D valve anyone using one anymore?

[TurbododgePirate]

Okay, a long time ago in a galaxy far far away, I remember reading about a "D" valve. Although, I have never ever seen one on a turbododge. Does anybody use one?

The basic idea was a large check valve located before the TB. When you suddenly stepped on the gas it takes a short time for the turbo to start to spool. The D valve would bring air directly into the TB bypassing the turbo until boost was achieved for a quicker spoolup.

I just wonder does it work? Does it really spool up the turbo faster? It seems to make sense.

[cordes]

It supposedly works, but I haven't seen or heard of anyone using one in a long time. I know that most of them were giving up the ghost before 20PSI which really doesn't help a lot of people. In all reality if they worked and were reliable, I would think that this bunch of cheapskates (myself chiefly) would be all over it.

[john1320]

Sounds like I good idea would be combing over WRC sites or shops that support these rally cars, and find out what they are using. I myself never heard of a TDer reliably using one.

[TurbododgePirate]

Sounds like I good idea would be combing over WRC sites or shops that support these rally cars, and find out what they are using. I myself never heard of a TDer reliably using one.

What rally car?

[Turbodave]

The "D" valve idea was the brainchild of Dan Culkin if I remmeber correctly, haven't seen Dan on the forums in a long time, but his brother Pat is on here.

It sounded like a good idea, but the extra plumbing and work for a small gain in power while out of boost probably isn't worth it to most.

[MiniMopar]

He used one of those sump pump flapper valves and it did not like the heat and pressure after a while. The idea is sound, but probably wasn't worth the effort. Hooking a vacuum guage to your upper IC pipe will tell you if you are pulling a significant vacuum up there at any time.

[Dusty_Duster]

The "D" valve idea was the brainchild of Dan Culkin if I remmeber correctly, haven't seen Dan on the forums in a long time, but his brother Pat is on here.

It sounded like a good idea, but the extra plumbing and work for a small gain in power while out of boost probably isn't worth it to most.

The only advantage I can see is if the turbo car is your daily driver, you want better fuel economy, and you spend most of your time driving in vacuum.

[turboz523]

I used one on my 89 t2 daytona for awhile, there was a noticable reduction in lag time, but I never ran more than 14lbs of boost with it. It didn't make a huge difference but you could feel it.

[John B]

They work well and were used by Porsche on their turbos long before Dan made one for his TD.