if the throttle map changes in real-time, and it becomes less aggressive or limited as things heat up.

This link might be helpful -- older ECU, but I bet the newer ones operate under same general parameters. Also explains how to figure out the hexidecimal values and interpret them.

Turbo Upgrade for VG30DETT

Well, things always change on these cars as they heat up. It's not so much that they suck when hot, it's that they're highly self-optimizing when it's not hot, and they have to back off as conditions change to avoid knock.

I'll try to see if I can get a video of my current throttle responsiveness sometime in the next day or two, using my tuner's setup + my tweaks on the throttle map + the 7AT torque map. I guess maybe two runs from 3K to redline in 2nd gear, one where I roll into full throttle roughly in line with the revs, and one where I just stomp it open, and then ditto from down around 1.5K RPM? Maybe one full pedal run from a dead stop through 2 gears would be interesting too. I think it probably will break the back tires loose on that currently, even without trying to preload like a drag launch.