Almost 40 mpg in my 1966 Chevelle !!!
 

https://ecomodder.com/forum/attachme...7&d=1585010771

Today I did a mileage run in my 66 Chevelle and demolished my pre-project goal of 35 mpg.
I filled my tank at a gas station near my shop and drove to the marina where we keep our boat. I make this trip a lot from home.
My GPS speedo said I drive 74.54 miles round trip back to the same gas station. This is compared to a Google map that shows 37 miles each way so pretty darn close.
I refilled to the point of spillage when I got back and it took 1.891 gallons.
That’s 39.94 mpg!
Granted the drive was probably 90% highway at speeds between 65-70, but I’ll take it.


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Build thread, more pics: https://ecomodder.com/forum/showthre...lle-30678.html

What engine, transmission and differential is your Chevelle fitted with?

I have a 2013 LFX V6 out of a Camaro. 3.6L (217 ci) direct injected with 4 variable overhead cams. It’s rated 325 HP and connected to a 6 speed double OD auto trans. Rear end is 3.07 ratio with 26.5” tall tires. RPM at 70 mph is just under 1700 rpm.
The car weighs 3260 lbs with the tank full. The only aero is a front air dam under the bumper.
My best around town/highway combo before was 32 mpg so this was a big leap.

Good job, LS!
 

I was hoping you might see this exceed your expectations, but wasn't too certain! :-) Congratulations on the outcome. I hope you enjoy the car. With the transmission you're running, how does it do in terms of acceleration? (I'm not familiar with the torque and power curves of that powertrain.)

Makes me wonder to which extent the aluminium-block engine, also shorter than the old-school engines originally available when the Chevelle was new, might have affected the handling too. BTW was the transmission also sourced from the Camaro?

Torque must have been an option for this engine in 2013 and the original owner did not check the box. It drops a gear on the freeway if you try to accelerate at all.

The car is super light for a 66 Chevelle. The engine and trans are from the same car and are lighter and sit back as far as I could situate them.

During the same project I swapped out the entire suspension for Hotchkis with sway bars front and rear, 2” dropped springs all around and 2” dropped spindles in the front. I’m going to change out the rear springs for 3” dropped shortly.

It handles like a go cart. I also added 4 wheel disc brakes so it stops well too.

I believe I could have gotten to under 3000 lbs but I caved and added Dynamat throughout and a couple other things for comfort.

That's good. On a sidenote, have you never lurked about trying a transaxle just like some previous generations of the Corvette resorted to?

The engine/transmission combo I used came together with the ECM that runs them. It’s very difficult to run this engine without the trans.

A transaxle would have helped with the weight distribution but I probably would have lost two gears, both being overdrives.
I didn’t even move the battery to the trunk because I didn’t want 5 lbs of 2/0 battery cable.

It doesn't seem to have really been an issue. Just to remind, the Corvette C6 and C7 had a transaxle based on the same 6L80 fitted to the 5th-gen Camaro when equipped with a V8. I'm just not so sure about the possibility to fit 6L50 internals on the casing of a Corvette-spec 6L80.

I would venture a guess that a C6 or 7 transaxle cost multiple times more than I paid for my complete engine/trans/ECM/harness package with only 525 miles on it. These V6 engines are not in the “LS” price range.

And while I did have to build motor mounts and reshape/rebuild the K member, adapting a transaxle would have been beyond my capabilities.

Everything seems to be more expensive when it comes to Corvette stuff.

You'd be amazed at what many of these older cars can get. I went to a Pontiac Oakland Convention in the early eighties. I had a 1965 GTO Convertible with a stock 389ci, 3X2 bbl carburetor set up, four speed and 3.90 rear gears. BTW that center 2 bbl carb was pretty small compared to the end units. It wasn't that bad on gas as long as you didn't open up the other two fuel dumps. It had the aerodynamics of a cinder block, weighed around 3,500lbs and rolling on Bias-ply tires.

