When I first got the car, I was really surprised to find out that Buick hadnt put a bypass valve on the car. Just about every factory and even aftermarket turbo and supercharger system Ive seen was always equipped with a bypass valve to dump boost pressure when you slam the valve shut, which obviously protects the turbo from damage. God knows how much longer they can last with this. I had the goal of doing this a year and a half ago, but I was too busy with other things. Another cool thing about a bypass system, and NOT a blowoff valve, is that under high vacuum, while cruising, air is being completely bypassed around the turbo. Its basicaly running like an N/A motor...straight from the intake tube and into the throttle body. I still have yet to see if this improves mileage at all. Then when you get under boost, the valve is forced shut, and the turbo system seals and works like it should. Its basically like an on/off switch for the turbo. Another good thing is that there is nothing but metered air being circulated. So when you let off the trottle, you wont get any huge rich spike which causes stalling, hunting, etc.
Anyway, it works GREAT. In the process I also discovered I have a 62mm TB. Awesome! I always wanted to get one...always wondered why my engine was so strong at low throttle.
I used one of my Bosch 103 bypasses left over from when I made a dual bypass setup for my cobra when it had the blower. I used 110's on that system cause it has a brass ring inside vs. the plastic one in this, which is alot stronger and intended for higher boost. But I had it sitting around and wanted to put it to good use. One good thing about the 103 is that is has a much larger stroke. Something like 10mm vs. only 3 or 4 with the other ones. This means alot more air can be dumped when u shut the throttle, and its also open alot more while cruising, further enhancing the N/A like characteristics. I really need to get some pics of this system. Just need to find my USB/camera cable. What I did was, I got a 1" threaded steel pipe, about 2" long, drilled out the up-pipe, tapped it, and threaded in this tube..its basically a bung. Had to do it this way cause I have no welding equipment. Then I drilled a hole through the intake tube, drilled a smaller hole in a section of silicone tubing, slipped this silicone tubing over the intake tube, and clamped it on with 2 hose clamps to seal it. The dump side of the bypass squeezes into this hole and into the intake tube, and the pressure side of the bypass connects to the up-pipe bung with some heater hose...only about 3 inches worth (the whole system is very compact) The vacuum line runs to the furthest to the firewall steel tube that comes off the vacuum block, where it T's off to the MAP sensor. I used hard line cause the bypass vacuum/pressure signal needs to be strong and responsive.
Anyway, when I get under boost and rapidly pull out of the throttle, I hear a nice muffled dump of air going into the intake tube...not the loud obnoxious blast of a blowoff valve that ricers consider the sign of a fast car. The rpm's immediately drop FAST down to idle speed, and there is no drop below idle rpm's, no stalling, no hunting, nothing. Its just like an N/A car, and that stupid fluttering sound is GONE...you know, the sound of an impellar being slammed into the bearings like a hammer and the accompanying flutter. I imagine a turbo could last 10 times longer with this. Should be considered mandatory when some people spend big bucks on one. By the way, I didnt have to change the tune at all. I pulled the orange ECM wire cause I figured Id probably have tune issues, but when I was done, I had all the exact same settings on the extender as before. Its also running is closed loop at idle like it shoud...actually that is the one change. I had it running with open loop idle cause idle sucked. But the bypass system seemed to help that, and I noticed the engines starts alot quicker now too.
Anyway, it works GREAT. In the process I also discovered I have a 62mm TB. Awesome! I always wanted to get one...always wondered why my engine was so strong at low throttle.
I used one of my Bosch 103 bypasses left over from when I made a dual bypass setup for my cobra when it had the blower. I used 110's on that system cause it has a brass ring inside vs. the plastic one in this, which is alot stronger and intended for higher boost. But I had it sitting around and wanted to put it to good use. One good thing about the 103 is that is has a much larger stroke. Something like 10mm vs. only 3 or 4 with the other ones. This means alot more air can be dumped when u shut the throttle, and its also open alot more while cruising, further enhancing the N/A like characteristics. I really need to get some pics of this system. Just need to find my USB/camera cable. What I did was, I got a 1" threaded steel pipe, about 2" long, drilled out the up-pipe, tapped it, and threaded in this tube..its basically a bung. Had to do it this way cause I have no welding equipment. Then I drilled a hole through the intake tube, drilled a smaller hole in a section of silicone tubing, slipped this silicone tubing over the intake tube, and clamped it on with 2 hose clamps to seal it. The dump side of the bypass squeezes into this hole and into the intake tube, and the pressure side of the bypass connects to the up-pipe bung with some heater hose...only about 3 inches worth (the whole system is very compact) The vacuum line runs to the furthest to the firewall steel tube that comes off the vacuum block, where it T's off to the MAP sensor. I used hard line cause the bypass vacuum/pressure signal needs to be strong and responsive.
Anyway, when I get under boost and rapidly pull out of the throttle, I hear a nice muffled dump of air going into the intake tube...not the loud obnoxious blast of a blowoff valve that ricers consider the sign of a fast car. The rpm's immediately drop FAST down to idle speed, and there is no drop below idle rpm's, no stalling, no hunting, nothing. Its just like an N/A car, and that stupid fluttering sound is GONE...you know, the sound of an impellar being slammed into the bearings like a hammer and the accompanying flutter. I imagine a turbo could last 10 times longer with this. Should be considered mandatory when some people spend big bucks on one. By the way, I didnt have to change the tune at all. I pulled the orange ECM wire cause I figured Id probably have tune issues, but when I was done, I had all the exact same settings on the extender as before. Its also running is closed loop at idle like it shoud...actually that is the one change. I had it running with open loop idle cause idle sucked. But the bypass system seemed to help that, and I noticed the engines starts alot quicker now too.
