Here's the thing. I really could care less about the supposed better gas mileage or about trying to save the Planet. I needed to primarily pass smog on my highly modified 1990 GMC show truck. I have been tinkering with my truck since I bought it new. I have had trouble passing smog for the last ten years mostly because smog techs are afraid to touch it. Every engine modification was done with a "50 State legal" product and had the required C.A.R.B stickers. My engine bay is full of these stickers! I can now say I am very proud to add the Dynovalve C.A.R.B. sticker. Here is a short list of my truck's mods: Built 5.7L w/ 4bolt mains. Reworked Vortech heads with full roller cam valve train, Edlebrock performer intake, Vortech 8psi Supercharger,hi-flow air intake, full MSD distributor and BAL ignition system, MSD Boost-a-Pump fuel system and Doug Thorley Headers. I had to replace my Hi-flow catalytic back to a stock 4 years ago because California requires stock cats. That hurt my performance somewhat.
Every two years I cringe at the thought of smogging this truck. This year I knew I would not pass as it was running extremely rich. Starting up the engine was not a pleasant experience as the fumes were seriously nauseating. Fearing the worst, I installed the Dynovalve after reading a bunch of posts about PVC problems. A lot of them talked about how the wrong sized PVC could adversely affect engine performance. Many complained they wish there was a PVC that could adjust to their engine modifications. Something adjustable. I had an ""ah ha" moment when I research what the Dynovalve claimed to do. This PVC should do a way better job then my stock one.
Because of the way my truck was running I figured I was in store for some expensive repairs for this smog so I decided to install the Dynovalve first to see what it could do. Immediately after the install, I notice the engine idled way better and the noxious fume were GONE! I took it out on the freeway and hammered the pedal. On a hot day the engine would ping normally so I would have to back off but now it accelerated beautifully! WOW! I think I will increase the boost with a pulley change now. Two days later I took it in for a smog test and I was already figuring it would fail but to my utter disbelief IT PASSED! As far as gas mileage, I picked up 2 miles or 20% so I am very happy with the results. I now plan to install the Dynovalve on my 03 Cobra.