How dangerous is it to...

[Addicted2Fun]

Change out the Mid pipe (with cats) and CB w/o a tune?

I was thinking about doing this but feel as though i should ask if that is advisable.


*I edited this to make it more likley what i was thinking about doing. Any and all information is very helpful, thank you!*

 

[Black Sex]

Change out the intake to a CAI and your Mid pipe (with cats) and CB w/o a tune?

I was thinking about doing this but feel as though i should ask if that is advisable.

unless you change the amount of boost you shouldnt need a tune

 

[TVSCobra]

unless you change the amount of boost you shouldnt need a tune

+1

 

[Steeda30]

The only thing I'd be worried about is changing the intake configuration, as that can affect the way the MAF reads the incoming air - it may be allowing some air to go by unmetered, depending on how the CAI curves and how the MAF is turned.

Once the car's tuned with a given intake setup, the addition of more or less boost won't require a retune, so long as the injectors are providing enough fuel and the MAF is not pegged.

*EDIT* if you're on a factory tune then it'll most likely be rich enough to be safe even if it does lean it out some.

 

[Jefe]

Ive got the JLT RAI and Bassani Catback/Catted X. No tune. Runs a little lean up top. Probably getting a tune here soon

[ame="http://www.youtube.com/watch?v=dLwK_OgnyIs"]YouTube - 04 Cobra Dyno[/ame]

 

[Steve2050]

My car only has a CAI/catback and far as I know it's on a factory tune. No worries.

 

[SicStang03]

Ive got the JLT RAI and Bassani Catback/Catted X. No tune. Runs a little lean up top. Probably getting a tune here soon

YouTube - 04 Cobra Dyno

Why did he run the car all the way to rev limiter?

 

[03cobra#694]

Once you move the MAF!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[AaronK]

You should be ok unless you MAF position changes... better safe than sorry though

 

[Jefe]

How much wiggle room do you have in moving the maf position? Mines about 30 degress higher than it used to be

 

[SicStang03]

either way it's less than 100 to get your A/F checked just for a piece of mind

 

[Addicted2Fun]

How about just changing out the mid pipe and CB w/o a tune? would that be alright without a tune for like 2-3 weeks and just have them install the pulley/cai?

 

[T-Pain808]

Pesonally, I would just wait, and get a tune.

 

[04sleeper]

unless you change the amount of boost you shouldnt need a tune

+1

That is 100% Bad advice!

A/F is tuned through the MAF by AD Counts. Boost has NOTHING to do with it. If a car has the MAF Transfer Function dialed in properly then you should be able to run what ever boost you want. (So long as you have enough headroom in MAF voltage/ AD Counts.)

How do you think turbo cars are tuned? They can run all different boost levels with just the push of a button. With a proper tune, you can run all boost levels with the same tune.

A good rule of thumb is any time you move the MAF position, you should check your A/F. (Moving the MAF can throw off AD Counts/ A/F)

I'll give you a quick example with my car. I went from a JLT 12" High Boost kit to a Metco RAI kit, I figured it might be a little leaner but actually ended up being a full point richer! I had to retune for it to get back to my desired 11.4 A/F ratio.

I'm not saying all cars will be like this, because every car is different. But you can not just say "You should be fine", as that would not be correct.

I recommend having your A/F checked.

Better yet, make a small investment in a wideband and keep an eye on it yourself.

Just my $.02

 

[Jefe]

Whats a desirable A/F for daily driving?

 

[04sleeper]

Whats a desirable A/F for daily driving?

If your Short Term Fuel Trims are set correct, then you should be in the 14.64:1 (Stoich) at cruise and idle. Wide open throttle 11.4-11.6:1 is a good pump gas A/F.

 

[BlackBeauty44]

If your Short Term Fuel Trims are set correct, then you should be in the 14.64:1 (Stoich) at cruise and idle. Wide open throttle 11.4-11.6:1 is a good pump gas A/F.

Isn't that close to what our cars run stock. i know they run lean at idle but pig rich at wot especially the 03 cobras

 

[03yellow]

your fine without a tune

 

[Addicted2Fun]

I updated the question.

 

[About2bite]

Better yet, make a small investment in a wideband and keep an eye on it yourself.

:beer:

Probably the most important gauge in my car