Headers? High Flow Cats? Tune? Looking for advice....

[Indydriver]

Originally Posted by ST1LE

I have heard it is really raspy without cats, they really help to bring down that rasp. I love the sound of my LT's + HFs through my NPP.

Second this.

[CrystalRedTintcoat]

Originally Posted by ST1LE

I have heard it is really raspy without cats, they really help to bring down that rasp. I love the sound of my LT's + HFs through my NPP.

Apparently the camaro has cats, resonators and mufflers each of which reduce sound. The resonators are just behind the cats.

I suspect a lot of people delete the cats and the resonators or go with high flow cats straight back to the tailpipe was no resonator and no muffler. Maybe this creates the rasp? Dunno.

There are some YouTube videos demonstrating nice sound by keeping the resonators and deleting the muffler.

As for me .. I plan to move to high flow cats, drop the resonators and keep the NPP. Fingers crossed that I'll like this sound.

[Nicky Pass]

I went to NicKey yesterday....which is about 45 minutes from me and I must say, Stefano and his shop are top notch. He talked me through everything he'd do, he showed me all of the parts and gave me a sound demo of a few cars. We shot the shit for like and hour!

I'm taking my car there for sure. I just have to play the weather game. I've got to get it there on a day it won't rain. The weather in Chicago is streaky.

As for the tune....as long as they'll cover parts outside of the motor, I'm fine. They can't deny a power window because of a tune.

[Camaro Dude]

So all you guys here, who are essentially building bolt-on modded cars, with no tune for warranties sake, are saying that there is no KR happening at higher rpm's and WOT????

I'm thinking that in theory there should be, you should be running lean right?
But wait, since you would have no tune, then the oem protocol would be to use the lower octane fuel map, hence the infamous fuse pull, so that the high octane parameters are set in place again.

Thinking out loud here until a guru chimes in to set me straight.

[Green Machine]

Stainless Works Headers
No Cats
3" Stainless Works chambered exhaust
Dyno Tuned
CAI, Ported TB, etc...

I love the sound, its loud but not to loud and there is no drone.

I have a video its not the greatest quality and doesn't do that car justice lol

http://youtu.be/O1aYcEyCflY

[X25]

Originally Posted by Camaro Dude

So all you guys here, who are essentially building bolt-on modded cars, with no tune for warranties sake, are saying that there is no KR happening at higher rpm's and WOT????

I'm thinking that in theory there should be, you should be running lean right?
But wait, since you would have no tune, then the oem protocol would be to use the lower octane fuel map, hence the infamous fuse pull, so that the high octane parameters are set in place again.

Thinking out loud here until a guru chimes in to set me straight.

When the flow is increased by headers, the ECU overcompensates and makes it even richer than stock. So it's relatively safe, but wastes power, fuel, and also probably is hard on cats, too, since you burn the extra fuel there. Well, if you stil have real factory cats that is.

[Camaro Dude]

Originally Posted by X25

When the flow is increased by headers, the ECU overcompensates and makes it even richer than stock. So it's relatively safe, but wastes power, fuel, and also probably is hard on cats, too, since you burn the extra fuel there. Well, if you stil have real factory cats that is.

Agreed.

I mentioned this because a buddy's logs showed a lil KR happening in the higher rpm guages with scoop and cold air intake.

I think Ted from JRE once wrote, headers will not lean out your AFR ratio, but depending on brand of cold air intake, it can lean out.

[ST1LE]

Originally Posted by Camaro Dude

Agreed.

I mentioned this because a buddy's logs showed a lil KR happening in the higher rpm guages with scoop and cold air intake.

I think Ted from JRE once wrote, headers will not lean out your AFR ratio, but depending on brand of cold air intake, it can lean out.

Yes, this was my experience with my Roto Fab. My tuner said mine was very lean and in his experience Roto Fab leans it out the most of what he has seen.

[CrystalRedTintcoat]

Originally Posted by Camaro Dude

So all you guys here, who are essentially building bolt-on modded cars, with no tune for warranties sake, are saying that there is no KR happening at higher rpm's and WOT????

I'm thinking that in theory there should be, you should be running lean right?
But wait, since you would have no tune, then the oem protocol would be to use the lower octane fuel map, hence the infamous fuse pull, so that the high octane parameters are set in place again.

Thinking out loud here until a guru chimes in to set me straight.

You raise a compelling argument about running too lean, or something else for that matter. In fact lying restless in bed last night I had similar concerns and started researching handheld tuning computers/tuners. Net net, after reading multiple C5 threads on tuners, I've convinced myself to reach out to "Ted Jannetty" for a tuner and either a canned tune or custom tune based on the mods I've made and I'm planning to make.

Originally I planned to remain stock and not muck with the program module but, really, if I'm going to make multiple changes (CAI, resonator delete, shorty headers, mid pipes with high flow cats, o2 sensor extender), albeit all bolt-on in nature, I figured it's wise to think about a proper tune. Then again I'm trying to logically speculate here so I don't know what I don't know.

I'm sure "Ted" will want to sell me a tuner and a program but I'm also hoping/expecting that his advice will be clinical with an honest assessment of what's needed vs what's optional.

Does anyone have advice?

OP, what did you learn from your one hour "shoot the shi^" session with the Chicago tuning guy?

[CrystalRedTintcoat]

Originally Posted by Camaro Dude

Agreed.

I mentioned this because a buddy's logs showed a lil KR happening in the higher rpm guages with scoop and cold air intake.

I think Ted from JRE once wrote, headers will not lean out your AFR ratio, but depending on brand of cold air intake, it can lean out.

Sorry, I'm a neophyte .... What's KR and AFR ratio?

[Camaro Dude]

Originally Posted by CrystalRedTintcoat

Sorry, I'm a neophyte .... What's KR and AFR ratio?

KR means Knock Retard.

You can datalog and check to see if you have any.

AFR means Air Fuel Ratio.

You can datalog and look at your fuel trims at partial throttle since it's still in closed loop.

For WOT (wide open throttle) AFR readings, you would need a wideband air fuel ratio meter, preferably hooked up pre cat.

[X25]

I decided to go with inTune device ($389 shipped) with a custom tune from Florida Speed ($100 option when you buy the device from them) tailored to my car's mods (and logs that I will provide). A safe tune that brings the numbers within the ballpark of ideal is more than enough for me, since it usually also translates to a very safe tune that works in every condition and environment.

I just got the headers coated, and once I am done installing headers and the tune, I will take it to dyno for a sanity check. I will keep my build thread updated with my progress.