ETC Throttle Response

[samh_08]

I hate to say it but I miss the no bull 'throttle feel' of drive by cable and, God for bid, the carburetor on a well tuned muscle car.

I have a DBW LS1 1mb PCM and an E38, and I cant seem to get them to feel the same. No matter what I do, it seems there is always a lag and they need to have throttle follower in order to not 'catch' themselves after a quick jab from idle.


I know Im not the only one feeling this way, but Im hoping someone comes along and says they felt the same way AND figured out how to fix it

[swingtan]

Log APP and ETCTP and overlay them on the same chart. This will show you the real "lag" between the pedal and the throttle blade.

Then you can make some judgments on whether or not it's a mechanical delay or some other factor causing the lack of throttle response. Post the logs.....

[samh_08]

Good call, just found this from a LS1 log (attatched below). Will have to log the E38 tomorrow, but Im thinking you already know the answer to that too .

In reality, its only low to mid throttle operations that make the ETC feel sluggish. I've tried messing with the response tables and it makes the response more aggressive, but still has the lag.


To be honest, I dont know what controls the throttle on the E38, so Im in the dark on that one.



Im open to suggestions

[swingtan]

Don't forget, that the LS1 controller only logs at 10 fames per second, vs the E38 logging at 40 frame per second. The LS1 log may actually miss some lag due to the speed at which it logs, but I still don;t think that's going to be the cause of the mid throttle lag. I'd like to see logs of APP, ETCTP, IBPW and O2 (narrow voltages and wide band).

Simon.

[samh_08]

I'll have to get you some new logs that are up to date with my tune. I try to run closed loop speed density, but am finding that the narrowbands seemingly arent giving me enough fuel.

I would like to run open loop to avoid this, but I dont know how to compensate for weather and WB02 inaccuracies (I run LC1 serial connection.)


Fuel and spark aside, do you find that there is built in lag that is not adjustable? Im talking about the computer being able to respond as fast as reaching the throttle linkage with your hand and wicking the throttle back and forth.

[swingtan]

There are a number of US based calibrations that seem to run a "slower" throttle blade response, when compared with the Aus based tunes. U've not yet seen a Holden vehicle that has a noticeable blade lag and measurements show have shown the blade move pretty quickly.

If your NB's "are not giving enough fuel" than I'd say the underlying fueling is just plain wrong. The NB's should only offer minor corrections and normally will work up to 50% error on the fueling (STFT's plus LTFT's). So it's very possible that the base fueling is off, giving you poor response. The LC1 should be pretty close, providing everything is in good working order. If you doubt the LC1 and the fuel trims, I wouldn't be going OL. You have no way of telling where your fueling is....

Let's see a log and work from there.

Simon.

[samh_08]

Heres a log from my stock E38 ('11 Silverado). Shortly into the log I start quickly jabbing the throttle. Mind you there is no WB02 data.

Let me know your thoughts .