Operating your TR for maximum mileage

[angelfj1]

The early sidescreen cars boasted mileage in excess of 30 mpg. Considering the price of gasoline today, how about some suggestions for maximizing mileage. I'll try to get this kick started with a couple of recommendations.

- maintain rated tire pressure.
- remove all unnecessary "cargo" from boot.
- accelerate and decelerate slowly.

It would be interesting to hear what mileage you get now and then after you try some of the posted recommendations.

For you tuning experts, how would we modify the recommended tuning specs to achieve maximum mileage?

 

[Guest]

Al Gore. Is that you sneaking around BCF using Angelfi's name?

 

[TRDejaVu]

- accelerate and decelerate slowly.

Frank, firstly this is not meant as a flame.

Back in the day in the olde country, if people wanted a car for practical transport reasons (the majority) they would buy a basic Ford, Vauxhall or Chrysler family car. Most of our LBCs were designed as sports cars, not an old version of the Prius. Do your suggestion above and there goes a big part of the fun factor (the cars aren't fast, but the whole visceral feeling of them makes you think otherwise).

If this sort of car was my daily driver I could understand it, but most of the time they are used for a couple of hours of entertainment at the weekend. If people can't afford the difference in gas costs between doing the weekend drive in the LBC vs. a modern fuel efficient car then they probably have other more pressing financial issues to take care of before an LBC.

It would probably be dangerous using hypermiling techniques with our LBCs.

 

[DougF]

There isn't a whole lot beyond what you mentioned, tire alignment. Some tires will help with mileage over others.
I'm thankful that I don't have a big block street rod that gets a whopping 3-6 mpg like the fellow down the street. How much is racing fuel selling for these days?

 

[Andrew Mace]

Ian's probably correct about buying habits in the UK "back then"; however, I think it was somewhat different in the US. I have no data to back it up, but I suspect that a great number of "sports cars" sold new in the US were used as daily drivers -- second cars or commuter cars. It certainly was true in my family. Yes, we started in late 1958 in a Triumph 10 as dad's commuter and migrated to a Herald in '64, but that was followed by a Mk3 Spitfire and then a GT6+, both used (like the cars before them) as commuters as well as for weekend rallying and autocrossing. And when I got my first TR3A in '72, it wasn't much to look at, but it also served well and long as a commuter car! Here in the rust belt, that's probably why so relatively few of these cars survived: they were driven until they wore out or rusted away!

Until the late 1970s, when I started using old Volvo 140 series cars as winter beaters, the only car I "babied" and stored in the winter was the 1951 Chevrolet that I inherited from my great aunt in North Carolina!

 

[PeterK]

Accelerate rapidly to speed, then coast.

 

[JodyFKerr]

This is why I enjoy driving my mum's spitfire. I can drive it like a maniac (at least up to 65mph) and it uses so very little fuel that even my lead foot easily gets 30+ mpg. It's got me sorely tempted to pick one up for myself.

 

[tdskip]

Not LBC specific but you'd be surprised how much over a tankful this will save - don't race to the stop light.

If it is red or turning red just coast until you get there provided you aren't causing traffic issues behind of you. Seems like everyone, down here at least, accelerates to the red light, slams on their brakes in the Escalade, waits, then slams on the gas when it turns green.

Saving a non-renewable resource doesn't strike me as left/right/center, just seems smart.

 

[waltesefalcon]

I used to drive my 1500 as a daily driver for about 4 years. My current MKII has never been used as such, mostly because I have never driven it with the windshield on it. However that said it does get fantastic mileage with it off.

 

[Don Elliott]

Frank - On a trip from Hamilton Ontario to Montreal (all night trip about 1963), I got 43 miles to the Imperial gallon. I have overdrive. There was no traffic on the 4-lane 401 Highway that night and no gas left in the tank when I got home in the morning.

About 1959 or 1960, I entered my 1958 TR3A in a "gas-mileage" competition and got over 50 miles to the Imp. Gal. or 62.5 Miles/US Gallon.

All I did was lean down the carbs, inflate the bias ply Dunlop Gold Seal tires to 45 PSI, accelerated slowly and turned off the engine in neutral any time there was a slight downhill or a long straight road until the car was almost at a stand-still. Then I'd drop the clutch in 4th gear to re-start the engine. Oh - yes - I never took it over 1500 RPM and tried to stay as long as I could in 4th overdrive.

A TR2 with overdrive won because of the smaller SU carbs.

 

[Monkeywrench]

Vacuum gauge. Drive to keep the vacuum as high as possible.

Tune the motor. Get a wideband AFR guage and become "one" with your carburetors. Get on a dyno. Where the timing is ideally set and your jetting/needle specs is where the engine is most happiest and efficient. These engines are happiest around 12.8-13. You might be able to get away with going leaner. BUT and a big BUT, BE CAREFUL, as you will be treading with detonation. This isn't something you want to be doing if you're new at this. Even then, you will have to be on top of it at all times. Fuel type, and engine specifications (head work, compression, piston design, etc.) will dictate your ideal timing.

If you have an aftermarket temperature gauge, experiment with blocking the grill off. Don't trust an oem gauge.