I got a hair over 19 mpg on my way up and back with the top down at 55 mph. I always wondered what I could have gotten with say 3.08 or even 2.73 rear gears in that car on the highway.

My buddy was working at a Chevy dealer at the time and drove his take home car a brand new 81 Z/28 automatic to the convention. He barely got 17 mpg on the exact same trip running the speed limit of 55 mph.

Beautiful! I’ve got a 1966 El Camino. Your build really inspires. Who did the engine harness?

It’s the factory harness out of the Camaro. I had a guy in NY modify the harness and ECM for my application. I would do the harness myself if I had to do it again. And I’d have the ECM done closer to home because it’s been UPS’d back and forth across the USA way too many times.

Alright, I'm impressed. This is a cool project and your results are outstanding.

A word of skepticism - I tend not to be very trusting of short fills, even if it's to the point of spillage. But even if it's 2-3mpg off (or more) those are still outstanding numbers.

Yeah, me too. It was 90+% highway at 60-65 mph. And the purpose of the trip was to maximize the mpg, so I drove like there was an egg under my throttle foot.

I have been getting 30-32 on full fill ups driving it as my daily driver, still more highway than in town.

I’ll do another all out mpg run of a greater distance soon.

That's quite impressive. Nice work.

Outstanding performance! Congratulations!

And that car is beautiful. It reminds me of a '63 Pontiac Tempest I had. It was powered by a 326CID V8, if I remember correctly, with a three-speed manual transaxle located in the rear. It ran very well, but got nowhere near your mileage.

The 1st generation of the Tempest was a really interesting design, even though some of its features didn't make their way into the following generation.

The only application I have ever seen of that transaxle used in a swap was in a Jaguar V12 into the front of a Corsair Monza.

If you want a fascinating read about a fascinating car and an even more fascinating guy, check out the build. Make sure you go through all of the pages...

https://www.corvaircorsa.com/V-12-01.html

I was lucky enough to meet Jay and drool over this car years ago.

Unbelievable, a 12 cylinder Jag engine installed in the front of a Corvair! Wow!

The fact is, my family also bought a '60 Corvair when they first came out, but it had the air-cooled opposing-six that developed all of 80HP. It was a two-door stripper model and didn't even have a heater! But it was a snazzy little car. I still have a Franklin Mint model of it on my shelf "just for the memories."

Our Corvair was a great car for this Class-of-61 Senior in high school, that's for sure. I'll tell Ralph Nader one thing: if that car had been the dangerous roll-over killer he claimed it to be, I must have been an outstanding driver. I used to run that little Corvair at pretty good speeds on curvy roads pretending to be Graham Hill, stiff-arming the steering wheel and all. The car gave no hint of being dangerous, and if it were really treacherous enough to warrant the abuse Nader gave it in his "Dangerous at Any Speed" book, I wouldn't be typing this today.

The only accidents I ever had in our Corvair were when a girl rear-ended me at a stop light on a wet day, and when I missed double-clutching it going into first gear while rolling around a corner, because the car didn't have synchronizers in the first gear. The only damage was a broken shear pin on the stick shift connection.

Incidentally, our very next car after we sold the Corvair was that transaxle Tempest I mentioned earlier. Both of those cars were kind of odd birds at the time. I talked my parents into buying the Corvair with threats that if they didn't, I would use my paper-route money on a second-hand, 500cc, single-cylinder Triumph motorcycle I was eyeing at the time and rode home for them to gasp over.

They probably saved my life, getting me four wheels instead of the two I wanted, even if it was Dangerous at Any Speed.

There was a Brazilian SUV named Gurgel Carajás which resorted to a transaxle setup similar to the early Tempest, but instead of some unique design it relied on a repurposed Volkswagen transaxle not meant to be mounted remotely from the engine.

Because Brazil. Their import laws and domestic production laws necessitated some weird tech evolutions (convolutions? contortions?) but you gotta admit, it was pretty cool seeing how they worked around the limitations.

https://upload.wikimedia.org/wikiped...raj%C3%A1s.jpg

I'm digging nearly 40mph out of a decades-old muscle car. Modernize the muscle and the results are pretty trick. And the all-disc conversion for getting the whoa on the ponies, that's just smart.

