16 replies to this topic

[Spitz]

Recently installed an AA 1275 motor.
Seemed to get terrible gas mileage with the HIF6 so I swapped it out for an HIF4
Still sucky mileage.

~17MPG in town....with reasonable driving habits.

Plugs look good, AAM needle, clean paper filter in stock housing, brakes aren't tight, mechanical pump (checked sump..no smell of fuel)

Any ideas as to possible problem? Thanks

[rozzer1275]

I suppose that is US gallons?

as you say its running ok, cam timed good, ignition good, compression good, not too rich and there is no fuel leaks or drag probs.


I can think of only 2 other options

1 calculation/ reading error with your figure ie is the mileometer under reading?

or

2 (what i had when mine started getting bad economy) bed wetters on scoters nicking your fuel.

[Spitz]

I suppose that is US gallons?

as you say its running ok, cam timed good, ignition good, compression good, not too rich and there is no fuel leaks or drag probs.


I can think of only 2 other options

1 calculation/ reading error with your figure ie is the mileometer under reading?

or

2 (what i had when mine started getting bad economy) bed wetters on scoters nicking your fuel.

I'm in Canada....we use real gallons, not those funny pretend gallons the US uses.

Yes car seems to be running fine.
Forgot to mention....running a 3.1 FD also.

My mileage calculations were accurate.
(km travelled x .62 litres used divided by 4.5)

I imagine I will get better mileage on th hwy...but still not what one would expect.

[Ouster]

Do the exhaust fumes smell of petrol?

[Spitz]

Do the exhaust fumes smell of petrol?

One of the first things I checked Ouster.
After car is warmed up (ie: no choke) no smell of fuel.

I realize an AAM is a rich needle, but it's a 1275 after all running a 1.5" carb, alloy intake, LCB.

My hopped up 1130 with twin SU's gets amost twice the mileage.

Everything that I can think of points to a proper mix. Plugs look good, no fuel smell out the rear, the pipes not covered in soot. I havn't driven it with a heavy foot. Maybe I should next try an HS2 ! lol

I should also ad:
While I had this motor in another car last summer, I calculated it as getting 39mpg on the hwy (with 1.5 Hif4 carb it has now).
I did nothing to the motor during the swap..even same plugs, coil. Only thing I swapped out was a starter and altenator.

[dklawson]

Spitz, when you posted this on the MM board you used the same MPG figures. The last time I was in Canada, you guys used liters for fuel (not U.S. or Imperial gallons). So, if your figures were in Imperial gallons, you may want to add that to your MM post if you haven't already. 17 MPG Imperial is much worse than 17 MPG U.S.

For reference:
4.55 Liters = 1 Imperial Gallon
3.79 Liters = 1 U.S. Gallon

[Spitz]

Spitz, when you posted this on the MM board you used the same MPG figures. The last time I was in Canada, you guys used liters for fuel (not U.S. or Imperial gallons). So, if your figures were in Imperial gallons, you may want to add that to your MM post if you haven't already. 17 MPG Imperial is much worse than 17 MPG U.S.

For reference:
4.55 Liters = 1 Imperial Gallon
3.79 Liters = 1 U.S. Gallon

Yes I realize this.....see my post above.
Yes we are litres, as is the rest of the world (except the centre of the universe..lol)
It's always much easier to state mileage(kilometreage) in mpg however, rather than litres/100km. It's easier for the masses to understand and what most people use I think.

The US is I think the only place still selling by the gallon....and a smaller gallon than anyone else used.

Back to the issue.
I think on the weekend I will put a strobe on it and see where the timing is...I've not touched it though

[Nightrain]

Does anyone know the jet size in the HIF6 (1.75"SU) and the HIF4 1.5"SU), if it as as I suspect a 1 instead of the 0.9 one fitted in the HS4 this will be your problem.

[Spitz]

Does anyone know the jet size in the HIF6 (1.75"SU) and the HIF4 1.5"SU), if it as as I suspect a 1 instead of the 0.9 one fitted in the HS4 this will be your problem.

The 1.5" jets are .090" . Thats what the AAM I have in there is.

I think you can fit .090 needles in a 1.75 carb, but can't fit .100" needles (from 1.75") in a 1.5" carb.

[alicetheauto]

If the exhaust doesnt smell strongly of fuel then it is surely either burning it all to counter a resistance in the engine/gearbox/transmission/brakes, OR the fuel is not getting there in the first place? Blocked fuel pipe/sender/filter in fuel pump?

[dklawson]

Yes I realize this.....see my post above.

Sorry Spitz, I wasn't suggesting anything about what you'd posted on this board. I was only suggesting that you may want to add to the MM post that your calculations were in Imperial Gallons, not U.S. Gallons... since U.S. Gallons are what most those guys are going to interpret from your message.

[Spitz]

Yes I realize this.....see my post above.

Sorry Spitz, I wasn't suggesting anything about what you'd posted on this board. I was only suggesting that you may want to add to the MM post that your calculations were in Imperial Gallons, not U.S. Gallons... since U.S. Gallons are what most those guys are going to interpret from your message.

18mpg for a MINI is crap whichever gallon you use...lol

[alicetheauto]

I agree, I averaged 57.8 the other week over a 200mile run....

[tmsmini]

Do the speedo gears match the final drive? I am assuming they do as you used the motor in a different car with no changes. Are the speedos the same?

Terry

[Spitz]

Do the speedo gears match the final drive? I am assuming they do as you used the motor in a different car with no changes. Are the speedos the same?

Terry

Terry,
I hear you.
Speedo is off. I checked this with GPS. I do 107 indicated km, I have done 100km
I allowed for the difference in the two 100km trials I did.

(You know it's bad when you can almost see the fuel guage moving