mr_blackstock
G'day,
I recently swapped over my old k-jet system with one I knew to be from a good setup, ie. my old car. i was hoping to not only cure the sick K-jet I had, but to drastically improve the fuel economy by doing the swap. well the swap went very well, the car is running great! idles sweet, good power, perfect.
but, the fuel economy is still very poor, I was getting 350kms per tank (just hitting the red) now I am getting 400kms per tank. I checked the cold start jet to make sure it was not still squirting fuel, it wasn't, I leaned out the K-jet until she was sputtering, then riched it up a little to get a good idle.
I am not sure where to go next, what would cause it to use that much fuel?
Cheers, Gareth
Angus242164
I used to get about 420-430km per tank with a K-Jet B23E with a manual trans with overdrive, so it's probably not far off the norm, and if it's an auto then I'd say it's probably normal.
If the ignition timing is right, the mixture is right, plugs, leads, cap and rotor are in good shape, air and fuel filter in good condition, no exhaust problems, and you have no vac leaks anywhere, then I'd say it's as good as it's going to get.
I think AJ gets pretty good economy from his mildly modded B23E 244, he might be able to comment further.
Philia_Bear
Unless manual and fresh engine 400km a tank is pretty normal
My 85 with a fresh b230e and m45 manual pulls down 500-550 per tank
Ive seen one with an m47 conversion get close to 650km tank as normal
Ive also seen a worn out b23e with a aw70 auto puĺing 300km tank in near all city driving with the aircon on
A_Volvo_Driver
I get about 350ks to about 40 litres. That's running k jet, m45 and a fun 3.91 diff
Ex850R
*drives like rally car?
Angus242164
240 tank is 55L, usually about 50L is usable, so your economy may not be as bad as it seems Scott.
mr_blackstock
G'day,
Thanks for the feedback everone, maybe I have rose coloured memories of my old 240's economy. I might try to perfect the timing a wee bit more and start running 91 octane.
Cheers, gareth
A_Volvo_Driver
No, I'm not complaining really. Since you spruced up the k jet it was been more efficient and more fun to drive. I usually fill up when the gauge gets to the red. At that point I've done about 350ks and it takes 35-40 litres to fill. I think my gauge is crap lol.
Angus242164
Fair enough Scott, the gauges are always pretty crap!
Gareth I've got grand plans to put a straight LPG setup on my 245L when I finally get around to that project, not sure if I'll end up doing it, but I did buy a brand new Impco 200 mixer recently when I found one for a good price.
The plan is to fit a donut tank from an AU-BF wagon under the floor in place of the fuel tank, and a clean-air Impco setup, which is very simple and easy to tune, and less prone to a lot of the issues other systems have. I'd run the Bosch ignition system usually used with K-Jet, and a K-Jet intake manifold. The engine will be a B230F bottom end with a 405 head and K cam, and an M47 box.
If LPG prices remain high, I might not bother, and just stick with K-Jet instead.
240Joe
Once the gauge gets to red you have at least another 100km, the needle actually goes a mm or 2 below red ...but once you get to that stage don't try and drive up a hill. Haha
I wish my 240 feul economy was as good as those listed. I've got some work to do!
A_Volvo_Driver
You need k jet bruh!
240Joe
I have one kjet and one LH2.4, both need some love!
mr_blackstock
I saw a second hand lh.2 on eBay for around $50. Is Lh.2 heaps more fuel efficiant? Or only moderately so? I reckon it would be too much hassle converting if the gain was minor, and k-jet has been good to me in the past.
Gareth
egads (she/her)
Not a big gain from lh2.2, maybe a bit from lh2.4.
A_Volvo_Driver
I run my car on 98 octane... That is supposed to make a difference
Angus242164
The higher the octane rating, the slower the fuel burns, which makes it less prone to pre-ignition (pinging) and means you can run more ignition advance, and more boost in turbo applications, before pinging occurs. This can give you a bit more power.
Running on lower octane fuel can actually give better economy (especially when the lower price per litre is considered), if the timing is suited to the lower octane (faster burning) fuel.
Given that the pre-unleaded B23E engines we're talking about were designed to run on "super" which was higher octane than 91, I'd recommend 95 octane. You should be able to drive the car pretty hard with the recommended timing settings on 95, and not have it ping at all, close to sea level at least.
I'm a big fan of the E10 95 octane fuel sold by United, it's cheaper than 91 octane fuel, doesn't contain enough ethanol to cause issues, and on these cars that aren't oxygen sensor equipped, it shouldn't use any more fuel than ethanol free 95 octane fuel.
Dauntless
Do you have any L/100km figures? It's difficult to compare if not. I normally get 350-400km per tank, but I'm only putting about 40L in at that point.
I average about 11L/100km with my 82 244. I run it exclusively on BP Ultimate 98 or United Premium 100, and ignition timing is turned up to suit, around 20 deg BTDC from memory.
213,000km on the engine, and running a H cam, extractors, free flowing exhaust, 3.73 diff and M45 gearbox. It sits on 3300rpm at 100km/h.
Given the price difference between octane ratings, you're usually better off adjusting the timing to take advantage of higher octane fuel, your economy should increase enough to offset the higher cost, and you get better performance.
Is your car manual or auto? Have you checked the items Angus suggested?
perko
400k's to the red sounds pretty normal for round town. my '84 gets 10L/100k round town, 7-8 on the highway.
350,000, m46 and could really do with a full service
mr_blackstock
I have been running all my vehicles on 95 octane for ages. I might check the timing next, and call it quits and be happy! I just finished tinting a full set of windows, yet to put them in yet, should look fully sick mate!
She is an auto, not sure what type of box she has though.
Cheers, gareth
Dauntless
I'm not sure if an 84 would have a BW55 or AW70, though I'm sure someone here will know. If it's a BW55 and you want to stay auto, it wouldn't be hard to swap in an AW70L. BW55s came standard with a 3.54 diff ratio, which you could swap for something shorter. This would give you better performance and economy.
