VistaBlue

Ok, so, I did some searches, but came up empty on my questions.

I noticed most people saying, with a CAI+Tuner, they can't pass emissions, and so they revert to stock tunes for emissions, and then go back to the tune.

Now - what if you have an O/R H/X Pipe? How do you pass, then?

Also wondering the real difference between H/X pipes. I see most people go with H, yet some say the X sounds better. Is there a power difference?

Thanks for any help.

SirKnightTG

You can pass no problem with a CAI+tune as long as the tune is written for emissions. People get passed with CAI/headers/cams/etc all the time. The key thing is having cats and a tune for emissions.

You can't pass with an O/R setup. You'd have to have cats of some sort (stock or high flow).

H sounds deeper and X sounds higher pitched. I greatly prefer the H. The MAC prochamber is awesome as well. I would have went with one but it would have required welding and cutting since my headers are Kooks and not MAC so things would not have matched up perfectly.

East87

1. Once my Delaware inspection comes up in 2011, I'll try to go through as-is. If I fail, I'll throw on the stock midpipe and reset the computer to stock.

2. I LOVE my o/r H. Video in sig.

3. The H sacrifices 3-5 horsepower for sound vs the X, but there is a bit of torque that you get from the H due to the backpressure vs the X. All these numbers are minuscule, which makes the o/r pipe really just a sound mod...unless you've got headers or something.

4. For o/r pipes: X = nascar, H = musclecar. IMO. Depends on your mufflers too.

2007VistaBlueGT

CAI and a tuner isn't the problem, it's the tune itself. A lot of tuner seem to think that you need to over do everything to make power.

kentompkins

So a relative stock 05 GT with a JLT CAI tuned by Brenspeed for 93 octane should pass with all the hassel of going back to stock first?

moburto07GT

My advice would be to call Brenspeed to verify that they did not turn off the rear o2 sensors. Because on most of their tunes unless you specify they will turn off the rear o2 sensors. Which if your state/county does obd2 testing it will give a not ready signal, and you will fail the emissions test. Because their computer will be unable to read the rear o2 sensors. You can either have them send you a tune for emissions or return the car back to stock if you don't have anything done to it other than the CAI and Tunes.

GT Bob

I really don't know why most of these guys turn off the rear O2's on their tunes. Unless your running a catless exhaust, you gain absolutely nothing by turning them off. The only reason they are there is to tell you if the cats are working for not, and have ABSOLUTELY ZERO bearing on the AFR's the cars computer commands...

And to the OP, the poster above me has hit the nail right on the head. Tell whomever does your tune to leave the rear O2's turned on, and you'll be 100% ok for any emissions testing.

onederful100

the reason why places turn off the rear O2's could be that when a customer sends in the list of mods, they may not put that they have aftermarket catted mid pipe, bc some aftermarket catted midpipes still throw a CEL. so i think places just turn off the rear O2's so you dont get the CEL from the hi flow cats.

VistaBlue

I guess what I was getting at was - how do you pass with the O/R pipes? Do you just change back to the catted/stock tune everytime you do emissions?

East87

If DE does a sniff test or a visual inspection for cats (I really have no idea), I will put the stock midpipe back on and reload the stock tune or a tune that doesn't shut the rear O2 sensors off.