...GTP38R WW2 "After" Testing

[Strictly Diesel]

OK, before I get into this I have to point out that I had a total "senior moment" (another reminder of being "forty something") during my setup for this testing...and unfortunately it totally screwed up an important piece of the data I was trying to collect. What's worse...the problem stems from forgetting that my own truck was running a piece of my own equipment...something I've been building for years...so go ahead...call me a dumbass now and get it over with!

Yes...you guessed it...forgot to take the Mother F%$#ing overboost kit off the damn truck :doh: :doh: :doh: :doh: !!! Since most of the testing was being done under cruise control, towing a trailer, it just never occurred to me. My decision to make the WOT pulls came at the end of my "cruise" testing...as I got to the hill I thought "Hey..lets log a WOT pull up this hill with the trailer". Then I did it again during the "after" testing...still not thinking a thing about it...until I opened both logs, graphed them and spent about 30 seconds scratching my head and staring at a pair of graphs that flatlined perfectly at exactly the same pressure :doh: :doh: :doh: :doh:. What followed was gratuitous use of 4-letter words...the kind that make my daughter giggle and my wife leave the room.

Because I wanted my before/after testing to be as accurate and representative of the performance of the COMPRESSOR as possible, I even installed one of Bobs "TurboMaster" wastegate controllers prior to the testing. Since the TM operates strictly on EBP (no boost pressure applied to a diaphragm), I felt that what we "should" see is the results of a wastegate that was opening at the same backpressure in both cases. I also personally did the removal and installation of the compressor housing and wastegate actuator during the swap, to make sure that the adjustment was not touched.

So now I will present you with the data I did collect. To be perfectly honest, I'm at a loss with regard to my interpretation of the data. Each graph (except the WOT ones) represents about 8 miles of driving (about 14,500-15,000 data points per line) at 72mph with about 10k# of trailer behind me. Leg 1 and Leg 2 are essentially the same drive, just the opposite direction. I did have to chop some data points off the front and back ends of the graphs to get the "hills and valleys" to line up in the before and after graphs.

I will break my posts up by reading (MGP, EBP and Boost/EBP Ratio)...lets start with Manifold Gauge Pressure:

In ALL graphs, BLUE = Before (stock wheel) and RED = After (WW2)

I find it interesting that during leg 1, the stock wheel made more boost...and during leg 2 (same road, opposite direction), the WW made more boost. The only factor that I can't account for here is the possibility of a tail/head wind that may have affected the load on the truck...and the subsequent boost readings. I'm pretty disappointed with the fact that both legs are not showing consistent data (one wheel out-performing the other)...tells me something out of my control was affecting things.

I posted the 3rd (WOT) graph just so you can ointlaugh:

Next up...EBP graphs...

 

[Strictly Diesel]

Here are the Exhaust Backpressure Graphs. Pretty much what you would expect, when stock wheel boost was higher (leg 1), stock wheel EBP was generally higher. When WW boost was higher (leg 2), WW EBP was generally higher.

I like the looks of the WOT EBP reading...but unfortunately I don't have a matching MGP graph that is actually valid so we're missing an important piece of data.

 

[Strictly Diesel]

These graphs show the Boost:Backpressure ratio (1:1 being considered "ideal" by many) for each of the legs.

It should be pointed out that the data for the WOT run is NOT VALID because the calculation for BOTH graphs (before and after) is based on the flatlined boost reading instead of an actual boost reading. I posted it just as a comparison...but the lack of valid boost data means that we have NO idea if the difference is significant. If the boost was about the same all the way to peak, it's looks to be significant. If the boost from the WW would have graphed lower across the board than the stock wheel, the lower EBP shown here may not mean a darn thing.

 

[Strictly Diesel]

There is one more graph view I want to post...watch this spot...need to generate the image files.

 

[Strictly Diesel]

OK, here are "leg 1" and "leg 2" with the data sorted by MGP (from lowest boost to highest boost). You can see the thin lines representing boost (purple and green) and the corresponding EBP (blue and red). This gives you a better look at what the EBP is for a particular boost pressure...while towing 10k# at a constant 72mph.

