Jet-A-Vator carb grid.

[jakobnev]

If it was my project, i would make the grid slide out of the way at full throttle.

[Isaac Zackary]

Originally Posted by freebeard

I'm betting Isaac Zackary reads the whole MM series (if he hasn't), based on his avatar...

But I did find this: VW Type 1 Mileage Master MPG Engine Combo « VW Parts – Aircooled.Net

Yep. I've read those. And yes, my white Beetle in my avatar is the vehicle in question, only now with 165's instead of those wide tires.

I do have a heated air-cleaner. It's a 1972 oil bath that draws hot air off of the head, not the exhaust. The engine is a 1600cc. I'm trying to do the unthinkable, a 9.5:1 CR with a 0.040" quench! My programable ignition is the CB Digital Magnaspark Distributor.

Ya, I know, dual carbs and such should be better than my single carb 34 PICT-4. But this is what I want to try to work with.

[freebeard]

I don't have the paint chips for 1972, possibly L-80E, Light Ivory?

My weekly driver is similar, 1971 1302 in Shantung Gold. When I got it it was so stock the 34PICT had parts on it I'd never seen before (the dashpot that slowly closes the throttle) but that went away when it was replaced with an adapter plate and 32PICT. I had a 34 but couldn't find it until later. It also has the CB Magnaspark, but the low end one with Ford internals and the red coil. The only other parts not stock are the front tires (165-50R/15), the adjustable Macpherson struts and LED headlights in H-4 reflectors. Wink mirror and AM radio delete. Just last weekend I got a set of five Marathon/Jubilee/Baja wheels, but they will get blasted and Plastidipped before they can go on the car.

I'm trying to do the unthinkable, a 9.5:1 CR with a 0.040" quench! My programable ignition is the CB Digital Magnaspark Distributor.

That's what it would take to do that. Well, maybe that and water injection.

jakobnev -- That would be a whole different part. It would have to slide in an airtight box. But the idea has merit, the size and spacing of the holes is tuneable. Until they sold the first one they blurred out pictures of the holes. If you had a plate that was 1.5 times the width of the intake, it could cover and uncover holes to have a variable restriction.

In the VW's case raising the stock air cleaner could have it impact on the hood in the open or closed position. It's right up there in the hood hinge-line. The Karmann Ghia and Thing air cleaners move the problem somewhere else.

Now you've got me thinking. My last car was a 1302 and I took it from 17 to 34mpg. My best tank ever with this one was 37mpg, but it will do 34 consistently as well (when it's in tune, I'm in the 20s right now). My goal is to get Prius-like mileage (~45mpg), half with engine mods and half with aerodynamics. Really good ignition management, high compression and water injection on demand might get to 40mpg.

Which would be awesome. What do you get right now?

[aerohead]

Originally Posted by Isaac Zackary

Any thoughts as to whether this device will actually increase fuel mileage? It's basically just a grid that sits under the carburetor.

Aside from the discrepancy between the heat content of Diesel fuel compared to gasoline,the reason a Diesel engine is more efficient than a gasoline engine is it's lack of a throttle plate,running always at W.O.T..
If you add an additional restriction to your gasoline engine's induction system you're shooting yourself in both feet.
If anything,you want a Mitsubishi GDI research engine of the 1990s,which is throttle-less,and picks up 15% thermal efficiency accruing only to its LACK of intake restriction and superior volumetric efficiency.
Save turbulence creation for your combustion chamber design.That's where it counts.

[Isaac Zackary]

Originally Posted by aerohead

Aside from the discrepancy between the heat content of Diesel fuel compared to gasoline,the reason a Diesel engine is more efficient than a gasoline engine is it's lack of a throttle plate,running always at W.O.T..
If you add an additional restriction to your gasoline engine's induction system you're shooting yourself in both feet.
If anything,you want a Mitsubishi GDI research engine of the 1990s,which is throttle-less,and picks up 15% thermal efficiency accruing only to its LACK of intake restriction and superior volumetric efficiency.
Save turbulence creation for your combustion chamber design.That's where it counts.

I'm with you, at least somewhat. Yes the restriction is counterproductive. Think of it this way, if you stretch out the air to twice it's original volume and then squeez it into a 10:1 compression ratio, do you still have a 10:1 compression ratio or a 5:1?

There is one drawback with WOT on a gasoline engine. When at WOT the cylinder temps get so high that detonation becomes a problem. The common "fixes" have been to not only retard ignition timing, but to enrich the AFR way past stoichiometric. (Which is the reason even new cars smell just as bad as old cars when the fly by you at full throttle going up a mountain pass). I'm wanting to try to use cooled EGR as an alternative so I can hopefully keep my AFR lean at WOT.

In order to keep the throttle open wide I'm sticking with a smaller engine. Plus, I'd like to install taller gearing in the transmission.

As far as having two restrictions as being a shot in the foot I don't thinks so. The average restriction will tend to be the same. Since the Jet-A-Vator imposes a slight restriction I'll have to keep the throttle plate slightly more open to maintain the same speed. The only way I could maintain a constant WOT might be to hook an engine up to a generator that matches full output of the engine.

[freebeard]

That would be a chassis dynamometer.

aerohead may be thinking about a Rabbit diesel pickup in another thread.

So what kind of mileage do you get without the Jet-A-Vator?

[Isaac Zackary]

Originally Posted by freebeard

I don't have the paint chips for 1972, possibly L-80E, Light Ivory?

The PO painted it pearl white. Parts of the car were an orange 1972 1302 and a light blue 1971 1302!

