[Healeys] fuel consumption

[WILLIAM B LAWRENCE]

I suspect a bust either in your measurements or your math. Doubling the fuel consumption would necessarily entail an extremely rich mixture, assuming the fuel is not going somewhere else than the combustion chambers. An imperial gallon is approximately 20 percent larger than a US gallon so your conversion would seem to be backwards. Are you sure you were not measuring US gallons in which case your imperial mileage would be closer to 12 mpg. Still not good but more logical. At this point I would throw out  the existing data and start over.

Bill Lawrence
BN1#554
________________________________
From: Healeys <healeys-bounces at autox.team.net> on behalf of Bob Spidell <bspidell at comcast.net>
Sent: Sunday, July 3, 2022 3:17 PM
To: healeys at autox.team.net <healeys at autox.team.net>
Subject: Re: [Healeys] fuel consumption

A friend and I used to take a long road trip--up to 5,000 miles--in my BJ8 every year for over 20 years. He checked our mileage at every fuel stop--useful if your gas gauge goes on the fritz--and I checked the odometer against the roadside markers (it was spot on). Through three engines the mileage stayed very nearly the same: 15MPUSG in stop-and-go city driving, best I got was 25 on 'slow' (55MPH), flat highway driving (eastern Oregon, when the troopers used to enforce it) and at freeway speeds (70-75MPH) I got around 18.  When I went from the 3.9 rear end to a 3.54 I expected a mileage 'bonus,' but at most I got a tenth or two better MPG.

29.6 miles per USG is extraordinary; these conversations come around every few years and no on ever claimed much more than I was getting.


On 7/2/2022 8:48 PM, m.g.sharp at sympatico.ca<mailto:m.g.sharp at sympatico.ca> wrote:

Hi listers,  As you might recall, I just had the engine rebuilt on my BT7 last year.  I only have 670 miles on it so far.  My fuel consumption seems exceptionally high.  I have just checked on one fill up, and need to repeat to be more certain, but on the last tank I got an awful 10.1 miles to the Imperial Gallon (14.8 miles/US gal).  I used to get about double that.

I have checked the tune on the carbs using the usual method and checked it with a quick plug check (I have yet  to do a proper plug chop), and if anything I think I am running a bit on the lean side.  The exhaust seems good, just rich when the choke is on, however the engine does “hunt” a little when at idle.  It runs beautifully otherwise.  No fuel leaks at all.



My questions:  1) what are others getting for fuel consumption? And 2) any thoughts on how to improve it?



Thank all - Mirek


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/healeys/attachments/20220703/bc35f0d3/attachment.htm>