I was looking into ways to do odd things to make more power. What else is new. I came across a standard, root type supercharger hooked up to a corvair engine that was pretty kick ass. I like superchargers in that they are cleaner to install that turbos and do not have the lag. Then, I found the Vortech centrifugal superchargers and felt that these just might be an interesting way to bolt on power.
http://www.vortechsuperchargers.com/catego...n=SUPERCHARGERS

Cheap? No friggen way, but cool! Used ones can be gotten for much less if you know what model to use.

I need to read up on what is required of an engine to be supercharged vs turbo charged if there is a difference in configuration.

An interesting aside for my specific interests regarding the reverse running corvair engine; the 4cyl Honda ones would be easily adaptable, possibly. The only problem I see is that there are no 3.1L honda 4cyl engines.

So, what do y'all know about supercharging? How about thoughts on doing it to a TIV or any other power plant that we could throw into our cars?

Roots style blower

I am still a big turbo fan, though. THere are a lot of sizes and with the aftermarket availability of EFI, you should be able to get the lag down to something respectable.

I really like this Turbo bug clip. The guy posts on Jake's site, and his set up looks sweat!

Sandeep Bug

Sorry for highjack. Back to supercharging!

Volumex supercharger
Click to view attachment
Click to view attachment

Paxton has been around since the begining of hot rodding Here is a 1965 example but they have been around longer than that.

http://www.paxtonauto.com/article.php?id=4

You need to add an AC clutch to the drive belt so you can switch it off and one like Mad Max.

Get a Supercharger off a Merceces Kompressor ... has an electic clutch already.

There is a boxster supercharger set up used for 3k in seattle.
craigslist

Or there is this electric setup;
http://www.superchargerswarehouse.com/Pors...-Superchargers/

Dick Landy Industries did a Rootes type for the Type 1, maybe you could rig up 2 for the Corvair. Definite WOW factor.

Really? I have a hard time believing that Porsche sanctioned the use of its name with this product. If it worked,3psi would be nice for $200. Shit, I would chain 3 of them and get 9psi

Picture? Example? Diagram? Hieroglyph?

Mercedes SLK compressors are roots style and very cheap to come by. Over here they are used plentyful to whatever engine you can come up with. Just make a bracket and pick your pulley size for the rpm/pressure..

Advantage of SC vs Turbo , is no lag...instant power and if you keep the roots under 10-12 psi, no cooling required (roots chargers are very hard to cool, you need to custom build a cooled intake.)

The rotrex chargers are the new thing, I just built one on a Honda S2000...450hp, intercooled..they are beautiful.....

Check out Kraftwerks for some nice units.....or Rotrex

Ah, a fatal flaw in the centrifugal setup:

"But the biggest disadvantage of the centrifugal supercharger over its positive-displacement counterparts is the low boost pressures produced at low engine RPMs. As we mentioned earlier, this is because the centrifugal supercharger's air-flow rate increases at the square of its shaft RPM. The result is that a centrifugal supercharger will typically produce maximum boost at the engine's redline with hardly any boost pressure below 2,000 engine RPM. However, boost pressure does build quite quickly in the upper half of the engine's powerband.

CONCLUSION

The lack of low boost at low engine RPM means that the centrifugal supercharger would be suitable for quick reving, light cars with manual transmissions rather than heavier vehicles or vehicles with automatic transmissions. Thus, if you have a truck or a car with an automatic transmission, a positive-displacement supercharger, which makes full boost as low as 1,500 engine RPM, would be a better option. "

From:
http://www.custom-car.us/superchargers/centrifugal.aspx

Wow, they are real cheap in comparison. I wonder what direction they rotate.

This will have to be incorporated into my engine at some time.

Now I want a supercharger on my 914.. thanks guys..
@Type47, is your motor able to breath with that carb on it? Seems kinda small for a supercharged engine?

And how do you connect the belt to the impellor fan?

