You can get an o2 sensor simulator / CEL delete part on kingmotorsports.com i believe. Look around, maybe someone else can enlighten us but i believe it fools your ECU into thinking you have an o2 sensor when you dont have one or a cat.




Regarding down pipes. Is there a high flow cat available for the GE? I like the idea of more free flow but im not sure i want to sacrifice emissions control. Besides isnt it actually CA illegal to delete your cat? ( yeah yeah im a fuddy duddy about some things - ill drive 110 on the freeway but i dont wanna break emission laws)

 

Yes, it's illegal to delete the cat in our state.
I haven't seen any high flow cat specific to the GE
but you can use a universal cat from Magnaflow.

 

Is that magnaflow high flow cat mated to a down pipe or would i need to have that fabricated?


When would they pop me for that violation of emissions? Upon smog check? or could that be noticed when / if i get pulled over?



EDIT:

Regarding the Megan down pipe, does that have a cat or is that a resonator?

 

+1 raton for finding the article. if air has to be moving at a certain velocity to scavenge the cylinders, larger pipes would just change the rpm at which that happens, right? basically, every exhaust system is "tuned" to an rpm range? a range at which the force required to move air along the exhuast is most efficiently countered by its tendency to keep moving and pull more air along with it. so while a 60mm exhaust can be effective on a fit that is turboed and tuned for high rpm, its most efficient flow rate is out of range of a stock motor and rendered inefficient.. eye candy? just thinking out loud to see if i understand this.

PS Megan downpipe has a small resonator. the other b pipes are straight through, or at least the ones ive seen.

 

Read my post "the great debate" It is reflective of my experience with just installing an axle back system which greatly affected power delivery on many levels. needless to say I am back to stock.
I would never try to deter anyone from performing mods to there car but I feel with the fit you will spend lots of money just to relocate where the power comes in during the rev range with a little more pull at best in a limited rpm span.
remember also my car is an automatic which really magnifies this problem.
stick shift fits will handle mods better because you can more easily keep the car in the rpm range where the power is made.

SS RICH

 

Just like i posted in another thread...

This is from neons.org and not from me!!


These are general guidelines I calculated from David Vizard's formulas.

1. For avoiding significant restriction from back pressure, the pipe should flow at least 2.2CFM per horsepower produced.
2. A straight pipe will flow ~115CFM per square inch of area (using inside diameter of the pipe)
3) I used the formula: (115*pi(diameter/2)^2)/2.2
4) The pipe size will become more restrictive the further you go above the zero loss horsepower.
5) Similarly, try not to go too big on piping for your set up. I think Vitor dynoed 2.5 vs 2.25 on a 160whp set up and had very minimal gain. Putting 3" on your stock Neon will be very loud for no good reason!
6) Add length as a factor.
7) Each 90° bend will reduce airflow by 8%!

Exhaust Diameter (inches): 2
Zero loss Horsepower 164.22

Exhaust Diameter (inches): 2.25
Zero loss Horsepower 207.84

Exhaust Diameter (inches): 2.5
Zero loss Horsepower 256.59

Exhaust Diameter (inches): 3
Zero loss Horsepower 369.49

Exhaust Diameter (inches): 3.5
Zero loss Horsepower 502.92

Exhaust Diameter (inches): 4
Zero loss Horsepower 656.88

Thats a dyno graph of Vitor with his (then!) 160Whp Neon... Notice how adding a 2½ catback Versus the 2¼ stocker didn't change a thing and even reduced high RPM power!!



I would stick to a Header and a Axleback except if i were to throw Nitrous or Boost into the Equation!

Marko!

 

More excellent info i just found on a GM site!


Replacing the stock production exhaust system with a low-restriction, free-flow one is usually one of the first modifications made to any vehicle in the name of performance. We all know they're louder, but how much performance do they really add? We've all seen supposed dyno tests, usually run by the exhaust manufacturer's themselves on their own dyno, indicating vast power gains, and psychologically, we always equate a healthy exhaust rumble with increased power in the seat of the pants, but how much power are we really gaining? To find out, we're running a simple backpressure study, and our results will be posted here as they come. Admittedly this study is not totally scientific as there are many uncontrolled variables, but it should be sufficient to provide a rough estimate. It is generally accepted by automotive engineers that for every inch of Hg of backpressure (that's Mercury - inches of Hg is a unit for measuring pressure) approximately 1-2 HP is lost depending on the displacement and efficiency of the engine, the combustion chamber design, etc. Our sources indicated that in the case of the L67 3800SC, 1HP per inch of Hg is reasonable.
1 inch Hg backpressure = 1 HP lost
For reference, we have the following conversions factors:
1 ATM = 14.7 PSI = 76 cm of Hg = 29.921 inches of Hg = 1.013 bar



Also read this!!
How to Make your Own Effective Exhaust System > MotoIQ > Magazine Articles

Marko!!

 

Subscribed. Great info in this thread.

 

This is strange..... I ordered a Megan down pipe 5 hours ago.....

 

Awesome info! So what does this do to muffler selection? I'm assuming you want the 'highest flowing' option you can have, but how can you find that out? Does this mean there isn't that big of a difference between different axle-back options?

 

I don't know. I just read SS RICH's post (somehow I had skipped it), and with my Fujita and HKS, I have had absolutely no difference from stock other than a nice rich sound and a little better throttle response. I have had no loss of torque or power that I can feel. As far as maintaining exhaust velocity, I can vouch for that because I can see that in the colder months. You should see how fast the exhaust comes out when it's cold and you can see the steam (vapor). I'm no flow dynamics engineer, but I'd have to say that these axlebacks essentially have no great effect on power--at least anything that you can feel. Like has been said before, you want to make more power, then turbo/supercharger/nitrous or K20 swap are the ways to go.

 

I have never gotten anything but noise out of any stock motor that I did exhaust changes on and even then larger pipes would almost always cause the engine to run badly except for maybe 25% of the power band at best.... The Fit is somewhat more able to adjust to freeing up the intake and exhaust thanks to the ECU but there is going to be a slight loss at the bottom end but a throttle controller will help that out..... A really efficient cat back and intake may cause an increase in combustion chamber and exhaust temperatures that causes a decrease in ignition timing that can be witnessed with a scan gauge and cause a loss of fuel mileage unless you drive at low RPM where the effectiveness of the changes in the intake and exhaust aren't evident except in loss of low end torque from loss of flow velocity..... It takes a multitude of tuning tricks and small modifications to realize an usable power increase and the Honda engines just keep getting harder to do that with as the years go by.

 

A properly designed Header WILL give some gains on a L15A engine... The stock piece sucks!! The Collector is a joke and the pipes are really small... as for gains from an axleback and intake combo, they will be there but if you gain 5Hp from a 110HP engine in a 1150Kgs car, it's unlikely you will feel it!!!

Marko!!