bellmouth to divorced downpipe
 

Will i have to have my map tweaked again if i do this as my bellmouth is on its way cheers and which is best bellmouth or divorced

I wouldn't worry about it, I've looked in to this before and whilst people have their favourites I didn't find anything conclusive that one was better than the other, and I really wouldn't bother having a map tweak for it.

You think it wont affect at all swapping from a nurspec r to a milltek system if i kept my downpipe i have on and change center and back box be okay

Guessing they're both 3" systems? If so then yes I'd say you'll be fine!

Both 3 inch original center resonator longer milltek is shorter nurspec back box smaller milltek is longer box but angled

Just irritating me as some ppl say will mess air fuel up

Yes I know you'll get some people who say you should have a 'tweak' if you so much as change to a different panel filter.. but I really wouldn't worry dude.

The exhausts are like for like essentially, would seem ridiculous to me to have any ECU changes done on this basis.

Ok buddy really aappriciate your help

just to echo whats been said already - I've changed my backbox/exhaust a few times now

Starting with a magnex backbox/standard center/standard downpipe bit by bit up to the vortex afterburner backbox/center and a fully open downpipe.

Yes tweaks were needed when the downpipe on, but also when I switched from the vortex backbox to a smaller backbox you could see a difference in torque output.

You already have an aftermarket downpipe, your map should be fit to accommodate changing to another aftermarket downpipe without any problems.

Take a video of your boost gauge on a 3rd or 4th gear run before and after to compare - if it's going to spike it's most likely to be in the higher gears where any change in flow will be more apparent.

I have a toucan screen so will datalog the boost propperly

So...if I wanted to change from a tsl rear box(which it was mapped with) to a quieter devil rear box,would I need a map tweak....
It was mapped with an open mouth down pipe and de resonated centre by the late JGM.

Cheers

you aren't changing the downpipe though just the backbox? So no i wouldn't worry about the map unless your going from a 5" unrestricted backbox to a single 2" tip - if it's not much of a difference in size then you shouldn't have much need to worry.