Question; can a SC bee hooked up to a CIS without modification to the CIS action? It would appear to be possible since it is volume/fuel dependent.

same way they did the AC. although it might need a beefier belt
914 had a pulley behind the impeller. belt exit went behind the fan housing to the right opposite teh alternator

or maybe could be like they did the smog pump. it was mounted atop the fdan housing. there was an extender shaft in front of teh fan. the fan housing had a 3 legged bracket suspended in front of teh fan mounted to the 3 holes that the Bus used for teh fan screeen

Jake has said that boosting teh type 4 creates head sealing challenges. perhaps modest boost #s would be OK

You might want to look at a Corrado G60 supercharger. These are fairly small scroll compressors, and can be found pretty cheap. Looks like you could use a modified smog pump setup and mount it above the engine.

It can be done on CIS, but I'd recommended a warm up regulator off an audi 5k turbo or similar vintage turbo brick. It's boost sensitive and will increase pressure as the boost comes on.

Might as well look into alcohol injection too.

I've never dealt with a supercharger, always turbo's..
BUT, it looks like a supercharger would be simpler to plumb and would keep the exhaust away from the incoming air.
And could be placed closer to the intake ports which would = less lag all by itself.

The only question I would have is how much HP does it take to run it ? The big draw of a turbo is that it doesn't take HP to run relatively speaking. Unless you count the restriction in the exhaust flow.

As far as the electric fan "Superchargers" I'd want a lot of proof they really do work..

Judson made superchargers for VW's and Corvairs in the 60's.. I have seen some show up on E-bay at times.

Unless you're up for a fight, run away from G60s. The apex seals, timing belts and bearings tend to wear out and the darned things turn into hand grenades. Since they haven't been made in 10 years, they're all pretty worn.

Rebuild kits are available, and when rebuilt they're amazingly efficient. The process of rebuilding them isn't so much fun. Another thing I've become good at that I wish I hadn't.

I've come to the conclusion it's just easier to replace them with Opcon units.

You need to add an AC clutch to the drive belt so you can switch it off and one like Mad Max.
[/quote]


could that actually be done , ala mad mel ' max

it could be done, though it would be easier with FI then a carb... I would imagine if the charger stopped spinning with a carb on top, the fuel would have issues getting to the already too long runners.

Zach

Not mine. The guy who built this move the fan housing so the belt could be driven.

Hell, if your goin electric, you could just throw one of these in each intake tube.
http://www.hobbyking.com/hobbyking/store/u...idProduct=15170

There isn't a lot of room at the top/front of the 914 engine. Mounting the SC might be a significant problem; especially if it takes a decent sized belt and pulley to run. Remember that the 914 firewall leans back a pretty decent amount, which causes problems for anything you want to put in front of the fan.

Turbos are much more flexible about where they are mounted.

--DD

"You can't supercharge a 914."

I would love it if you did this. A much more worthy project than lifting a Subaru Forester.
It would be worth a big lump in the firewall protruding into the cabin between the seats. Show up in that at WCR and you could follow your "that guy" award with "the other guy" award. Imagine the status.

I think there are more effective ways to get the same power, but a blown TIV in a 914 would just be crazy unique and cool.

I will likely SC the bus first.....or I might do the /6 Centripetal SC are flexibly mounted. Also, you can mount a roots one in a different place. Hell, you could put a pulley on the flywheel end and mount the SC and intercooler in the trunk.

I had some time this evening to read up on CIS and turbo together. Simply put, stupid easy and cheap if you do a SC in comparison.

A regular CIS set up on a 914 (as with ejm's turbo TIV) needs only a turbo warm up regulator from an Audi 5000, turbo Volvo or the like. It senses the air pressure and adjusts the fuel. Done.

This can be adapted to SC or turbo.

What I am trying to find is a diagram that shows where the turbo/SC is in the system. Is it before the air box forcing air in, or after it sucking air through?

Here is a good diagram.

you probably already figured this out given the chart, but it is almost always behind the air filter, and not in front of it.

Zach

Thank you captain obvious

anyone care to speculate as to why turbos are more prolific than SC?

Here is another one:

is that a 911 turbo?

No

Dead easy on the injection side. Depending on your application you may want to go to larger flow injectors, but it's not likely neccessary.

