Tenn, are you sure it's *NO* cost to flow? To me, anytime you put something in the path of moving air, it must create extra drag and take up some space causing more of a restriction than if the material was not there. It may be just a minute difference, but I'm thinking that that tight of a mesh has to cause at least some added restriction. That's why I was hoping Gene could measure the flow both with & without the TAG in place under a specific condition to see what the restriction is.

I'm headed out to mow the yard now. I'll check back in later....

Joe

 

I too am not sure I meet the requirement since all I have to tow is my boat which only weighs in at about 3-4k if I were to guess. I may take you up on it anyway if someone more appropriate (bigger load) doesn't. I am curious about this fluctuation/vortex and would likely get a TAG if I did this IOT see if that reduced or eliminated the fluctuation. Of course if the fluctuation was due to surge, none of this will affect that.

Now, back to my other question, what does 450=(10.5"/15")650, mean in terms of a vacuum in the intake? I am having trouble figuring out what that means. 10.5" at 450 CFM? I guess I need you to explain those values to me.

Also is there a typo here?

 

You are correct, I worded that poorly. It would be clear that anything placed in the intake tract that has volume would diminish the total flow potential of that tube by the amount of it's volume it occupies there, but just at the face, not through it's length. However, I feel there is at a minimum some turbulence in the intake, not sure it is a full blown vortex or not. I believe the turbo can "suck" the necessary volume through a tag without a performance hit, especially if it is better quality air. Let's not get caught up in the term suck. I use that as a simple term to describe what is going on as the turbo creates a low pressure area on the front side.

 

Let me say that if your logic is correct, that the vortices are indeed rare, I must be the luckiest dog alive. I get to see this all the time. As I said, it is more likely to occur (visably) with higher humidity.

 

You're actually the best choice so far, because you've got a stock turbo, which I think is the most sensitive to whatever vortex effects might be occurring. Also, I want to collect CFM on a stock 99.5 configuration to make a model for that. I'm officially closing the bidding, and please send me an email to kempegenek@gmail.com with your info for how to make out the check, and where to send it. I'll make it a nice round $100 which should cover the gauge + shipping, hose, and fitting. I'll send a fitting like I used since I've got an extra one. I'm going to post this first, then get back with the rest of your questions.

 

The more I think about this, the more I think it's not as minimal as I first though. Air going through a tube creates drag with the sides of the tube. A thousand little tubes the same size a one large tube (like the tag stuck inline with the intake) would create more drag on the air going through it that just the large tube. Am I wrong on this? I don't know how long the TAG is, but I have to believe it creates a measurable amount of drag on the air passing through it. Would love some measurements on that. Hint hint...

Joe

 

I suppose an email is in order then. One must respect their elders, and I look for them whenever I can anymore since I am no longer a spring chicken myself. I will send the email a bit later Gene, along with some questions, so it will be later.

Like Izzy, I was mowing the yard, well the front, then could no longer resist the pool, so I spent some time there with a few beverages. Just came in to catch up, then do back yard.

I still have to summarize my trip results. Oh well, at least the truck has been washed, did that yesterday. The wife really loved that with all that needed doing after a week away.

Edit: also, there's 13 laps to go at Indy. I will get back to your ? Izzy.

 

Hey guys, you want some dyno comparisons of TAG versus no TAG? Well, I've got some info for you then. This is from Turbo Diesel Register mag (I know, it's a Dodge thing - but seeing how I'm in charge of the upgrades to my buddies Dodge, I wanted to learn more). I know it's a Dodge, but the turbo principle should be the same.

They tested several different setups of airboxes, filters, and intake tubes. 3 of them they tested with and without the TAG. In 2 of the 3 tests, the TAG, the TAG caused torque to dropped a couple of ft-lb and HP went up a couple. Boost was nearly identical.

The one test that the TAG did show improvement of about 4 ft-lb and 2 HP was with a chip and using a smooth flow intake tube. The same test on stock fueling was one of the tests that showed a drop in torque & increase HP. The one flaw in this test in comparing to our open filter setup would be they always did use an airbox. But, with a high flow conical filter the airbox may not matter.

Here in a bit, I'll get the summary chart scanned an posted so you guys can see it.

