Hi,
Will shortly be fitting a decat downpipe to my95 WRX. Already has a straight through centre section and can rear box in 3".
Before I fit the down pipe I need to know the following.

Will it need remapping?

If it is fitted will it di any engine damage if not remapped?

Can I just replace the ecu to overcome any potential problems and if so which one?

Prob silly questions to you but if you don't know you have to ask!

Cheers
Del

 

Is the ECU a Z4?? ifso leave it be ....a remap could be useful after all ur mods so's you are not trying to emulate 100 ron fuel....my 93 import has not been mapped yet and runs fine with V-max {optimax} plus an octane booster, plus full stainless inc manifold

 

Thanks for the quick reply.
Not looked at the ecu yet but if its not a Z4 should I fit one

 

Z4 is the import ECU it give u 260bhp with a TDO5 turbo {not sure with a TDO4} but it does mean the std octane fuel in the uk simply wont do BTW its located in the passenger footwell.

 

Ok fella,
Thanks for the help

 

When I had my old '94 wrx it originally came with a standard exhaust & airbox. I changed to a decat down pipe & exhaust & a K&N induction kit. The car ran fine (on Optimax) with no problems for a number of years before I sold her. I've since learned that the OEM ECU in the early cars are less prone to being fussy about such upgrades & theat the cars run a little rich on fuel as std anyway....

 

i have heard on other forums that the very early imprezas were run on 99 ron fuel in japan and its only in the last ten years that japan started to use 100 ron so your car shuold be ok on v-max

 

I had a MY95 WRX, which has a TD05 & Z4 ecu as standard so yours should too.

Fully decatted, used Optimax and octane booster until I fitted a knocklink.

Zero activity, and when tried on Optimax alone still zero activity so I only used Optimax.

Current opinions now suggest that a Z4 should be fine on Optimax/V Power alone, which is what I found myself with the knocklink, even though the full decat naturally upped the boost to approx 1 bar/14ish psi.

 

Run my 93 wrx with z4 on 98/99 ron its perfectly fine.
if in doubt disconnect the battery to let the capacitors int he ECU drain (couple of hours if you have the time) make sure you have plenty of petrol of your choice then reconnect the battery,go for a drive which includes pootling along at normal road speed for the particular type of road then blast it through the gears (no need to redline it but give some high revs) and the ecu will 'learn' the new settings