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Wicked Wheel G2 for 38R Test Results

22K views 67 replies 30 participants last post by  groomzybanshe 
#1 ·
Hey all... I apologize for the long delay in getting these results out. Between getting ready for the Christmas holiday, working on the suspension for my 6.0L (which is another story in the works), and helping Corey get to her doctors appointments (why are ALL the good doctors in Atlanta, which is 40+ miles away???), I've just been short on time to get this information posted up. My apologies to all of you folks that have been patiently anticipating these results. So without further ado, let's get to business.

I'd like to start by saying MANY, MANY thanks to Jason Seay for the use of his truck as a test mule for a number of different 38R-based turbo combinations, including stock, a 1.15 A/R non-WG housing, the Bat-Mo-Wheel, and most recently the new 38R Wicked Wheel. This is not to mention a number of other parts we've tested and validated such as the CPR Fuel System, the Walbro replacement Fuel Pump, and the 250cc/200% Stage 3 injectors utilized in the current configuration. It is in-depth testing situations like this that help to provide an accurate analysis of what works, what doesn't, and where the best cost/benefit ratios are found. Jason, you are awesome!

Now on to the good stuff.

We had fairly recently tested this truck with a combination of different exhaust housings and turbo wheels to determine whether or not there was any benefit to making modifications to the factory Garrett 38R turbo. The conclusion we arrived at was that the stock 38R actually worked very well right out of the box providing the best combination of spool characteristics, peak boost output, and EGT control. Swapping to the larger 1.15 non-wastegated housing provided no benefit, actually causing a small drop in power and considerably more turbo lag. Swapping the compressor wheel had an even worse effect, losing nearly 4 pounds of boost and dropping power output nearly 50 HP. Not a positive outcome by any means. With all this in mind, we put the turbo back to a stock configuration (1.0 wastegated exhaust housing and stock compressor wheel) and validated that every thing was back to normal. With power levels back to where we started, we were ready to move forward.

When DieselSite released the new G2 Wicked Wheel for the stock turbo, the first thing I asked Bob (besides "Where's Mine?"...) was whether or not there was an option for the 38R. As it turns out, there was and I was handed both wheels to test. Since the transmission was still out of Jason's truck at the time, I test the WWG2 for the stock turbo first. The results of those test were, without a doubt, some of the most surprising I've experienced from the world of bolt-on performance parts. Given those results, I couldn't wait to test the new 38R wheel and see if the gains were going to be anywhere close to what we found on the stock 7.3L turbo, if there were any gains at all. I must say that I had some reservations as to whether we'd see any gains, given the losses we'd observed from the previous components we tested. We dug in, yanked the turbo again (for what feels like the 20th time), and after a small snag we finally had the new wheel installed and the turbo back on truck, ready for another round of dyno brutality.

Well, I'd have to say that I was a little disappointed that I didn't pick up almost 12 PSI like I did with the WWG2/Stock combination, but that's where my disappointment ends.

As usual, all dyno runs were performed in 3rd Gear with the Torque Converter locked and 8000 Lbs of load on the dyno. We performed a few dyno runs with the stock wheel/housing configuration and achieved a maximum boost of 34 PSI and a best HP of 555 @ 2680 RPM. Then we yanked the turbo and installed the new 38R Wicked Wheel. We made no changes whatsoever with the tuning... We strictly wanted this to be a bolt-on test. The results were immediate and impressive.

Dyno Run - GTP38R, 1.0 W/G housing, Stock compressor wheel
(All values rated at 3500 RPM)
Max Boost - 34 PSI
Max EBP - 52 PSI
Max EGT - 1400
Peak HP - 555 @ 2680 RPM
Peak TQ - 1116 @ 2625 RPM

Dyno Run - GTP38R, 1.0 W/G housing, WWG2 compressor wheel
(All values rated at 3500 RPM)
Max Boost - 40 PSI
Max EBP - 53 PSI
Max EGT - 1400
Peak HP - 572 @ 2660 RPM
Peak TQ - 1161 @ 2550 RPM

Dyno Plot - Stock Wheel vs. WWG2
(Click to enlarge)


