Gcg Hiflow Over Boosting To 18 Psi

[DFAULT]

So the story goes like this:

- Bought a rb25 GCG high flow, started boost creeping to like 20 psi +

- So then i was told i needed a OP6 Rear housing, chucked that on

- Now it holds a stable 18psi which is still too high for me

- its not the actuator as we've runned the car on the dyno with the wastegate open

Mods: ususal supporting stuff, 3' free flowing exhaust, decat pipe

It makes no sense as i've seen many people use the op6 rear housing without having such high boost

Hope to hear your opinons

Cheers

[Wacky Dee]

think they make less boost on rb25's and more on rb20s ..could that be it ? Something to do with smaller engines making more boost easier...but I obviously don't know much about this stuff so I'll shutup.

[W0rp3D]

I have an op6 and run .8 bar with out a problem.

What sort of dump pipe do you have, some ppl have problems with the wastegate flap hitting and not fully opening with a jjr dump pipe.

[paulr33]

its the actuator and the actuator setup

it is the sole device for boost control

check or change the actuator

check the dump setup

check the boost controller (if you have one)

[DFAULT]

Wastegate flap is left open and hitting 18 psi

meaning it can't be actuator

the dump setup is fine, its 3 inch and flap does not hit

[W0rp3D]

Wastegate flap is left open and hitting 18 psi

meaning it can't be actuator

the dump setup is fine, its 3 inch and flap does not hit

so if you remove the actuator from the the exhaust housing end you will still get 18psi at the plenum??

This is not right, this means that you wastegate flap is not opening, do you know 100% for sure that it was not welded up and the previous user was using an external gate instead?

if i was you i would pull the turbo off and check to make sure the flap is working fine, also how do you know that the flap isnt hitting the dump pipe, the only indicator that this may be happening is the exact problem you have.

[geraus]

how much kws did you gain from the op6 rear? does it lag? when does fullboost come in?

[hypergear]

Machine wastegate whole 3mms over sized. It should fix it.

[benl1981]

GCG do this as an option i.e machine out wastegate and add bigger flap. Should probably be done as standard issue..

[kwickr33]

GCG do this as an option i.e machine out wastegate and add bigger flap. Should probably be done as standard issue..

LOL so people who didn't pay for this option are left to over boost

[Pal]

i had this problem on my highflow. kept on going to 17 psi no matter what i did (even machined out wastegate) ended up being to rich a tune and to free flowing exhaust. had to put a restriction plate in my exhaust and when i was ready to run the higher boost level i took it out and got a retune and that fixed it run a flat 15 till i got a quieter exhaust, now it drops away at the end of the rev range

[DFAULT]

I wasn't actually able to run a bigger flap due to not enough meat on the housing

___

Thanks 'Pal'

i'll proably try running a proper cat, hope it reduces the boost