Hi all
seen a few mentions of the above on a decat version.
Can someone explain to me how/why this happens and what effect it has on the car?
DaveTS is prob a bit of an expert on it.

Dave?

Cheers

jas

 

Probably best asking this is in the drivetrain section but from what I have read there doesnt seem to be a cure at the moment so I guess you wont get many informed replies.

 

try this thread
http://www.scoobynet.co.uk/bbs/threa...threadid=80851
Oh and moving to drivetrain..

 

thx guys

 

jas

If anything is not clear after reading the thread, ask away.....

 

cheers Dave
Nice motors.....

 

Is spiking when there is a lack of boost and then a massive surge of boost?

Sorry for the simple question

jas

 

Basically yes. It's when the turbine spins up too fast before the boost control can get hold of it and pull it back to the table in the ECU.

If you watch it on a boost gauge whils driving the car under load in a higher gear, you will see when the turbo spins up the boost gauge will momentarily peak, or spike, at, say, 1.7 bar, then rapidly (in a second or two) drop back to the held figure of 1.15 or so when the ECU gets hold of it and gets the boost control solenoid to operate the wastegate.

The restrictor is in the pipe from the compressor to the boost control solenoid, and basically controls how quick the solenoid responds by how much air can flow through the hole in the restrictor.

It has been said that the initial boost spike on an STi7 can be brought down to a safe figure by just changing the restrictor to one with a bigger hole in, but almost everyone that has actually tried this says it does not bring the spike back to a safe level with just a change of restrictor.

 

cheers dave
Your a star.
You should be a university lecturer

jas

 

jas



You go on a sharp learning curve when you find you have 1.7 bar boost spikes!

 

LOL
I can well imagine
How are you finding the STI?
I like them but have only had my WRSprt RB5 for a year.
love it to bits and will prob keep it for at least another 18 months and then who knows....

 

jas

The STi's are excellent - and not too much tweaking to do - PPP, 18's, lowering springs, tints and that's about it!

 

Dave I thought a person of your stature would only accept 19"s

P.s look in members gallery i'm sure you will be impressed