Tame the Torque

[Roger Ramjet]

Street driving a blower car on factory tires is a challenge ..... and can be embarrassing. I don't know if anyone else has tried this, or even wants to, but I think this is a very simple change to aid traction. The supercharger bypass valve is an intake vacuum controlled device to reduce airflow and boost during cruise. The valve is normally open (bypass) with spring pressure and closed by vacuum on top of the blower during throttle opening. The instant torque hit when bumping the throttle is from the bypass valve closing.

I pulled the vacuum tube off the vacuum motor. A Harley CV carb pilot jet can be screwed into the vacuum motor inlet tube. I used a #44 or 0.016 inch jet. Then put the vacuum tube on again over the jet. The result delays the closing of the valve. The engine runs normally aspirated for about 1 second then goes to boost. This condition is much more controllable with throttle than the instant torque hit without the jet. Since the jet works in both the open and the closed direction, the valve does not open during shifts.

Here is a source for the jets.
http://www.harley-performance.com/cv-carb-jets.html

[norris_83]

whats the stang referance for?

if this works, it might be a very nice set-up.. would like to see dyno graphs overlaid if possible..

[PQ]

I don't know how to read that graph, but I fillow the logic. Makes perfect sense. The barb to the actuator already has a restricting nipple but certainly could use some more in your theory.

How did it work for you?

You'd really have to get it just right but if you could time it just right, it would be awesome.

[Roger Ramjet]

Look at the 3rd (center) group, TPS green trace. This was a throttle stomp at 3000 RPM in 3rd gear. Notice the second group, the MAF blue trace continues to increase smoothly. About 1 second after throttle application, at 3655 RPM, the tires can no longer take the torque and loose traction. The result during normal throttle roll on is much better traction - even in cold weather.

[norris_83]

The scan is from a Ford? Did you try this out on a blown Ford?

[PQ]

On the magnuson there is already one there. You'd have to replace it with a more restrictive one. And wouldn't the boost shutter stay shut to long during deceleration?