As you can see by the dyno graphs, gains were observed across nearly the entire RPM range, with particularly sizable improvements in the 2000-2500 RPM and 2850+ RPM ranges. Visual observations included slightly faster spool times and reduced smoke output. Backpressure only increased by about 1 PSI, while Boost increased around 6 PSI. EGTs stayed about the same, peaking to 1400 Deg. at 3500 RPM. One interesting thing we did observe was that as the ambient temperature got hotter, the boost and low RPM power would rise more quickly, but there would be a slight loss in peak power. I suspect that heat soak in the block, intercooler, and ambient air would actually help provide a more efficient combustion and help spool the turbo faster in the lower RPM ranges, but end up with a minor loss in the upper RPM ranges caused by slightly hotter aircharge resulting from the increase in boost. However, since these losses were minimal and not in the "normal" operational RPM range for most people, I don't consider them to negatively reflect on the results.

As for the wheels themselves, here are the comparison images where you can clearly see the differences between each wheel.

Wheel Comparison (L to R - Stock Wheel, BWM, WWG2)
(Click to enlarge)


In regards to turbo surge, I didn't really experience any with the stock wheel/exhaust housing during dyno testing so I can't really say if this wheel would offer any improvement in such a scenario. It is generally accepted that a compressor wheel with single length blades may suffer from surge, but since the 38R comes pre-assembled with a ported compressor housing, we didn't see any indication of surge at all throughout a host of test RPM ranges. We also didn't see any significant benefit to running an aftermarket modified ported housing, but that may have simply been the nature of this particular vehicle configuration.

We plan to do a little more testing this weekend with some modest tuning changes to see just where we end up on the power scale, but overall I think the new wheel is a fine complement to what I thought was already a good turbocharger. Once I finish some injector testing on my personal 7.3L running the stock turbo/WWG2 combination, I'm seriously considering this as an airflow upgrade. After all, I'm all about relatively simple (and relatively inexpensive) bolt-on stuff. If I can run a stock turbo that moves air like a 38R (maybe that's a little optimistic, but we'll see :D ) or a 38R without having to switch to a T4-flanged setup (like a 4294, S472, or other setup), all the while saving a couple thousand bucks in the process, then it's a win-win situation! As we continue to push my little red truck, we'll keep everyone updated.

Enjoy.
 
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#4 ·
Nah.. haha. Im not a PMR hater, just cautiously aware. :) I'd love to get a G2 WW when the time comes.

It should be called the WWII...
 
#11 ·
the stock turbo with smaller injectors got 43 psi, its close to the same, but if a stocker gets 3 lbs more, why even go with a 38r? just for the longevity? i dont know much of anything about how all this stuff really works so fill me in.
 
#14 ·
Plus the stock turbo made more boost with less back pressure. But you would have run another wastegate on a stocker I would think to make this power level, which can be costly.
 
#12 ·
That's awesome! And very exciting! This is the setup I'm gonna be running in the new year, I have a few questions though, mainly with fuel, what fuel modifications where done to this truck? If stock what fuel pressure was observed? Also was this ran on a stock hpop? Can you post up all other modifications done to this truck, and any seat time on the street with this truck? How much boost/egt's/smoke was it making on the street, I also am looking forward to further tuning to see if you can benefit from this wheel anymore.
 
#13 ·
The test truck in this video has the following modifications:

Vehicle Specs:
2001 F350 CC/DRW, 2WD

Mechanical Mods:
- Stock block bored .030" over (Completely rebuilt ~5000 miles ago)
- Mahle pistons
- Forged rods
- Stock camshaft
- ARP studs
- Twisted Diesel built transmission

Performance:
- Full Force Diesel Stage 3 Single Hybrid, 250cc/200%
- GTP 38R (Stock 1.0 A/R Wastegated housing, WWG2 Compressor Wheel)
- DieselSite Adrenaline HPOP
- DieselSite CPR Fuel System (Pressure at 68 PSI)
- Full Force Diesel Walbro Replacement Pump
- K&N Filter
- Water Meth (Currently unused)

Other than little bolt on stuff here and there, I think that's about it.

I haven't had the opportunity to drive this on the street with the new wheel in the turbo. However, even with the old wheel smoke was only an issue when the tuning was turned up, but even that cleared up quite well. Check this video...



