[Gigaherz]

That is the question..

I just got an svt intake manifold for my turbo project. Looking through the tb opening at the rotating runner assembly it looks like it's a pretty good abrupt obstruction to flow when the DSI is activated and the short runner section moves in the way of the throttle opening somewhat. The svt runners are already long as it is. I was thinking maybe it would be best for a turbo app to leave the runners in the short position all the time or better yet see if the manifold can be split apart, so the inner assembly can be removed making flow in the manifold better and increasing the volume of the chamber as well. Problem is that manifold glue is probably damn near impossible to seperate. Unlike the 10 minutes in the oven headlight mod some have done.

Would be interesting to hear the experiences of the boosted svt owners on here as to how much of an effect the DSI has. Especially from people with broken dsi cables leaving the runners in the short position all the time. If I hear it is worthwhile I'll keep it and make the DSI functional.

 

[Saleen09]

Tom has done alot of testing with the DSI on my car and believe it or not, keeping it in long runner mode actually made more power. He tried all the way up to 7k in small increments.

I am sure he'll chime in with more detailed info.

 

[Gigaherz]

That would make sense since with the runners retracted the flow through the manifold would probably be better and more uniform I'm guessing.

That is good to know! Thanks.

 

[mountandriver]

will the factory svt intake handle boosted presure or you talking about an aftermarket intake

 

[whiskeytangofoxtrot]

It handles boost, you just have to use upgraded clamps.

 

[mountandriver]

that's realy good .... i've just bought a little turbo and i'm just trieng to figure out every thing on a tight budget

 

[OrangeSVT03]

that's realy good .... i've just bought a little turbo and i'm just trieng to figure out every thing on a tight budget

Good Luck, I thought the same thing. Now a few thousand dollars later I'm almost done

 

[belacyrf]

Good Luck, I thought the same thing. Now a few thousand dollars later I'm almost done

Few thousand??? plehhh...

Stop your whining.. you have a long way to go

Saleen.. get Tom to chime in here about that DSI testing. I'd like to hear some more info on that!!

 

[Dudley]

I'm also curious to see what Tom has to say. My [crude] understanding was that long runners work well with a turbo because they make more low-end torque, which helps to spool up the turbine faster. I'm not sure how much it hurts performance at higher RPM's, though.

 

[Gigaherz]

Ahem..(cough)TOM!(cough)...

 

[Sonic04SVT]

All engines's (even FI) powerband is determined by runner length, diameter, and so forth. The length of the intake has a tuning effect in which it at some RPM's it aids power production and and at other RPM's it hinders it. The exhaust headers also have a similar effect (length, diameter, collector style, and so forth).

The longer runners would probably work best to spool the turbo up faster and offer more low-midrange power, I just wonder how much on the top end it would hurt. Seems like if the turbo was still in good efficiency at higher RPM the switchover would help out, unless there is something funny happening at the actual switch over (boost drop, surge, etc..). Maybe something causes more harm then good during the switchover which results in lower performance because a turbo is more symbiotic to the engine (X boost is not generated at X RPM's like a supercharger, but rather boost is created by things like engine load, heat, etc... Same reason a cam change can kill a turbo but not necessarily a supercharged car etc..).

Anyway maybe someone with some dyno time can chime and explain it to us