The bottom turbo (the bigger one) blows into the INLET on the smaller top turbo.

 

Hey if I am having fueling problems will it cause the egts to run hot and not be able to spool the Ht3b?

 

To a degree, yes. Low rail pressure can create this scenario.

 

That might be my problem. I have great RP until I flog it and then it drops. At 1/2 throttle I am perfectly good, RP is where it should be, but anything past that and it drops off to around12k and then runs up very slowly.

 

Well there you go then... but it seems to me that a stage II should keep up with your sticks...

Is that a Floor It or an II cp3? Also whose 120 stix are you using? They are not all made equally...

 

That is almost a mirror of what my truck when my Floor-It pump died. Anything past about 60% throttle and rail pressure would drop like a rock. Mine would go down to around 8k at any rpm when I got past the 60% throttle mark.

My pump had about 2000 miles on it. I think somebody sent a crap core to John as it wasn't my original pump.

 

Chad, If for some reason I cannot find a problem with my turbos tomorrow I will start checking out the fueling. It would be my luck if both my bottom turbo and fueling went to crap at the same time.

 

Quite a while ago I had my stg 2 pump "begin to die" at the same time I installed a 62/71/13ss HTT Turbo. It happened the same day, and I chased what I thought were wastegate issues for days until I figured out the pump was not working properly. It was very frustrating. Nothing I did to the wastegate seemed to make a difference in my boost.

 

yes it does, but that doesnt mean it spools it. the turbo is just like a jet engine. the exhaust section converts the thermal/flow energy into mechanical energy by spinning the turbine-- which in turn spins the compressor sending air somewhere else. In theory you could unhook the compressor from the motor or the other turbo and both turbos would still spin the same because it doesnt depend on that side, but it wont do that because you need charge air to get drive pressure to spin the turbos at full speed.
So bearing this info in mind. if you look at the exhaust side, it goes to the small turbo getting it spooled, which in turn helps spool the larger turbo by sucking air through the larger ones inlet side.

 

I quoted the wrong person initially.. Oops. That why my post didnt make sense. I was responding to someone else right before KKB that was asking how it flowing.

 

With this in mind and being said. If I am seeing 10psi on my bottom turbo under WOT and when I let off I am seeing a spike to 20psi. Is it possible that the bottom turbo is just not matched right and that is what is causing the problem? This is what is happening on my truck, or is it possible that an exhaust leak is probably not allowing enough DP to spool the bottom turbo.

My exhaust manifold has a decent leak at the front slip joint. It is not horrible, but I am guessing that it may be what is causing my problem.

 

wow...it leaks? what manifold?

12ksi WOT is a HUGE problem...turbo problem or not.

Start there.