I did a CIS Turbo 1.8 watercooled engine a few years ago. Added the turbo warm up regulator and added 10psi. Problem is, boost is addictive so I ended up adding a Hobbs switch and some cheese ball circuitry to fire the auxiliary injector under heavier boost.

The ignition side is a bit trickier, almost have to go aftermarket to get the curve right.

Turbos almost always go between the air box and throttle body. this is for simplicity and throttle response. When the throttle closes it causes a high pressure area and the turbo spools down. Since there's no gears, this doesn't hurt anything.

Superchargers almost always go between the throttle and the manifold. If it didn't that same high pressure situation would add huge loads to the bearings in the charger. Since it's after the throttle, when it's closed a vacuum is created between the charger and throttle. The vacuum doesn't create much of a load as it isn't mass, but the absence of mass.

Supers get their power from the crank, and it takes a little HP to turn the charger. Turbos get their power from the velocity of the exhaust gasses. This lets a TC produce more power then a SC given that both chargers produce the same amount of boost.

Also, on a TC, the power tends to come in a big rush, where as a SC tends to build power linear to the RPM of the motor. For the guy in the drivers seat, the turbo can be a bigger thrill when the power comes on.

And, supers need to be put somewhere that can be belt driven. The most common place for a super is right on top of the engine, which usually leads to cut hoods - they can be difficult to put under a car with stock body panels. Turbos can be plumbed in anywhere along the exhaust system.

Finally, since there are so many turbo cars on the market right now, turbochargers are cheap at most pick and pulls.

Zach

Since everyone is speculating....which is usually as far as it goes..........

A turbo is more efficient. It stays out of the loop till called upon. Mr.2 gets close to 30mpg highway cruising IF you keep your foot out of it. It seems to be a toss up cost wise for proper installation of either ......but the turbo adds complexity.

Since my overall intention is to put this into the bus, instant, linear power with a SC is more appropriate. I also intend to use low boost. I dont want to get too complicated, after all

I don't know if it adds complexity.
It DOES add more plumbing, which can be interesting at the best of times. I don't know if thats any more complex then trying to make a super fit under a stock hood though.

But no matter if the air charge is coming from a turbo or a super, it still needs to be cooled and the engine has to be able to take the extra strain from boost.

Zach

For a low boost bus, I'd go with a small SC. No exhaust modifications necessary, no intercooler necessary etc.

Yup, the plan is the 230 SLK SC to be used Cheaper, available, not needed to be mounted on the intake.

SC can be mounted like an AC compressor. The centrifugal ones are smaller, easy to place, but $$$.

Turbos lag, SC is linear and can start boosting from 1500rpm up. I have heard of twin turbo, how common is twin SC?

You may note that I said "proper installation". Apparently that means different things to different people, including those that will add a turbo anywhere in the exhaust system then bitch about turbo lag.

Here's a couple pics of "proper installation". You want complexity?..... you can find it here.

An SC is no walk in the park either.

Turbos don't always lag a lot. With modern technology you should be able to pull off 7lbs pretty low. Again, on that watercooled 1.8 we crossed 7lbs at about 1400 rpm. A properly sized cermaic centered hair drier makes a lot of difference. We were using a single 28 pulled from a 300zx twin. There is a nice thing about the slight lag. Clutches will last more than a week

I'm not sure I'd go twin anything on a 2 liter or smaller, but yes, twin supercharger has been done. Haven't seen it in production though.

Who's complaining........

Uh, ya....that is more complicated than I want to do. The small SC with no IC, instantaneous boost linear up to red line is a beautiful thing (in theory).

I would guess that a /6 CIS with two ports blocked would have the right RPM profile for a 2.0 /4 (gas amount to air and RPM). This thought comes about with some reading on swapping CIS turbo systems onto non turbo engines, ,and CIS on to non CIS. Some are easy like Volvo 240 turbo onto a GTI n/a engine. There is a guy who already unsuccessfully tried 2.7 Porsche CIS to corvair with crappy results, though. I hope to not follow in his foot steps...I see some things I would already do differently.