shane159

Just wondered if I fit a decat and down pipe to my 2006 sti 2.5 will I need to get it remapped to suit or can I just fit it hassle free???

I dont want the car to be going into limp home mode or anything like that

Why I ask is I went to buy a decat last week and the company I was buying it off said that I wouldn't be able to fit one unless it was mapped, now Im confused, dont know If he was just saying it to make money or he was being straight up with me???

Scooby_Stu_

iTrader: (12)

Hi Shane. Yes you will need a remap after fitting a decat downpipe, it would over boost without a remap.

garetgax

iTrader: (3)

boost creep=engine death

shane159

Thanks for that buddy, looks like I best get saving then.

sponners

iTrader: (4)

could fit it along with a boost controller to lower boost slightly, then get afr's and knock checked to make sure everything is still ok.....which it probably will be.

dynamix

iTrader: (3)

My 2006 STi went to 1.6 bar on half throttle with the decat by accident before mapping - DEFINITELY needs remapping for it.

sponners

iTrader: (4)

with a boost controller (manual or electronic) and boost run at standardish pressure then it should be fine on std map???

(would need to be checked though just to make sure)

Scooby_Stu_

iTrader: (12)

As dynamix said, it's not worth the risk. I got andy at scooby world to fit my decat downpipe and simon (JGM) came and mapped it at scooby world the same day.

Stuart.

a16pse

Hi there i have the same dilema with my STI PPP ILL GET IT MAPPED AT THE SAME TIME AS THE DECAT THEN , just out of interest what BHP would i expect and would it be worth the £1,000 or there abouts it would cost, cheers steve

sponners

iTrader: (4)

a remap will make a world of difference to the permance/feel of the car.

but some people who read this thread aren't so wealthy and will think they HAVE to get a remap if fitting a decat.
(just think of all the classic scoobs with decats and you cant even map them ecus)

the ecu's main reference is airflow/boost so as long as its somewhere near to standard (will go more) it is still just a subaru map.....so is still a safe map.

dynamix

iTrader: (3)

There is a world of difference in boost control between classics and newages.

sponners

iTrader: (4)

I take it by that that the newage is worse than the classic?

either way as I said fit a aftermarket manual or electronic boost controller

(eliminate ecu controlling boost)

dynamix

iTrader: (3)

Just get a remap and get the job done properly ...

EBC will cost close to a remap and it wont even be close to being safe unless you run at whatever boost it is as std - but then what is the point of decatting unless to get more power. If you get that more power through the decat without mapping it will be running off the last column of the main maps for fuel and timing and may not be safe or at the very least wont be very nice to drive.

The 2.5 STi in particular, when decatted, is like the turbo running metaphorically naked around the playground shouting look at me i'm free. They boost like heck and take a lot of taming on the boost control and will go way beyond the edges of the 'safe' subaru map.

sponners

iTrader: (4)

what at near standard boost pressure?

isn't this thead about how to eliminate boost creep/hike after fitting a decat?

what is the boost cut set at as standard on these cars? (without looking at their std map - I would guess that the car will be relatively safe upto this level)

agree electronic boost controllers van be expensive and a PITA to setup, thats why I'm a fan of the manual controllers such as a dawes at standardish boost levels.

ps do you offer a remap service?.....I'm guessing you do. (we all ave to earn a living)

dynamix

iTrader: (3)

Why would you want to decat unless to increase performance? Why bother with the expense, the hassle of changing for MOT's, the potential for roadside emissions checks ... unless there was an upside.

If you run at exactly the same boost levels as before the decat - it aint worth it.

If you decide to twiddle the **** on the MBC one way and sneak a bit extra boost (or set it up wrong initially), you are going into untested cells on the subaru map. If you twiddle a bit more (temptation is too strong to resist sometimes) - you will be off the end of the map and rather than running safe at this point you will be running blind and entirely relying on the ECU's ability to remove timing in the event of det. It does this very well mostly but it will not be optimised for fueling nor timing and is a wasted opportunity and cost for no benefit.

Risk it on your engine by all means but unless you drive a 2.5 sti you really cannot comprehend how much these want to boost all the time. Without taming it you will have 1.6 bar at 3000 on the std turbo before the ECU's boost control finally panics and start trimming it back. It might be too late by then, it might not but do you feel lucky?

This thread is about whether he can fit a decat to a 2006 STi without remapping - the answer is dont do it IMO and agree totally with the company selling the decat to him.

CRAFT

Just a quick question along the same lines here, I'm thinking about getting a 100cel sports cat downpipe to fit to my STI7, already have a full TSL firestorm system on the scoob with a TSL remap, will I need to get the sportscat downpipe addition remapped also?

CRAFT