Charles,
You gained 3 mpg my having the factory cat converter installed, over the straight pipe? You have a Bonez resonator on that pipe too?

Any clues why you gained mileage with the stock trim?

 

got the n flash today dammnnnnnnnn does it drive better.. idk why flash i had previously since i bought it used...

 

I cant wait. getting the flash this week along with some minor crap.

 

checked under the hood yesterday there is a sticker for the N flash. :D

 

Went from M to N.
-Noticed that the car revs smoother through the rpm range and no hesitation when letting off the throttle from high rpm and throwing it into next gear and going full throttle.

- Car idle is the same, minus a dip in the idle when coming off the choke (happened only twice)
- Exhaust note seems the same to me
- Maybe a little power under partial throttle, but I think it's just due to the smoother revving.
- haven't checked out gas mileage/soot on the tailpipes, so I can't comment.

 

Charles,

One idea is that since removing the cat decreases backpressure, the oxygen sensor is not reading correctly and causing a somewhat rich condition. Might not be out enough to turn on the CEL, but just enough to run rich. At least older O2 sensors needed backpressure to operate correctly, I don't know if that is an issue with the sensors on an 8.

 

Would be interesting to use some type of independant O2, CO, and CO2 analysis of the exhaust with and without the cat. Then if you can get numbers from the ECU, compare what the car O2 is seeing.

 

Isn't the 4th component CO2?

 

I got flashed today! w00t. I had the M now i have N. My idel is a 4519578429729180 + 1 times better and i feel a noticeable difference in power. Also much better gas Mi. I thought my gas guage was broken because i had gone 20 mi w/o it moving..so i started going to 9k from every light. After a few, i FINALLY got it to move some. So i'd have to say better gas mi too...

my exhaust sounds louder as well...i <3 it

 

Did your car come with the M or did you have it flashed up to the M?

 

I got the N flash last week and my gas mileage seems to have gone down. I was averaging around 19.5 with a mix of city and freeway driving before and I only got about 220 (15.8 mpg) out of the tank after the flash.

Unfortunately, my car was hit on the right fender by a coworker in a company car so its being taken care of but I won't get it back for two weeks. Once I burn through a couple of tanks of gas I will have a better idea of the mileage.

It does seem to have a bit more power though it could be my wishful thinking.

 

columbus, where did you get your car flashed? byers on sawmill? i have requested this service, but paul the service manager, didn't recognize what this "n-flash" was? is there some other technical words that i should tell him so he knows? thanks again.

 

i had to get the M flash...my car came with nothing. they didn't even know what the hell i was talking about when i went to get the M. lol.

My gas mi. is tons better...i'm not too sure why Columbus's has dropped...seems odd...

we'll find out on wed. for sure about the power additive because i'll be running my car at the track.lol

 

Lol

 

I had it done under warranty at Bob Boyds in Lancaster and I had to talk to one of the techs to find out which flash they had done. The service manager gave me a blank look when I asked about the N flash too. There is alot more knowledge on this board than you'll be able to find at a dealership.

 

Well finally drove mine a bit since I had the N flash upgrade two weeks ago. I believe I had the buggy M flash because my car was flashed last October, one week before they put a hold on the flash update and eventually came out with the new M. Not positive though.

My observations:

- Didn't really notice a power difference, the sound maybe, it's hard to tell
- Smoot on pipes is significantly less than previous flash
- Mileage is looking better. Same driving habits. I have just over 1/4 of tank left and have driven 205 miles so far

EDIT - Officially 18.4 mpg. City/Hywy mixed

EDIT #2 - 19.4 City/Hywy mixed

**Synopsis - Gained about 1-2 MPG with new flash.