Mods please leave here for a little while.

I helped my brother find a scooby,MY97 STI
Before picking the car up it was mot,d and my brother supplied a Hayward & Scot system including open neck downpipe,it is full decat,which was fitted after mot.
I test drove the car when we first looked at it,and it was faultless,its performance was almost up to my own which is lightly modded,i was actually very impressed with it .
Since it seems having the system the car feels like its not boosting right and it just has a rough running problem.

Could it need remap since having the full decat fitted?????

Any help appreciated

 

Correct

 

Is it not just related to the Lambda sensor?

I've got a decat mid section already fitted to my UK '97, but was looking to buy a front decat downpipe next week!! Not sure now if I have to have a remap, or does it differ on various models??

 

Any one else had probs after decat on same age/type of scoob

 

I did a centre decat and it added 15 bhp & 18 ft/lb torque, but I know of several people who have gone the full decat route only to have trouble. You may need to look at a larger fuel pump for one thing.

If you have the P reg STI, like me, why change it? Subaru spent years and millions of pounds developing a fantastic car, that will give virtually any other car on the road, a good run for it's money. Put the front decat back on, keep it on Optimax and enjoy your 0-60 in 4.6 secs! Modding is for WRX's! That'll start the arguement!!!

 

I used to have a 98 STi type r so the same as a 97 and that had a full decat with no problems. Used to run optimax and nf with no knocklink activity

 

Thanks for the replies,it seems that the exhaust fitting may be just coinsedence.I have now spoken to power engineering,as i have used them for many years on my cosworths and past scoobys,and there opinion is that the exhaust shouldnt cause this,so now booked in for rolling road diagnostics.

 

I have MY97 STi3. Had no running problems after fitting headers and de-cat system but these cars are mapped to run on high octane Jap fuel as standard. The ecu on STi v3 & 4 can't be re-mapped so if you want to mod it, it's an after market ecu, Apexi Power FC is a good one. Meanwhile a Knocklink is a worthwhile addition. Also run it on Optimax with Octane Booster to be safer.

Hope this helps