The Lotus Cars Community banner

1 - 7 of 7 Posts

·
Registered
Joined
·
52 Posts
Discussion Starter #1
Hi, new to the forum but I read stuff here all the time. Don't own a Lotus (yet) but hope to one day...

I saw this charger than thought maybe you guys might be interested, still looking for more data on the unit.
http://www.bahnbrenner.com/vw_audi/products/1190/SR2_2087_Twin_Screw_Lysholm_Supercharger
Says its an SR2 2087 made by Lysholm, look about right for a 1.8L and the price is right.

I have been looking around and noticed there are STILL no twin screw kits available for the Elise/Exige. I believe the main reason is because of the counter rotating engine and the fact that twin screw compressors have to be manufactured left or right hand because of their lobe profiles.

It is quite easy to make a reversing gear set it consists of three gears 0o0 thats it. All that would need to be done is to manufacture a snout with three additional gears to reverse the rotation and feed off the same oil used for the syncro gears, not hard considering they are on the snout side.
Hell, I'll even design and model the damn thing if someone wants to put up cash to have it made.
 

·
Registered
Joined
·
52 Posts
Discussion Starter #2
Actually after some thought and a few models I must digress, this only takes two gears to do... Its even simpler than I thought, in fact I am considering designing a system that hooks up at the idler pulley then transfers back to a belt which could be tensioned by using a double wide tensioner pulley with grooves in one end in place of the stock tensioner, not a problem because the stock belt is wrapped backwards over this pulley so its already spinning clockwise, and the gear system uses equally sized gears and output pulley so you end up with a 1:1 ratio. Basically the stock inside belt and new outside belt will be turning the new tensioner pulley at the same speed so the is no "rub" or slippage.

The idea here is to make a self contained 2 gear unit. Small, with its own oil and sight glass and a pulley that can then spin the twin screw snout in a clockwise direction. This is a simple and reliable design, uses the most of what already there without adding much complexity. You would need to order a snout that is about 1" longer or position the twin screw so it sticks out a bit farther than the stocker because the second belt would be a bit more than a belts width over.

I thought it might be easier to just put a drive pulley in and wrap the back of the belt over it but you cant just hook up to that because you will get bad slippage trying to drive a supercharger off the back of a belt... I only thought of this because I noticed thats how the water pump is done on the 2ZZ, but then its not a supercharger and requires much less force to turn.

I do have a question for you guys, on the room side of things... How much room is there from the frame/clam to the engine pulleys?
Maybe if you are going to do some work on your car you can just give me a rough measurement with a tape measure.
 

·
Registered
Joined
·
52 Posts
Discussion Starter #3
So, any one want to measure from pulleys to frame clearances?
I also need to know if the water pump pulley is larger on the Elise S and Exige S vs the NA models.
I am figuring that it is because when I look at this

It shows the belt coming off the idler pulley and going over the tensioner pulley and water pump pulley directly to the alternator pulley.
\Then I look at the supercharged engine and see this

There is no way the belt would clear the pump pulley if you were to take the supercharger pulley out of the circuit.
Thanks
 

·
Registered
Joined
·
52 Posts
Discussion Starter #5
Yea, I just googled "Idiot" and found this pick... LOL

Anyone have information on different pulley sizes?
 

·
Registered
Joined
·
341 Posts
Are you asking about clearance in the engine's longitudinal direction? I see about 1.5 inches between the alternator pulley (#7 in your diagram) and the engine mount. The other pulleys have at least that much room, I think. I say "I think" because most of the belt isn't visible from above. The end of the engine is tucked under the clam.

And of course, the engine moves around, so the static clearance may not be entirely relevant.
 

·
Registered
Joined
·
52 Posts
Discussion Starter #7
Yes, thanks.
However I have become aware of a much easier way of doing this.
 
1 - 7 of 7 Posts
Top