I spike 20-21 psi and taper to 16 psi by redline (so sad) and with hallman mbc

 

23psi, hallman and greddy bov. WG is adjusted... less then 1 psi taper i see on boost gauge.

 

boosts at 23 and stays at 23 avcr all the way

 

Are you joking?

 

^altitude

 

I spike to 22psi and hold at 21.5 with the Hallman MBC, feels good

 

After removing my Greddy Type S and installing a FORGe EVo15 BOV...i am holding 1psi more and longer at/after redline. 29psi-25psi@redline

 

When you are testing this, what gear are you usually using?

On a stock IX, when does the tapering begin?

 

Wow! I've been waiting so long for someone to open the doors to the crypt and resurrect this thread.

 

Now that its been brought back to life, I too have a question for everyone....Let's see what you all think......

Can a turbo taper to a level of boost BELOW its preset level of preload, or spring pressure? Lets say that the WGA is adjusted to a spring level of 20 PSI. Or to phrase it differently the turbo's wastegate is preloaded to 20 PSI. Furthermore peak boost level is set via a boost controller at 22 PSI.

Let's say that this is on a stock, unported IX turbo which have a tendency to taper usually anywhere between three to 5 PSI. So, this turbo reaches its peak level of 22 PSI dictated by the boost controller and then starts to taper. Will the taper stop dropping at the 20 PSI at which the waste gate is preloaded to, or will it continue to taper down beyond the preload level?

 

22 psi to 15 it spikes for less than a second!!! No boost leaks maybe tune?

 

Yes it can taper lower than the preload.

I have an evo IX turbo with an fp 25 psi actuator spiking 32 and dropping to 22 by redline.

 

The more free flowing your motor is, the less boost the turbo will make at redline (elevation will also affect the taper). Also, exhaust backpressure is pretty high at redline with the stock turbo, so its pretty easy even for a FP 25PSI WGA to get pushed open.

 

This is what I recall from some of my setups. BBK was on w/e wga CBRD uses and the FP Black was using the 18psi wga. BBK was using AEM Tru-Boost and FP Black is using HKS EVC 6

BBK: 33psi spike to 25psi @7k (500whp)
FP Black: 30psi spike to 27.5psi @7k (530whp)

When my FP Black was creeping it would make 29psi out the top and 560+whp! but had no powerband

 

Thanks for responding to my question, 1UpMoto. I used to assume that my FP 18 PSI actuator would lift at 18 PSI without adding any preload. But that was not the case. My supposed 18 PSI WGA actually lifted fully at 14 PSI and not the advertised 18 psi.

I have exchanged PM's with another fellow EvoM member, about his 25 PSI FP actuator and he assures me that he installed his FP 25 pounder with half a circle of preload on his turbo. And that setup in this fashion, it opened at 17 PSI. So, you can't just assume that because it is sold as a 25 pounder that it isn't actually cracking and lifting earlier. In fact they do lift earlier than advertised.

No, I mean that someone who has installed it initially with zero preload where it just slides on and off(full circle) and then manually adjusted the preload up to 25 PSI. And then, when set up as such, the thing would still be able to taper below that proven 25 PSI set point.