Greetings, this is my first post here. Someday I hope to build a fuel injected turbo /6, so I lurk here quite often. I have owned a half dozen 2.2/2.5L turbo cars, and was an active member for a LONG time on the various related mailing lists and message boards.

This topic has been hashed out a few times on the various 2.2/2.5L turbo forums over the years. (FYI Their goal wasn't to increase mileage, but to increase performance.) The easiest way to generate sizable vacuum is to vent the crankcase into the exhaust with a one-way check valve to prevent the exhaust from filling the crankcase.

As someone else mentioned, your engine, especially your rings, need to be in good shape for any crankcase ventilation to be effective.

Good luck.

Thanks for chiming in here! Does the exhaust scavange atmosphere out of the crankcase? I absolutely believe your reports here. This is not to challenge the fact that the exhaust probably creates the best "suck" on the check valve, But, it seems as if the intake tube would have a similar effect, if maybe to a lesser extent.? I plan on plumbing the same kind of check valve into the intake tube between theh air cleaner and the turbo inlet. In theory, the same volume travles through there as travels through the exhaust. I think MPG Mike's experience with this has been mostly with small 4 cylindar engines such as the 2.2/2.5. He mentioned a Plymouth Breeze, and a Toyota Camry in his case studies. How did your 2.2 Mopar guys deal with the problem of too much vacuum on the crankcase? Or were they worried about that? Were these strictly race only applications or daily drivers as well?

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Have a look at this:
http://forums.corvetteforum.com/showthr ... ?t=1450082

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

I get the basic theory.....I wonder about the actual results adding up to an advantage.

My biggest problem with this system is at WOT when vacumn is zero .....blowby builds crankcase pressure and you have no breather. I predict blown seals and a fat oil pan and valve cover.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

And my biggest problem with this system is the same as with much of the rest of what MPG Mike recommends: A lot of it has at least some basis in sound theory, but there's never any before-and-after data, just "Try this, it works". I want to believe, I really do, but...

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

But you do have a crank case breather, and no pressure inside the crankcase. That is what the check valve is for. As far as the inside pressure goes, the crankcase sees nothing different. If pressure builds, then it is vented through the check valve into the air cleaner, just like stock. The check valve is inserted in the standard breather to aircleaner hose.

As far as solid data, Mike does have case studies, but he does all this stuff at once, and then it seems as if he doesn;t know for sure which mod produced the most improvement. Last month he went to a University in New Jersey and taught two one week seminars on improving the fuel efficiency of mainsteam daily drivers. They took 4 cars and modified all of them, and in some cased almost doubled the gas mileage. The cars were a Ford F150, a Toyota Camery, a Plymouth Breeze. and the afformentioned Cadilac.

I am not sure how he demonstrated his improvements. I know one of his tricks is nothing new. It is simply pushing the tire pressure up real high. Of course that has been mentioned here on the Forum many times. But my point is, if this is one of his techniques, then he must have taken the cars out on the road to test this out. He was honest enough to say that one of the cars, a 2000 Cadilac got worse. But then he said the second class, the second week figured out why, and corrected the problem and improved it. I did not question him further, but wish I had. That would be useful information. Since I love toying with my cars, I don;t mind trying this stuff out.

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Yup, that's one of my two main frustrations trying to assess his mods. The main difficulty is that there's usually no benchmarking done before the mods. If there were, I'd have an easier time accepting a package of five or six or twelve mods all done together and presented as a "Here's what-all we did that resulted in this particular car going from 18mpg and 66 drive-wheel horsepower to 26mpg and 74 drive-wheel horsepower" (or even "18 mpg and a 0-60 of about 16 seconds to 26mpg and a 0-60 of about 14 seconds"). I understand that there are practical and financial limits to how much testing can be done, but a little data would be better than no usable data at all.

Will I probably wind up contracting with MPG Mike for some cylinder head and manifold work at some point in the near future? Yes, but it will be a much smaller, more limited contract than it would be if there were systematic testing going on.
Agreed, I like trying things out that stand a reasonable and realistic chance of being worth the effort, either in terms of improved vehicle operation (performance, mileage, driveability, cleanliness of exhaust emissions) or in terms of learning. But there are practical and financial limits on my time and effort, too, so I might try out the drilled spark plug electrodes, for instance, but I probably would not try out those 2-piece intake valves without some usable data backing up the claims.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan, I'm glad to hear you are thinking of trying out his drilled out spark plug electrode. It seems like a harmless kind of experiment, with some potential. All of the things we talked about kind of fell into that catagory. While he says he knows how to improve a car's efficinecy with exotic head and valve mods, I get the impression he is now focusing on the kinds of mods that anyone can do, to any car, without special tools, and without spending lots of money. I think he is trying to figure out how to make money off of his ideas in a way that will be cost effective for the consumer, and help the environment too. He told me he will not focus on any economy measure that hurts performance. He feels the public just wil not buy it.
Sam

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From the McMaster-Carr catalog at http://www.mcmaster.com/. The part # 48935K25 looks like it could work, maybe even mounted in reach of the driver's seat.

