302army187

Ok. This got me thinking.

yesterday morning I finally rounded up my last "bolt-on". I went from stock header's to BBK shorty un-equal ceramic coated header's.

Ok, after fixing a few leak's i went for a test drive. Noticed that the exhaust note is more throaty, through the RPM's it has more "growl" to it, which is nice.......

but I felt NO change in power. nothing. So i was disappointed, but happy I finally have full exhaust, and full "bolt-ons"



Went to work last night 16mile drive mostly highway. Just cruised the hole way. In the morning when I was leaving i let the car warm up while i showed a co-worker the stock header's and the BBK's on the car.

while i was pulling out, i got on it in first and second, and completely surprised when my head snapped back from not expecting the extra pull the car has now.

stopped at the light, and when i went again, did the same, LOTS more mid-range power.


so why would i not gain anything from the header's just after then install, but after driving 20mile's the car all a sudden have more power?

from 2000 or 2200 to 4500rpm the car pull's MUCH harder, almost no more top end(stupid E7's), and feel's like there's more torque in the low down...
(not just me, took the girlfriend out for a ride and she said the same thing)


I thought that the computer monitors the air coming into the engine via the MAF, then sniff's the exhaust with the O2's and compensates for adjustment's instantly, not that it need's time between each mod to get use to the new "flow"....




CLIFF NOTE'S:
-finally got header's
-felt no new power afterword
-drove to work 20miles
-felt more power on way home
-why does the computer seem to take time to compensate for mod's??

AdderMk2

it takes time for the ECM to make adjustments... it makes small changes at a time

but when you took your car for a ride after first assembling it.. it was probably still in open loop

mjr46

drivibility is stored in the ecm's KAM= KEEP ALIVE MEMORY, usually after major mods I disconnect the battery, which resests the Kam AND after about 20-30 miles the Kam should have adapted to new parameters and drive normal

302army187

open loop?

you mean like "wtf is going on?"

302army187

i plan on doing that now. Isn't the best way to drive is to be easy on it for like 10mile's then romp on it a few time's?

mjr46

whatever you like...as for open loop , when the vehicle is in warm up mode until around 140 -160 ish degrees the vehicle operates off of preset programming in which fuel enrichment is calculated based on these preprogrammed tables.....once vehicle is warmed up it switched to what is known as closed loop operation in which fuel an spark are calculated based on the input sensor readings to the ecm and commands are then output to devices such as injectors based on what input readings were.

q8stang

open loop is when the coolant is not at operating temp so it uses preset programming which is usually on the rich side.. closed loop is when the coolant is warmed up and the ecm knows what afr the car is runing

302army187

i see now. make's sence.

when i first drove the car after the header's i drove it about 10mile's, but tword the end of the ride i dident have a single chance to open it up from traffic.

hmmm, going to do some more research on this. Still think ill go reset the computer too just to be sure it is set up right.

thank's for the info fella's.

q8stang

why was my post edited? i know for a fact closed loop and open loop is controlled by the 02 sensor but why coolant?

67mustang302

The engine uses coolant temp coming from the ECT to determine when it goes into/out of closed loop. That's why if you put a 160 thermostat in the car won't run right, the computer never uses the O2's to tweak the AFR, unless it's programmed to do so.