SD compressor wheel

[72Ford250]

Hey guys since i got to put a new wheel on my turbo heard rumors that the sd wheel will flow more air and will not surge due to the 1.15 ar housing? So can it be done???

[erics diesel]

I believe the stock wheel in our trucks is an upgrade to the sd turbos

[72Ford250]

Well it isn't a upgrade but a fix for there surging problem to much air jamming into the engine


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[BrianH]

Our wheel is what they call the wicked wheel. It spools a little faster than the sd wheel, but flows the same.

[72Ford250]

Then why does there's surge if it flows the same?


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[JSchuricht]

The OBS wheel is ued in the SD to help with surge, it also has the tendancy to lower boost slightly. Wouldnt hurt to try the SD wheel. I keep looking at my old SD wheel and thinking of putting it in my OBS. Probably wouldn't be a noticable difference.

[ol_Blue97]

Just get a new OBS wheel... you will be happy with any new wheel if its as bad as you say

[85_305]

Originally Posted by 72Ford250

Hey guys since i got to put a new wheel on my turbo heard rumors that the sd wheel will flow more air and will not surge due to the 1.15 ar housing? So can it be done???

Our trucks have a 1.15 housing (hot side) stock.. the wheels in our trucks stock are the wicked wheel and whats used to cure surge.

Originally Posted by 72Ford250

Then why does there's surge if it flows the same?


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I dont believe that you have an obs thats surging w/ the stock turbo, unless there's something else going on.

[72Ford250]

Originally Posted by 85_305

Our trucks have a 1.15 housing (hot side) stock.. the wheels in our trucks stock are the wicked wheel and whats used to cure surge.



I dont believe that you have an obs thats surging w/ the stock turbo, unless there's something else going on.

Umm I wasn't saying my surged I was saying if both wheels flow the same then why does the sd turbo with the factory wheel then surge and with wicked wheel/obs wheel that supposedly flows the same won't surge? Isn't the theory of the sd surging is beacuse the .84 ar housing is spinning the super duty wheel at a fast speed and trying to put to much air into the engine so if the wheels flowed the same (sd wheel and obs wheel) then wouldn't the obs wheel surge also surge in there turbo?


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[BigFuel]

It's in the design of the wheel. The OBS (Wicked Wheel) wheel has every other flute at a different height so that it takes big scoops of air but half as often. The SD wheel has all the flutes the same length taking half as much volume of air but twice as often. So either way the wheels are moving a relatively the same amount of air. SD surging has more to do with the late 7.3L's inability of their engines being able to consume the air that is being produced. Having a tiny turbine housing with a poor wastegate design leads them to produce massive air too low in their power band and the air backs up in the intake plumbing. Instead of fixing the problem the correct way (like the aftermarket has) people went with the OBS wheel that will allow some of the air to creep backwards when in over-boost rather then fighting/stopping the exducer as the SD does. Hence, lower boost but smoother power. Surging doesn't happen on the top end, it happens while the engine is climbing from the depths. Ford (well Garrett) fixed the 6.0's and newer by cutting holes in the compressor housing to allow the over boost to vent back into the air cleaner tube.

OBS Wheel



SD Wheel