Wastegate Actuator for manual vane control

[burn_your_money]

That is not correct.  A single spring does not work like that unless it is a single spring with a rate specifically for that purpose.  With a single spring with a rate the same as the main spring in a dual spring setup, you will need to mash the pedal almost the same amount when you hit a hill.  The only difference with a dual spring setup is that the first part of the accelerator's motion causes less of an increase in fueling up to the point when the intermediate spring is fully compressed after which the performance is exactly the same. 

I'll add my $0.02 CAD.

The caged governor on our VWs is a min/max governor. It only effects the bottom and the top of the RPM range. In the middle RPMs, your foot is a direct link to the quantity of fuel injected into the engine. That is why you have to give it throttle to go up a hill. With a single spring, the entire RPM range is governed by that spring, therefore you do not need to give it more throttle to get up a hill. You may need to downshift depending on load though.
This is why you can't use a caged governor on a genset, it will not keep a steady RPM based on engine load.

I'd love to try an uncaged governor in a VW, I think it would net fantastic mileage once you get used to driving it. An uncaged governor can use multiple springs to help get off idle smoothly.

[libbydiesel]

I have tried several uncaged springs in VWs and you most certainly do need to give it more pedal to go up hills if the spring rate is similar to the stock main spring.  The engine speed varies very much with load with the single uncaged spring just like the stock caged dual spring setup in fact it is almost difficult to tell the difference in performance if the rates match.  As I mentioned, the only difference is that the first part of the pedal (when the intermediate spring is being compressed) has a little less effect on fueling with the stock setup.  The driving experience is so similar that I really marvel that VW/Bosch went to the trouble of the dual springs.  It's similar to having the multiple accelerator return springs to give an imperceptible change to the feel of the pedal. 

[theman53]

I don't know what spring is in my cummins pump that I got off truckinwagen, but I hated it. All I know is he told me it was a single spring. The way it drove compared to my other pump was weird. Don't know if it would be the pump or the spring, all I know is I hated it.

[RabbitJockey]

That is not correct.  A single spring does not work like that unless it is a single spring with a rate specifically for that purpose.  With a single spring with a rate the same as the main spring in a dual spring setup, you will need to mash the pedal almost the same amount when you hit a hill.  The only difference with a dual spring setup is that the first part of the accelerator's motion causes less of an increase in fueling up to the point when the intermediate spring is fully compressed after which the performance is exactly the same. 

I'll add my $0.02 CAD.

The caged governor on our VWs is a min/max governor. It only effects the bottom and the top of the RPM range. In the middle RPMs, your foot is a direct link to the quantity of fuel injected into the engine. That is why you have to give it throttle to go up a hill. With a single spring, the entire RPM range is governed by that spring, therefore you do not need to give it more throttle to get up a hill. You may need to downshift depending on load though.
This is why you can't use a caged governor on a genset, it will not keep a steady RPM based on engine load.

I'd love to try an uncaged governor in a VW, I think it would net fantastic mileage once you get used to driving it. An uncaged governor can use multiple springs to help get off idle smoothly.

That was my understanding of it.  Libby is it only vanagons you have driven with a single spring?  Sae papers say they made the change because the drivability wasn't good in a small car which is obviously considerably lighter than a vanagon.  But mr Libby probably still has more experience with the 2 different set ups than anyone else,  like I said before I haven't ever even driven a cummins or anything

[libbydiesel]

I have only used the single spring in vanagons.  At some point I may try one in my rabbit, but it is a low priority (curiosity only). 

As far as what you guys are saying about the single spring is also how I understood the behavior from what I had read until I actually started experimenting with them.  There is a difference to the performance.  The first part of the accelerator pedal's movement has a more dramatic effect on fueling and the top part has less but it certainly doesn't create an instant pedal position cruise control.  I wish it did.