bay kombi economy theory
tomnseals - June 17th, 2006 at 06:41 PM
Hi all,
I've been looking at the original kombi sales brochures on The Samba WS - a great and interesting resource, and found that my 2L kombi - newly
rebuilt - is getting around the recommended factory mileage around town and on the open road. The problem is that the factory mileage is crap - 15 -
18mpg around town and a more acceptable 25mpg on the open road. I'm comfortable enough with the highway mileage but not the around town mileage.
It's well set up, I've been picky about which mechanics I use, over several years of Vdubbing and the guy we've got is good, and he's been over it
a couple of times. Valves, points, timing, carby setup, the works. What's more, I've canvassed this with plenty of bay kombi drivers and their
figures vary not much, except for the few who claim to get up to 26mpg around town.
I haven't been through a tank of fuel on this theory yet but here it is:
The gear ratios aren't made to drive in fourth at 60kph. Third gear is plenty for around town.
I base this on the factory mileages for Splitties. They got up to 30mpg around town according to sales figures - and according to accounts from
friends who have owned the originals. There is nothing particularly heavy about kombi bodies that buggers up the power/weight ratio. It's just the
gear ratios in the later buses that doesn't work around town in a conventional manner.
I'm kind of crapping on now, but ... has anybody tried this?
Cheers,
Tom
bus914 - June 17th, 2006 at 06:54 PM
you shouldn't compare fuel economy of twin carby 2L kombies to single carby, single port 1200cc splitties. the difference is power. power = fuel
consumption. in a 2L kombi you can keep up with traffic. in a splitty you wouldn't even try.
[ Edited on 17-6-2006 by bus914 ]
Vw nutter - June 17th, 2006 at 07:11 PM
u mean only just keep up with traffic with a 2ltr kombi, and dont even mention hills!, but overall is ok
bus914 - June 17th, 2006 at 08:01 PM
hills are no problem, 4th gear all the way. (even Mt. Ousley).
1303Steve - June 17th, 2006 at 08:30 PM
Hi
Were those figues is US gallons? They are different 1 gallon [Canadian and UK (Imp)] is equivalent to: 1.201 US gallon.
A big factor in highway consumption is speed, keep it around 90kph and you will get better consumption, but lots of hand signals from other
drivers.
Steve
rocknrob - June 18th, 2006 at 07:47 AM
"The gear ratios aren't made to drive in fourth at 60kph. Third gear is plenty for around town."
I totally agree with this. recently put 225/60/16 tyres on and 4th is needed even less around town. 1st 2nd and third became very usable
gears...changed the whole car to drive for the better...don't know about the fuel but it is probably better.
tomnseals - June 18th, 2006 at 10:53 AM
| Quote: |
Originally
posted by 1303Steve
Hi
Were those figues is US gallons? They are different 1 gallon [Canadian and UK (Imp)] is equivalent to: 1.201 US gallon.
A big factor in highway consumption is speed, keep it around 90kph and you will get better consumption, but lots of hand signals from other
drivers.
Steve
|
It's hard to tell the figures from one to the next. If I read it right the figures quoted are imperial gallons.
I have no particular beef with my highway consumption. On one trip, sitting between 90 and 100kmph I managed to average 450k per 50L tank, which is
fine by me. That's enough keeping with the traffic and enough economy too ... little enough gesticulation 
tomnseals - June 18th, 2006 at 10:55 AM
| Quote: |
Originally
posted by rocknrob
"The gear ratios aren't made to drive in fourth at 60kph. Third gear is plenty for around town."
I totally agree with this. recently put 225/60/16 tyres on and 4th is needed even less around town. 1st 2nd and third became very usable
gears...changed the whole car to drive for the better...don't know about the fuel but it is probably better.
|
Hi Rob, I like your tyre idea too. Will try that out next time around!
tomnseals - June 18th, 2006 at 11:02 AM
| Quote: |
Originally
posted by bus914
you shouldn't compare fuel economy of twin carby 2L kombies to single carby, single port 1200cc splitties. the difference is power. power = fuel
consumption. in a 2L kombi you can keep up with traffic. in a splitty you wouldn't even try.
[ Edited on 17-6-2006 by bus914 ]
|
Actually I'm comparing single port 1500 and double port 1600s (both T2) to T4 engines generally. The chief point I'm debunking by the comparison is
the often stated theory that kombis can't be economical primarily on account of their wind drag and because of the power weight ratios.
Ok, so the power weight ratio changes a fair bit when you jump from T2 - T4 ... but my concern is with around town driving and differences in mileage
there.
DoNkEy - June 18th, 2006 at 11:59 AM
what's a mile? or a gallon :P
I never was taught these measurements in school.
I am happy if i get 10km\L with the 2L
tomnseals - June 18th, 2006 at 08:35 PM
| Quote: |
Originally
posted by DoNkEy
what's a mile? or a gallon :P
I never was taught these measurements in school.
I am happy if i get 10km\L with the 2L
|
A mile = 1.6km
An imperial Gallon (UK) = 4.5L
An US Gallon = 3.8L
I've tested the theory on my last tank and I'm getting 25mpg (imperial) = 9km/L around town now that I'm staying in third. The theory, for my part
(and in the absence of further and more rigorous testing) seems to work very well. I was getting between 6.5 and 7km/L = approx 17 - 19mpg previously.
As we've sold our Subaru for the kombi I'm pleased to be getting better around town mileage. However, I still am very taken with Rob's lower
profile tyre idea and I think I'll change to lower profile tyres soon as I need newbies anyway.
Cheers all,
Tom
Chewy - June 18th, 2006 at 08:44 PM
So whats your theory? Dont lug the engine? Use third where you would usually change into 4th?
Cheers
tomnseals - June 18th, 2006 at 09:09 PM
| Quote: |
Originally
posted by Chewy
So whats your theory? Dont lug the engine? Use third where you would usually change into 4th?
Cheers
|
Thanks for your generous take on this.
It was conterintuitive to me not to change into 4th at around 60. That's what I've done driving every other vehicle I've ever driven and it's
worked fine.
It seems to me that to get significantly good around town mileage is a fair achievement - very few other bay kombi drivers get this around town - and
VW published crap performance figures when they were new.
Cheers.