D-Valve

Has anybody experimented or tried a D-valve (sorry dont know the proper name.) Its installed right before the throttle body and allows the engine to pull air from the atmoshpere instead of the turbo. Once the turbo starts to build boost it shuts the Dvalve. From what I have read it helps with turbo lag by quite a bit. My question is how would this effect tuning with MS or LH? Im doing a +T on my sons 240 and aiming for lot of bottom end power. Anyways here is a link to what Im taliking aboug.

http://www.shelbycsx.com/csx321/buildup/dvalve.htm

I just got done reading. Interesting. That won't work on LH though unless you run a hose from the valve to somewhere between the MAF and the turbo. On MS you would be all MAP based, so that wouldn't be necessary. Tuning shouldn't really be any different because you aren't adding boost or anything like that. The ECU should react the same.

This would be an interesting experiment on my Camaro because it has some really long and fairly small turbo piping. I don't think the 240 is lacking there for a simple +T though.

Why am I not surprised that its a Turbo Dodge site.
Honestly, if it worked...there'd be more talk about it. The last update on that site is 2001.

thinking on it after I read it a few hours ago. The only way it would help with turbo lag if the turbo set up was limiting the air flow before the turbo kicked in. Lets say you had a spunky engine and you turbo was killing the lowend power. Which we know on a 2.3 they are doggy taking off anyways, so, I dont think a Dvalve would be beneficial. Just my thoughts, but on some applications it might just work.

fastcomet said:

Has anybody experimented or tried a D-valve (sorry dont know the proper name.) Its installed right before the throttle body and allows the engine to pull air from the atmoshpere instead of the turbo. Once the turbo starts to build boost it shuts the Dvalve. From what I have read it helps with turbo lag by quite a bit. My question is how would this effect tuning with MS or LH? Im doing a +T on my sons 240 and aiming for lot of bottom end power. Anyways here is a link to what Im taliking aboug.

http://www.shelbycsx.com/csx321/buildup/dvalve.htm

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Any metered air system will hate it. Any map based system technically won't care.

This is just dumb turbododge nonsense. I've been part of that community for decades (loves me some turbo 2.2/2.5 action) and they used to constantly come up with hillbilly pseudo-engineering like this. As far as the TD crowd is concerned, a modded 1G DSM BOV is the best anyone can hope to use, and other such garbage.

I'm not seeing this be helpful in any way.

miguels244 said:

I'm not seeing this be helpful in any way.

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Basically, the point when boost hasn't started to build up, engine sees turbocharger as a restriction. But it is rotating and let air flow into engine quite freely.

There were some innovations during 80's in rallycross. Martin Schanke had several experiments with extra throttle bodies. His idea was to keep turbo spinning, so engine would react faster. Engine management systems has come a long way from that so haven't seen those since.

A pre turbo throttle body might be what you are looking for, it keeps the spool up during shifts by reducing the work the compressor side is doing. More info:
https://www.f1technical.net/forum/viewtopic.php?t=3012

A crazy Brit tried it on lh2.4, with succes. The only downside would be the compressor side seeing vacuum resulting in a little oil in the charge air. I'm still looking to try this eventually, the oem throttle is 63mm, the 13c inlet 60mm O.D. So a machined adapter to attach a OEM throttle to and a cable should work. Link:
https://youtu.be/kmfRKxGSwvQ

Yeah, that's called a draw-through setup, and unless you're using a turbo with carbon seals, your engine is going to ingest a lot of oil. Old Garrett turbos, like the ones used in the 80s, were all made that way, but I don't think mitsubishi turbos were.

The first Turbo Dodge cars (T1) were draw through with the throttle body in front of the turbo, and it worked...but there are better ways to accomplish an increase in spool time (which I can assure you is minimal, I've had a T1-based turbo dodge) such as better mapping in the ecu and waaaaaaaaaaaay more modern turbos.

The aircooled beetle crowd does draw through a lot on their turbo setups, it's a good place to look for info if anyone is interested. It is important to understand that the Turbo Dodge crowd is firmly buried in the past, regurgitating terrible information that is way out of date. It's no surprise that every single one of the 'engineering' websites they refer to all look like something someone made on Geocities in the late 90s...because that's when they were made.

Well partly, the setup I'm referring to has 2 throttles, one pre turbo, and on on the manifold as stock. Ideally you'd set it up to keep the pre turbo one open to an extend where it does not result in oil leakage from the turbo, whilst still reducing the amount of work (air pumping) it is doing. 1980's turbo F1 cars ran the same setup, with 2 throttles.

It's a bit more involved than a carb setup, and would require an additional cable to the original throttle wheel. But judging from the before and after in the video its well worth it in a track application where turbo wear and longevity is less of an issue.

OttoB said:

Basically, the point when boost hasn't started to build up, engine sees turbocharger as a restriction. But it is rotating and let air flow into engine quite freely.

There were some innovations during 80's in rallycross. Martin Schanke had several experiments with extra throttle bodies. His idea was to keep turbo spinning, so engine would react faster. Engine management systems has come a long way from that so haven't seen those since.

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That's what a CBV is for.
Need a big one?
A small throttle body in parallel with the compressor...actuate according to taste.