ok i got this 08 fit sport AT, and was just wandering will it make that much difference adding a header back exhaust system and intake since the car is making somewhere around 90hp. looking at the megan racing setup (header,mid pipe, and axle back) and maybe a DIY intake?

 

I have heard of "noticeable" differences, but keep in mind you will probably want to add a wideband o2 sensor and e-manage to the list if you are doing all that. The car has been proven to run lean with I/H/E

 

Umm no.

Several local members have been running full I/H/E with no problems. You do not need to run an aftermarket ECU upgrade with these simple bolt-ons. Intake and header will show the most gains. B-Pipe and Axel back will show the smallest gains.

 

I'm sorry! My mistake... The car did not start running lean until they dyno'd with a test-pipe (cat delete). I retract my previous statement!!!!


I/H/E was OK. Getting rid of the cat leaned it out a bit too much.

 

a MT would make a bigger difference

 

yes i do agree

 

running lean (even 14:1 at WOT) with bolt-ons does no harm to the engine, u'll even see better fuel economy.

no engine tuning needed.

 

Doesnt mean they arent running lean.

And how does it not damage the engine? If the engine is running lean enough to detonate its not doing harm?

 

x2..........

 

Hey Cavie-
Actually when I dyno ed my FIT the A/F was around 10.2...what is the proper A/F ratio?

tonyd

 

If you notice, i retracted that statement later. I was thinking of the dyno runs with a test pipe.

10.2 is very rich.

 

see thats the thing, it wont run lean enough to detonate in the first place. esp with just bolt-ons. (i/rh/e)

i've tuned some bolt-on honda's and seen up to 14.3:1 A/F without any detonation or knock, on basic 87 octane. Heck, in some cars, i set to run open loop 100% of the time, and during light throttle cruising, we go as lean as 16:1. Very good on gas mileage, and no detonation/knock read.

It all varies on application and conditions. Regarding the Fit, it will never run lean enough to damage with your basic 3's. You can check your plugs to verify.

 

that's crazy! I've never seen 14.3 @ WOT without knock, but then again i usually deal with turbo cars, and start to see knock at 12.3-12.5 wot.

I am not saying you are wrong, nor am i denying the fact. Just saying i have never seen it myself. I believe you...it's just nuts to me. lol

 

oh def not on boosted applications. 14.3 only on a bolt-on. of course, i didnt leave it there, lol.

but on big boost applications, its not uncommon to set light throttle cruising to 15:1+.

 

Cavie-
I am running a test pipe w/ cat delete....my local shop said 10.2 so with that being said the FIT doesn't run lean? So maybe everyone shouldn't worry as much....dunno

tonyd

 

Ok, so then why has there been all this commotion about the cars leaning out? I really don't understand why or how people can dyno the same cars with pretty much the same mods, NO tuning, and get different numbers. (I realize the possible variables ie: temp, elevation blah blah blah...)

makes no sense to me. I just wanted to make sure people are being save with their cars, but i guess i assumed too much (like reliable information).

I'm not mad at anybody, nor am i implying anyone is lying. I'm not trying to argue or upset anyone. Tony, in no way am i trying to contradict you. -it's ridicules that i have to put this stupid disclaimer on my posts-

 

Who makes it? And the lean condition happend when an Intake, header, cat-delete, and cat-back are together.

Im still worried. My car doesnt have any performance problems. Other Fit owners that drive my car say its WAY faster than theirs.
I still think 13.7-14.0 is pretty damn lean.

 

just check your plugs if u're concerned. If u see any knock/detonation spots, then its time to worry. Otherwise, fagetabowtit

also, knock is audible. u will hear it.

 

Yes, I know its audible. My friends 92 Sentra use to knock like mad. Completely stock, stock timing and all. He had to run premium or it would knock.

Ben said that the car only ran lean when adding the testpipe in addition to other mods.
Im still missing the header. I want one though.

 

i like that Weapon-R race header. very nice design and long primaries, best ive seen for the Fit. It'll def make more power than header+TP.