6.7 turbo testing update. It has been a few weeks so we wanted to give some updates on our 6.7 turbo testing. We have exceeded our goal of a solid 600-650hp unit… so we might make this design a good “stage 2” turbo option for those who are willing to push their bottom end on a quick spooling vgt as they approach 700hp. Big thanks to Chris Buhidar with Truck Source Diesel & Off-Road for helping out on the tuning side to get the truck dialed in.
Test Truck 2011 f250, 180,000 miles, KC modified 2015 turbo, No Limit Air filter, stock 2015 cp4 and then RCD Stroker pump. We had issues with our brand new 2015 cp4 and instead of swapping it out we upgraded.
The dyno graph below displays 3 runs, I will break down each one.
BLUE – 1600us tune 630hp: on this run we were having issues with holding rail pressure. At 2600rpms the rail pressure would drop all the way down to 19k. Even on a reduced 1550 and 1500us tune the pressure was still dropping off. You can see the power really falls off on the top end because of fuel pressure dropping off.
RED – 1600us tune 650hp: Exact same tune as before but we added a stroker pump, this graph represents what you should see on a healthy 2015 cp4 that holds rail pressure on a 1600us tune. You can see the power curve is EXACTLY the same as before, except it is able to maintain rail pressure past 2600rpms. We were impressed to see it hold 600hp all the way to 3600rpms. On this tune the truck cleans up the fuel to NOTHING at WOT.
GREEN – 2000us tune 686hp: With the new Midwest stroker pump we were able to maintain a rock solid 29k rail pressure all the way to redline on the 2000us tune. I have no doubt we could have bumped up to a 2200us tune with this pump, we were very impressed with its performance. The truck cleaned up the fuel in the mid-range, but the turbo could not quite keep up on the top end and would start to haze pretty good (I will post a video in the comments). We have no doubt we could have hit 700hp with a piping kit and new air filter (air filter on the truck is old and dirty)… BUT if you are serious about pushing past 700hp then it is time to go non-vgt IMO. The slower spool up of the non-vgt should help the bottom end to last longer.
