you'll notice a difference with a tune. it depends on the car but some get a really noticable gain and others gain a little but either way youll get some extra hp

I myself got better gas mileage, I cant speak for everyone else.  IM getting atleast 25 in the city and over 30 on the thruway

Last edited by se-rman6 (2008-08-17 20:00:16)

gas milage wont really change unless your always got your foot in the gas. Because gas milage really comes from when the car is in closed loop while cruising on the highway, etc. It is controled by the ecu which you cant change unless of course you get a wideband and trick the computer and stuf...blah blah...to much to explain. Read in the wideband section ans safc sections. You will learn alot. Sooo, yes you can get better gas milage, but will have to pay upfront for it. Safc, wideband, datalogger. Knowledge which is in the wideband sections and safc sections to tell you how to take over closed loop and tune it yourself for better MPGs.

hmm interesting never knew wut closed loop means. ill look into that. already sounds expensive

Do i must need a apexi safc controller or im good whitout it ?

you need a safc of some sort, weather it be a SAFC NEO or a SAFC2. And you need a wideband and datalogger to street tune. OR just a SAFC and get it dyno tuned. BUT your tune will drift so gettinga wideband to see when it needs tunning again WILL be needed

ok well i do have an o2 spacer on the 2nd one, would that cause my shitty gas mileage?  thanx for the info on differences between closed and open loop.

silverspec wrote:

closed loop means the stock ecu is controling your fuel maps by way of info its getting from the 1st 02 sensor on the header. Open loop is when the ecu disregards the 02 sensor because you are under more than ussual throttle( not idle or reg. cruising) and the car goes to open loop. Open loop is what most tune. You can take your 02 sensors out but youll get SES lights and its not worth it.
With a good wideband and datalogger you can control closed loop to a certain point. so yes gas milage is possible.

Street tunning takes some time. But shouldnt be that bad, just a few good pulls and datalogs to look at.

just to correct you on something, when you remove the o2 sensors your car never goes into closed loop, you will always be riding around in open loop

silverspec wrote:

closed loop means the stock ecu is controling your fuel maps by way of info its getting from the 1st 02 sensor on the header. Open loop is when the ecu disregards the 02 sensor because you are under more than ussual throttle( not idle or reg. cruising) and the car goes to open loop. Open loop is what most tune. You can take your 02 sensors out but youll get SES lights and its not worth it.
With a good wideband and datalogger you can control closed loop to a certain point. so yes gas milage is possible.

Street tunning takes some time. But shouldnt be that bad, just a few good pulls and datalogs to look at.

sorry, i read that wrong i guess.