Wednesday, September 10, 2014

Lie to Me

It is with a sick feeling in my gut and a bitter tang in my mouth that I write this.

I've been had. The VolksarU 0.1 design, as described here over the last 18 months, is not sustainable. In short, if you've been pursuing a solution based on the VolksarU 0.1 work to date, you're in the same hole I'm in: Wasted time, skull sweat, useless products, squandered money, and hours of my life that I'm not going to get back.

It is the hours that I'm the most pissed about, because they're the only currency that matters. You get a certain number of them when you're born, and like a unmarked gift card, you redeem its value one heartbeat at a time without ever knowing what the balance is left on your account. When you run out, you're done. Kaput. So I resent the hours lost more than anything else.

So I'd better define 'not sustainable.' The reasons that I started down this path, not just of a liquid cooled engine but of the dual, in-bay radiators were numerous:

  • In-bay offered more protection
  • In-bay leveraged the use of common stock VW components that are still in production
  • In-bay leveraged the cooling intake already built into the body of the T2B (73-79, aka 'Late Bay') 
  • In-bay offered the greatest potential for an inexpensive solution that could be accomplished by the owner/operator with only common home tools and very few inexpensive, specialized services.
  • Most of all, in-bay had several 'worked examples' which advertised themselves as 'working solutions.' So in-bay was prior art and not especially innovative. Making the installation simple was what required the innovation, and that's what I set out to do with VolksarU: make it simple.

Instead, I've been had by builders who have done in-bay installations, crowed about it to the world, put up videos, shown off their work in pictures and forum threads, and claim 'it just works!' The most important details were left out: What are your coolant temperatures? At what speed? What fans are you running? How much are you running your fans? Under what load? At what mph? What RPM? What gear ratio and final drive? Early bay with small intakes, late bus with large intakes...etc? There's a saying in science: If you can't explain it using numbers, it is opinion, not data. Or put another way, (this one's mine) "anecdote is not the plural of data." So lots of chest beating out there, but damn little data.

This is common among whirly-gig shade-tree mechanics: Make it work just well enough to say "It runs! It's Miller Time!" This makes engineers scream and start pulling hairs out of the back of their hands. The blame is shared: The shade-tree mechanic over-represents the work and the claims are accepted at face value by other "shadys" and by a few engineers who unwisely let the contagious optimism get the better of their natural pessimism.

There's a saying that has been around in various forms since the 18th Century (and probably longer) that sums up this Murphy's Law-esque phenomenon: "Never blame intentional malice for what is more likely unintentional carelessness." I'd say that sums up what's happened here pretty well.

What caused this fiction to topple was when D.W. in Connecticut (who I'm acquainted with and who does dead clever fab work that would make NASA proud) finished restoring his 1970 low-light Bus, did the dual in-bay VolksarU 0.1 style installation: and VoilĂ , Instant Overtemp Conditions! When he properly started asking the engineering questions, some facepalm inducing facts came to light:

  1. No one had built a test harness to see what the true temperature in the engine bay actually was.
  2. No one had instrumented what the coolant temperature differential (the ability to cool) was under various scenarios. No one at all.
  3. No one actually knew how often their fans were running.
  4. Critically, there are no worked examples capable of sustained freeway speed without overheating. (There are reasons for this, which I'll get to.)
  5. But most important, until D.W. 'put his hand up' publicly to report the design failure, no one who had spun these tales of inexpensive functionality had ever reported 'what the final results were.' Not one of them. (Though props to BoxerMick in Colorado, who was discovering and truth-telling the limitations of his installation about the same time (August 2014) that the rest of this all came to light. To date, he's still running at temperatures that would cause a production engineer to give a thumbs down for running without a safety margin.)

All of the shadys eventually justified their half-truth one way or another: "It's good enough for in-town driving."  "I drove mine cross country!" (And your engine blew up less than 6 months after you got to your destination, a fact you failed to report until someone ratted on you.) The haters & purists (which are usually synonyms) came out in force to laugh and make personal attacks...against those who had uncovered the fraud! These are the types of detestable vermin who cheer when someone fails.

