Hiya

Need some quick advice you tunning guru's, just about to replace my WRX intercooler with a STI one, would this need remapping again or would will I be okay just changing it. Also, I am right in beliving that I also need to change my undertray to a STI one as well?

Cheers fellas

Yes and Yes. The STi undertray is wider to accomodate the larger IC.
You ought to have the STi bonnet scoop too but that is not as important as the undertray. I bought a new undertray as i could not find one 2nd hand.
I also plumped for a genuine new scoop too, cost a fortune all in, but i did not want some nasty fitting crap looking one.
If you dont remap, then why change the IC?

Does he really have to remap? the uprated IC will only help with intake temps id assume?

Thanks for the replys :luxhello:

I only wanted to change the intercooler to lower the charge temps, but was a little unsure if it needed remapping. Iv already got an STI scoop and in the middle of tracking down an undertray. I just dont want to risk damaging my engine. I had a remap a few weeks back and dont want to spend out another £400 unless its really necessary. On that note though, if im likely to get a good gain by mapping again, might be worth doing :freak3:

Well, the only thing i changed on my car last was the IC, undertray and scoop. Then i went to see Bob Rawle! lol.
Although my car was not mapped to its best before i saw Bob, it made a bloody big difference when i left :)

Hiya

One more quick question, will putting an STI Intercooler and Undertray have any ill affects on the engine until I get it mapped again?

Cheers Fellas

changing to the bigger IC can only have positive effects whether you remap or not. As you say you want to lower charge temperature. Cannot see the need for a remap personally.
ken

I just stayed off boost until i had mine mapped for safety.
RCM agreed on this point, so i would think they know what they are talking about!

Hmmm, two conflicting opinions, I know the STI intercooler is 2 inches bigger, but other than thats, it identical to the WRX one. I know id probly be better off getting it mapped, but whats problems could be casused as a resut of changing to an STI intercooler without getting it mapped?

Bigger intercooler, more air being compressed into the engine?

Perhaps cause it to run lean without any changes being made to fueling, ignition mapping etc.

Ask the person who mapped your car, see what they think to be honest.

A "tweak" mapping shouldnt cost more than £100-£150 and you may be surprised how different the car may be after. ;)

I think its just cautious to get it looked at, i fitted a FMIC from the original V1 tiny TMIC, quite a difference i think you'll agree and that was fine, got it checked out on the RR to be sure but everything was OK. Still on a Z4 ecu so couldn't be "mapped" any way.

Dave :)

Fitted a larger 98 intercooler to my 95 about 6 months ago.. worked fine but the car started overboosting as it was cold and the larger intercooler was doing a better job of cooling the air.. kept hitting fuel cut, couldn't afford a full remap so returned it too standard.

No need to get the ECU re-mapped if fitting the STi intercooler.....The ECU will still see all the air going in (MAF) and deal with things accordingly :D

Not much point in fitting the STi scoop or undertray either.....the STi intercooler is one of subaru's finest and can cope with the lack of flow of air unless going for big power.

What it will do is decrease charge temps and reduce the pressure drop across the intercooler improving performance....something the ECU will notice and adjust ignition / IAM etc :)

BUT

The poor old ECU will just think it's just another day at the office (cold air in winter) and not take full advantage so performance gains not massive...You need a re-map to take advantage of the situation :) :)

Shaun