Tire pressures and alignment is a big one. 0 toe up front is ideal.

Make sure your brakes aren't dragging at all. Drag the car down the driveway with a fish scale to measure improvements in rolling resistance. This is how top racers do it.

Synthetic fluids/grease in the transmission, rear end, and wheel bearings.

Accelerate a little quicker, but not too quickly. You'll burn less gas maintaining a speed versus accelerating over a long distance.

Drive for momentum. Acceleration is what burns excess fuel. Back off coming to red lights, the less you have to accelerate back to speed, the better.

Keep the soft top up at speeds over 40mph. This will make a big difference.

 

[tinman58]

I just did a 226 mile drive to Half Moon Bay and up the coast with our Tr club, and the last thing I cared about was the gas milage. $4.09 a gallon for the good stuff in Sausalito.

 

[Andrew Mace]

Saving a non-renewable resource doesn't strike me as left/right/center, just seems smart.

 

[glemon]

We did a fuel economy run in my club last year, I organized it, we only had 4 people show up (typical driving event gets maybe a dozen to 30 people). So I guess there are not many who think fuel economy in an LBC is fun.

I drove my wife's Honda fit, which was soundly trounced by a midget, a spitfire, and an MGB GT with a v-8 in the MPG race, don't remember all the figures, but the brit cars did quite well, we probably didn't drive far enough (about 50 miles) to get very accurate readings, as the Spitfire guy got about 60 MPG top up to top up.

Anyway, the other MPG trick is to make sure your mixture is lean enough (but never run too lean). I think a lot of cars are tuned a little on the rich side becasue of fear of burning exhaust valves and faster warm up, but leaning out the carb adjustment can help the MPG. I got slightly over 30 mpg with my TR4A on a trip years ago. TRs are good MPG cars for a stone age 2 litre motor.

 

[booley]

try skipping gears, first to fourth. i believe some of the standard shift corvettes did this automatically to help meet the CAFE regulations.

 

[TR3driver]

Couple more things:

Inflating tires well beyond the factory recommendations will improve mileage. May shorten tire life and/or worsen handling though, so some experimentation is in order. I find that the sidewall maximum makes a good starting point, then back off if you see unacceptable wear in the center or the car seems too "jittery".

The TR3 workshop manual has an interesting graph of BSFC (brake specific fuel consumption) that shows the engine is actually most efficient (least fuel burned for power produced) at about 2500 rpm and 3/4 load.

But I'm much more into "smiles per mile" than worrying about "non-renewable resources". After all, if we don't burn it, the Chinese will. For sure it's not going to get left in the ground.

And if you want really good fuel mileage, ride the trolley/bus/train. Practically any form of mass transit beats any form of personal transportation.

 

[69tr]

On my '69 with overdrive I got around 27mpg on the highway..I didn't check it around town.

I hope it does as well when I finish rebuilding the engine and get it back on the road.

 

[sail]

- accelerate and decelerate slowly.

In a sports car?

 

[angelfj1]

Vacuum gauge. Drive to keep the vacuum as high as possible.

Tune the motor. Get a wideband AFR guage and become "one" with your carburetors. Get on a dyno. Where the timing is ideally set and your jetting/needle specs is where the engine is most happiest and efficient. These engines are happiest around 12.8-13. You might be able to get away with going leaner. BUT and a big BUT, BE CAREFUL, as you will be treading with detonation. This isn't something you want to be doing if you're new at this. Even then, you will have to be on top of it at all times. Fuel type, and engine specifications (head work, compression, piston design, etc.) will dictate your ideal timing.

If you have an aftermarket temperature gauge, experiment with blocking the grill off. Don't trust an oem gauge.

Tire pressures and alignment is a big one. 0 toe up front is ideal.

Make sure your brakes aren't dragging at all. Drag the car down the driveway with a fish scale to measure improvements in rolling resistance. This is how top racers do it.

Synthetic fluids/grease in the transmission, rear end, and wheel bearings.

Accelerate a little quicker, but not too quickly. You'll burn less gas maintaining a speed versus accelerating over a long distance.

Drive for momentum. Acceleration is what burns excess fuel. Back off coming to red lights, the less you have to accelerate back to speed, the better.

Keep the soft top up at speeds over 40mph. This will make a big difference.

Bob, these are great points. AFR = air-fuel-ratio, is that correct? How would this be done?

The soft top improvement is due to aerodynamics, I assume. Would a hardtop be even better?

 

[TRTEL]

This has been a fun string to read, because it reminds me of the mileage runs like some of the folks above have discussed. And of my mentor(who raced and was a tool and die maker) and who constructed the most complicated triple carbuerated TR3 ever when horror of horrors Super Shell started to edge towards a buck. I wish I had a picture, but all I can remember is that he removed the balance tube on the standard TR3 manifold and shoehorned in a micro SU attached to a custom (of course)induction tube. All operated by a true Rube Goldberg, but flawless in operation, horribly complex bell crank system. He could switch carbs by the choke pull. But as I remember for all that work it only resulted in a modest improvement, maybe 10% at most.

Tom Lains
TS's 8651 & 58107