 

I don't see a typo. I'm using restriction data for an AIS...The Donaldson filter (7.3 L AIS) at 700 CFM gives 16 inches of H2O restriction which produces a 16" H2O vacuum at the turbo inlet when the flow is 700 CFM..., and the above is just scaling this one data point in a linear fashion. I measured 10.5" H2O restriction (vacuum) on the gauge, and estimated a (10.5/16)=(0.6563)700=459.4 CFM flow for that 10.5" gauge reading. My gauge, and soon to be yours too, reads 15" at full scale which for me gives a max possible CFM=(15/16)700=(0.9375)(700)=656.3. Clearly, none of these measurements will actually have a 0.1 CFM accuracy, I'm just showing how I'm getting my numbers.

I think this is the data to use for your filter... these are two data points I found, and when I find the link, I'll send it to you.

The Baldwin filter at 350 CFM gives 5.75 inches of H2O
The Baldwin filter at 500 CFM gives 16 inches of H2O

You can see that this isn't quite linear, and I'm still trying to find additional test data on my AIS to improve those estimates at lower flow rates. Anyway, the 15" gauge on this filter would give (15/16)500=468.8 CFM at full scale, and of course a gauge reading of 5.75" is 350 CFM, and you can interpolate between 0 to 468.8 using these two points.

The reason I went with the more expensive gauge that reads both + and - was to monitor for any small back flow pressures at the turbo inlet that would indicate surge, no matter how small the effect might be. I was afraid to go with just a vacuum gauge, and then have the needle break off if I got a puff of air coming back out the turbo inlet. So far I haven't seen that, but as I reported in the Zoodad thread, I have seen up to a +1.5" RAM air effect at the turbo inlet, and I proved it's real by taping over the Zoodad hole and making measurements, and the effect disappeared and I only saw a vacuum.

 

Exactly what I believe as well. Very common occurrence, and that being the case, a question.
Why aren't jet engines built with a TAG like device to prevent it?

 

I don't want to get into a prolonged TAG discussion, and if my hand was steady enough to draw a pic in paint using my mouse, I wouldn't have to try and describe this in words. I think the TAG actually enhances air flow by a little bit in normal conditions, and this has been borne out in some extensive dyno testing that was published in a recent issue of TDR.

Imagine the air flow as lines coming straight into the blades of the compressor wheel. This is the angle of attack on the blades that gives the best bite on the air, and most efficiently scoops it up and slings it to the perimeter of the wheel, through the thin slit, and into the "snail shell like" structure of the compressor housing, where boost pressure builds up and then flows out of the turbo outlet. The spinning blades impart a twist to the incoming air stream which tends to get pulled along with the blades. For a given wheel rpm, a fixed slip angle between the blades and the air stream develops, and this changes the angle of attack, and reduces the efficiency of the scooping action a little. By forcing the air stream to be straight right in front of the blades Click for full size image their scooping action is enhanced, and you wind up gaining back the small restriction, and then some, but the dyno results were only slight, a few HP at most.

EDIT...
My connection goes in and out, I just noticed that jtharvey is covering my reference to the TDR date on the TAG, Thanks jtharvey!

 

basically those Turbine Air Guide units are trash. I know the guy that came up with the idea and makes them and I have never seen a gain on a dyno with a truck using one, nor have i ever seen a decrease in HP with a truck using one so. And the testing was done on a 7.3 with an open element filter, so maybe it works best for an airbox, who knows. Truthfully i wouldn't want the thing infront of my turbinator, as I have heard stories of the local guys runnin them and one broke and ate the compressor wheel, lodged somne chunks of turbine wheel in the motor. That cummins spent a couple weeks gettin overhauled.

Cowboy Steve

 

Here's the chart. Click on the thumbnail to get to my webshots. It would be easier to read if you follow the link on the right side of that page that says view full size.

 

These are pics I took several months ago, when I was at DP in Asheville doing my CCV mod. I removed both TAGs and again inspected them carefully using a magnifying glass. It's highly recommended to do this prior to the initial installation, and to use a jewelers file to go over any burrs that were left behind after production. I did read about some reports of small pieces coming lose on the early units, but was told that the furnace brazed version like I've got have been trouble free so far.

EDIT... I forgot to mention a comment I had about restriction. I haven't measured the with and without TAG CFM with my gauge because it's a little bit of work with my bad back to do it, and I doubt I could measure a few tenths of an inch of H20 anyway. Keep in mind, that even a brand new clean Baldwin filter has a 16" H2O restriction at 500 CFM, and I seriously doubt a TAG adds much to that.

 

Gene where'd you get your TAG from?

Cowboy Steve