i just bought a Turbo XS UTEC because i have plans on upgrading turbo and all that good stuff. but i was wondering if i where to install it right now and tune it with just the mods i have on my car. would it give me a more gains or anything in that nature. or would it be a big waste of time and money to have someone tune for nothing. just a question from a fellow subie owner.

any feedback would be awesome.

 

Puting a UTEC on a stock Impreza can do wonders. Infact before putting on bigger, better parts this could be a good way to learn some tuning with a safer setup. I would _highly_ recommend getting a wideband 02 sensor for your car, or no matter your setup, you can still hurt your car. You might want to take a look at wrxhackers.com too.

jason

 

i know this might be a noob question but bare with me what is a wideband O2 sensor?

 

You car has a couple of O2 (oxygen) sensors. It measures the amount of O2 in the gases leaving your engine. It compares this with the readings from your MAF sensor (essentially measuring O2 intake) , along with the fuel used and figures out your Air to Fuel Ratio (AFR, parts-air : parts-fuel). I don't know how many O2 sensors an STi has, but a WRX has 2: one near the exhaust ports and another rear one way down the down pipe. The WRX UTEC shows values from the rear sensor and the STi UTEC shows none of them. Don't be sad, because it doesnt really matter. Most cars, including the WRX and STi, have stock O2 sensors which are good for monitoring AFRs only under very specific conditions and for specific purposes - this doesn't including tuning. These stock sensors often have a short range that is also in the wrong area on the AFR scale. For tuning you want to be able to read at least as rich as 10.5 and as lean as 16.0:1. The stock WRX rear O2 sensor reads from 12:1 to about 24:1. This basically sucks. Running 11.5:1 with 17psi at 5000rpm is just not healthy for your engine on pump gas. But with the stock O2 sensor, you'd never know. UTEC logs are forced to just report "rich" with its 11.5:1. You should have about 10.8:1 there, bit you have no clue. The stock sesors are also not very fast or very accurate. As you get further and further from stochiometric readings (14.7:1) the readings become more unreliable.

Enter the aftermarket wideband 02 sensor. My VW WB O2 (from TurboXS) reads about 9.5:1 to 25:1. What gives the WB better ability is that its got a 5 volts reading range, while the less sensors have only 1 volt. (This volt business is an industry standard) Its also supposedly not as fast at reading O2 as the more expensive Bosch WB O2 option from TXS when you buy a Tuner... but hey, I'm not a perfectionist... and I'm cheap The Tuner plus VW WB O2 is about $400. If you're going to tune on your own, I'd HIGHLY recommend getting one. There are cheaper options, but the Tuner hooks right up to the UTEC and puts O2 logging right into the UTEC log.

jason

 

it took my a while to finally understand your post. so it is better for me and my car ifi get a wb o2 sensor along with the utec right? so i can read all the AFR and all that good stuff? what WB O2 sensor do u recommend?

i see that the one your talking about on the turboxs website that txs tuner pro but thats kinda pricey 700 bucks and then what i paid for the utec. thats alot but if i need it then i should buy it.

is there another wb o2 sensor or something in that matter kinda cheaper that i can use.

oh i also see the tuner w/bosch 02 sensor thats probably what ill be getting.

 

whats the difference between the bosch and vw

 

If you aren't getting the Pro, don't bother getting the Bosch, would be my thought. Either go ***** out, or don't. There's no reason in paying more for not much more functionality. So, Tuner + VW or Pro + Bosch. You, personally, I don't think need the Pro... I mean I don't think I need it either. I'm basically using it to learn, not to get the best tune. I'm tuning my car the best I can and soon it will be in the care of a professional who will finalize what I've done. Then after that I can use the Tuner to make changes for weather conditions, etc.

jason

 

so u recommend for me to go with the Tuner w/ VW O2 Sensor with the utec? would be the best.

i was planning on taking it somewhere for a pro to tune it not a heavy tune just a good one, like a dyno tune.

 

so i guess the question now is, do i still need a wb o2 sensor if i am going to dyno tune my car to a set map?

 

They will tune it with a tailpipe sensor. Its not a necessity... but you'll always be going back to the tuner and his dyno when you make a change.

jason

 

when u say make a change? like add something to my car, like headers or intake or whatever. or do u mean like something have to deal with the weather or if i wanna run race gas (just using as example). i would like to have different maps if possible.

i plan i keeping this set up for a while then going bigger turbo all that stuff, which is when i would buy the o2 sensor.

 

Yep, all those changes apply.

Many have learned the hard way....

jason

 

if you have cats put the sensor infront of them to get teh correct reading

 

runnin catless