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LarryHughes LarryHughes is offline
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Join Date: Dec 2009
Location: Florida
Posts: 45
Garage
FWIW, I've finally completed a 2 year evaluation of the UTCIS digital WUR.
The bottom line is that I replaced the UTCIS with the stock Bosch WUR.
Why? Tons of reasons resulted in unsatisfactory performance on my '79 911 SC 3.0 NA. I'll try to elaborate.
1) Poor build quality. On my unit, there is an active component soldered in line on the wiring! Just hanging out there in space. IMO, unacceptable.
2) Start temp sensor. As was explained to me, the UTCIS grabs temp once, presumably at or near power on. But if you watch the real time digital data, you notice that the sensor report temp +/- 10C, a HUGE variance. Somehow, the unit doesn't seem to grab temp correctly. Since the temp sensed drives how long the warm-up cycle lasts, this is a critical problem. I returned the unit and the only noteworthy change was that they put a shrink tube over the exposed component. Sensed temp is all over the map.
3) As best I can figure the algorithm out, the unit senses the start temp, then holds the mapped control pressure for a specified period of time regardless of throttle setting. Assuming the start temp is correct (and it isn't), the problem with this algorithm is that it ignores vacuum input so any change in throttle setting appears to be ignored. In contrast, the Bosch WUR still responds to throttle settings, allowing one to drive the vehicle before the warmup cycle is complete.
4) I like the idea of being able to tune fuel control pressure according to throttle setting. But in practice it doesn't seem to quite work. It's like the stepper motor is slow to respond.
5) IMO, one of the problems in the UTCIS implementation is a lack of a systems perspective. Ideally, a digital control would control not only the WUR function but the auxiliary air regulator, matching their performance.

All that said, I learned quite a bit playing with the WUR. But, in the end, I abandoned it. It just wasn't getting the job done.
I'd also point out that Wayne at Pelican no longer sells this item. I think I now understand why.

The stock WUR is less than perfect. It has a rough idle on start-up but is throttle responsive. After maybe a minute, it smooths out. The UTCIS could never achieve this level of drivability.

If anyone wants to experiment, I can make you a good deal on a used UTCIS unit.
LarryHughes at cfl.rr.com
__________________
'09 Cayman
'01 996 Carrera, RIP
'79 911SC Targa sold to a collector in Germany!
'87 944S sold! '86 944 sold!
'74 914 2.0 sold but not forgotten - my favorite

Last edited by LarryHughes; 02-03-2012 at 03:46 PM..
Old 02-03-2012, 03:43 PM
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