Fuel Economy (yes i know.. wh0 cares about it?)

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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gt6-v8
Posts: 19
Joined: Wed Jan 02, 2008 11:38 pm
Location: United Kingdom

Fuel Economy (yes i know.. wh0 cares about it?)

Post by gt6-v8 »

Noob alert ! :-0

I've been running my Rover v8 with weber 500 (4bbl carb) for 300 miles now, and worked out i have no better fuel economy than with a distributor.

I haven't got around to connecting up the MAP yet, so am running on 2d only.

I'm wondering (back to basics) will MAP and remapping give me more mpg? or do i just trim back the advance a bit in all ranges?

currently 16mpg aint too good even on a 3.5 ltr.

People on rimmers site etc are claiming 25 with the same weber and a distributor.

cheers chaps.

KLAS
Posts: 93
Joined: Thu Oct 20, 2005 4:01 pm
Location: Germany

Post by KLAS »

yes, with connected MAP sensor you can get much better mileage at part throttle (assuming you full throttle curve is correct, if not tweaking it will help, too)

ggzilla
Posts: 20
Joined: Mon May 05, 2008 9:52 pm
Location: Seattle, WA USA
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Post by ggzilla »

I care -- it cost me $33 to fill up the tank today!

Yes, for sure. You need vacuum advance for best fuel economy. In general, more advance for more fuel economy. Just don't let the engine ping/pink/rattle/detonate.

I would think a well sorted distributor will give as good of fuel economy as MJLJ. But due to emission control and factory tolerances, not many do; you'd have to blueprint a distributor to be sure. Not to mention most 20 year old vacuum advance units are plain broken. With MJLJ, it's easy to reconfigure the curves.

mr_bridger
Posts: 52
Joined: Wed May 16, 2007 10:29 pm
Location: Coventry, UK

Post by mr_bridger »

$33?? man you dont wanna live in the UK!

my Celica takes £50 to fill up.... around $100 US

:roll:

price is currently about 115p litre (517p gallon) which is over $10 a gallon

Ross.

KLAS
Posts: 93
Joined: Thu Oct 20, 2005 4:01 pm
Location: Germany

Post by KLAS »

mr_bridger wrote:$33?? man you dont wanna live in the UK!

my Celica takes £50 to fill up.... around $100 US

:roll:

price is currently about 115p litre (517p gallon) which is over $10 a gallon

Ross.
i know what you mean

1,51€ per litre ...

gt6-v8
Posts: 19
Joined: Wed Jan 02, 2008 11:38 pm
Location: United Kingdom

Post by gt6-v8 »

cool,
Thanks all.
changed rods 1 more stage leaner today, will test this week.
3mm vacuum hose ordered now.

I'll be back when i screw up my ignition map later ;-)
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samco hoses now where the old ones are. and i even have an airfilter now! yaay
samco hoses now where the old ones are. and i even have an airfilter now! yaay
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