OnyxCobra

How much gain were you expecting from stock to shorty headers? I'm more surprised that you think there's a huge difference in power than i would be if you didn't notice much of anything.

grabbem88

the reason an o2 signal creates an open loop run..is mostly,cause of weak voltage or the exhaust temp isn't high enough to activate.the ecu will think the egine/coolant temp is faulty,and will stay in open loop.

if i'm not mistaken the ecu tables alway's falls back on what the engine coolant temp sensor is telling it everything else supports it.

mjr46

because what you had written was not totally correct, O/2 sensors are not output devices but are input devices all the o/2 sensors do are measure oxygen content in the exhaust which is represented in the form of a voltage signal to the ecm, to bring the 0/2's online quicker there is often a heater element in them, however, once the car is warmed up the exhaust temp keeps the o/2's in proper operating range, o/2's work effectively when heated to 800 c / 1500 f.......FYI open loop operation also occurs a WOT..........VITAL inputs to ecm to maintain The ideal/sthociometric A/F of 14.7 to 1 are O/2'S , ECT, ACT, TPS, MAF/MAP, all such inputs are used by the ecm to calculate the proper A/F RATIO delivered via the injectors .....closed loop operation doesn't occur until temp reaches a certain range

302army187

I wasent expecting a single change. I picked up the header's for $100 in brand new condition. and just figured "hey, it's my LAST bolt-on mod, why not"

But i put off installing them for a couple month's, and everyone i talked to was like "ZOMG, INSTALL THOUSE ASAP, HUUGE POWAR GAIN!!"

with having every other mod, but head's and cam, i was thinking id gain some upper RPM power from having better flow then the stock header's.

But was just surprized at the noticable midrange punch it added is all. its nothing AMAZING prob 8-10hp at the very max.


just got done welding in MM XL full length subframe's tonight.. now THAT is a "ZOMG" mod. haha, i love the was it changed EVERY aspect of the car

Ketis

which coolant sensor does it monitor off of?

mjr46

the one on top of the coolant return pipe on right front lower intake manifold pipe