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 

Mine runs out of steam about 2200rpm

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. 

  On 9/6/2019 at 4:38 AM, 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? 

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

Edited September 6, 20195 yr by kzimmer

  On 9/6/2019 at 1:35 PM, 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 

I'd say next step is to datalog then.

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.

That's why I went with Manton everything 

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.

 

 

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