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Sun Apr 18, 2021 11:22 am

I purchased this old pulley driven power adder yesterday and looking for Any any information about it.

Thank You!

Sun Apr 18, 2021 1:03 pm

G.E.M. made stacks for go-kart/motorcycle carbs. What's the diameter of that carb? I'm guessing that's off a racing kart or motorcycle. Maybe a snowmobile. That looks like it might be an old Tillotson carb.

Sun Apr 18, 2021 2:14 pm

I just found out from a friend of mine that a friend of his has this setup on a 58 vw.

The carburetor is a TILLOTSON HR 30 A

I will try to post a picture of the back side. The rotary bearing caps have vw Aluminum seal covers....very cool.

Sun Apr 18, 2021 2:32 pm

That "power adder/blower" looks like a Porsche 912 smog pump. Not conventional but it might work on a 36hp. Harley used a Tillotson carb similar to that on the shovelhead, and they were about the same displacement as a 50s VW.

Sun Apr 18, 2021 2:58 pm

Just looked it up, and that carb is stock equipment for late 60s early 70s Rupp and Ski-Doo snowmobiles. It took two of them to run a 600-750cc two stroke one for a 250cc. Sachs also used one on a 290cc single cylinder. I remember these carbs because a friend of mine had an old Ski-Doo 250 with one of these. It was conveniently pointed right at the rider so you could shoot starting fluid down its throat while you rode.

Sun Apr 18, 2021 3:33 pm

Here’s a whole thread on that smog pump.

https://www.thesamba.com/vw/forum/viewtopic.php?p=2683373

Sun Apr 18, 2021 4:18 pm

Sun Apr 18, 2021 4:21 pm

This is the back of the power adder. So its vw. It bolts to the intake. My friend told me he knows someone who is running this exact setup on his 58 Bug.

Sun Apr 18, 2021 5:07 pm

I think it’s more likely that this carb, blower/smog pump setup was put together for a motorcycle or go-kart. To get more than a pound or two of boost on a 1200 cc motor, you would have to be spinning that tiny smog pump at 15,000-20,000 rpms at 3500rpms engine speed, and even then you would choking the engine with that tiny carb. I’m currently building a 59 engine with an AMR 300 blower, that’s probably twice the size of that smog pump, and at a 2.7:1 drive ratio I’m only expecting to get around 6 or 7 pounds of boost.

The main thing is that carb, it’s just too small to run a 1200cc or larger engine. I don’t doubt you could get that smog pump to run on a 36hp, but not with that carb, and even then any power gains would be meager at best.

Wed Apr 21, 2021 8:38 am

no matter how much you want to call it a power adder, it is not. it's a smog pump from the 70's

Wed Apr 21, 2021 8:54 am

Erik G wrote: no matter how much you want to call it a power adder, it is not. it's a smog pump from the 70's
Don't forget the electric superchargers.

Wed Apr 21, 2021 5:43 pm

Yep, no such thing as a free lunch. However, I bet that thing would make a 200-300cc a bit more peppy.

Fri Apr 23, 2021 3:47 pm

joes50pu wrote:

Looks like somebody got creative with a couple of 80mm gas caps.

Sat Apr 24, 2021 4:46 am

You can double your HP by putting your fan shroud hoses direct into your carb