Any other mods. I see you have parking sensor.

 

no, only a camera that i activate with a button on the dash board and i see thought on a TV.

 

Check this site:

QTP Website
As you can see it's installed after the header for more power gain.

 

pretty cool. I wonder what the HP gain would be on a Fit. 10 HP?

 

No i do not think that the gain is 10 HP. My opinion is it about 5 HP.

 

Haha, I was actually being sarcastic when I said that. Some of the stated gains from the website on other cars are ridiculous.

 

Yes yes, I know what are you mean.
There are some guys that says that.

 

So you just changed the pipes and install back the stock mufflers, is that any good in performance wise.

 

I've never seen this before. What's the purpose of the mod? I'm not trying to knock it or anything, but I don't understand the point of bypassing the muffler.

 

To be free flow system

 

You will not see much gains from this. You're better off going with an electronic exhaust cutout welded right after the header and dumped into atmosphere.

The current design as he has it may not be efficient at all compared to the stock muffler alone. Exhaust gases may be reverted back into the muffler with that close-to-90degree bend back into the muffler. Let alone, the catalytic converter is still there, which is the biggest restriction in the exhaust system.

It would have been better if u had it dumped out instead of going back in the stock pipe, like the Mustang Saleen exhaust system.


For those that do not care for loudness (because you can control it via switch) and want peak HP, look into DMHperformance.com's e-cutout. They are the best i've used. QTP, QTec, summitracing, jegs, all failed. DMH has a 4-5 year warranty on theirs and replace it if it ever leaks.

 

Was thinking of buying one, and will install it after the header, so it worth buying in performance wise.

 

yup. but theres also negative sides to cutouts.

-be sure its mounted AFTER the 1st primary o2 sensor, but before the cat. Which sometimes could be hard b/c the primary is usually right before the Cat, but i havent seen how its like on the Fit.
-loss in low end daily driving with cutout open, but you get peak HP when u floor it.
-for BEST gains and minimal loss in torque, you would need a tune. This is the biggest factor in making power.

You will see even better results with F/I, and no need to go bigger exhaust either.

 

Kimo if you are going to try it you have to mount it AFTER the second O-2 sensor. If you mount it between the sensors or before the sensors you will have a MIL every time you open it. And will have to clear the MIL before you see any performance benefit so you never see any gain because every time you open it you get a MIL. And it's no fun clearing a MIL every time you try to use it on your daily driver now is it?

 

the secondary o2 sensor only determines if u're catalytic converter is still working, thats why its mounted inside the cat. the primary o2 is the one that determines and reads a/f. If you're still running a cat, then u should have no CELs when running the cutout right after the header, and before the cat. Exhaust gases are still flowing into the cat, even with the cutout open.

Even if he happens to get a CEL from the secondary side, it will not affect any fuel maps nor go into limp mode, as it only codes for P0141 or similar secondary 02 malfunction. does not affect anything on how ecu adjusts fuel/timing. Much like running a testpipe, or no secondary o2 sensor at all. Also, the CEL will not light up right away, he would have to be cruising for a while with the cutout open before the MIL will light up.

 

Not enough exhaust will be flowing past the second O-2 sensor just like guys that are getting MIL using some brand headers. And on a FIT it's a MIL (malfunction indicator light) there is no CEL that's for older hondas.

 

CEL=Check engine light. MIL=Malfunction indicator light; MIL=CEL=SAME MEANING

Again, cutouts are generally only open during WOT runs, not cruising. Having it open for several runs will not illuminate a CEL/MIL. And so what if it lights up? Does not inhibit performance nor throw the car in limp mode, so no worries. The light will turn off after car is turned off and started again with cutout closed.

What codes are throwing up with the guys using the aftermarket header? Did they damage the primary during install? O2 sensors are very sensitive to shock. I dont see how there could be "not enough flow" to the secondary if the cat is still there and the header would provide MORE flow.

All in all, no negative effects to running cutout after primary o2, but before the secondary o2/cat. Running post-cat would not be beneficial to getting a cutout anyways.

 

if it was me id just remove the cat and get a spark plug non-fouler thing at autozone and call it a day, no CEL to worry about.
exhaust cutouts give me the vapors! especially on turbo cars

 

Kimo you will just have to ignore all the idle speculation about putting an exhaust cut out between the primary O-2 sensor and the converter because on your Honda City both the primary and secondary sensors are screwed directly into the converter body.

So unless you want to cut apart your converter you are out of luck. Unless you want to plug the hole in the converter, make a custom pipe, weld in a new O-2 sensor bung, move the converter to the rear, lengthen the wires to the secondary O-2 sensor, and then end up with a MIL anyway because of the difference in flow between the two sensors will show a MIL because the difference in flow will indicate to the ECU that the converter is clogged, that is a lot of work just to end up with a MIL.

As for your idea to mount the cut out right after the header I can tell you with 100% certainty that you will get an immediate MIL. I know because when I had the header off my JAZZ, to wrap it, I started the car with the exhaust not connected to the header, just to see what it sounded like, and as soon as the engine was started I got a MIL due to not reading any flow at the primary O-2 sensor.

And for the less informed out there a CEL (check engine light) and a MIL (malfunction indicator light) are not the same thing. Older model Honda's had a CEL because that system was just for monitoring some engine functions so it was called a check engine light (not check motor light).

Newer Honda's have a MIL because the light is an indication of malfunctions in several systems not just the engine only. Honda spent big bucks to make the change in all their manuals, repair Cd's etc so I guess Honda thinks they are not the same thing either or they would have just gone on calling them CEL but they didn't did they. Just go to your Fit/Jazz/City owners manual or repair manual there it is MIL.... Malfunction Indicator Light.

 

if this is true, then yes, do not do cutout b/c its useless with the cat still on. On the USDM Fit, the primary o2 is on the header, not the cat.

By removing your exhaust, do you mean the cat with it? B/c if ur primary is mounted on the header like the USDM's, it will not illuminate the CEL/MIL. If your primary was NOT in the exhaust flow, then yes, it'll light up right away b/c it needs heat to activate the sensor, in which u did not leave it in the exhaust stream to heat. The secondary is not as prone b/c it can be bypassed via defouler method. Secondary will run just fine with minimal flow, its inside the catalyst, and does not measure flow rate at all.

Why are you worked up about the light showing up? it will not affect any performance or gas mileage as long as the primary is still functioning the way it should. The first sensor is located on the manifold or header (USDM Fit at least) and measures O2 content of the exhaust as it escapes from the cylinders. This sensor is used by the PCM/ECM to calculate fuel trims and look for combustion problems. The second oxygen sensor is located after the catalytic converter and is used only to measure catalytic converter efficiency. The PCM/ECM does NOT use any data from the secondary O2 sensor for engine management. The PCM will set an CEL(check engine light)/SES (service engine soon)/MIL(Malfunction Indicator Lamp) light if the catalytic converter is removed, the sensor is removed, the sensor goes bad, or detects "inefficiency" from faulty cat. Hell, i dont even have a secondary o2 connected. No CEL, no problems passing emissions. I used to run the defouler method and it worked great before i got rid of the sensor altogether.