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OK, this is a little different.

"The 2.7-liter flat-four was reportedly sourced from a 914 and subsequently built by the seller’s shop for the current owner before installation."

The exhaust is amazing and the owner says the headlights are real 356 lights along with real brand new Fuchs. This is going to bring all the money.

Last edited by WNGD
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@edsnova posted:

Sway bar on swing axle is bad juju, and indicates ignorance.

Engine looks cool.

Amen to that. Similar to the electric heater discussion that rolls around every October, the electric fan thing (like the sway-bar on the swing-axle) reveals that ideas that look good never die. It's better (apparently) to look good than to cool good, and that looks marvelous, darling.

There are different kinds of fans for different applications. Axial (propeller) fans move a lot of air in "free air" applications (like sitting in a box in your window), but don't do nearly as well in high-static situations (like dead-heading directly on to a set of T1 heads with a lot more aluminum and iron than places for the air to go). Porsche successfully used an axial fan on their 6 cyl, but there's a lot more places for air to escape with a P6 than with the T1 because the fins have a lot more open area. The cylinders are also made of aluminum in a P6, rather than iron in a T1 (aluminum transfers heat much, much better).

Centrifugal fans like the one VW put in your car are for high-static applications.

Maybe this would work better than I think it would because T4 heads have more and better cooling fins, with more open area. T4s with T1 upright fan conversions tend to over-cool, so who knows? I'd bet the guy who did it was just guessing as well. I'd still rather just bolt a V2 DTM on it than risk overheating anytime the temp is above 70 deg.

... and before anybody brings it up, yeah - drag racers use electric fans (typically also a forward curve centrifugal "squirrel cage" fan) to eliminate the HP loss of driving the cooling fan. The cooling fan eats HP (it's said up to 20 hp with a T1 setup*) because the VW cooling fan is moving a lot of air. Like "a lot" a lot (as compared to little fractional HP axial fans trying to move air in a high static pressure environment).

I'm not saying it can't work. I'm saying I'd not like to be the guinea pig.

*when you get an engine dynoed, make sure the numbers are with the fan belt on. Some guys (not Pat) cheat.

Last edited by Stan Galat

Stan, that is intriguing. I suspect that stub pipes from each port go into the cans, that then have the pipes that exit to the crossover pipe.  There's a lot assumptions in that, but if so the cans could be acting as a Helmholtz resonator. I know they can be used on intakes and exhausts to do everything from deadening sounds to creating favorable shock wave formation for scavenging.

That crossover is clearly a premade part, probably for a V8 or V6 dual exhaust set-up. I'm not sure whether that indicates the genius use of an existing part for performance, or to save a buck. I'd love to see comparitive dyno sheets of the same engine with that and something known like an A1 sidewinder.

Stan, that is intriguing. I suspect that stub pipes from each port go into the cans, that then have the pipes that exit to the crossover pipe.  There's a lot assumptions in that, but if so the cans could be acting as a Helmholtz resonator. I know they can be used on intakes and exhausts to do everything from deadening sounds to creating favorable shock wave formation for scavenging.

Everything I know about exhaust I learned from online and email discussions with Glen Urban (Modok) from TheSamba, and from A Graham Bell's 4 Stroke Performance Tuning. The exhaust section of the book is like a master's class in how scavenging works. I'm sure you're familiar with it, given your background and since it was written for motorcycle racers.

There's (of course) very little on Helmholtz resonators. I have a rudimentary understanding of them, which is why I was curious how this one worked in the real world. The principle is what both VW and Porsche did with the big 'ol can mufflers, and is the driver behind Vintage Speed exhausts. It seems like the cross-sectional area of the resonator on the 1/2 and 3/4 exhaust ports wouldn't be big enough to accomplish what they need to, but what do I know? I'd just like to see some numbers.

If it were mine, I'd have put a Tangerine Racing tri-Y on it. That's a clever bit of kit, with the ports that should be paired (1 and 4, 2 and 3) being the primaries. There is even an option of a big "beehive" Helmholtz resonator prior to an exhaust outlet. I can't begin to understand the whole thing, but it really, really works. I drove a Speedster (Rich Drewek's Beck) with a 2.6L RAT T4 and a Tangerine tri-y. It was brutally strong.

I really doubt this would perform as well, or as well as an A1 T4 Sidewinder. But again, I wouldn't know without numbers.

A guy once approached me at a show and told me his shop was working on an early Spyder for a guy who had raced it, and they were getting it ready for a life on the street.

I went out and looked at it the following week and it had the weirdest exhaust I’d ever seen: super long tubes that wrapped around the engine compartment and ended in a big canister thing that looked like a built in RV vacuum, exiting through a single tip.

No idea how it worked. The guy used to race it so I assume it didn't suck. It sounded great, too. Almost like a Subie WRX. I assume that canister was a resonator.

