HOTLAP

the Magnaflow "X" pipe with high flow cats just arrived today and I'd like to install them this weekend.

Question: if I open up the exhaust side - wouldn't it make sense that I'm going to need a tune - as in theory the exhaust will be flowing better with less backpressure from the factory cats and H pipe?

I already have the Magnaflow axle back exhaust installed and have not done anything to the intake side (YET). Am in process of ordering the JLT CAI and SCT tune...

TIA - Bradley

Wanted to ask those of you who have changed out your exhaust (above cat & back) did you need to get new gaskets or can the stock be used and will I need to use a high temp gasket sealer - or anything else for that matter that I should look out for when intalling my x-pipes?

2005MustangGT

I'm not 100% certain, but I've hollowed out my cats (adding more air flow-less back pressure) and finally after about 3 days the service engine light has come on...which indicates to me I will need a re-flash/tune for optimal performance...so I would suspect you will need the same since in essence you are doing the same thing, except you aren't killing the enviornment like myself.

HOTLAP

Yeah - I'm thinking along the same lines - Brent (Magnaflow) did say that they were going to dyno the "X" pipes again to determine if a tune was needed or not with this mod + the Magnaflow cat back......their 1st dyno run did get approx 19rwhp (IIRC) with these mods and no changes to the intake side.....still I don't like the idea of driving with the engine in a too lean condition - can't be good for it??

Blk05GT

You might be able to get away with it as rich as they run these cars from the factory however if you have a SCT on the way it is probably safer to just wait.

2005MustangGT

LEANER IS MEANER!!!!!!!!!!!!!!1 :angry:

wild stray

If you have already ordered the tune and intake, even if the light comes on it will only be for a short time. I have headers on mine and the light didn't come on. Going in for a tune next week. Main concern is for someone to make a mod that leans it out too much and keeps driving it that way.

HOTLAP

Thanks guys - you've confirmed what I was thinking - I'll wait until everything gets here then install and hit the Dyno/Tuner shop the next day. Can't wait!!

At least I can install my ud pullies - that won't create a lean condition.