 

[4duggan]

Sub'd

 

[Strictly Diesel]

All that said and posted...my conclusions are not as "scientific" as I would have preferred...and I'm not going to reinstall the stock wheel to do it all over again.

What I will say is this...

1. This wheel is quieter than my stock wheel by a long shot. There is still a "tone" from about 2psi to about 4psi that I don't care for, but for the most part it's only an issue on deceleration. It also does have the "air rushing" sound that several people have described, which I suspect will be different with different intake kits. I've got an AFE stage II kit on my truck, which I consider loud.

2. This wheel exhibits significantly less loss of boost and performance during "stall" situations. When my tuning (which I can now fix since I'm not trying to leave things the same for testing purposes) locks the TC at the same time as the 3-4 shift, it would darn near kill the charger with the stock wheel (it would drop to about 5psi). With this wheel, it still drops, but only to about 15psi and it still keeps pulling through it.

3. This wheel doesn't have nearly the surge problem the stock wheel does. With a load (heck, even unloaded), low enough RPM and a bit of throttle...it wasn't hard to make the stock wheel surge. I've heard a tiny bit of surge from the WW, but I had to work much harder to get it to do it...and I don't think I've heard it surge any time when I was not intentionally trying to make it do it.

For me...WW stays installed...the surge/stall benefits alone make it worth it. I wish the data had been more complete :doh: but it is what it is.

 

[lincolnlocker]

lmao dennis! anyway to take the overboost kit off and log a wot run just for the hell of it?

live life full throttle

 

[PDT1081]

All that said and posted...my conclusions are not as "scientific" as I would have preferred...and I'm not going to reinstall the stock wheel to do it all over again.

What I will say is this...

1. This wheel is quieter than my stock wheel by a long shot. There is still a "tone" from about 2psi to about 4psi that I don't care for, but for the most part it's only an issue on deceleration. It also does have the "air rushing" sound that several people have described, which I suspect will be different with different intake kits. I've got an AFE stage II kit on my truck, which I consider loud.

2. This wheel exhibits significantly less loss of boost and performance during "stall" situations. When my tuning (which I can now fix since I'm not trying to leave things the same for testing purposes) locks the TC at the same time as the 3-4 shift, it would darn near kill the charger with the stock wheel (it would drop to about 5psi). With this wheel, it still drops, but only to about 15psi and it still keeps pulling through it.

3. This wheel doesn't have nearly the surge problem the stock wheel does. With a load (heck, even unloaded), low enough RPM and a bit of throttle...it wasn't hard to make the stock wheel surge. I've heard a tiny bit of surge from the WW, but I had to work much harder to get it to do it...and I don't think I've heard it surge any time when I was not intentionally trying to make it do it.

For me...WW stays installed...the surge/stall benefits alone make it worth it. I wish the data had been more complete :doh: but it is what it is.

What about your non-data logged gauges? Did you notice a difference in EGT or actual boost pressure?

 

[Strictly Diesel]

lmao dennis! anyway to take the overboost kit off and log a wot run just for the hell of it?

Yes, just have to make the time. It may not be a "loaded" run but I will try to do it just to see what the data looks like.

What about your non-data logged gauges? Did you notice a difference in EGT or actual boost pressure?

To be honest, I don't watch them all that often. The programming and parts in this truck are pretty well dialed in (with a few small exceptions)...I can point it up the same hill I tested on and stand on it to well over 100mph and barely break 1250°F...so I just drive it and generally don't care. I have not noticed any significant increase or decrease in EGT under heavy throttle, seems to run up to about 1100°F and then climb slowly over 1200°F the same as it did before...depending on whether it's loaded or unloaded and how long I stay in the throttle.

Both wheels "seem" (remember my age limited memory) to be making about the same peak boost (30-33psi...ish) with my truck setup the way it is (essentially a daily drive/tow program...most certainly not "balls to the wall"). From my intermittent boost gauge glances...I don't think the difference is very large (if any). This is where the datalogger was supposed to help me, it would have let me see "responsiveness", climb rate and peak boost...side by side :doh:.