Possible valve float?

[Youngblood24v]

Truck runs great but when I go WOT it just feels like it runs out of power on the top end. I have the wastegate at ~40Psi and drive pressure will hit ~55-60psi at WOT. Truck just kind of dulls out at anything 80+mph. Is this symptoms of valve float? Truck does have stock springs in it and I know I’m already ordering some new ones since it needs them anyways just hadn’t gotten around to it yet. I have 3.54 gears so I’m not reving the truck out as I only see roughly 2000rpm while going 70 in od 

[Evan]

Mine runs out of steam about 2200rpm

[Bullet]

I wouldn't think so...sounds like it's just defueling at a certain rpm.  I run up to 60psi boost and rev to 3500+ and I haven't had any float issues with stock springs and rods. 

[Youngblood24v]

7 hours ago, Bullet said:

I wouldn't think so...sounds like it's just defueling at a certain rpm.  I run up to 60psi boost and rev to 3500+ and I haven't had any float issues with stock springs and rods. 

It shouldn’t be defueling is the thing. All defuel permaters on the quad are turned off. And I shouldn’t be out of injector as my turbos only a 67mm with a small backhousing, could my turbo be choking it out on the top end? 

[kzimmer]

Are you sure your wiretap is working? Can you datalog this condition?

Edited September 6, 2019 by kzimmer

[Youngblood24v]

14 minutes ago, kzimmer said:

Are you sure your wiretap is working? Can you datalog this condition?

100% wiretap is working, I’ve verified with a test light that’s it connected and you can feel the difference between can only mode and with wiretap mode 

[kzimmer]

I'd say next step is to datalog then.

[pepsi71ocean]

Combined high boost and high RPM I can see how one can see some valve float. but my truck seems to hammer the same between 1,800 and 2,400rpm. I tend o keep higher rpm towards 2,200rpm ad that's about where i find the max for my truck loaded.

[Dieselfuture]

That's why I went with Manton everything 

[dieselautopower]

Drive pressure could be fixed by porting the wastegate port from about 5/8" to 15/16"  It will almost double the from w from the wastegate and reduce drive pressure closer to a 1.2:1.0 Boost (48psi drive, 40psi boost).  There is lost energy overcoming all that back pressure.

 

Our new 103# spring will be ready to go beginning of next week.  Matched specs with our new computerized spring dyno.

 

Remember that these trucks move a lot of air and are not very aerodynamic.  Drag soaks up a lot of HP.  I guessd on some of these but 60MPH is 50HP, and 100HP is 188HP.

 

 

[Mopar1973Man]

@dieselautopower could you please post up that link I wanna add it to my collection. Please.