Last straw

[Lonestar10]

Watching ct with turbo at 58% full throttle is 36lbs boost, 72lbs exh pressure, 101k turbo RPM at 1500 engine RPM fuel of 325mg. Atleast at full chooch I don't get vibration and rumbling in my floor anymore

[Lonestar10]

Might have found issue. Was doing cutout test 4-5-6 chugged like champs 1-2-3 lost RPM and died running 1 cyl at a time. Both me and my dad were at shop so I pulled a timing and metering actuator off his 870. Tried timing with cutout no change then tried metering and Wala 1-2-3 chugged like champs. Waiting for a new metering actuator from Kenworth to get here then test drive time to see if I get the power this 550/1850 should have.

[Unilevers]

you really should try to get it better than a 2:1 ratio on TDP. They run much better the lower you get it and there is no reason a 871 cant achieve better ratios.

325mg/stroke is getting it done and is a fairly healthy power level, how much power you wanting to make?

[Lonestar10]

So when the computer was commanding 325 it wasn't getting it the metering actuator was bad with tune before the metering actuator I might be able to hit 31 lb of boost now that I fix the metering actuator she's actually touching on 40 with the same tune. The metering actuator was failing to let fuel through she's ripping it up now

[Lonestar10]

Now she's doing 39.2 lb of boost and 53.3 pounds of exhaust back pressure much much better and at 52 on turbo instead of 58

[Magard]

Sounds like a better turbo position number. I’m 53% in a Volvo to make 38 with a little elevation

[Rawze]

(10-18-2019 )Lonestar10 Wrote:  Now she's doing 39.2 lb of boost and 53.3 pounds of exhaust back pressure much much better and at 52 on turbo instead of 58

now you need to back that down to about 36-37 or so max. -- 39+ is going to take its toll on those pistons in the long run.

It is good you found the bulk of the problem though. I did mention that the front bank of actuators was something wrong in this post as one of the thigns still needing done ...

Rawze Wrote:and a few others. it also did not fair as well on the front 3 cylinders as it did the back 3 during cut-out tests. I told him that the metering/timing coils should be swapped front bank to back bank and see if this imbalance follows the coils or not...

ref: http://rawze.com/forums/showthread.php?t...4#pid44284



does not mean your done -- your still welcome to get back this way for a day or 2 in the near future for some more followups / finish what has been started with it.

[Lonestar10]

10-4 good sir well c i drove my dispatcher insane trying to get out there lol we usualy dont go any further than the NW tip of kentucky to load aluminum.

[Lostfarmboy]

When I look at exhaust pressure on CT it has 105 to 106 kPa with the truck shut off is that normal? And if it is do you just compensate for that when you try to figure out the actual exhaust pressure?