Viewed in retrospect, there are several show-stoppers, all of which are addressable if you spray enough money at it. So if you've been following VolksarU as 'cheap speed,' then you missed the whole point the first time around. Stamp 'CHEAP DREAMER' on your forehead and then go back and read the FAQ, specifically the part about priorities: Reliability, Cost Control, DIY Friendly and Longevity.

The VolksarU 0.1 design fails for the following reasons:
  1. A Subaru 2.2L engine / transmission pair makes 65MPH for 2700RPM in 5th gear. The VW engine / transmission pair makes 65MPH for 4200RPM in 4th gear. We have a fundamental collision of assumptions here. If you're turning a Subaru at 4200RPM for mile after weary mile, you're wearing the engine at a tremendous rate by combination of more heat, more friction, more wear just to keep up with traffic in an already cooling limited environment. Result: short lifespan for the engine in real-world use. Fail.
  2. A traditional Subaru factory installation puts the top of the engine about even with the top of the radiator. The coolant pump only has to be able to lift a 'head' of 6 inches, then it's out to the radiator inlet, and falling with a free gravity return the whole way. Also, counting all of the turns the coolant must take, I count 4 turns (stock) until it is back at the engine. By comparison, using dual scirocco radiators creates 11 90° turns. All of those turns require pressure and power; they're not free. If a stock Subaru configuration lifts the coolant 6 inches before gravity takes over, the scirocco radiators require a head of 18" from the pump because they are completely above the top of the engine! 3x the lift? That's crazy. The majority of the pump's energy goes into getting it pushed up the first hill, just like a roller coaster, and then has to keep pushing it through the labyrinth of turns of those two radiators. That's bad news when you're beat'n the dog at 4200RPM just to keep up with traffic. Fail.
  3. Finally, and most damning, the engine compartment was only ever designed for active cooling, meaning when the engine's running, there's a fan running, too. Nothing short of body surgery is going to change that. Fail.
There are fixes for each one of these, but if you think I'm going to test them all, you're nuts: I'm already a year over-due on this project. Some of the things that might be done to change the game are:
  • Have your VW transmission rebuilt with a different 4th gear and final drive gear. Now put the biggest tires that will fit on it: 27 inches tall. All of these changes mean that you won't have to turn the engine as fast, so you won't be making as much heat. That won't make your transmission any more tolerant of the much greater torque and horsepower from the engine, but it will lower your RPM. Another alternative is to replace the VW transmission with the proper Subaru one with a flipped ring & pinion. That will make the engine very happy. But will that fix the overtemp problem and allow you to keep the radiators in-bay? I look forward to someone else being the first to spend their dough to find out.
  • Active cooling: When the engine turns over, stone-cold in February, start the radiator fans on high. You might not overheat before you get where you're going. So do you feel lucky? What's your travel range in the dead of summer in Galveston? You might get to the grocery store. Or not.
  • Change radiators: something that doesn't require as much work from the coolant pump. I cannot fathom how you would do this successfully in-bay without murdering the exterior aesthetics, but again, I'm letting someone else figure that out. I'm done with trying to make 10 lbs. of bologna fit in a 5 lb. bag.

Instead, I'm revisiting one of the alternatives based on actual documented success. VolksarU 0.2 "Pot-Belly Pig" will use an aluminum radiator with a small scoop between the frame rails.

So the moral of this story is three-fold:


  1. Don't trust. Politely verify. 
  2. If it sounds too good to be true, it hasn't been measured enough.
  3. Don't be an optimist. They may enjoy their lives more, but they make lousy engineers.


And finally, to the liars (not telling the whole truth is a lie): Your personal pride interfering with sharing the whole truth has cost a lot of people a lot of money and their more valuable currency, time. You've made yourselves and the rest of us look ridiculous to the haters. So take a lesson: When your 'Miller Time' engineering goes wrong, don't just sit on your hands and hope something magically gets better. That is the logic of a 5 year-old.

Be an adult: Put your damn hand up.