EGTs were quite reasonable for a 550+ HP truck, peaking at about 1350 or so on the street at about 90 MPH. Under normal driving, EGTs are 550-600. I'm cleaning up a few small details with the shifting due to changing the gears from 4.10 to 3.73, and then will reassess the drivability and operational parameters.


BERG:
My initial impression is that the turbo is quieter compared to the stock wheel. I wasn't able to get over to the shop this afternoon to shoot another video but will definitely get one posted up by this weekend. :D
 
#15 ·
why would you need another waste gate? i have the red hose to the waste gate unplugged on my truck, idk if it really made any diff but a friend told me it might so i did lol.
 
#16 ·
Boost pressure doesn't equal air flow, gentlemen.
A 38r moves more cfm at the same psi compared with the stocker.
 
#18 ·
Absolutely correct. Boost is a measure of restriction, not necessarily airflow. In terms of comparison, the biggest point of interest is the ration between Exhaust Drive Pressure and Boost. The lower the ratio, the more efficient the turbo is. Also, another thing to look at is what RPM the turbine is spinning. If you are making more boost (at roughly the same backpressure) without a significant increase in RPM of the turbine, then the compressor wheel is moving more air. Of course, the only way to accurately measure RPM is with a specialized optical pickup. I've got information on one and will be looking to pick one up in another week or two. Costly little buggers. :D
 
#17 ·
okay, but how does that work? i could see if the intercooler pipes were bigger that it would be flow more air at less pressure. how with the same size intercooler pipes does it lose pressure but gain air flow?
 
#55 ·
Much less heat. Denser air from a more efficient compressor.

Stock is designed for stock, anything much above that and it becomes very inefficient.

.

.
 
#19 ·
I read that Bob may be engineering a wheel for the H2E. Is this in the works or just a thought?
 
#20 ·
I talked with Bob about it yesterday about what applications he was thinking of covering and he said he was pretty sure he was going to produce one for the H2e. Since he has one on his truck, it's an ideal test platform. He's working on the 6.0L wheel at the moment but thinks that he'll be looking at the H2e after the first of the year. :D
 
#23 ·
how can you measure the cfm?
 
#24 ·
Cool, I would interested in trying the wheel for the H2E.
 
#30 ·
Their is a modded h2e kit available...we sell them.

Question has the 38r with the wheel been mapped? More boost doesn't always get more cfm...
 
#27 ·
The D66 uses the original 38r wheel, how do yall think it would do with this new wheel?
 
#34 ·
I wish I could come out on the forums more often. There is just so much information I would like to share and I just don't have the time. There is a lot of misinformation floating around about turbos, and I figured this was a good time to address this.

If you increase boost with the same turbo and the only change is the compressor, you in fact increased CFMs.
If you increase CFMs, like adding a larger turbo you don’t necessarily increase boost.

Boost is a measurement of restriction, but the restriction is the intake valve. So, the straw “example” doesn’t really apply at all. The boost measurement is inside the tube, not before it.

Case in point.

Garrett GTP4294 vs GTX4294. Two turbos, with the same inducer, same exducer, same center section, same turbine wheel and same housings. The GTX has a redesigned compressor wheel. It flows 10-15% more CFMs. These are Garrett engineers. I'm certainly not going to tell them they don't know what they are doing. The reason or inspiration I had to make these new wheels was how impressed I was with the GTX in my truck.

How do you explain a HP increase with no more CFMs?

Bob
 
#36 ·
You can only flow so much through a straw in a given time.
 
#37 ·
And the rest of that equation is: for a given pressure.

Raise the pressure, the flow increases. Doesn't matter if we're talking water, air, or oil. The higher the pressure, the larger the pressure drop across the length of the straw because of friction and many other factors, but the flow definitely increases.

To calculate the flow rate of any distribution system, ie: straw, pipe, etc, you must know the pressure or velocity as that is a critical component of the calculation.

Bob
 
#39 ·
DIESELSITE is right on the mark! listen to him, yes if you put a leaf blower on a straw rather then your mouth you would get more CFM flow and pressure( boost) out of the straw. think about it.... turn your garden hose valve open 1/4 open and see how much water and pressure comes out then open the valve all the way and you have much more water (volume/ie:cfm) and pressure( ie: boost) it is a known fact if you know about the way it works. now most do not so listen to someone that does, he is right on with the info!!!!!
 
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