I remember a while back, a website that offered a pneumatic dump valve for turbo exhasut. I connected right after the headers, and when the intake manifold reached a certain pressure, it would open the valve, allowing the exhaust to dump out under the car rather than through the stock exhaust. This allowed for quite cruising when not in boost, but awesome spooling performace when the car was pushed. I cannot find the website and was wondering if any of you guys have heard of it and know where it is at.

-Justin

 

If you have a properly sized exhaust then "backpressure" shouldn't be an issue because it will be provided primarily by the turbine. IMO this is overengineering for a problem that could be solved by choosing the right size exhaust for your turbocharged car. Plus, in my opinion, bypassing the catalytic converter is just bad form. At least a hi flow cat, if not the stock one, will make it so you're not just spewing toxins directly into the atmosphere.

 

so what size is good for turbocharged car??
3" i am guessing

 

My friend has something like that on the end of his dump tube of his GT series turbo. Says it works great for those that want performance as a daily driver. Wish I knew where he had got it...

 

yeah it is a good idea for a car as long as you don't floor it at every stop. I f you do, the smoke and the noise well draw way to much attention and get you pulled over like you deserve. But when you do floor it and need the extra power the car starts to move, the valve opens, and bam, free blowing exhaust, let go of the throttle, and its quite again. I think its a good idea.

 

2.5" is fine on the Lancer. I don't know if anyone has gone larger, but I don't think there's much reason to do so for most of us. I could see omarboy going larger, but that's about it.

 

i have an greddy exhaust 3 inch which was loud but after i put my turbo on its quite as hell, dont kno why

 

The larger exhaust on a N/A will almost always be louder than with a turbo or sc. Wish I knew anything about science to quantify my claim... It's just what I've heard and read.