boost creep?

[poorboy]

I've read everywhere and people take about boost creep but no one actually says what it is. The impression i get is you lose boost. Is this correct or am i mislead? Need to know before i do any of the free mods and stage 1 mods to hopefully get to 300hp...lol

[motomullet]

I think its when you dont have a blow off and only a wastegate.

theory being the wastegate doesnt flow enough to keep the boost in check.

but im probably wrong.

[16ggst]

half right.. you can still have boost creep with a blow-off valve...
and its the rise of boost not dropping

Boost Creep: While boost creep also refers to an unwanted rise in manifold pressure, its cause and effect are totally different from those of spike, as is the way it manifests itself.
As you know, boost pressure is controlled by the wastegate, which allows exhaust gasses to bypass the turbine wheel. In effect, it creates an alternate route for the hot exhaust coming out of the motor to take, which means that any gas passing through it will not spin the turbine wheel.
Now, if this wastegate cannot flow enough to bypass the required amount of exhaust, then that means that too much of the gasses are going to go through the turbine wheel, meaning that it will have too much energy imparted on it (it will be spinning too fast). As the excess exhaust gas amount gets greater and greater, the turbine wheel spins faster and faster, and the boost level rises.
Creep happens ANY time when the wastegate cannot bypass enough exhaust gas to keep the boost under control. This can happen when the wastegate is too small in diameter, or when the design of the wastegate doesn't allow it to open enough, or when the wastegate simply doesn't have a good enough flow path to divert a lot of exhaust. It can also happen when you increase the amount of exhaust coming out of a motor (running more boost/airflow, making more power).
Since this tends to get worse and worse as the engine speed rises (more cycles per second is more conducive to more exhaust gas, to a point), that means that one will see the boost climb to the preset level on the boost controller, and then it will gradually creep up past that line to a "minimum" given the circumstances.
That minimum can be 2 psi above the set boost level, or it can be over 30 psi, depending on how the wastegate is designed, how big it is, the car's setup, and more.
It is also important to not that you certainly can have spike AND creep at the same time, which would result in the boost level jumping up, settling to the preset level, and then slowly climbing back up again as you approach redline

[04_sti_man]

well from my exp boost creep kicks ass, crazy tire spinning awesome time everyone should try it.

john where did you get that write up dsmtuners? to lazy to write it out. lol j/p dawg

[16ggst]

nah i yahoo searched it lol...

[WRKLS97]

yup sounds like boost creep can be fun and suck all at the same time

[mhassett]

Boost Creep is kind of like the boogey man... One hides under your hood and breaks your ring landings - the other hides under your bed and breaks your neck. They both are scary - and get you when you least expect it...

I've had first hand encounters with both...

http://www.pitofhorror.com/Myers/archive2.jpg


http://engr.smu.edu/rcam/cpm3v/gsrebld/DCP01957.JPG




PS - I think the Boogey man killed Santa

:069:

[16ggst]

i dont mind a little boost creep lol.. the 16g would go from 11 to 18 psi

[mdt62]

PS - I think the Boogey man killed Santa
:069:

great now im outta work..lol

[poorboy]

so in other words i should watch what i do when modding all because of this little scary monster called boost creep. thanks for all those 50cent words tho...now i'm all confused..lol have to get the dictionary out later and look up all the words.

[16ggst]

with your stock turbo and it being a turbo car you dont have to worry as much because of lower compression, richer fuel maps at high boost... it tends to hold together pretty well. And with little to no mods you would prolly hit a boost cut before you hurt it

[poorboy]

alright then...i was just on dsm and they had all these free mods to the wastegate and a bunch of others, so i was reading more about running a straight pipe and they mentioned boost creep.j/w