Engine/Transmission (1998.5 - 2002) Wastegate riddle...

[jtisdale]

When I run the stock elbow and the box off, I get 25psi. With box on 3x5, I get 30psi and with the box on 5x5, I get 32psi. By switching to the elbow that came with the turbo, I get 35 with box off, and 40 and 45 respectively. What is going on here? This makes no sense to me. Am I over running the wastegate? How can I physically tell when it is opening? I would have thought this little experiment would have shown linear results.

The only change made between runs was the elbow.

 

[bmoeller]

The elbow restricts the amount of boost that the wastegate actuator sees. This allows for more boost before it opens.

 

[jtisdale]

Thanks, but that part I understand. Maybe I didnt ask the right question for the answer I am looking for. Why does the gate open later with the extra fuel of the box? Shouldnt it be opening at a constant(consistant) pressure determined by the configuration of the elbow?

Thanks,

Jim

 

[SEmerson]

It open slowly at the same pressure. But if the fuel is higher then it needs to open more than it did before to output the same psi.

 

[csevers]

The wastegate is opening at the same psi but you push it harder with the higher setting on the box. More fuel = more heat= more exhaust to drive the turbo and over drive the wastegate. With my hx40 gated at 38 I could push to 42 on 5x5 plus water.



Is that what you are looking for?



Craig

 

[jtisdale]

Thanks guys. Craig, you win the cupie doll and the cigar for round one. I am overdriving the wastegate.



Round 2...

What good is a wastegate if I blow right past it? (pun intended)



Had I known this sooner, I would have saved a pile of $ and just went with the 16cm nongated.

 

[Bob4x4]

If you are concerned with a few more psi,enlarge the wastegate opening to flow better. Be careful to leave enough material to seal well.



Bob