as355f1

hi, i need to turn the boost down on my sti as its boosting to 1.3bar i want to turn it down to 1 for reliability, i tried undoing the actuator bar and unscrewing it but it did not make any difference, can anyone tell me how to do it
i bought the car like this so i think the numpty that had it before me wound it up
also any ideas why my speedo may have stopped working its a 98 sti, or is there a way to check the speed sensor ? and yes i have checked all the multi plugs, if the kph / mph converter has buggered would this cause it ?
thanks
Jim

fishfire

If it is running 1.3 bar constanly, then I would say someone has fettled with the boost as 0.9 Bar is what it should run standard.

What other mods have been done? What I am trying to get at, is why you think 1.3 Bar would be dodgy. If your car is completly standard and hasnt been remapped, then yes I would say 1.3 is a tad high!


Did the previous owner fit a manual bleed valve or an electronic boost controller, if so this will adjust the boost up and down. If there is nothing that you can see, there is a chance the boost may have been adjusted as a result of the ecu being replaced and remapped for higher boost i.e Power FC or the standard ecu has had a chip or a daughterboard fitted. May be worth having a look at your ecu which is located under the the carpet in the front passenger footwell. If it is the standard ecu there wont be any visual way of knowing if it has been modified.

What boost gauge are you using. I bought a cheapy once and it was waaaaaay off!

If you are concerned about it, you could bypass the boost solonoid by running a vacuum pipe prom the compressor housing nipple, direct to the waste gate actuator nipple. Your boost will then be governed entirely by the actuator then and iirc should only make around 9-10 psi.

Idealy you need to get someone who knows their way around an impreza to have a look see for you.

Hope that helps a bit

fishfire

Sorry, should have also said, if the wastegate actuator is in anyway dodgy that too can affect your boost. As you think this may have been played with I would get this looked at too. is your actuator removable? if so it might be worth seeing if you can borrow a friends and seeing if it makes any difference

as355f1

actuator and turbo looks newish and car is standard except this week i fitted a new bottom end so the motor was out and i fitted a decat pipe and equal length stainless headers and up pipe looks totally standard apart from that and i am using a hks boost gauge
Jim

scoobyboy

put a larger holed restrictor in the boost pipework

as355f1

what pipe would that be fitted in ?

jim

as355f1

how would you turn the boost down on a car out the factory ?

debbiesonic

iTrader: (7)

It's not as simple as it might sound to do that. You could fit an electronic boost controller, or fit a different actuator that operates at a lower pressure.