

| Subject: | Re: Exhaust Design |
| From: | Chris S |
| Date: | Sun, 14 Feb 2010 19:22:17 -0500 |
I live for the day you answer a question without simultaneously bashing WBX and gloating over Subaru. We are all very familar with the ancient nature of WBX design. 2010/2/14, Scott Daniel - Turbovans <scottdaniel@turbovans.com>: > Hi All, > well , that is certainly exotic looking and is bound to help some. > > What I would think though is ..... > given the relatively extreme crudeness of the intake runners and plenum, > is that if you can't get much good air flow going in, getting it out > downstream of the cylinders isn't going to help very much. > > I am talking about that small square hole in the air flow meter that all air > that enters the engine has to go through, and > the crudeness of plenum and intake runners, and only one intake valve per > cylinder , and 'ok' ports. > > for comparison ..........and to look at a somewhat similar engine > ........and aluminum block opposed four , ( just a decade-plus newer in > design ) like the waterboxer but 'a whole lot more' ..........just look at > the intake system on a Subaru engine , starting with the 1990 EJ22. > > The throttle body is nice and big. The air mass meter obviously has to flow > better ........since the air does not pass through a small squareish hole , > like it does in the waterboxers Air Flow Meter, and there is no flapper > valve in an air mass meter, like an air flow meter has. > Then look at the plenum area and intake runners. > The subaru plenum area is nicely cast into nice, large, 'swooping' cast > aluminum intake runners.........one nice casting. > They squeazed in a little more intake runner length by curving the intake > runners up some, then they turn and go straight down into the heads and have > 2 intake valves per cylinder. You just look at that shape ...and you know > there is going to me more air getting into the cylinders than in a wbxr > engine, by far, is my guess. Inatake runner length is good for low end > power, more is better in that regard. > < some modern engines even have two different pathways through the intake > system....one for low end, one for top end ) > > You just look at the soobie intake ...and see how much more air is likely to > flow nicely with those intake runners compared to the > really...........'industrial grade' , like farm equipment almost > ,......waterboxer intake set up. > > I even have late-night wild plans to fit a subaru intake onto a waterboxer > engine ....though ........that might be impractical, and not even produce > that much of an improvement. > > There must be bigger air flow meters around that would work. > There have been attempts to fit an air mass meter to a waterboxer engine > .....not totally successfully I don't think. > Besides flow reasons, and air mass meter has no moving parts in it , and is > thus likely to be far more reliable, than an air flow meter with mechanical > sweep arm on electectrical contacts. I have said this for years ( > regarding fixing things , especially cars ) ...wherever electrons and > something mechanical interface - that's a weak spot. Arcing in switch > contacts would be an example, and the air flow meter sweep contacts are a > really good example. > In air mass meters ........in my experience, I've never seen a problem > with a subaru one. In my 88 740 turbo volvo sedan, > I have to clean the fine wires in the air flow meter every once in a great > while. You can even buy 'air mass meter cleaner' in a spray can, like > electrical contact cleaner, which probably works as well. > > anyway ..sorry to get off there... > but , I would have to say the entire intake area of a waterboxer engine is > rather restrictive, just eyeballing it. > and ...don't forget ........ > One of VW's traditional strategies ( not true in late model VW's ...but in > all air-cooled VW's , and waterboxers too ) .....is to keep it underpowered > to reduce stress on the somewhat underbuilt engine, to help it last longer, > at least with stock internal parts. > > The exhaust here looks wild and exotic - might as well plumb a turbo into > it if going to all that trouble ! > . > and ....I 'bet I could' fit Subaru sequential distributorless ( though I'd > use a distributor body for a place to mount a cam position sensor ) Fuel > injection to a waterboxer engine. Can't think of any real reason that > wouldn't be possible. Those are darn strong and consistent fuel injection > systems. > > Scott > www.turbovans.com > > > Subject: Re: Exhaust Design > > >> Here's a good read with pics on a tuned system. >> >> http://www.thesamba.com/vw/forum/viewtopic.php?t=270833&highlight=exhaust >> >> >> On Sat, Feb 13, 2010 at 10:36 PM, Kim Springer >> <kimspringer@astound.net>wrote: >> >>> Hey listers, >>> >>> >>> >>> Has anyone ever measured up a stock exhaust system to see where it's >>> designed to make HP. I assume VW did this a long time ago. >>> >>> >>> >>> I guess another way to ask this question is: Did the folks making SS >>> exhaust >>> systems in a 4-2-1 or 4-1 design improve on what VW designed? >>> >>> >>> >>> I have a book that helps to design 4-Stroke intake and exhaust system >>> lengths, inner pipe diameters, etc. >>> >>> >>> >>> All this talk about hollow cats makes me wonder about the secondary pipe >>> length. Not that anyone is going to gain 10 HP out of this.just >>> wondering. >>> >>> >>> >>> Kim >>> >>> 88 Tristar #7 (it's either going to get painted or sold in the next year) >>> > -- Chris S. Disclaimer: "Death and serious injury may occur"
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