V4JDMSTi

iTrader: (2)

Frayz help! or anyone else that may know the answer for that matter.

I've recently changed my exhaust to a 3" system from a 2.5" and i fitted a v6 sti intercooler. Since then every now and then it feels like i hit a brick wall when accelerating hard. Is this where the boost is hitting more than the limit and causing the fuel cut?

the boost gauge says i'm hitting around 14psi and holding 12psi when it's running ok. typical thing is i've not been looking at the gauge when it happens.

There's no real pop and bangs or crackles from the exhaust if that makes any difference.

i really don't want to have to stick the stock cooler back on as it was a really tight fit. i know it's going to be a nightmare to swap back.

Mark_B4

I suspect, It'll be the exhaust that's causing the issue, as it'll flowing the air quicker, causing the turbo to spin faster, thus creating slightly higher boost.

Fuel cut or maybe a miss due to a dodgy plug, I had the same issue after changing my exhaust a few years back... the higher boost seems to make things more prone to failure.

NickBes

Could that not be the coil packs? Mine did something like that when Zak was mapping it and he changed the coil packs as they were cracked and problem solved. Just a thought, I am sure Frayz will be along soon though.

V4JDMSTi

iTrader: (2)

i've got a new set of plugs that i can stick in so will give those a go. i had thought coil packs and or maf, but i'm hoping not. lol.

when i just had the exhaust and not the bigger ic on it was fine. plus if i ease on the loud pedal it's fine. it's when i plant it that it does it. first of all i thought that i was hitting the rev limit. which as it goes has always been before the red line.

i don't think the ecu has been played with. i took the cover off the other day and it's a w6. what ever that means. but when it was on the rollers last i thought 270 was a bit generous for an induction kit and 2.5" decat system.

NickBes

If you do try that, when you remove the coil packs to get to the plugs they will have a little rubber cap thing on each one as I recall, take that off carefully and inspect the end of each coil pack as that was where mine were cracked.

wozzaa

Sounds like the same problem I've got

frayz

iTrader: (7)

Alway difficult to exactly diagnose problems without seeing/experiencing them first hand. However in this case id be more swayed to say it was the car hitting the fuel cut defender.

As Mark B4 said, the new exhaust is causing a boost spike when the car is underload and you nail it. It wont do it when you progressivly add the throttle as the loading isnt as great.

Id be looking to get it mapped properly asap mate.

V4JDMSTi

iTrader: (2)

cheers guys. mapping means new ecu though. but something i've wanted to do anyway. so will have to wait for a bit.

tax is up at the end of the month so perhaps take it off the road and do some more to it. i'm sure i'll be able to buy the ecu within a couple of months with the saved petrol money lol.

guess i could always use the old mans wagon, if i could ever find the keys lol.

bibo_boy

I had a similar issue.....

Zak put on a Dawes and a knocklink...

I think the Dawes controls the boost better than the stock solenoid and the KL for piece of mind?

Speak to the man!

Mocom Racing

iTrader: (2)

for Bibo.

The most likely cause is the intercooler; there will be lower pressure drop through the STi intercooler assembly than the early type you had previously, lessening this restriction is now causing overboost.

There are various ways to lower the boost to correct levels but the easiest and 'probably' the most reliable would be the Dawes.

Knocklink what do you need one of them for

**Disclaimer - the last question is said in jest

V4JDMSTi

iTrader: (2)

i have a dawes device, just never fitted it lol. how much to fit it / set it up and supply and fit a knock link? will do me until i can afford get the simtec fitted.

bibo_boy

They work better fitted lol...

I think the knocklink is about £140 and the Dawes is about 1-2 hrs as the car has to be road tested and monitored. (lots of fun!!!!!)

Best check these as I may be out of date.....?

V4JDMSTi

iTrader: (2)

that's not bad really. would rather have it running right as it's spoiling things at the moment.

will have to look at making up somewhere to put the knocklink. centre vents are out as they've been replaced with 3 gauges.

bibo_boy

You can take the box apart and carefully mount the LEDs in the top of the Instrument Cluster.

There's a few pics around the site.

V4JDMSTi

iTrader: (2)

that's where it is on my dad's wagon. looks good. never even seen it come on though. which is a good thing i guess.

bibo_boy

First large green light should always be on and the second should occasionally flicker?

V4JDMSTi

iTrader: (2)

nope no lights at all. will have a look and make sure it's connected.