I will be getting an axel back exhaust (mid pipe&muffler) and was wondering if this addition would warrant a retuned? I'm currently tuned by uprev with z1 intake, crawford plenum, kintex HFC and motordyne xyz. Any input would be greatly appreciated, thnx

 

not necessary

 

^^ cool, i didnt think so, just wanted to get some feed back

 

You currently do not have an aftermarket mid pipe and Muffler? Larger diameter piping obviously will be more free flowing and might affect a/f ratios slightly.

Personally I would.

 

No, stock. I was gonna wait till I got an exhaust but I was gonna be austin tx and just went for it. The motordyne xyz dump to 3inches and stock contricts back to 2.5 I believe. SO even if the car has been giving new a/f ratio targets to learn it wont be able to meet them?

 

Yes you have to get a tune. The car will not run properly without one.

 

Unfortunetly I can't answer that specific a question in regards to the targets, but just airing on the side of being tuned optimally for your set-up.

 

thnx man, been trying to call uprev but they must be busy busy

 

The ecu goes into open loop mode when full throttle, meaning it won't correct rich or lean air fuel ratios. In most reflash dynotune cases where people have added intake/exhaust etc, the cars come in running lean when full throttle. With dyno tuning we are able to get the air fuel back to a safe ratio, which picks up power at the same time. (There is a lot more that is done as well - but I am keeping it AFR specific to relate to this conversation.) At the same time, I have never heard of someone bolting up an exhaust to a stock 350Z and it blowing the engine.

 

Ahh ok, thanks for the explanation, my car is tuned now for my mods. I wonder how much just an axel back will lean me out.

 

Hey gabez. fyi just text the phone number it a lot easier for him to answer you. Lol dont ask how i know this. A retune never hurts and its only $125+gas. I did it when i got y-pipe and intakes.

 

thnx man, let me do that. do you go to any of the meets for SA i dont know if I know you already?

 

well i use to but got into trouble a while back.i went to one last week thursday and thinking about going back to this thursday.

 

Like previously stated, if your first tune is a good one, your not gonna hurt anything by adding an axle-back muffler. Personally, I would assess what you plan to do with the car and determine if a tune now is what you want. I'm not sure if there is a limited number of re-tunes available but that's one aspect I would review. The second would be the cost, is it worth it for you? Cost to gain will likely be out of favor, 0-4 hp is what I'm estimating, and that is optimistic. Put the thought in, and determine if it is worth the piece of mind or not. Really I don't see a right or wrong answer.

 

I chopped my muffler off ...and Y-ed it out to two mufflers..feels like i almost lost horsepower and pickup on the lowend..maybe its cause the reduced back pressure on the engine? idk