Supercharger DIY kit?

[fredn]

Sorry to bring a thread back from the dead.

(Actually I am not sorry or I wouldn't have done it.)

So this week I read with interest the Subaru diesel thread, where with great excitement the impossibility of reverse engineering that motor was discussed. It was great reading and I thank those involved for it.

The idea of supercharging the WBX seems way more possible than that and if we are discussing hypotheticals for purely conversational purposes then why not a supercharged WBX.

This thread left me hanging, it was ripe with possibilities.
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1982 Air Cooled Vanagon Carat Weekender Interior

[tencentlife]

It's hard to determine with absolute precision when a block needs align-boring, unless it's pretty bad, but there are lots of signs. It used to be done routinely to the air-cooled blocks when they were all soft magnesium alloy, mainly due to fretting of the center saddles, which would also clinch the center cam bearing. That was a good gauge, putting in new cam bearings and a good cam and tightening the case halves. If the cam was cinched, the whole case needed doing. The same could be done with the crank. Your used center cam and #2 crank bearings would tell you a lot. If a case is really bad, you can feel a ridge around the middle of the center saddles where the bearing has worked its way down into the saddle, leaving the oil groove area raised. That's pretty extreme. The saddles can be internal miked, but it's difficult to get a conclusive measurement at the degree of accuracy that's needed to make a definite determination. With the magnesium cases, you just went ahead and did it.

The wbx's, being aluminum and pretty well-balanced, need it very seldom, hench the unavailability of oversize bearing sets. I was rebiuilding a longblock I had bought outright years ago, and it had had a bad job done to it previously. You could see a bad chamfer on one edge of the #2 main saddles, and consequently it had just lost all the Babbitt from #2, after 90k miles, even though the other mains looked excellent. When I saw bits of Babbitt in the top of my filter at the last oil change (one of the nice things about the Trasko filter), I knew it was time for a teardown.

[WBX man]

[WBX man]

[istewart]

Slightly off-topic, but what compelled you to install the Renault UN1 gearbox? I know it's popular in kitcars in Europe, and some people have put very hefty amounts of power through it after beefing up 5th gear.

[tencentlife]

Well, camwise, go with what other folks have used if they know it works. I'm just speculating based on the additional duration compared to stock and to the one I'm using now. Where you bring in boost will be a big factor.

The mixed bearings: all the wbx's can use a T1 bearing set for all but the crank thrust bearing. But the wbx cranks have a 60mm #1 brng journal. The problem was, my case had to be align-bored to 1.00mm (2 steps) oversize. Full wbx brng. sets are easily available for undersize cranks (mine was still standard, though), but are completely unavailable for oversize cases. That's no problem for #2-4, since any T1 set works, but on the thrust brng you're stuck. Bob Donalds ( http://www.bostonengine.com/home.html ) had already encountered this problem and had on hand a bunch of thrust bearings he had had custom made in case oversizes and oversize thrust shoulders.

I'll see what I can do about illustrating the oil pickup tube mod.

[WBX man]

[tencentlife]

Rasmus, here's a follow-up to the engine rebuild post you should also see:

http://www.shoptalkforums.com/viewtopic.php?t=102662&sid=0eeda2501fafdd5548d847c7ba91cc8e

I really think you should plan on adding remote oil cooling if you're going to do a high-output wbx. Hell, I'd put it on every one of them, they all need to control oil temp to control oil pressure. My 2.2 now always has OP over 45 psi at highway speeds (2500rpm+), idles at 20psi, and temp stays under 220deg.F , even on the hottest days, AC full blast, and climbing the nastiest air-cooled-killing hills around, even the one that did in my original wbx (due to low OP, it chucked a rod). On that same long grade, which the stock 2.1 could only top at 50 mph, just needing to shift down to 3rd, this 2.2 goes over the top at 65, humming happily. This is the way these cars should drive.

I had run a 30mm pump in this engine before I rebuilt it, and it did very little to increase pressure, and nothing at all once it got hot. I got more benefit by shimming up the pressure relief valve spring 1.5mm than the HD pump gave. The big pump mainly causes too much pressure when the oil is cold, like 90psi. Controlling temp remotely addresses the real problem.

Full-flange cam bearings: yes, that's just the camgear bearing. Stock has only a half-flange for thrust control. A lot of the kits nowadays have the full-flange, but make sure that's what you're getting.

Sorry, my old digital camera was broken while I did the rebuild. I really wanted some pictures of the oil pickup tube mod, but I wanted to get the van back on the road (plus I'd blown all my money on parts, so a new camera had to wait).

I think the octanes you're getting over there are roughly equivalent to our octanes here, maybe a point higher there. The US uses a different, and I have to say better, methodology to arrive at the pump rating, which integrates a real engine combustion test with the laboratory analysis.

You're gonna have a high max hp point with that cam duration. Hope you're planning a pretty big exhaust system to make it work up at the high end.

