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Old 07-08-2012, 01:48 PM
TDIwyse TDIwyse is offline
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Location: Midwest
 
Join Date: Sep 2010
Posts: 405
Mein Auto: 4 diesels
There was time spent today fine tuning the controller settings. Turns out the MAP sensor voltage output range is peaking at ~3.3V with the remap. So the controller was adjusted for its “max” setting to be closer to this value instead of the 4.5V it was initially set at. Also increased the “start” point to closer to ~2.6V so it doesn’t inject unless the vehicle is really being pushed. This may be reduced a bit pending further data.

Attached is a comparison of the “new” vs. “initial” settings in regards to post intercooler “boosted air intake” temps and EGT’s for the same Remap/JBD 0% stack. Care was again exercised to avoid full fueling at low rpm’s.

The 90F temps today were not quite as hot as the 98F day’s data (~4.5 deg C lower) but the impact to IAT’s and EGT’s is quantifiably substantial with the additional injection at higher boost levels. In fact the IAT’s with the new setting are seen to actually be reduced to just below the starting value during the pull, and are kept to within 2C of the starting temps at 4200 rpm where the peak hp of the engine is typically found. Also the EGT’s are substantially lowered at this rpm point from 503 to 477 ( 937.4 F to 890.6 F).

The owner also put a switch in play so the injection can be disabled during DPF regens.

On a separate note, looking into ways to minimize low rpm torque but extend high rpm torque of the stack. Think there might be a way. It would involve making an RPM variable resistor to use instead of the manual potentiometer on the JBD. It would involve using a Freq to Voltage converter (something like this: https://www.national.com/ds/LM/LM2907.pdf) where one takes the tach signal (lower right pin on the OBD port has a beautiful tach signal) converting this to voltage that adjusts the variable resistor in the JBD (something like this: http://www.vishay.com/docs/70598/70598.pdf). And all of a sudden one gets the ability to add in the JBD rail pressure increase that is a function of rpm which would reduce the problem of too much low end torque. The circuit to be setup so at rpm’s below ~3k nothing above JBD at 0% is utilized, and then from 3k to ~4.5k the JBD distortion increases to the final desired level. The distortion adds to the remap only above ~3k and at increasing values to compensate for the torque roll-off. Now we have a torque curve that is essentially flat out to nearly 4.5k and could stay at/below the ~700Nm/520 lb-ft rating of the tranny.

Also including some pics of the place in the pipe the probe is located and how it fits in the chassis. It‘s tight in there . . .
Attached Thumbnails
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