Hypermiling a classic mini... help?

[drmiller100]

that seems to me pretty crummy mileage.

is your vacuum advance working correctly on the distributor? Is your ignition timing set correctly?

[HowGudAmI]

The car does get crap mileage, it should achieve high 30's (uk mpg) without particular effort. In terms of performance it does run well - which is odd given the poor economy (would think it would be rich leading to sluggish running when warm)

I should probably get it rolling roaded. Will cost me about £80 though which I don't really have

[jtbo]

Originally Posted by HowGudAmI

The car does get crap mileage, it should achieve high 30's (uk mpg) without particular effort. In terms of performance it does run well - which is odd given the poor economy (would think it would be rich leading to sluggish running when warm)

I should probably get it rolling roaded. Will cost me about £80 though which I don't really have

With our classic Volvos we have found out that petrol hoses go bad over time. Older cars usually have petrol hoses that are fabric covered, these can be deceiving, look fine, no apparent leaks, but they can be really badly shot while still working enough well to not cause any problems.

So if everything else checks out fine, then one have to check all pipes and hoses from tank to carburettor, if fabric covered are found, only way to really tell how they are is replacing them.

Also tank can leak and fill up pipe to tank connection can leak, that has been common with all older vehicles that have been running fine but just using lot of petrol.

Also checking that brakes are not binding is well worthwhile, lift car up and try to spin wheels and feel if they are spinning freely or not.

Older motors can also run quite rich without giving much of an issue, so exhaust analyzer test should be done to determine if mixture is within specs. One can adjust mixture without analyzer too, but I don't recommend that if lacking of experience, there is chance that by adjustment all looks fine, but it still is running rich, one needs to be able to do exhaust smell test to know that then.

Any leaks with carburetor are often compensated with richer mixture and masking real cause of issue, sometimes this is not very easy to spot at exhaust analyzer test either, but setting carb to base settings should reveal that.

These are quite general things, if you service car yourself, many things you will already know and are aware of current state and condition of vehicle, but if vehicle is new or if one is not very experienced with older vehicles, these should help a bit at least.

Also one thing to keep on mind is that old Mini was created when people were not so hurry and aerodynamics were left for aircrafts more or less, so speed can easily increase consumption greatly.

[yostumpy]

greetings fella. Firstly why have you called it a mini 'sprite'. never heard of that one, the Austin 'sprite ' was , as you know, the 'bug eye sprite', 2 seater soft top jobbie. just wondered that was all! So its basically a std 998 mini with big wheels? Do you have a single SU or twin SU's. Do you give it some welly around town, as that is poor mpg for a mini. You could block the grill, as there is no radiator behind it anyway. The underside is prob as smooth as you can get it really. Simple trick, try putting a stronger return spring on the throttle cable, so you have to push harder. You could double check the points gap, and dwell angle, then strobe the timing. Howz your air filter?. have you topped up the oil in the SU's plunger. Check your hand brake its'nt binding,/ sticking on. How are your MOT emmissions?

[HowGudAmI]

Thanks people !

Originally Posted by yostumpy

greetings fella. Firstly why have you called it a mini 'sprite'. never heard of that one, the Austin 'sprite ' was , as you know, the 'bug eye sprite', 2 seater soft top jobbie. just wondered that was all! So its basically a std 998 mini with big wheels? Do you have a single SU or twin SU's. Do you give it some welly around town, as that is poor mpg for a mini. You could block the grill, as there is no radiator behind it anyway. The underside is prob as smooth as you can get it really. Simple trick, try putting a stronger return spring on the throttle cable, so you have to push harder. You could double check the points gap, and dwell angle, then strobe the timing. Howz your air filter?. have you topped up the oil in the SU's plunger. Check your hand brake its'nt binding,/ sticking on. How are your MOT emmissions?

The Austin Mini Sprite was a 1983 limited edition - 5000 was the total production, half for Uk and half for export. They were either cinnabar red (mine) or a yellow color.

It featured 10" mini special alloys (same as the earlier 1100 special) - I don't have them on the car (12in revo's) but I do have them. It had a stripe down the side (not the one on mine) and 1275gt instrumentation (one of the only original bits left actually installed). There were other differences but they are not so on topic for this forum.

My car is a sprite but has lots of changes (restored 10 years ago - I acquired it 1 year ago) which has left it only on the original shell. The seats and wheels are in the shed though.


You have lots of questions - and the answer to all the ones about the cars condition indicate good,

As for my driving - it has been driven 'enthusiastically' most of the time. This tank I'm on at the moment is the first one where I have attempted to be conservative and adopt some coasting techniques and attempting dwl and p+g

[ecofreak]

Minis always seem to post good MPG, but when you get down and drive one, you drive it like a go kart and nullify any sort of MPG benefit.

Your best bet would be to really focus on driving technique. Neutral coasting and the like will cut through gas consumption, but so will soft acceleration and defensive driving.