[WBX man]

[tencentlife]

Rasmus, there's details about my engine here at STF (halfway down the page):

http://www.shoptalkforums.com/viewtopic.php?t=100129&sid=b318c1ae6d01d8c1a010b78c9231aaf3

It is a calculated 8.96:1 CR. I live at 6400' ( 1950m) altitude and use US 86 octane gas (probably around 89 where you live).

Yeah, I was thinking you could replace the stock diz with a unit that has the Hall generator installed, just to give the Digifant ECU the rpm reference signal it needs, and a vacuum retard function. Since you'd want to retard under boost, you'd need a unit that had the ability to retard by applying pressure on one side of the diaphragm, rather than suction. A diz with a two-sided diaphragm pod would work. Lots of possible choices, I would think.

Funny thing about the squirrel fan thang. If it can move 500cfm in free air, it could actually raise manifold pressure above what would be normal, which is something below atmosphere wherever you happen to be. Here's the basic math:

2.1 liter @ 5000rpm 4-cycle = 2.1 x 2500= 5250 lpm
5250 lpm x .0353 = 185.325 cfm

So on paper, it could move 500/185= 2.7 times the volume of air that the engine moves (on paper) at 5000rpm. The engine of course moves quite a bit less in static volume due to breathing restrictions, and so does the little fan. But on paper, it's interesting and would no doubt elevate manifold pressure (or lower vacuum, if you will). The problem as I see it is that a centrifugal fan is a very inefficient air mover, and would probably never be able to raise manifold pressure above atmosphere, which is the threshhold you need to exceed by several pounds to start to really get hp gains in a supercharged engine. So it would probably increase power slightly, but I could also probably get as much if I fed $119 worth of peanuts to a bunch of squirrels and put them in a spinning cage belted to the crankshaft.

However, I do like the idea of an electric supercharger, I mean a real positive-displacement pump or an efficient scroll compressor. The battery would be a good place to get instant surge power for no boost-lag. But you're talking real pump hp, a pretty heavy motor, and it wouldn't be at all sustainable without a much bigger alternator. At 70A alternator output you're just exceeding 1 hp electrically. I'd think it would take 8 or 10 at least to do any serious air stuffing.

[WBX man]

[WBX man]

[vwjedi]

Wow that is super natural! I think that is a squirl fan hooked up to the intake? I think I would install the "Tornado" first.

I am allways looking for extra power out of my WBX, however especialy as of late reliability is of utmost importance. I had a Nissan Frontier with the 3.3L Supercharged V6 from the factory, only put out about 5lbs of boost. It was just enough to hear it whine and use up a little more fuel, the torque/HP gain was very modest.

At this point in the game I am more interested in getting the 5cyl. Audi deisel engine, I know my Vanagon is no performance machine, I just want to get 35-40 mpg, that would get me excited.

Cudos to you for the interest, I would love to see a finished product.
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1987 Wolfsburg T25 still riding out. A bunch of other VW's passed on...

[Tomswesty]

http://cgi.ebay.com/ebaymotors/Supercharger-VW-Car...dZViewItem

Here is a DIY Supercharger kit.

[WBX man]

[WBX man]

[Captain Pike]

I don't hate the wasser, I just don't trust them.
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LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
....Bad Sneakers....

[tencentlife]

I4 CIS is the inline 4-cyl with Bosch K-jetronic. Bill hates the wbx.

Rasmus is coming here from over on STF, where I read many of his posts. Welcome! If you spend a little time there, you'll read many accounts of folks in the "Eurozone" running supercharging on mostly unmodified wbx blocks, for road and racing, and I've yet to see reports of compression sealing ring failures. Some of these rigs are seeing pretty high miles. I was skeptical as well about the ability of the wbx to handle high output, but a lot of people seem to be having a good time with it. The bottom end is not a problem, that's for sure. Rods would be the critical point of weakness, in my mind, other than the usual problems of blowing out piston crowns.

I like his idea, personally. If I hadn't just built up my wbx for higher compression Id be much more tempted to explore the possibilities of supercharging. As it is, with 9:1 CR I could afford a few pounds occasionally. It's just with the big weight of a Vanagon and the mountain terrain I live in, coupled to my lead foot, occasionally would turn into all the time.

Limitations? First off, I've read that the stock injectors are only able to flow enough for about 130hp, so they would have to be upgraded for the Phase II idea. I think up to that output you could get away with an unmodified Digifant. The increased manifold pressure would backfeed the stock fuel pressure regulator and increase fuel rail pressure under boost, albeit imprecisely. Some timing modifications would be in order, though, which are hard to accomplish with Digifant without just retarding across the board, not the best solution.

Above that level of power you would definitely need a fully programmable FI/ignition system.

[rs4-380]

trust me, running F/I on CIS is going to yield more headaches than benefit.

Low boost, may be "only" 130 hp, but that is close to a 50% power increase. I seriously doubt you will be able to run that safely on stock engine management.

Props to you if you want to do it, but it's going to be a ton of work to be dependable.
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Dave
87 EJ25 Syncro GL

[WBX man]