A case against pulse and glide

[GeekGuyAndy]

I drive the same vehicle on the same trip for 5 round trips a day now as a shuttle service for my college. Up until last week, the best FE I could get was 26.5mpg, and I could do it consistantly. I tried EOC a few times and was able to get 29.5mpg, which seemed resonable also.

But then I stopped doing pulse and glide and tried driving with a constant throttle, at 10% most of the time, and 15-20% on hills when needed at 3 points. With that, I was able to get 28.5mpg regularly, and 32.5 with EOC.

So that means that without using P&G I gained 7-10% gas mileage! I'm going to try out several different throttle percents over the next week and see what works the best, but I don't think that I will be using pulse and glide like I used to anymore.

I thought P&G was supposed to be more efficient since the engine is running at a more ideal speed, but apparently that's not the case. Does anyone have ideas? Can anyone with a SGII try this and tell me their results?

[omgwtfbyobbq]

I'ma guess automatic trans. area not good for P&G, and not enough throttle on the pulse.

[skewbe]

Confirmed. Best I could do around town with the auto saturn was like 40 w/p&g, when I put the stick shift in there I could get 60 no prob.

This really is a case against automatic transmissions if you ask me.

[GeekGuyAndy]

It's a Chevy Venture van, automatic, 3.4L.

I'm just surprised how much I read about P&G but no one talks about just constant driving. I guess automatics are the minority here though

[2TonJellyBean]

Phew... I had found the same thing. Once into top gear and especially when the TC locks up, DWL has been better for me than P&G. I was just blaming my poor P&G technique.

[skewbe]

Not in the minority certainly in the US, only 10% of cars sold were manual transmissions in 1998, and a lot of those were sports cars. We haven't been real serious about MPG here in the US.

[cfg83]

2TonJellyBean -

Originally Posted by 2TonJellyBean

Phew... I had found the same thing. Once into top gear and especially when the TC locks up, DWL has been better for me than P&G. I was just blaming my poor P&G technique.

We should be more clear on that. Maybe this distinction needs to go into the FAQ/driving tips section.

EDIT : i.e. the distinction that P&G may not be appropriate for automatics.

CarloSW2

[bowtieguy]

i too have an auto V6(3.8). not convinced of pulse and glide, but i do just glide on the last mile home, getting of toll roads,etc.
preliminary results good so far.

[northboundtrain]

I think there are significant inefficiencies in accelerating with an auto. The torque converter does not transmit energy as effectively as a clutch. As 2Ton said, keeping the TC locked up is probably best for an auto.

[rh77]

I don't really P&G often with either auto car in the Garage. Most of the time, my P&G involves EO-coasting down a hill at highway speeds, slowing due to drag, and starting back up at about 5 mph under the speed limit.

DWL on hills can be argued as a form of P&G, I suppose...

RH77