NAD226

I have a 95 UK model impreza, fited with a Milltek sport turbo back exhaust system and K&N induction kit. These have been on the car for about 8 mounths. Only since the weather has been getting colder have I had what felt like fuel cut occure when in high gears going hard from about 5000rpm upwards. Fitted a boost gauge last night to find that the boost is stable at .8 of a bar until 5000rpm then it climbs to just over 1 bar giving fuel cut. Is this going to be due to modifications on the car or do I have some other fault causing this. Please help

briforbes

Sounds like a combination of the free-flowing exhaust and cold, dense air due to the weather. I had this on my evo a couple of years ago. I solved the problem by fitting a manual boost controller (dawes device) to turn the boost down a fraction, something daft like a reduction of 1 psi was all that needed to cure the problem.

Also, I've just been having problems with fuel cut, which turned out to be caused by a tiny hole in one of the vacuum pipes from the boost solenoid to the actuator....might be worth checking your pipes for leaks in case this is the cause of the fault.

It it's just happening in the higher gears though, sounds like standard issue boost creep due to the exhaust and the weather.

NAD226

Would fitting a manual boost controller really cure the problem. Surely all of the bleed valve manual controllers only reduce the movement of the actuator and so can only increase the level of boost produced.
I shall check over all of the hoses for any signs of leaks. Is there any easy way to pressure test the hoses whilst they are still on the vehicle?

wrx_yank

get an ecu remap..(ecutek) that will solve the prob... and give you more power!!!

NAD226

Will the standard internal engine components reliably handle more power than the car has at the moment? With the car as it is it reached 265bhp on the rollers earlier in the year and has become problematic only with the colder weather. At what point is the boost creep likely to peak at?

vids

You should probably port the wastegate a little. Or just add the cat or some other restrictive device in the exhaust-system on cold days

Sounds like the same problem the us 2,5 sti has with a decat system on the vf39. They take a dremel and port the wastegate (something you could do yourself, no need for a professional tuner) so that it more easily can get rid of excess boost. Just see to it that you dont make the opening bigger than the door that closes it

You could read this thread about the Creep:
Everything you need to know about boost creep - NASIOC

T5OLF

iTrader: (4)

A Dawes device is not the same a bleed valve, a DD has a ball bearing and spring set up, If you lower the presssure on the spring the amount of boost pressure needed to open it (the bearing/valve) is less = less boost made, no fuel cut.
A dawes blows off at a set pressure and does not "bleed off".

Also improves spool up I'm told.

When I changed to a large K&N from a panel filter I had the same issue fitting a Dawes device fixed the problem....

NAD226

Where would you recomend that I get a Dawes device from, are their various models available?

harvey

iTrader: (48)

Get in touch with Alyn at AS Performance. He will post out a GBE valve overnight. Tell him what model Subaru it is for. The GBE is very similar to a Dawes, just I have found it a more precise piece of kit.