1:1 - EBP:MAP up through 35 PSI (so far) on stock 250,000 mile AD injectors as well. I am running a 364.5 SXE with a .91 housing.

Corey, thank you for taking time to share your experiences with us.

 

No one doubts how great the t4 kits are and how well they work. But KC Turbos has been working diligently to close that gap... every year our turbos get better and better. So a lot of these guys that have switched away from the KC38r to something else is not really a fair comparison. I saw someone say the s363 guy that had issues... he was running the very first variation of it and needed a bunch of tweaks to get it to where it is now. Not even close to the final turbo we came out with.

Also keep in mind... I don't know one person that has done a cummins conversion that has regretted it... but that is not to say the 7.3 sucks and no one should ever try modding it.


We also have a lot more sizes and options, the latest being the the new KC300x line of 7.3 turbos. Many have been patiently waiting to see how our extensive testing went last year.



The heart of these new turbos are the s300sxe style turbine and compressor wheels. The t4 s300sxe turbos just work so well on the 7.3 Powerstroke that we took a few notes from their playbook to help us create this new line up. Although they are not the typical slim nose hub compressor wheel with super thin blades we normally use… we decided to stay as close as possible to the original s300sxe wheels when doing our testing and the results were amazing.



The most amazing part of these turbos is the larger, higher flowing, s300 style turbine wheel. We offer it in 3 different sizes. 68mm, 70mm and 73mm. The smaller turbine wheels are 100% drop in for the ability to add them to your own DIY turbo projects (68mm for 99-03, 70mm for 94-97) The larger 73mm actually comes with a thicker shaft and only offered in our larger turbos. All other 7.3 drop in turbos on the market simply change out billet wheels while completely ignoring the turbine side… the original tp38 and gtp38 is ancient technology when it comes to turbine wheel design and really holds back the potential of these drop in turbos. This new wheel designs provide better spool up, cooler egts, and more power all throughout the power band.



The 7x7 FMW compressor wheels with thick hubs are designed after the s300 wheels, although this is not the typical slim hub we put in most of our turbos… it has shown to work awesome widening the compressor map and reducing surge. We have also re-worked our compressor cover for a larger MAP groove to help with turbo surge and flow more air, this is also found in the SXE style comp covers.



During the past year of testing we tried lots of different sizes and variations of turbos, we tested with stock injectors, big single shots, and small hybrids. We spent countless hours on the dyno, many nights at the ¼ mile track, towing from 1000ft up to 7500ft in elevation. We tore down each turbo afterwards to inspect the internals and upgraded all the critical areas of the turbo. We compared data logs and tweaked the turbos as needed to make them perform better, spool faster, make more power, and ideally be able to give YOU the customer all the info needed to pick the best turbo for your application.

 

Here are some back to back dyno graphs we did... You will see in this dyno graph that we also ran a stock OEM turbo and Garrett ball bearing gtp38r all with 180/30 injectors.
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Big shout out to Full Force Diesel Performance Inc.with all their help on this project so far, their injectors have been flawless!
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Mods 180/30 FF inj, CNC Fabrication, LLC S2 hpop, 4 line feed kit, walbro fuel pump, BHAF air filter. For anyone wondering… the 180/30 would not hold 3000 ICP above a 3.7ms tune. The 4.2ms tunes and 5.6ms tunes dropped all the way down 2300psi. Truck still made plenty of power… but not reaching its potential because of ICP issues.
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Stock Turbo: Blue- 390hp and 840tq

Gtp38r: Red- 438hp and 938tq

63/68/.84: Green- 445tq 967tq

63/73/.84: Orange- 471hp 1046tq
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You can see from the dyno graphs that our 2 new turbos spool faster, make more peak tq, and more peak hp… while making more boost and cooler egts. This becomes even more obvious when driving the truck around town and towing with it. Our new turbos blow the 38r out of the water in every single way… and these are journal bearing turbos. The magic comes from our new s300 style turbine wheel designs and BW 7x7 compressor wheels.

 

Here is a video lugging in OD... I can try to get something better later. This was about 1600rpms, towing a loaded down trailer, flat ground, zero smoke,

 

 

I always take the 1:1 comments with a grain of salt.. because the stock EBP sensor only reads up to 39.9psi... and i very rarely see guys who add a separate 0-100psi ebp sensor. So most guys don't know what is going on above 40psi of EBP which is usually where EBP gets away from you. I can tell you from the guys I have seen run t4 s300 with ebp gauges... they don't run 1:1 in the upper rpms at all. In fact that last guy I saw that actually had a gauge with 238/80 and 369/.91 saw 70-75psi of ebp right before he bent a push rod. Not bashing... just throwing out the info.

Here is a video our our new 63/73/.84ar with 205/30. Runs 1:1 up to about 35-40psi

 

Back to the original post... as others have stated a billet wheel will take care of your surging issues.

I WOULD NOT get the KC38r for your application. Too much turbo for stock injectors IMO, you will only gain lag and no extra power. In fact we no longer recommend the KC38r for anything under about a 180-200cc injector because there are better sizes out there.

The KC300x 63/68 or 63/73 would match your goals much better and cost less too. ($1150-$1200)

As others have stated a T4 with 363 or 364.5 would also work well.

KC Turbos in not a vendor on here... and I don't wanna get kicked off of here. But have tried to provide good info and answer questions that have been posted (don't ban me please LOL)

 

If we are being completely honest here, EBP/MAP was only brought up because of the statement the EBP was significantly higher. Which is not the case.

So, for everyday trucks with AD/AC injectors, not large injector trucks, like most of us have the EBP/MAP reading is still accurate. Good to know, thank you for sharing that information.

We are not doubting the amount of time, money and effort you have put into the KC SXE turbos in order to pass the savings on to US, the customers.

Another bullet point you are right on is the GTP38R is ancient tech, we have been saying that for a while now. The gap you are trying to bridge that spans nearly 20 years of technology is difficult at best to do. Taking the Borg Warner wheel design and putting it into a drop in turbo format is tough to do and make it work well and be affordable.

Kind of like how Dorman and many others took the bellowed up-pipe and bridged the gap.

The cost of a T4 kit and the chosen flavor of the Borg Warner turbo is more than your drop in turbo, but as you stated, no one doubts the T4/SXE setup and how well they work. For me and my truck I wanted to do it right the second time after the first time was modifying the stock turbo. I took nearly a year and decided on the genuine SXE, which only cost me a couple hundred dollars more than the KC38R after selling the take off parts. It guaranteed superior results in power and cool EGT's, even with stock AD injectors. Keeping in mind I had plans for 160/80 injectors, but the SXE has performed so well thus far I will probably stick with stock AD injectors like I have now. Like most others, I don't have aspirations of putting in large injectors.

My truck is a tool used for towing, not a race truck or a dyno queen.

Borg Warner has also spent "countless hours" developing their line of products, kind of like how International and Ford did. There is no doubt that the line of KC turbos, after countless hours has surpassed the GTP38R in every way, but the customer is the only one that can decide if that is enough of a gain vs. going with a genuine SXE.

I bought Dorman up-pipes instead of International when I replaced the OEM up-pipes. That was my call and it worked out. Turbos and charging systems are a much more complex component than simple up-pipes though.

Everyone must decide for themselves what to do or not to do for their truck to meet their goals.

I for one am glad this has been an educational thread and not turned out like the rest of them have.

I believe I have said my point of view and why I decided on an SXE instead of the KC. It was the right choice for my application which is long distance heavy towing with stock AD injectors.

 

 

You can look it up. It is a 0-5v sensor that reads 0-39.9psi (but will read 54.9psi absolute... but you need to subtract baro from absolute to get the correct PSI)

 

By absolute you mean 54.9PSI - Barometric Pressure (14.7) = 40.2PSI
So you are saying i shouldnt be able to see 41 psi using my Edge CTS2 nor any other OBS2 port reader?

 

It comes down to baro and what ebp is... but yes you understand the general theory. I can't tell you exactly what it will read because I have seen variances, but I would not trust anything reading out of the normal range of the sensor.

 

 

Lots of good info in this thread. Thanks to all who are participating

 

WOW!!!, very informative! Until this thread I had no idea there were so many realistic options available. One thing I do see is some of the information presented includes bigger injectors. Its great information and relevant. It does add a pretty big variable in the mix and I get lost. No problem though, I am learning.

While I am going to swap turbo's, it is tempting to run the billet wheel on my stock turbo to help with surge while saving up. We have several trips coming up. Am I reading correctly that if I put a new wheel on my stock turbo the assembly needs to be balanced to live? That would probably kill the deal. I really can't have this truck down a whole lot just to mess with it. This truck has low miles and I don't want to wreck anything.

I was able to get under the parts truck today and get one of the overload frame brackets off. My 20v angle grinder ate through the batteries way too fast! I'm taking the torch (and a couple of fire extinguishers) over tomorrow and getting the other three off.

I really appreciate everyone's input!