Quote:
Originally Posted by mikefocke
JFP if the low temp thermostat is so good, why would Porsche have specified a higher temp one? Was it based on predicted use patterns for the "not a race car" Boxster as opposed to the GT cars where racing was predicted? How does the low temp affect emissions? Is there any dumping of more unburned gas (think choke here) into the cats as the "choke" system stays on longer?
|
It was done strictly for emissions purposes.
We have put emissions exhaust "sniffers" into cars before and after the 160 stat install, and actually found slightly lower emissions at idle with the 160 F stat, which ties in with the better gas mileage claims by owners. We did not run the car for prolonged periods at varying RPM's, so I have no data beyond our simple test.
We have customers that have run one of these stats in daily drivers for over 100K miles, and their cats are still fine. Interestingly, we see more correlation between cat failures (read non mechanical cat damage) and running cheap gas, those that always buy the cheapest they can find seem to have more problems than those that stay with major brands of fuel; and this correlation also seems to apply to non Porsche brand cars as well, so I would tend to point at fuel quality as the major determinant for cat failures we see.