Engine build plan questions.

[Brian_e]

[jpaull]

[oprn]

Now that I am retired we are down from about 75,000 to 80,000 km a year to about 45,000 km. About 6 to 8,000 of that is in our street Buggy in the summer. The rest is in our Jetta TDI or the wife's 2.0 L Golf. The Buggy has the worst fuel economy at 28 to 29 mpg, the Golf next at 34 to 36 mpg followed by the Jetta at 54 to 56 mpg. This is all Imperial gallons so take 20% off that for US gallons.

Gas is hovering around $1.50 per liter at the moment so $6.83 a gallon. You can at least double the savings that Brian_e quoted. Realistically it will be about $2000 next year just for next summer at a 3 mpg gain.

My wife retires next spring and the plan is to spend our summers touring around western Canadian points of interest and between the our 4 children so the miles put on it will at last double, possibly triple. Mileage is not the only consideration, range is too. At the moment we are limited to 3.5 hours between fills. About the same as a Tesla! There are many places we travel that you are hard pressed to find fuel on that regular of a basis.

I deeply regret not putting a TDI in this Buggy when I switched engines. I did not because it would have turned it into a rolling junkyard from behind. I do have a line on an MG TD replica for sale. If I buy it I will sell the Buggy and the MG's 1500 SP and drop a TDI in the front out of sight.

We live in a different world than you guys do as far as expenses and distances travelled. So for those of us that drive these things there is a lot more to "performance" than knocking 0.3 seconds of a few 1/4 mile runs.
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Our cars get old, we get old but driving an old VW never gets old!

[58 Plastic Tub]

Brian is not building dragsters, he's building street engines and doing the hobby a great service by posting honest, real-world information. He's also 100% correct. The payback for building a milage motor is "never", because you're spending dollars to chase dimes.

Regardless, the best mileage I ever got with a T1 was a twin-plug, dry-sumped 2276 with 45 Dellortos -- it would do 30 mpg if the planets were all lined up.

But (and there's always a "but"), it was in the Speedster replica with a .93/3.44 final drive, top down, on an Interstate highway through the Midwest in the summer. I think having enough power to start with, keeping the engine in a good state of tune, and pushing something light and sleek down the road is where you gain the efficiency -- and I've stayed at a Holiday Inn Express so I know what I'm talking about.

Most guys building "milage motors" go through a lot of gyrations to build an underpowered lump with a weird cam, then throw a 009 and Kadrons on the result. Kads are a glorified pump sprayer for gasoline -- they have no real tunability in transition, no way to dial in anything more than, "yep, runs great as long as we spray enough fuel". If you get real carbs (Weber or Dellorto) and learn to tune them -- you'll pick up 5 mpg, almost guaranteed. A real ignition will make every bit as much difference as the carbs. The result will be power AND milage.

Regardless -- even with good parts, if you don't have a wide-band O2 sensor, you're just guessing

My contention remains -- if you want mileage, build a powerful and efficient STREET combination. Efficiency is power -- the idea is to burn all of the fuel (or as much as possible) and convert the heat into motion. Guys looking for mileage want a complete burn. Guys looking for power want the same thing. It's not either/or, it's both/and.

Most VWs have the aerodynamics of a brick. The only "free" place to pick up mileage is to make the car as aerodynamic as possible. Nobody thinks about that, but there's more to be gained there than anywhere else.
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Stan Galat
"A single point in isolation is a reference point. Two points is a line. Three points is a trend. Trends don't lie."

[oprn]

As far as what Brian_e builds and for whom I can't answer that but I do know that he does present some of the most practical advice on this site. Has he ever built an engine where the top priority is fuel economy? I will let him answer that one. That is the OP's top priority.

We all want more power. If anyone doesn't it's because they have never driven an air cooled VW in stock form. Can we have a sizable increase in power and still retain stock fuel economy in these 50 year old engines? That has been my goal and I am the first to admit that I have yet to achieve that. With Webers, crank trigger, wideband, gear ratio changes and lots of tuning and tinkering my mild street engine has gone from 18 mpg to the 28/29 region. That is still somewhat short of the 34 mpg my stock Beetle got back in the mid '70's.

I think there are two things standing in the way of achieving an engine with the best of both worlds. The first is the valve train. Any valve train that will give us a good kick in the butt at 6K RPM will have far too much friction and not be anywhere near efficient at a 2800 to 3000 RPM cruise. That is why I do not believe that a performance engine and a mileage engine are one and the same thing.

The second is what you stated 58 Plastic Tub, these old cars are just not aerodynamic enough.

The aerodynamics of a trike at 75 mph? I have no idea...
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Our cars get old, we get old but driving an old VW never gets old!

[Zed999]

A stock one doesn't keep up with the traffic, more oomph is required to stay safe. That's my start point, so getting more mpg is never going to be possible.

[58 Plastic Tub]

If we're talking about short-stroke, big bore engines running 009s and Kadrons through an EMPI Monza or similar -- then better mileage is 100% possible.

Use better carbs and a better ignition. Get a better header that's sized appropriately. Save your pennies and buy a wideband 02 sensor. Tune the engine.
_________________
Stan Galat
"A single point in isolation is a reference point. Two points is a line. Three points is a trend. Trends don't lie."

[oprn]

I cannot understand the thought process that justifies spending $6K to $8K on all the best and biggest engine parts, all the chrome bling and yet baulks at another $120 for a wide band to get it all running right. All that outlay of cash, a 009 is fine and 15 to 18 mpg constitutes a good tune!
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Our cars get old, we get old but driving an old VW never gets old!

[Brian_e]

[Zed999]

Over here, a lot of people will take it to a rolling road to get it "set up", but all they get is a main jet change and the knowledge that it won't burn a piston at WOT. Costs about the same as an AFR install.

To be fair, they're all camper owners who just want to be back on the road and go camping without breaking down (again) - that to them is success. They think breaking down is normal for an old vehicle, along with wobbly steering, poor brakes and a strong smell of petrol.

Not everyone buys an old vehicle because they like tinkering. I asked one of my customers once to point at the carb, he had no idea though his wife knew. They'd owned it for about 10 years and were on their 3rd engine.

[oprn]

I do understand to a degree why builders don't tune them. In my experience the tuning can take as much time or more than the building to get right. I am also convinced that you will never get it right until it is in the car and on the road.

I have been tuning a street Buggy for a local fellow, we found out who originally built it (2 owners and 6 years back) and I have since become friends with him. This fellow's hobby is finding the parts and building them to sell. He is presently working on #69. He gets them to the point that they run ok-ish around town. He told me he has become very fussy about who he sells to. They must have a clue about mechanical things and old VWs in particular before they buy. "The warranty stops at the end of the driveway because I have no idea how it is going to be driven and maintained."

I totally get that considering the way this one was (not) running when I looked at it for my Buddy and the aftermarket parts that had been slapped on. I have been sharing my struggles with him and comparing notes on what was done to it since he last saw it. It just confirms his conviction that there are a lot of people out there that should not own one.

I went through the same struggle with my own Buggy when I first bought it. It was advertised as ready to drive. Ya right! It didn't stall (much) and all the gears, lights (sometimes) and brakes (one grabbed) worked...
_________________
Our cars get old, we get old but driving an old VW never gets old!

[oprn]

Anyway, getting off topic. It would be nice to hear from the OP about progress on his trike project.
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Our cars get old, we get old but driving an old VW never gets old!

[oprn]

[Dusty1]