Weather has a strong influence also. Today was the first day I have driven my EVO9 with EVORed Turbo on it when it was 50F outside, got a little 1-2psi creep up in the 7000+ rpm area. Was running a flat 20psi in hotter weather.


I did a about a 45 min tech support call with a guy one time about boost creep, towards the end of the conversation he informed me that he was in Alaska and the ambient temperature was below zero. I didn't know what to say having lived in Texas for the last 39years I have never had a chance to operate a 400+whp street car in below zero temeratures.

 

[QUOTE=ForcedPerformance;6243265]Weather has a strong influence also. Today was the first day I have driven my EVO9 with EVORed Turbo on it when it was 50F outside, got a little 1-2psi creep up in the 7000+ rpm area. Was running a flat 20psi in hotter weather.


Your not kidding about the weather affecting the EVO red turbo. I had it set to 25-26PSI at 75 to 80 degree weather. Today it was around 50 degres and my EVO red turbo peaked at 30PSI.

 

I'm confused Robert ... this seems contradictory. What O2 housing do you have? Was this actually creep or simply a denser air charge?

 

I said that it got cold and my boost went up a couple psi above 7krpm. I'm not using any kind of closed loop feedback boost control so there is no "intelligence" that modifies what the actuator is doing.

Of course cold weather did not begin having this influence upon turbochargers with the creation of the EVORed model

 

woohoo horsepower

 

You describing it as creep is the confusing part, but I get what you are saying.

 

Nice numbers Waiting on my Red and then it's off to Sean Ivey's to work his magic again

 

Wait Bubble! You say that if peak boost is set at 23# and it creeps to 25#, then if you raise the boost level to 24# it´ll still only creep to 25#.

What about if you lower the boost level down to base wastegate pressure(assuming a stock actuator) which is about 11#, or any level between 11# and 24#, for that matter, will the same turbo always creep to the identical 25# limit eventually, if you were to keep your foot in it long enough?

It won´t will it? Why not?

 

I'm assuming that this discussion is based on creep due to a restriction in the WG itself or directly after it ... constant physical properties. If this is the case, the level you creep to should not change no matter the desired boost level. If it creeps to 25 psi at 5500, then it will go no lower than 25 psi no matter if desired boost was 22 psi or 11 psi.

This is also assuming that the turbo has a linear boost curve and doesn't fall off up top. If pressure falls off up top like the stock 16 does, then the minimum creep level may not be achieved since you hit the max turbine RPM beforehand. When it comes down to it, this the reason creep levels spike and fall in the first place ... limitations of the turbine. If the turbine had no resistance and the restriction in the WG was constant, the boost level would continue to rise indefinitely.

Now, if you bring the WGA and BC in to play it does add another variable ... this is because the spring rate in the WGA reacts to changes in pressure from the boost controller. The WGA can restrict the flow in the WG even further and cause higher creep levels, but never lower. So, if the WG was restricted bofore or after the WG puck itself, the WGA preload or BC settings would have no affect on the creep ... it would be irrelevant. However, if the WG puck has the ability to create more restriction beyond the constant limitations (as it's designed to do in a proper setup) then it can increase the creep level.

So, what I'm saying is that if you raise boost and creep increases, it's caused by the boost control system exacerbating the underlying creep issue ... the actual amount of creep isn't changing. So get a softer spring for the WGA.

 

was this issue ever resolved? If so, what was the fix?

 

This issue for the most part has been resolved by raising the boost to 25-26psi on 93oct now it does not creep anymore for the most part. The car is feeling great. If i had to do it over again i would have got the hotside and the wastegate outlet ported on the FP RED. But its a great turbo

 

so you raised the boost from 20psi to 25psi and pulled out some timing for pump?

you would think that the hotside would be ported good enough from fp? I mean how much can you actually port.. I wouldn't think to much.

 

^^^^^NO the boost was never at 20psi it was at 23psi originially and timing is the same, i just installed a wideband and it is still running 10.5-11afr at WOT at 26psi so its still running safely. This is on 93oct.

 

Looks like its a good bet to run the FP red @ 26psi+ if you want to avoid possible boost creep.

 

kool setup i like it!