Brass Adjustable Vacuum/Pressure Relief Valves

Adjust these brass valves to relieve vacuum pressure from 0 to 27" Hg. They can also be configured to work as pressure-relief valves for low-pressure compressed air applications. Pressure adjusts from 0 to 20 psi with the knurled adjustment screw. They are not factory set to a specific pressure. Valves have a Type 302 stainless steel spring. The 1/4" pipe size valve has a metal-to-metal seal with a Type 440C stainless steel disc; 3/8" and 3/4" pipe size valves have a Buna-N seal with a nylon disc. Temperature range is -40° to +250° F. Connections: NPT male bottom inlet and vented top outlet.
Pipe Size Ht. Each

1/4" 1 3/4" 48935K25 $7.70

3/8" 2 1/16" 48935K35 13.65

3/4" 2 3/4" 48935K45 31.48

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If I keep my car for 20 years, I just might finish it.

Greg, I opened up the link you posted and read it all. It was very, very helpful. It answers most of the questions we raised, or posed. But, the most important thing to me at this point is they offer/sell/market a vacuum relief valve that is adjustable. And, they recommend putting a vacuum gauge in the cockpit so you can monitor the vacuum. I feel like I can go forward with this.

Aaron, your link looks like maybe even a better solution. Mike mentions McMaster Car in about every 4th sentence. He gets alot of his hardware there.

On a BBC making most likely around 800HP they saw a gain of 55HP at 15" of mercury. Working the math from there, that is a 6 percent gain. They felt that 10" of mercury was quite safe for any motor in good condition. If one were to go tht route, then you would see 60% (maybe, assuming some linearity here) of 6% of 60% which would be 3.6%. If you took 3.6% of a 200 HP slant, that would be 7H-8 HP. Or maybe slightly more than the gain realized from a crank scraper. This is not earth moving, but it is something, and the more you build your engine, the bigger the benefit. The thing is, if you don;t damage your engine, it is free. If you limit yourself to 6" as Mike suggests, you would see only a 2-3 HP gain. And, this assumes this is a linear phenomenon, which we don;t know. There may be a curve to it that has a fat part, and skinny ends that drop off if you get out from under the curve. I still feel encouraged to try it.

Mike did say that he sets the vacuum to 6" at idle. And this Greg's link said that while they run 15" at race RPM's, it idles at a much lower vacuum. Maybe Mike is adjusting his valve for a higher cruise vacuum, and he is unaware of what his cruise vacuum is.

Again, good tuning is, for the most part, an accumulation of small improvements. Unless your talking nitrous, right Dennis.

Sam

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The science of running a vacuum on the crankcase is proven, and sound. There are only two questions: Is the improvement without utilizing a pump,(which only draws one HP), enough to make it worth the effort, and what precautions should one take to avoid damaging the engine from having too much vacuum?

The adjustable valve that Aaron found in the McMaster-Carr catalogue can also be used to control the turbo boost from in the car, and that may ultimately prove to be more useful. I am not sure how to plumb it, but I have been told this by several different people. I think you simply control a leak in the waste gate pull-off pot.

Sam

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The vacuum isn't for pulling pistons down. It's there to reduce various things that eat up horsepower, such as air drag on the crankshaft and possibly a few other factors.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

From what I understand (and I could be wrong). The reason for the vacumm system on "race" motors, is to allow a thinner, lighter, less tension, ring package. The vacuum helps to prevent ring flutter, and allow for a better seal.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Charrlie is right on. It helps seal the rings on the compression stroke. As he said it stops the flutter (unseating of the rings) and the ability to use low tension rings.

This is not a new theory and has ben in practice for a number of years now in the racing community. I think moroso makes a vac...expensive at over $300.

Ah, I thought there might be something ring related on it. Would this require rings set up specifically for crankcase vacuum?

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair