KC Turbos 6.4 turbo testing

[KCTurbos]

KC Turbos is back at it again. Testing our 6.4 Harley truck with some drop in turbos. We are still working on just the LP turbo options. This one is my favorite so far. It is a 75mm drop in unit with a lot of upgrades… no other drop in compares. Upgraded comp cover, 4” inlet, anti-surge ring with upgraded MAP groove. 75mm point Mill 7x7 Compressor wheel with larger s400 turbine wheel. Still running 100% stock HP turbo. Ez Lynk tuning from Chris Buhider @ TSD has been amazing. Datalogging and getting new tunes is a breeze! Having the SOTF switch to turn the fuel up and down is also awesome.
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We pushed stock fuel as far as it could go… twin pumps and 2400us tune and still ran as clean as stock. At WOT there was ZERO SMOKE. So we decided to bump up to 100% nozzles to see how much power we can squeeze out of a drop in LP turbo upgrade. First thing we wanted to test it to see if we could pull enough fuel out of the 100% nozzles to mimic “stock fueling” hp. We settled on 1300us with 100% nozzles to being fairly close to stock nozzles on a 2400us tune… both with twin pumps holding rock solid rail pressure. See CHART 1 for the results, you can see they make nearly the exact same HP and follow the same curve until about 2800rpms… which makes perfect sense because at the higher rpms the 100% nozzles can dump the fuel quicker keeping the spray in the “sweet spot” where the stock nozzles have to spray so far down the back side of the stroke they lose efficiency. The stock nozzles did make a tiny bit more tq… but it is close enough to be attributed to normal variance in dyno runs.
Chart 1
Red – STOCK NOZZLES: 708hp and 1426tq
Blue – 100% nozzles: 742hp 1411tq
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Now onto the fun part. We slowly started bumping up the PW to see how much power we could squeeze out of this unit. We actually went up 200us at a time but the graph looks weird with all the dyno runs on there and makes it harder to read. So we are only posting 4 graphs, but the data was consistent… as we kept adding fuel the power kept going up until 2300us where we started hitting diminishing returns and it got pretty smokey.
Chart 2
Light Blue – 1300us: 742hp 1411tq SUPER CLEAN! Way cleaner than tuned stock fuel and stock turbos
Green – 1800us: 857hp 1675tq. Still very clean. Cleaner than tuned stock fuel and stock turbos
Red – 2200us: 946hp 1787tq. Black Haze. About what you see tuned stock fuel and stock turbos
Dark Blue – 2300us: 1002hp 1866tq. SMOKEY. Not something I would hold WOT getting on the freeway
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This truck is a freaking MONSTER!!! Spools just like stock with too much power to use on the streets in 2wd. I like my trucks super clean so I like to drive around on the 1800us tune. The 2200us and 2300us tunes are pretty smokey for my liking and really need more air IMO to clean up the fuel better for street driving, but would be fun at the track. Very cool to see how much power we can squeeze out of just a drop in LP turbo.

[powerstrokeboss]

My oh my!
Triple digits, quick spool, and factory bottom end? I love it, intrested to see what it'll take.
How was drive pressure on the last run? I assume its ungated?

Very impressive for a drop in lp only, I'm scared to know whats gong to happen when you loosen up that hp turbo

[co04cobra]

Very impressive results! I also would like to know the drive psi now before you change the HP.

[silent64]

10 speed trans with 3:54 gears you'll start shopping for wings and a ' chute

[James W]

These threads are really informative, and your results super impressive!

[KCTurbos]

Originally Posted by co04cobra

Very impressive results! I also would like to know the drive psi now before you change the HP.

Yes sir, working on that. EZ Lynk has some limits that we are working through. We want to be able to read everything through the stock sensors instead of adding something like an Edge. So right now we are maxing out the stock sensors... but we don't know how much

Hoping to have it figured out in the next few weeks and will make sure to get data before switching out the HP turbo

[KCTurbos]

Originally Posted by powerstrokeboss

My oh my!
Triple digits, quick spool, and factory bottom end? I love it, intrested to see what it'll take.
How was drive pressure on the last run? I assume its ungated?

Very impressive for a drop in lp only, I'm scared to know whats gong to happen when you loosen up that hp turbo

Non-gated for now. Will probably add them later on to see how it affects things. But I fear gates are a "deal breaker" for many people so we want to develop the turbos to not rely on them.