Originally Posted by freebeard

My weekly driver is similar, 1971 1302 in Shantung Gold. When I got it it was so stock the 34PICT had parts on it I'd never seen before (the dashpot that slowly closes the throttle) but that went away when it was replaced with an adapter plate and 32PICT. I had a 34 but couldn't find it until later. It also has the CB Magnaspark, but the low end one with Ford internals and the red coil. The only other parts not stock are the front tires (165-50R/15), the adjustable Macpherson struts and LED headlights in H-4 reflectors. Wink mirror and AM radio delete. Just last weekend I got a set of five Marathon/Jubilee/Baja wheels, but they will get blasted and Plastidipped before they can go on the car.

Wow! Cool car! Mine has the dashpot. From what I understand, once the engine is leaned to optimal for fuel mileage the engine can stumble and even die if you let off the pedal too fast, which causes the engine to gulp a sudden rich mix. But that's just an assumption.

32PICT? You must mean 30 or 31PICT. Unless there's a 32 PICT that I've never heard of.

Where/how did you get LED head lights? I'd like to do all LEDs but am concerned about legalities. Well, mainly not being bright enough.

Originally Posted by freebeard

That's what it would take to do that. Well, maybe that and water injection.

I'd love to do water injection too! But I'm not even doing fuel injection. And here I'd have to figure out how to get it to work at below 0F temperatures. As far as the digital timing, I'd like to figure out how to get an Audrino with a knock sensor, a Ford TFI module and a crank trigger to work. I'd like to have separate spark maps for each cylinder. I think that would give me more than individual cylinder AFRs and possibly be much cheaper too.

Originally Posted by freebeard

jakobnev -- That would be a whole different part. It would have to slide in an airtight box. But the idea has merit, the size and spacing of the holes is tuneable. Until they sold the first one they blurred out pictures of the holes. If you had a plate that was 1.5 times the width of the intake, it could cover and uncover holes to have a variable restriction.

In the VW's case raising the stock air cleaner could have it impact on the hood in the open or closed position. It's right up there in the hood hinge-line. The Karmann Ghia and Thing air cleaners move the problem somewhere else.

Now you've got me thinking. My last car was a 1302 and I took it from 17 to 34mpg. My best tank ever with this one was 37mpg, but it will do 34 consistently as well (when it's in tune, I'm in the 20s right now). My goal is to get Prius-like mileage (~45mpg), half with engine mods and half with aerodynamics. Really good ignition management, high compression and water injection on demand might get to 40mpg.

Which would be awesome. What do you get right now?

Well I didn't get to drive it much. I kind of figured about 30mpg highway once. But the engine was in poor condition. So I'm rebuilding it, and my way. I got a Web Cam #73. Tight quench and I want to do ceramic coatings. Also I'm doing lots of oiling mods for better cooling. I figure if I want a 9.5:1 CR I need to have better control of engine temps too.

[freebeard]

32PICT? You must mean 30 or 31PICT. Unless there's a 32 PICT that I've never heard of.

According to TheSamba.com :: Carburetor Manuals it's a Type III carb. And according to TheSamba.com :: View topic - 34 PICT-3 vs 32 PICT-3 Give me your opinion and experience the 34 likes a vacuum advance distributor.

The LED headlights are no-name Cree-like Chinese knock-offs ($55/pr on eBay) in H-4 reflectors. Not being bright enough is not a problem. The round low-beam pattern compare to the halogens flat topped beam is, though. I'm using aluminum tape instead of eyebrows to fix that.



Water injection isn't like fuel injection, more like NOS. It's just dumped (unmetered, I think) into the intake manifold when it's triggered. It goes back to WWII bombers and was used for instance in the supercharged Olds F-85. Add alcohol as anti-freeze. There's probably discussion on this forum.

I call mine a weekly driver because I use a bicycle around town. I think VW's official figure is 28mpg.

Ceramic coating are helpful in the exhaust system and there is a 1/4" thick ceramic that is put on the piston tops as a thermal barrier. Thanks to the aerospace industry there are a lot of other coatings possible: anti-friction on the piston sides and valve train, heat rejection on the outside and probably others. I had my brake rotors and drums cryogenically tempered (for longer service life. I don't find the company in Michigan that did the work, it might have been Cryogenic Tempering Services, Cryo Treatment Services by 300 Below, Inc.. another company in Oztralia High Performance Brake Pads and Brake Rotors - Frozen Rotors or just Google 'cryogenic tempering'. It could be applied to engine parts as well, piston rings and such.

[Isaac Zackary]

Wow! I wasn't familiar with the Type-3's, so I didn't know about the 32-PICT. I'll have to look into it. I'll also have to look into the LED's for H-4 head lamps. Do you use other LED's?

You're right about water injection. But there's a problem with just dumping water without metering. First, in Racing applications it's ok because normally you just floor it and keep it in a high RPM power band. But for an engine like mine I'd need it from full throttle at 1,400 RPM clear up to 4,600 RPM. That's 3 times the amount of water needed! Plus there could be knock just off full throttle, meaning I might need even more control over Water injection. Water injection could potentially ruin an engine if it's too much or too little. There is one company, Aquamist I think, that does offer full water injection metering based on RPM and load. But it's supposed to work in connection with a fuel injection system by reading the amount of fuel being injected. Plus there's that problem of freezing. Alcohol could work, although the usual methanol is corrosive to the aluminum heads and such. But I'm not sure even it would keep water from freezing at -40° like it gets here.

[freebeard]

I've had (and still miss) a few Type IIIs. Dual 32s on shorty manifolds shipped between the single side-draft carb and fuel injection, which the Type III had before anything else. They are also the fall-back when fuel injection parts become unobtainable.

At -40° do you have auxiliary heat for the engine oil? Just use that. Can you get engine load from manifold vacuum? I seem to remember someone measuring spark plug impedance to measure something, maybe it was premature detonation.