Smooth Throttle for UpRev

wstar · 10-04-2011, 08:48 PM

Quote:

Originally Posted by Jordo!

It's because VE and MAF counts should go up with higher TPS and RPM -- but, the load tables must also activate different cels in the VVEL maps, which is where all the actual throttling takes place. Finally, there are target AF maps that also correpsond to those load values.

Basically, no matter how you scale the tables, actual physical VE will not reach maximum levels unless RPM is approaching redline and throttle (as controlled by VVEL) is wide open.

If the values in the table don't corerespond well to physical reality you will most likely get herky jerky engine responsiveness as it tries to maintain whatever the target AF ratio is for the corresponding load cell.

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".

Quote:

Can you adjust timing or fuel on tip-in? That's a great way to improve throttle response!

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.

Quote:

Also -- do the values in the map correspond to injector duty cycle? I'm guessing that they do, although exactly what 3800 means isn't clear to me... uprev doesn't use intuitive cell values for a lot of the maps...

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.

Quote:

Originally Posted by DIGItonium

You know how the VHR ramps up pretty slow under 3k RPM compared to DE/HR? Does this mean it still has the capability to ramp up pretty quick? I just want to verify the lag or slowness is really in the software than physical or mechanical.

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.

DIGItonium · 10-04-2011, 10:21 PM

Quote:

Originally Posted by wstar

Well, some of that is simply lack of low-end torque... I'm quite sure it's mechanically capable, but a lot of this stuff may require access to VVEL tables.

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.

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