boost drop question

[kneedragger89]

i am completely new to the turbo world and have a question. i replaced my waste-gate actuator because my stock one broke and i was over boosting to fuel cut(about 12psi), but i digress. obviously(well it seems that way to me) it is not pulling as hard. but i had the guys who installed it adjust the WGA so it boosts to 9psi(that seemed safe stock from what i have read) and it will boost to 9 for a second and drop to 5 immediately. tell me what you know about it and what to do. they said maybe a new SMIC or exhaust. Tell me what you think about any of this, i mainly want help to hold boost lol duh, but any help for this noob would be greatly appreciated. thanks

 

[yudkib]

boost spike?
do you have any kind of boost control? and was the WGA installed by a reputable shop? could be improper adjustment...

oh and one last thing, youre lucky you didnt grenade your motor with a shot WGA. especially stomping on it at 12psi. ive heard a ton of stories about that, including a family friend.
also stock boost is 6-7 psi, not 9, and with nothing (from what i understand, absolutely zero) to support upping boost, expect to get badmouthed from some people around here. these engines are just not meant for boost. read one of the thousands of other threads on the subject.

 

[littlemimus]

yeah....u should leave it at six till u get the mods to support that boost level.....

 

[kneedragger89]

thanks. he adjusted the WGA to allow it to boost to 9. And i have heard alot of good stuff on the shop that installed it. And its not a spike, when it was first installed it was boostin to 7 and would fall to 3 or 4. And i had no idea it was boosting to 12 i did not have a boost gauge at the time, i just wanted to know why it was hitting fuel cut with stock everything. i just want to know what i can do about or why it it is dropping off like that.

 

[yudkib]

so it was boost spike when it would boost to 7 and fall to 3, but its not boost spike when it boosts to 9 and falls to 5? seems off...

what WGA did you buy?

 

[kneedragger89]

so it was boost spike when it would boost to 7 and fall to 3, but its not boost spike when it boosts to 9 and falls to 5? seems off...

what WGA did you buy?

sorry i must of said something wrong. is it a boost spike if it goes to the boost its supposed to, or is it a spike since it falls off after it reaches the boost its supposed to? and its a forge.

 

[pavone]

ive heard the forge unit does drop of boost like that, dont know why it does but heard it does. also have heard the atp unit (non adjustable) will give u an extra pound of boost - run 8psi - and not drop off. cheaper to boot!

 

[J_Naoto]

i have a forge wga and it spikes also, but ive read others had the same problem so it's normal. i had an atp and it held boost perfect before it went bad

 

[kneedragger89]

i have a forge wga and it spikes also, but ive read others had the same problem so it's normal. i had an atp and it held boost perfect before it went bad

well thats kinda good to hear lol. thanks for the help. any way to help it hold boost? i am about to get a new intercooler will that do anything for it?

 

[kneedragger89]

i am also getting a forge bpv now. i have read that it helps hold boost.

 

[BOOSTR]

Are you using the stock cat piping? If so replacing that will free up some of the exhaust backpressure and help you hold boost. It's your money but don't just throw away perfectly good parts unless you have confirmed that they do not function based on something you read on here. (bpv)

 

[yudkib]

yeah the BPV isn't your issue. im 90% sure its your WGA. especially since other people are saying their forge spikes. its not the BPV, or intercooler or the cat for that matter. the intercooler is a good investment but won't fix your issue.

cant you change the springs inside the forge? if so try that, or buy an ATP... theres people out there who would buy your forge. the BPV is just about a waste. the only reason i have one is because it came with the car.

 

[kneedragger89]

Yeah i was getting the intercooler anyways just thought i would throw that in to see if that would effect any of the advice. and i will look into the springs for the wga. and any recommendations on the cat piping that has been popping up in my search alot.

 

[J_Naoto]

they do have different springs for the forge wga. i changed mine to a stiffer one to run more boost, but it still spikes and doesnt hold.

 

[kneedragger89]

they do have different springs for the forge wga. i changed mine to a stiffer one to run more boost, but it still spikes and doesnt hold.

i hope forge has a bad new year for making a crap part. so is there any advice other than a new WGA?

 

[cougar10agREDUX]

Internal wastegates are more prone to spike. Especially on small Turbos.

Edit: boost spike occurs because the wastegate has to settle. This only takes a second or two. so if your speaking 9psi and holding 5. The wastegate is set for 5psi.

 

[yudkib]

ive always been somewhat confused myself as to how WGA's actually work. its kind of black magic to me... i get how its a spring and opens when it gets over pressure, but i dont really see how boost control prevents this from happening. its a weird science to me.

anyways, i know a quality EBC like a profec II can help with spike, but is that only if the PSI being run is higher than the wastegate pressure?

 

[cougar10agREDUX]

ive always been somewhat confused myself as to how WGA's actually work. its kind of black magic to me... i get how its a spring and opens when it gets over pressure, but i dont really see how boost control prevents this from happening. its a weird science to me.

anyways, i know a quality EBC like a profec II can help with spike, but is that only if the PSI being run is higher than the wastegate pressure?

The spring keeps the wastegate closed. Boost pressure acts on the diaphragm until it overcomes the spring to fully open the wastegate. Also note that even tho you may have say an 8psi spring in thwre the wastegate will start to crack at a much lower pressure. Say 3-4psi. This is where an ebc can help improve spoolup by setting when the wastegate starts seeing boost with the risk of higher spikes. With an external wastegate the ebc applies boost to the otherside of the diaphragm to control boost. An ebc may help with spikes if you 4un more pressure than the wastegate

 

[yudkib]

applying boost to the other side of the WGA makes sense. i figured it was something like that but i just wasnt sure what.
but an EBC wont help with spiking if you want to run the same boost as what the WGA is rated at? (or less)? correct?
(i.e. by assisting WGA operation with vacuum)

 

[cougar10agREDUX]

applying boost to the other side of the WGA makes sense. i figured it was something like that but i just wasnt sure what.
but an EBC wont help with spiking if you want to run the same boost as what the WGA is rated at? (or less)? correct?
(i.e. by assisting WGA operation with vacuum)

with an internal wastegate theres only one port so you can't apply boost to the other side of the diaphragm, the boost controller cuz doesn't give it a signal until the set psi. you cannot run a lower pressure than the spring in the WGA, like i said the spring keeps it closed. boost controllers can't give vaccum in boost, and giving vac to a WGA would only close it. if you run higher boost than the wga spring, an EBC may help with spiking if it has a scramble boost setting. it all depends on the EBC, wastegate, the WGA, size of the turbo and how much boost you run. internal wastegates are gonna spike more because the flapper doors are small.

external wastegates spike too but its not as much. i spike to maybe 13 psi and hold 12. but with my EBC i can make it spike more or less, but that also affects response.