Hypermilling on LPG

[pmiulian]

So, things have happened in the last 2 weeks. I got a SG - yeeeeii
And it turns out, it is all worth it. I already had a vacuum gauge installed, but the SG showed me that I didn't know how to use / interpret the vacuum gauge.
With a little SG, a lot of P&G and some DWL, it seems that I am going from a 27 mpg city driving, to an unbelievable 38 mpg city driving. Not 100% sure of that, but that's what the SG indicates. I just filled up the lpg tank and I'll have to wait for the next fill-up for the official numbers.
So all of this is city driving - I can't wait to get a chance to test it on the highway.
Great tool this SG - it does open your eyes on stuff that you thought you knew. Also, it's addictive

[pmiulian]

I did a 950km trip this weekend and I tried P&G on the highway. The car was fully loaded, but the FE was poorer than I expected. So I got 37MPG highway driving, using P&G, compared to the 38 mpg of city driving. This can`t be right. I`m doing something wrong.
I did use a full grill block upper and lower grill. And the speeds for my P&G were usually 40 - 60 mph or 45 - 65 mph.
Maybe I`m not accelerating as I should, or maybe the speed I use is to high.

[euromodder]

Originally Posted by pmiulian

This can`t be right. I`m doing something wrong.

Did you calibrate the SG first, using a few actual fill-ups ?

Maybe I`m not accelerating as I should, or maybe the speed I use is to high.

You should accelerate rather swiftly at a fairly high engine loading (LOD on the SG), say 75-80 %, using low revs - in the highest gear that the car can handle.
This puts you in the range where engines usually get their best BSFC, i.e. where most HP is produced for the gas being used.

[pmiulian]

I really don`t need to calibrate the SG. When I use it, I just target for the best FE ... so it doesn`t matter how wrong the SG numbers are, as long as they are consistent. Besides that, I have an additional lpg tank which the ECU doesn`t know of - so the SG will get data from the gas tank which is always full.

I think that my SG shows me the actual HP that the engine produces, not the % of power used. At idle I get LOD=2, and when accelerating I get LOD to 30-40.
From what I understand, the BSFC says that my engine ( 1.3 gasoline ) is most efficient between 1800rpm and 2200 rpm, so I try accelerating in this range. On highway driving, I get to 3000 rpm - that is the rpm for 65 mph.