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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???
 

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

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Discussion Starter #3
Well it isn't a upgrade but a fix for there surging problem to much air jamming into the engine


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

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Discussion Starter #5
Then why does there's surge if it flows the same?


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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.
 

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

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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.

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.
 

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Discussion Starter #9
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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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

 

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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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They dont flow the same; the obs wheel flows slightly less but has a different turbine design in the blades.

The OBS hot sides are 1.15's... the SD's are .84's.... so yes, the .84 is prone to spooling up extremely fast, so fast that the motor cant consume all of the air so it starts surging. The 1.15 on the OBS is so big that it doesnt have this issue.

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

Super well written :thumb:
 

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Now is this hot or cold side wheel? yall keep talking about the hot side housing being small on SD but larger on the OBS but my confusion comes in when yall talk about the compressor wheel or inducer wheel.

Yall say it allows some of thre charge air back through the turbo into the intake tube so that being said this "wicked wheel" or stock OBS wheel should be the compressor wheel on the inducer side.

My problem whith what i see here is with my turbo the blades are like the ones in the SD pic not like the OBS pic but as far as i know this truck is totally stock aside from what looks like a changed muffler.

Am i looking at that right and if i am this means i have an SD wheel?
 

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Sorry, this does get complicated as we have adapted a set of phrases that would confuse others. In the talks concerning just the turbo the "hot side" would be the side involved with the engines exhaust. AKA, turbine side or when speaking of just the propeller, the exhaust/exducer wheels. The "cool side" will be the intake side of the turbo. AKA, compressor side or of just the propeller, the compressor/inducer wheels. In the pictures above these are inducer wheels. Notice that these wheels are curved forward as they scoop air and shove it out of the compressor. Exducer wheels are flatter with the curved part of the wheel backward to allow air to escape.

This "hot side, cold side" wording is flipped for several of us as we have InterCoolers installed on our trucks. For us (after the turbo) the hot side is the intake tube from the compressor to the IC and the cold side is the tube from the IC to the Engine. I know, even more confusing.

The SD turbos and OBS turbos are the same Garret 38 turbos but with different build strategies. The SD has a smaller turbine housing so that it will spool faster but also has a wastegate that bypasses air once the turbo reaches the desired pressure. The OBS turbos do not have a wastegate and thus are built with a larger turbine housing that spools slower but is less prone to damage. For this reason a SD will smack us off the line but once we get above 2k RPMs our turbos will catch us up very quickly.

In this thread we where discussing compressor surge that the SD guys have and we do not. The shape of their flutes move more air then their engines can eat and the backed up air overpowers their turbo and spins the blades backward to exhaust the backed up air in the inter cooler pipes. The "wicked wheel" (note: they now have a wicked wheel 2) is based on the OBS wheel and builds and maintains the air charge appropriately in the SD setup. The SD guys have a more efficient turbo design but as they always do when they want more power they come back to the OBS designed stuff. They have a inducer wheel, we have an inducer wheel but when they put ours on theirs it's a "Wicked Wheel". They have a D66 turbo upgrade, we have a D66 turbo upgrade but when they put our on theirs it's called a Super D66. For cruising and trailering from the Factory you want their 4R100 auto tranny but when built right they want our E4OD auto trannies.

The pictures are a bit misleading. Without removing the compressor housing from the turbo you probably won't tell the difference between which wheel you have. I realized I typed a lot and it is probably as clear as mud. Feel free to ask more questions. :thumb:
 

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HAHA i appreciate the reply and going into detail but i know most of the phrases and intercooler talk and pick up on the others as i read them which isnt that hard. Mainly i was just trying to understand which side yall were talking about cause in the discussions it keeps bouncing back and fourth from hot and cold side.

I went back out and looked at mine again and i have the OBS or as its called "wicked wheel". Not new to diesels or intercooling and all that but turbo talk can and does confuse me alot of the time but the basics and a little more i got haha.

Again i appreciate it though, im learning more turbo knowledge as i go hahaha.
 

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Great info Matt. Would you mind explaining how the hot side/cold side switch when an intercooler is in play?
 

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Great info Matt. Would you mind explaining how the hot side/cold side switch when an intercooler is in play?
They dont really switch, just a matter of the same termination. The turbo termination should actually be, exhaust side, intake side and intercooler termination should be, hot side, cold side, which is also marked on your IC boots, Black boot hot, blue boot cold.

So to answer your Q, the intake side of the turbo is the "hot" side of the intercooler, flows thru and to the engine thru the "cold" side pipe. :dis: :thumb:
 

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He is talking about the turbo and intercooler seperatly. As far as turbo goes there is the "hot" side this is the exducer, turbine side, or exhaust side however you want to call it then there is the "cold" side this is the inducer, compressor side, or intake side again however you want to call it.

As far as the intercooler goes the hot side is the tube coming off the inducer or compressor side of the turbo(going to the intake) and routs through the intercooler and the cold side is the tube coming from the intercooler to the intake of the engine(calling it cold side cause the charge air is already cooled).

Hope that helps.

EDIT: didnt see Elmo already posted.

Here is a question though since the "wicked wheel"(stock OBS inducer wheel) is an upgrade for a SD or at the very least the way i see it a fix for a common known problem due to the tight turbine housing(exhaust housing) would a stock SD inducer wheel build better boost in an OBS truck? I ask this cause the SD guys use our wheels to fix their surge problem cause their turbo lights too quickly for the enigne to take in but it in turn slightly lowers their boost numbers. Would our trucks benifit from the larger "gulp" of air for lack of a better term with no surge problem cause we have a larger turbine or exhaust housing? The way im looking at it is like a SD guy looking to fix his surge but keep overall boost up buy sacraficing spool time for better breathing buy swapping a larger 1.00 or 1.15 housing like we have vs their .84(basically creating a small ammount of lag so the engine can keep up).

Would that work or would it create too much lag in our trucks(whicvh i doubt as were not changing the size of our turbine or exhaust housing but rather making our inducer wheel or intake side take in more air), would the added suction slow it down?
 

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You can use them but lag and surge is the result, but they do work in a pinch
 

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Ok I was just curious, I don't need to switch but just was curious since our exhaust housing was larger that it wouldnt surge in our trucks and we could gain a little boost.
 

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I'm not a turbo expert, but I believe the surge is caused by the way the wheel fins are cut and laid out.
 
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