sweanders

I was wondering one thing about all of the supercharger installations:

Is it possible to with only an hour or so in work time to disconnect the supercharger? Not remove it or anything like that, just disconnect it.

This is because of that every year the car needs to get a emissions+safety+bunchofotherstuff checked and it's not legal to modify a car in ways that raises the power with more than 10%.

So I was thinking if there is any way to simply disconnect a belt or something, anyone eho knows?

I know of one guy locally who has a turbocharged VW VR6 and he replaces a pair of pipes every year, it doesn't run well but he gets it through the test every year..

sweanders

They only do the dyno testing if they suspect that something is wrong.

We are however allowed to have stuff mounted in the engine compartment if they are not in use.. Hehe..

Ian928

I suspect you could just take off the belt on a centrifugal compressor and let the air pass trough it. I can't see any easy solutions on a positive displacement compressor though...

sweanders

Anyone who knows what kind that Tim Murphy is using in his kit?

Ian928

Tim Murphy is using a centrifugal compressor. I believe one of his installations should run without a belt. He can probably verify if the engine gets enough air by doing this.

I am surprised you get away with this! I don't think you could do that in Norway, sadly. What you could do here is to replace your brakes with GTS items and claim that your engine with compressor don't produce more than the GTS' 350 +10%. The test station would then update the cars registration papers stating that the car is legal with the modifications. I believe you could do the same in Sweden? That way you don't have to worry about being caught with the belt on, or worse, loose your insurance if you run off the road with the belt on! You could have a set of pulleys producing very low pressures in case the test station demanded a dyno test.

Lagavulin

Hi sweanders,

The power steering, alternator, and air pump belts would need to be removed first in order to remove the supercharger belt.

It may be possible to loosen and move the sc belt away from the crankshaft pulley enough without having to pull the other belts, but I'm not sure about that, but would save lots of time.

Lastly, remove any combination of plumbing after the supercharger discharge and you're 100% normally aspirated; that'll take 10 mins.

sweanders

Lag: So if I basicly if I keep everthing connected and let the SC-belt be in place but remove a piece of plumbing the car won't be supercharged anymore?

Ian: It´s a bit of a grey zone in the Swedish system and the risk I
m taking is that my insurance company will go a bit berserk..

There are a lot of US-make streetracers and others who don´t have any problems getting there 700hp+ cars through the test every year so I don´t worry to much about it. Would just feel good to know what way to go.

I don´t think that the extra speed will cause any more problems since I already have a tendency to drive way faster than the speed limits most of the time already and intend to keep the cats on.

Bernie

Well,
The car won't be supercharged but it will be as loud as hell blowing air around your engine compartment.
This may be the "alert" your friends at inspection would be looking for.

If the noise doesn't grab their attention, their hair blowing straight back anytime they walk near the hood will.

sweanders

Bernie, that's no problem for me.

They've always laughed at me when I come to their place and put the front license plate on with scotch tape before the inspection..

GoRideSno

A simple answer for any system may be to just put a very large pulley on the supercharger. A large enough pulley so that it is moving just enough air to keep it around the stock HP would be used.
With the Whipple the pulley can be changed in about 10minutes.

With the whipple and the eaton you could just remove the belt too. Some air will bypass the the SC through the bypass valve and some will be sucked throuh the SC as it freewheels. The engine will run mormally at lower rpm levels.

HTH,
Andy K

Niels Jørgensen

Hell, it seems as if, for once, Denmark isn't in the front of the pack when it comes to stupid anti-car laws.

In DK there's a 20% limit if you change the "identity" of the car, which basically boils down to complete engine swaps or replacing major parts of the engine. As long as the engine is std. you can bolt-on whatever you like.

Only downside is that the car will need to be re-evaluated after install and taxed accordingly.

Wait a minute! Maybe I can argue that a "bastard" Porsche is worth less than stock in which case they owe me money, at a 180% tax, even a small reduction in value should easily cover the SC cost, perfect . Oh well, maybe not..

Lagavulin

Actually, that's not what I meant to say, but sure, that would work perfectly well if you could get away with it. You could buy a cheap radiator hose of the appropriate shape, and affix it to the blower outlet to direct the charge downward and away.

Even if you did it the 'proper' way which consists of removing all the belts, etc, it would be a couple hours work at most. The rest of the year though, you're burning up the back roads of your country having a blast with your forced induction 928. Everyone's different, but that's what I do with mine; yahoo!

Now that's funny!

Z

Besides the methods already mentioned, you may have some other options as well. If you disconnect the hose from the blowoff valve that goes to manifold vacuum and connect it to the vacuum reservoir, like the vacuum line for the flappy is, the blowoff valve will stay open all the time. With the blowoff valve open the supercharger can't build boost, or at least as much boost as usual. There will be at least one other easy method, but I can't talk about that yet. It's still in development and I'm sworn to secrecy.

It's kind of interesting that they let you have the stuff on the car but it's okay if the power is low enough during the test. Can you adjust the throttle cable so that the throttle only opens part way? Can you tape a block of wood under the gas pedal? I NEVER thought anybody on here would be looking for ways to reduce power in their 928.

Tony

As far as HP and stuff, all i have to say is thank Gawwwd we dont have to deal with the "politics" of this stuff like they do!

ViribusUnits

How the heck ar you suppost to make your 20 year old car put out 1000 hp with rules likes that???

I mean, why?!?!?!?