DrX

iTrader: (7)

Lots of good research going on here.

It now looks like the key to staying out of REP mode is to maintain the difference between TPS1% and TPS2% at less than + 3.5. This is based on a range of 0 to 39.2% for each sensor as shown in the screenshots of my logs. This is not too difficult to adjust with separate 5V refs to each sensor. The low refs probably don't need to be split based on my initial tests.

With respect to acheiving more throtltle opening, you may be able to do something without cracking open the TB if you drop the shared 5V ref a little and bump up the common low ref slightly to maintain the correlation. I haven't tried this yet and it is still a theory. Not sure if the TAC module would think that the TB was open too much at idle or if this would be taken care of by the key-on self calibration.

Otherwise, if you only dropped the shared 5V ref you would have to straighten out the outputs from both sensors to keep them in line throughout the full range. Unless you went inside the TB and corrected the resistance in the 5V crossover trace.

Couldn't find any more small resistors around the house, so further testing will have to wait until I dig some up.

DrX

iTrader: (7)

BTW. I think it is starting to look better already even though I haven't brought the high refs right down to where I want them yet. I don't want to slam it against the stop though.



I did have to hack up my poor TB quite a bit in order to do this testing. Still works though and looks better than the pics after I cleaned it up.

KySilverado

iTrader: (7)

Wow. Assume you have tapped into the traces and are changing resistance to them with resistors?

moregrip

iTrader: (8)

very nice!

BigTex

iTrader: (16)

Before too long, we'll end up cutting the whole TB in half and welding the 90mm inlet to the truck controls.

TurboBerserker

iTrader: (1)

hey! I just had an idea...


/sparks welder

DrX

iTrader: (7)

Yes. Think I had the best results so far with just 100-200 ohms on the 5V to TPS1(a single 100 ohm resistor along with a 100 ohm trim pot to vary the resistance until it is optimized). I could move the throttle blade back and forth just by turning the screw on the trim pot. Works out that I would have to remove resistance somehow on the feed to the TPS2 sensor(i.e bump up the voltage a little) in order to get any more throttle opening without losing the correlation. Best I could get so far was probably around 92% opening- same as the stock 78mm setup. Correlation was within .5 most of the way up. It was a littlle wider at WOT(1.2). If I slammed the pedal down quickly I could sometimes hit 4.0V on the TPS1 and you could see the PCM/TAC module close the blade back down slightly to keep it from going over 3.9V. Once either TPS sensor hits a V value that equates to 39.2% TPS there is no further throttle opening.

KySilverado

iTrader: (7)

Hey that was my idea.

DrX

iTrader: (7)

That would be too easy though!

Here's what I have so far. Don't know if it's worth it to push it any further. Probaly wouldn't have much effect on airflow anyway. I think this equates to 93 - 94% open, based on a range of 0.5 - 4.3V for sensor 1 and a value of 4.0V at WOT. Don't know how I got the PCM/TAC to let me get up to 4 from 3.9 but I'll take it. Could probably squeeze some more out but I would have to bump up the high ref to sensor 2 to over 5V.

Click here to watch 90mm-LS2-TB-Range

moregrip

iTrader: (8)

Outstanding DrX, how do we replicate the circuit? are you happy with the outcome?