Hello.

Wantng to get an explanation on boost creep. I just got my car from the Dyno and due to my lack of understanding of the concept I set my wastegate preload on the low side thinking it would help with boost creep. Engine was only able to build 11-12 psi and I was expecting more. My thinking was that boost creep was the inability to maintain low boost pressures but this wasn't the case. I will be increasing the preload to put the psi in the 16-17psi range. Does boost creep become more apparent or less controllable at high boost levels?

 

to understand boost creep you first have to understand what boost control is and what is actually doing. as the turbine spins faster from increased thermal energy expelled by the motor, the compressor speed increases and subsequently boost increases. the job of the wastegate is to VENT or bleed off this thermal energy in tandem with a controller of some kind, typically a mac valve, to maintain the desired boost. where boost creep comes in is when this process does not work. like trying to empty a container of water with a 1 gallon bucket while someone simultaneously pours in 1.5 gallons.

this issue is most evident on stock twin FDs. without wastegate porting you will have a hard time controlling higher than stock boost levels if at all. this subject has A LOT of variations and factors and i just tried to summarize it in 100 words lol. this is the gist of what boost creep is. to answer your question, it would become more apparent and much less controllable at higher boost levels. because of what it is, at lower boost levels is either non existent or very minor. so boost creep isnt the inability to maintain low boost pressures, its the inability to maintain the DESIRED boost level due to an inefficiency with the method used to bleed off the thermal energy.

it can also be a sign of a great EFFICIENCY with an exhaust, turbo, manifold, intercooler or so on. this is where matching equipment comes into play which is a whole different conversation.

 

Thanks that makes a lot of sense. I'll just need to turn up the boost and find out. And then invest in an emap.