I can guarantee you 5 MPG more than what you get at present if you so do a grille block modification (cover your radiator and give the car less drag area) and a full underbody pan. The good thing about a Mini is that you need less materials to accomplish these mods!

Happy Hypermiling,
ecofreak

[minispeed]

I also have a 78 mini race car, it was my first car and I have replaced almost everything on it. I have often though about doing a FE project on another mini but with our winters here and the rust problem I`ve stayed away. However if I had the cash I would by a fibreglass mini sprint pick up and build a hybrid. A series motor up front, 850cc and a plug in electric in back.

To start if you are going to change anything about the engine it's a good idea to read "tuning the A series engine" by david vizard, it's mostly for race but there is fuel economy tuning info in there too. A carbed mini should be able to do 50mpg UK at 70-80km/hr without any fancy aero mods or engine changes.

First thing I would recomend is to pull off the 12s and put back on the 10s. This will lower the unsprung weight and will use less gas to accelerate. Also if the 10s are 145 they will be more aerodynamic. The 12s do have a slightly taller gearing which would help if you do a lot of 50mph+ driving. Check out this site to see the RMPvsSpeed
Guessworks - Gearbox & Speedo Ratio Calculator You can probably sell or trade the revs and buy new 145s if you need them or if your 10s have 165s.

If you never use your back seat you can save a lot of weight by removing the seat covers and the carpet from that area. There`s also a lot of sound deadening material that in my opinion never did anything to make the car any more comfortable. I would recommend pulling up the front carpet taking all that out and putting just the front carpet back in.

If you are willing to spend money and spend some time playing around I would say invest in a megajolt. This will eliminate your distributer, points and coils and replace them with an updated electronic ignition from ford. You can buy all the parts for around $200 USD, the mini forum will have a lot of into on it and for a mini specific sensor seeA Series Crank Trigger Kit - Detailed item view - Specialist Components Online Shop I have a lot of their parts, including this sensor on my car, I just haven't got around to wiring up the mega jolt yet.

One part I would avoid is any kind of cheap LCB header or exahust system. After reading a lot I pulled my large diameter system off and replaced with a maniflow medium bore LCB header and an RC 40 side exit exahust. It's a lot quieter, but test after test has shown that the mini 5 port engine responds very well to this exahust and will develop more low end grunt with it.

I would be very careful of doing a grill block because of the side mounted radiator. However that means that basically the non radiator side of the grill is useless for cooler. Minis have been known to benefit from ducting air from the grill to the radiator. All this hot air then needs to escape through the side of the car, usually through the wheel well so allowing it a quick easy exit will mean you can block off more of the front grill and accomplish the same level of cooling. Also the fan is reversed from the optium direction as it pushes air instead of pulling it. A front mount radiator with an electric fan will improve FE.

Try building a plastic air dam to stop the air from going under the car, but also be aware the fins on the transmission are made to cool the oil so you would want to add an oil cooler to compensate.

If you have an SU you should also be able to play around with different needles for pretty cheap and lean out the mixture. The SU is a great carb, I just bought one this winter after years with the webber 45.

[HowGudAmI]

Thanks once again.

I am pretty clued up on a lot of the stuff you are saying non FE related - I frequent TMF.

My car has a 3.44:1 FD which gives 4081rpm 70mph real speed.

It would be uneconomical for me to change the wheels to my 10's - as the tires are done for on them. So would have to buy a set.
Luckily my car has 7.5inch cooper disk brakes at the front so If I ever needed to change it would be easy (the 8.4in disks are not compatable with 10's - the 7.5inch disk brake was the smallest ever at the time specifically for the 60's coopers I believe)

[minispeed]

Originally Posted by HowGudAmI

Thanks once again.

I am pretty clued up on a lot of the stuff you are saying non FE related - I frequent TMF.

My car has a 3.44:1 FD which gives 4081rpm 70mph real speed.

It would be uneconomical for me to change the wheels to my 10's - as the tires are done for on them. So would have to buy a set.
Luckily my car has 7.5inch cooper disk brakes at the front so If I ever needed to change it would be easy (the 8.4in disks are not compatable with 10's - the 7.5inch disk brake was the smallest ever at the time specifically for the 60's coopers I believe)

I the 8.4" disc and wish I had the smaller one for weight and to go back to 10s. My 13s are way to tall and heavy so I really need to get a set of 12s. Are the 10s 145 tires? If so it would prob be worth a shot to switch them just to do a FE test run.

[some_other_dave]

Note that in some cases the taller gearing from larger wheels and tires more than makes up for the extra weight and frontal area. There's a thread around here somewhere about a guy who put very large wheels on his Scion xB and saw a very noticeable increase in highway MPGs without much if any loss in the city. (Part of which I assume is down to driving technique.)

Testing would tell you which is better, but that would cost some money for the new tires for your small rims...

-soD