I want to wire open my bypass valve - (97 355) Not a whole lot of room to work with down there - It looks like I have to remove the airbox's and the heat shield to gain access. Is this correct? Or is there another way of getting at it? Appreciate any info from someone who has done it in the past. Thanks - Frank
Why would you want to reduce torque and reduce the effciency and life of your cats by running them at a lower temperature? With the butterfly working you get more torque and the same power. It's just for boulevard cruising then that's as good a reason as any I guess, but if you want to out drag the hot hatchback from the lights, leave it connected. The challenge cars have them removed mainly because they operate mostly while open, but also to remove the possiblilty of reduced power if it fails. Michelotto lock open the 360 inlet manifold for the same reason on the N-GT cars.
A number of reasons why... 1st...better sound at idle (I think) and why not experiment? 2. Not irreversable... Can easily change back 3. No Impact on torque TQ - do I search on old Chat and you will see the dyno numbers + excellent write up by Mitch. (TQ whole at 2500-3000 rpm).
The first picture shows me actuating the exhaust valve. The red arrow points towards front of the car. I am standing in the center of the rear area reaching forwards to the edge of the exhaust heat shield. Then around that edge, under the valve body*, and to a ball joint. Vertical movement at the ball joint rotates the crank (flat part caked in rust) which in turn rotates the exhaust valve. It is easy to apply enough vacuum with your mouth to actuate the valve. Likewise 2-3 pounds of force by your little finger can actuate the vavle. The vertical movement of the actuation rod is shown in red, the rotation of the crank in red, and the axis of the exhaust valve in green. To wire this thing open you can lasso the shank (fixed on crank, rotates in ball joint) with mechanics wire and then wire to the top of the vavle body.
Thank You Mitch - I bow down to your knowledge and expertise and you have come through again. Mine is pretty stiff. From previous posts I read (I think) 2-3 psi in the vacum tube or 3/4 lb tension to open. To test, I used 100LB fishing leader. When I go to wire it I'm going to use aircraft safety wire and I want to do the wrap under the valve to hide it from a concours judge, so I think I'll pull the shields...a have small hands, but not that small. I'll post something when I finish. Thanks Again Frank
How about bypassing the vacuum solenoid, (Inside right rear fender), remove the vac lines and connect with a male-male nipple? Vac from the reservoir will keep the valve open, and valve will still look stock. Mark
Hmmm...I'll look at that. I prefer to keep it simple as possible if I want to go back...just a snip of the tins....stock again! I was going to take the boat out today, but its raining...so I think I'll start the project now... Thanks
Overnight, I thought of another option: Wire the valve partially open so that you reduce the backpressure during low RPM operation but enough fo the exhaust is blocked to prevent the nasty waves that can cause a hole in the TQ curve in the 2500-3500 RPM range. The vacuum then pulls the valve completely open in the higher parts of the rpm band.
I'm working on it right now.... How about this..... Re: the Vacum Line.... I have a small in line valve that is used on aquariums....the valve is very small and 100% adjustable with a small knob on it... You can set it full open / full close / 50% in a matter of seconds....just reach in and turn... More on this latter...
