Weird things after shorty header and test pipe install

[EP3Lov3]

I noticed my car has been going through gas more than usual and after i drive the car for a bit, i can smell oil. All this happened after i installed a shorty header and test pipe and I used a sparkplug nonfouler diy mod as my o2 defouler. Also have a greddy evo 2 catback and motor only has 53K on it and is a K20A3. What can be the cause of the oil smell and gas guzzling. The smell of oil only comes after the car has been driven for a bit

[ep3colin]

The smell is very normal once you delete your cat, as for the mpg difference how drastic are we talking? Possible driving habit?

[EP3Lov3]

I have to put in $20 worth of gas in sometimes twice a week, and gas here is about $3.50 per gallon

[ep3colin]

Mpg is the only way to tell if your gas usage has increased or decreased, I personally get 260ish a tank city but 320-330 highway

[EP3Lov3]

So the oily smell is normal since I'm catless?

[USAF EP3]

So the oily smell is normal since I'm catless?

Yes, since the catalytic converter would usually clean up your exhaust emissions but now that it's no longer installed you're spewing all those NOx and CO out and whatever else your cat was picking up. Totally normal.

Also you MPG is going down because now your ECU is confused from the extra flow your just added to the engine, right now it's probably seeing a LEAN condition compared to what it had before you added those parts. Stock our ECU's trim long term and short term fuel depending on the driving conditions and from what the O2 sensors display. Try disconnecting your battery for 5 minutes and then reconnect and do an ECU idle relearn, it should help out a little with the MPG's.

[AKEP]

did you put the defouler on the o2 sensor furthest away from the engine?

[EP3Lov3]

did you put the defouler on the o2 sensor furthest away from the engine?

yeah i did that

[civsirmt]

was the header and test pipe new?
they have to go through a few heat cycles to get rid of it.

[SkareKrow]

When I installed my Race Header I had an oily smell for about two days which was about 100miles that i drove.
After that I just have the gassy smell when I come to stops after a pretty hard drive or just been driving for a while.

Its normal. Make sure that all the.bolts are tightened correctly into the head. Sometimes a small leak can make it smelly for quite a while. =)

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[SkareKrow]

When I installed my Race Header I had an oily smell for about two days which was about 100miles that i drove.
After that I just have the gassy smell when I come to stops after a pret

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[Powers]

Alright what about a decent sized cloud of smoke when your heavy on the vtec? I got a race header catback and tune. It was about 45 today as well.