The Helmholtz resonators are typically used in exhausts for purely accoustic reasons to kill drone at steady state throttle settings and/or at peak torque. They aren't usually used on exhausts for tuning the sonic shock waves for scavenging. I don't think what we're looking at is anywhere near big enough to do either well. It may just be an atempt to give a larger overall system volume.

We'd need a lot of details and I'd need to rumage around in my desk to find my HP calculator to attempt to figure it out. For instance for high rpm scavenging, one could get the same effect as shorty or zoomie pipes to open atmosphere and get some sound attenuation if the canister equalled something like 5 times the cyclinder displacement.  I think they'd have to dump into the same canister as well because each junction (maifold tube into canister, canister to exhaust, exhaust into crossover, etc.) will generate its own shockwave. As built this pairs shockwaves from cylinders 1&2 and 3&4, and that's not optimal. The same canister would solve that to a degree.  The shockwaves aren't the same as the sound waves. Soundwaves travel at the speed of sound, the shockwaves are supersonic.  At least that's how I remember it from velocity stacks and airbox design, there are a lot of cobwebs back in that setion of my brain.  For exhaust we just concentrated on primary diameter, length, and which cylinders were paired. we got really good at making things worse before we got anywhere near making things better. My only out of the box success was a copy of a Honda NCR megaphone designed for a 700cc single. Note the word copy...

Yeah, Michael - I think this is another thing not unlike the electric fans and sway-bar. A terrible idea, beautifully executed.

We work on Aaon package RTUs, which this car reminds me of. They’re 3-10x more expensive than a Carrier or York or Lennox, but they’re gorgeous. Really heavy sheet metal cabinets, hinged latching doors, beautiful wiring diagrams, fully customizable

… but they are alway half-baked. We have one roof with 8 of these, every unit eats one inducer motor at least once a year. They’re just fractional HP motors with a larger than normal shaft, making it so you have to buy their $500 motor. They spin those inducers at 3000+ RPM and hang a fabricated $350 aluminum blower wheel on the end of a 2” long shaft, so that the only thing supporting the weight of the spinning wheel is a tiny bearing on the shaft end of the inducer motor. It’s madness, and there’s not a single thing that can be done.

It costs at least $2000 per unit, and as I said, there are 8 on the roof and this happens to each of them every year.

They LOOK fabulous, though - like someone really thought about them.

Me, too - I’ll buy that shirt!

Speaking of Helmholtz resonators (something that I had never heard of before but they make a lot of sense), I can mention the way that Acura deals with engine/exhaust droning.  

My Acura RDX 4-cylinder Turbo is noted for having a pretty loud exhaust drone at around 60mph.  That, of course, will nevah do for a snooty Acura driver who expects a whisper-quiet cabin, so what’cha gonna do?

This is what Honda did, and I am not making this up:

Since the cabin was whisper quiet to begin with, they turned the whole cabin into the equivalent of a Bose Noise Cancelling Headphone with an “Active Noise Canceling” system.  There are something like seven different microphones all over the car from the engine compartment to the exhaust, all sampling noise in their respective areas.  Then, no fewer than three on-board computers sample all that noise and quickly figure out what they need to produce for sound waves to cancel out the “unwanted” noise from the car.

Then, they inject that noise-canceling sound wave into the car’s wicked expensive, 1,100 watt, 16 speaker car theater system and, “Presto”!   The outside noise goes away.   It is amazingly effective and cannot be altered or turned off.  That’s the good news.

The bad news is that it uses the car’s sound system to dynamically cancel out unwanted sounds.  That takes a whole lot of sub-woofer poop to make those cancelling sound waves and THAT steals power from producing music Bass through the sub-woofer.  What you end up with is mediocre music bass/mid response ALL THE TIME.

The cure for mediocre bass response in these cars (according to the Acura owner forums) is to pull a power/audio plug on one specific computer that sits under the center console.  I did that and Bass response greatly improved, immediately.  

Think of it as an electronic Helmholtz chamber.  It is SO effective, that they use those microphones in the engine compartment and at the exhaust to sample the noise, and then inject some of the engine noise back in to the cabin through the infotainment system!
Pulling the plug on that little computer makes half of the engine noise magically go away so it becomes a soft and thoroughly enjoyable engine purr as it shifts through the gears, AND the music Bass response gets a lot better.

Think of it as a gift from our Sainted Japanese Engineers.  They must have learned this stuff from Sainted German Engineers.     🙄

Last edited by Gordon Nichols

IMHO The electric fans - alt placement etc. limited the interest, ppl tend to not be drawn to experimental stuff.  If that speedster had conventional fan shroud etc  it probably would have reached a higher number.                                                                 I've been in BAT que for a month receiving canned messages, finally heard from BAT today they claim to be generating the auction text tomorrow for my review, we'll see if that's so....

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