Brazil is still quite strange sometimes. On a sidenote, I have already seen some Gurgel Carajás converted to a more conventional solid rear axle, usually sourced from local Chevrolets such as the Chevette or the Opala. There were some complaints about the torque tube system fitted to the Carajás, but I never remember the reason.

https://4.bp.blogspot.com/-ZsBkdaOLW...640/rfwewe.JPG
justacarguy.blogspot.com/2016/09/have-you-ever-seen-tires-this-angled

Ralph Nader is no hero. He used politics to force General Motors back to the center of their lane. This is typical of the staged photos they used. Lifted suspension over a hill crest with an off-camber curve.

This is just great for that speed. For example: My 1997 BMW 523i E39 (2,5 r6 petrol engine with 170 hp, runs with E10) did about the same mpg at this speed - only changing the 3.15 rear axle to a 2.64 axle. Considering, it´s a fuel injected, relatively modern engine, this isn´t pretty low, compared to your chevelle.

Hadn't been for his defamatory campaign against the Corvair, I believe GM and even Ford and Chrysler would've had the chance to try different approaches in order to not only retain competitive in overseas markets, but also to get rid of that mindset stuck in the Model T era.

same gas station and pump correct? other wise it's not valid

Same station, same pump, about 6 hours apart. Still, it was a pretty short test.

Nice camber and caster the car has going on! My god, no wonder all of aftermarket suspension companies thrive.

The aftermarket suspension companies are out of control.

https://i.ytimg.com/vi/RnC0tPWoUUA/hqdefault.jpg
Extreme Camber Cars JDM Compilation Part #2

Like the political left, you need to know enough to quit while you're ahead.

All that negative camber looks so out of place.

[QUOTE=freebeard;644412]The aftermarket suspension companies are out of control.

https://i.ytimg.com/vi/RnC0tPWoUUA/hqdefault.jpg
Extreme Camber Cars JDM Compilation Part #2

That doesn’t look like aftermarket suspension. That looks like 5” wheel spacers and blow torched springs.

Wheel spacers I don't see so often, but I usually see some random econobox with blow-torched springs in my country. Even in neighborhoods where it would be supposed to not cope with the harsher conditions of the poorly-mantained pavement.

Hard to believe you got that sort of mileage, even with the newer drivetrain. Those old cars were not aerodynamic and were heavy.

But I'll take your word that you've accomplished it.

Damn, he must be buying new tires quite often.!!!

I’m 99% sure I got a good read on that one run. But as I stated before that was a specific run, driven like there was an egg on the throttle pedal, coasting for long distances, never going over 65ish.

My tank averages have been in the low 30’s which is still not bad. Not my goal of 35 mpg but I’m quite happy.

I’ve since added an air dam under the front bumper and am just starting to look at how I can block off a large portion of the grill (from behind so it won’t show). I would like to do a belly pan but that may be a ways off.

I consider my car pretty light for a 66 Chevelle. 3260 lbs with a full (20 gallon) tank is about 500 lbs lighter than most Chevelles of the era and about 750 lbs lighter than the 2013 Camaro the drivetrain came out of.

I’m also wheel shopping and the ones I have my eyes on will shed 25 lbs from the rotational mass. This can’t hurt.

yep, getting rid of rotational mass will help.

Pretty impressive fuel economy. Those Chevelles are nice cars.

I just wanted to say that your build is awesome, and somehow should be much more widely viewed. With the current world picture on fuel prices and everything else that's going on, magazines like hot rod and Car Craft Etc should be sharing information on builds like this 4 people who actually want to drive their cars rather than trailer Queens. As a person who really likes older cars as well, more attention to you're kind of good reality might help to interest younger people and keep the older car Hobby more alive in the future! It has always been frustrating for me to be involved in many cross-country trips, and rarely or ever see any older interesting car moving on a road at all!