Supercharged mk1

[abreut]

You change the boost by changing the ratio of the crank pulley to blower pulley (like gears on a push bike - crank cog:rear whell cog). You make the crank pulley bigger to spin the blower faster and make more boost, or you make the supercharger puller smaller to do the same thing. With these blowers its easier to get a bigger crank pulley off some other vw model.

[gldgti]

You change the boost by changing the ratio of the crank pulley to blower pulley (like gears on a push bike - crank cog:rear whell cog). You make the crank pulley bigger to spin the blower faster and make more boost, or you make the supercharger puller smaller to do the same thing. With these blowers its easier to get a bigger crank pulley off some other vw model.

i concur...

[thestu]

You change the boost by changing the ratio of the crank pulley to blower pulley (like gears on a push bike - crank cog:rear whell cog). You make the crank pulley bigger to spin the blower faster and make more boost, or you make the supercharger puller smaller to do the same thing. With these blowers its easier to get a bigger crank pulley off some other vw model.

ok yeh thats cool i understand that

thanks for your help bro

did you have k-jet 1.8? was it a stock motor?

[gldgti]

i think grunmk1's was a 2.0L with EFI

[abreut]

No worries. I had an AGG 2.0l which was EFI already and I used a microtech ECU. I'm not sure how to set it up with k-jet, it would make things trickier I'd imagine but its not impossible. Good luck though, it definitely gives you a good power boost!

[thestu]

No worries. I had an AGG 2.0l which was EFI already and I used a microtech ECU. I'm not sure how to set it up with k-jet, it would make things trickier I'd imagine but its not impossible. Good luck though, it definitely gives you a good power boost!

ok cool!

well there is a first for everything! hope it works

one last q...where do i run the bov? between the ic and the throttle body?

[gldgti]

yeah, usually close to the throttle body between the air mover and the throttle.

[thestu]

yeah, usually close to the throttle body between the air mover and the throttle.

ok. i learn more and more everyday

[abreut]

Heres a pic of my old setup, you can see the bov (or bypass valve in this case) on the pipe-work heading from the intercooler to the throttle body. Just one thing, with a blower if you say back off at 5000rpm the pressure doesn't just vent in a split second and give a little whoosh like on a turbo, it just keeps pumping out with a massive roar. It is REALLY loud. With this type of blower there are ways to get around this by activating the clutch on the blower to shut it off when the throttle is closed but I never found a way I was entirely happy with because when you'd stand on it again there was a slight delay before the blower clutch disengaged again and the power came back on. I had some ideas on things to try to get around this problem.

[thestu]

Heres a pic of my old setup, you can see the bov (or bypass valve in this case) on the pipe-work heading from the intercooler to the throttle body. Just one thing, with a blower if you say back off at 5000rpm the pressure doesn't just vent in a split second and give a little whoosh like on a turbo, it just keeps pumping out with a massive roar. It is REALLY loud. With this type of blower there are ways to get around this by activating the clutch on the blower to shut it off when the throttle is closed but I never found a way I was entirely happy with because when you'd stand on it again there was a slight delay before the blower clutch disengaged again and the power came back on. I had some ideas on things to try to get around this problem.

ok yeh i understand that! very nice. was it fun to drive?

[abreut]

Yes it was fun. I had the supercharger clutch wired up to a switch on the dash so I could literally turn the blower on mad-max style. The rest of the time I could just drive around normally and quietly and the blower would just free-spin under vacuum. When I flicked the switch I would get an instant extra 45-odd kw and a great whining sound from the engine and the exhaust note would almost double, it was great fun.

[gldgti]

Just one thing, with a blower if you say back off at 5000rpm the pressure doesn't just vent in a split second and give a little whoosh like on a turbo, it just keeps pumping out with a massive roar. It is REALLY loud. With this type of blower there are ways to get around this by activating the clutch on the blower to shut it off when the throttle is closed but I never found a way I was entirely happy with because when you'd stand on it again there was a slight delay before the blower clutch disengaged again and the power came back on. I had some ideas on things to try to get around this problem.

why not exhaust the BOV through a hose back into the feed pipe into the blower?

[thestu]

Yes it was fun. I had the supercharger clutch wired up to a switch on the dash so I could literally turn the blower on mad-max style. The rest of the time I could just drive around normally and quietly and the blower would just free-spin under vacuum. When I flicked the switch I would get an instant extra 45-odd kw and a great whining sound from the engine and the exhaust note would almost double, it was great fun.

thats nuts! that what i was saying to dad i could just wire the switch up under the dash so that if there were cops i would just flick it off how long did it take you to do? did you move the alternator under it? i was thinking of doing the opposite...and having the sc under the alternator...so its at least a lilbit hidden...but i think im going to have to get a 2.0lt with a computer because the k-jet gets in the way massively! is there a small intercooler tucked up the front on the right?

[RhysQ]

sweeeet! thanks for the advice. i'm trying to find some for sale now

have a look in the classifieds of www.boostcruising.com. there are usually a heap of forced induction parts available from there all from australia.

happy hunting!

[abreut]

why not exhaust the BOV through a hose back into the feed pipe into the blower?

I actually did do that, I had to when I went for the engineers certificate. It was still really loud because i was just using a pod filter so it didn't muffle the sound that much. What I needed to do was run either a massive bov or a few normal sized ones. I was investigating large solenoid activated bypass valves at the time which would have had the added bonus of creating a less restrictive intake path for the motor when the supercharger was turned off. The other thing that would have helped is venting into a large chamber of some sort and then into the intake.