BearKiller

I am building a larger Y-pipe in my exhaust and am thinking of adding an exhaust brake of my own making, implemented in the forward collector of the Y.

I figure on operating it with a cable-control mounted on my shift-lever.

It will be something on the order of a stove-pipe damper that is cable actuated with a heavy spring to release it.

I have also thought on having a spring between the cable and exhaust-brake-lever to allow extreme back-pressure to be vented; this may or may not be needed.

Okay, experts, please give me some feed-back on this; will it work??

Just how closed will the exhaust need be for braking effect??

How much closed is too much??

Has this been done before??

Thanks.

MoparMarv

Well I'm in the same boat. This will get some laughs but I'm working on an exhaust brake for my VW rabbit truck. I have some aircraft bleed air valves that are right about the size of the exhaust and they have motors on them so it can be done with electric rather than a cable. I'm curious to see what people have to say on this topic as well. My main worry is what if any damage is done from using an exhaust brake? My cousin from the next state over tells me they cause increased valve wear or something like that? How true is that?

BearKiller

Let's hope it doesn't come down to sink or swim.

wannadiesel

The best thing to do will be to install a backpressure gauge. The stock exhaust valve springs will only handle 30 psi of backpressure before you are risking valve float. The HD springs will take 60 psi. Most exhaust brakes close all the way but have an orifice that is sized to keep the pressure at a safe level up to about 500 RPM over the governor. There are some (BD brake, PacBrake PXBR models) that use spring tension to control backpressure. These brakes are more effective at low RPM than the orifice type.

edwinsmith

I've heard about the exhaust valve float problem but what harm will that cause other than reducing the braking action?

wannadiesel

Valves kissing pistons at 3500 RPM isn't pretty. Can cause: bent valves, cracked pistons, bent pushrods.

Ron E

Since all the Scrioccos were A-1 based like you truck, a great, and easy upgrade would be swapping the entire 4 disc system from a 16V Scirocco. Allso some of the A-1 cabriolets had 4disc set ups. too. 84-back GTI's, had 'em, but are hard to find. But, they do a world of good over the front solid-disc and drum rears.

I don't think you'd have a horrible time adapting A-2 (85-up) parts either.

scottmn1

Hey Bearkilller.......How is that homeade exhaust brake coming along. I would be very interested in hearing more about this as I would like to do the same thing. I am a fabricator myself and I get a lot of satisfaction out of building my own stuff(provided it works properly and dependable when finished) The whole concept seems pretty darn simple to me. But then there may be something I'm not thinking about too.

Scott