Forum,


Just got a 3'' catback installed but the AFRs are idling at 15.2 (avg) and not 14.7 (avg). This is not a reading from evoscan, this is a reading from off of my UEGO. Is this normal? I don't think so because I just finished doing a bunch of searching. I drove the car from the shop to the house (approximately 3 miles). I noted the AFRs at idle while at lights and such.

Anyways, is this normal to have leaner AFR after catback install? Going to log WOT and Idle with evoscan tomorrow.

 

That is a totally fine idle afr.

 

If you have a lean situation after exhaust install you have a leak on the exhaust before the o2, its registering more air hence why its going lean but its not going to stay steady at 14.7 it'll bounce from mid 15s to mid 14s.

 

you sure man?

 

There are no leaks up top. I know what you are talking about I had a blown gasket on the O2 Housing before that made it go full lean at idle (the readout). I am more than familiar with the bouncing you are mentioning. I remember 2 years ago when the UEGO went on and I started tuning AFRs. I was like I thought it was supposed to be 14.7 lol.

How's that Kinugawa treating you bro? I was going to get one but decided I didn't need that much power. Went with the 20g Tomei solution.

 

that afr is fine at idle. My idle is closer to 16 than 14.7. Idles great. I have had 2 evos for a total of 6 years and this is how they both always have been. With ambient temperature change i see 17s and it still idles fine until i get a chance to tweak it back to the 16s

 

Its really solid and **** pulls really hard, just change the wg for any good aftermarket and get the oil feed line from the oil filter housing just in case shiat happens.

 

15.2 idle AFR is nothing to be worried about. My narrowband switchpoint on my ZT-2 is set to 15.5.

 

Hey champ,

just a question on your set-up (looking at your list of mods)

you are running a larger turbo and 25psi boost…

all that power on the stock intercooler?

 

No the wg is a 25psi but im running 28psi with an ebc the intercooler is an aps intercooler.

 

Guys it's weird but somehow the afrs now bounce sharply between 14.7 and 15.3. Does the computer learn or something? I didn't tune the idle at all. Wifey wanted to drive it around so we jumped in and it was just regular today.

 

Yes it learns via the fuel trims.

 

Ah the mighty Raptord answered one of my posts Cool. I should get forum points for that! LOL


Thanks man, awesome

 

sorry to be off topic.

well thats great work champ

aside from the head bolts, cams and lifters… your running stock pistons and crank.

apparently a tuner where i am, claims that 250kw @ the wheels (335whp) is the "Safe" power with a stock motor.