I'm putting a turbo in my car and getting it tuned right after. If i get exhaust in the future would i need it retuned? what about down pipe? can anyone please tell me what would make me have to get a retune if i got a new part?

 

You need to reaserch a little more. When installing a turbo you will need a down pipe right away not after. And if your going from diffrent exhaust sizes then yes it will need a retune. Your making your turbo let exhaust out easier since your gonna be making it bigger so with that the turbo is gonna spool up faster and in turn giving more air into the motor across that givin rpm range so yes. If I were you look into a electronic cut out. You can have the stock piping flip a switch and go straight to open down pipe. Or there's some that work off psi so say you past 6 psi it will open up switching to pretty much a 3inch or whatever you chose

 

when i got my basemap initially for my turbo d16, i told john vega at phearable i was running a 3" exhaust. i asked him if the tune woudl differ if i ran a 2.5" instead with my current tune, he said yes and recommended a retune.

i think if you tuned for 3" and run a 2.5", you will run a little richer. and if you tune for 2.5" and run a 3" later, you will run a little leaner.

 

i do have downpipe, i meant if i get a bigger one. but thanks!

how much of a difference does exhaust make? because if its only like 5hp then might as well not bother. ive seen exhaust add 20hp sometimes, how does that happen?

 

it depends on how much power you are running.

MANDREL bent 2.5" will support up to 300hp of flow
if youre running 3" with LESS than 300hp, you will have better spool (by a few hundred rpms), and gain that 5-6hp youre talking about, while getting a louder exhaust note.

anything over 300hp run 3"

id personally run 3" after 250hp tho.

 

I run up to 28psi through a 60mm exhaust (I know, I know). I recently installed a cutout in my 2.5" downpipe. When I uncapped the cutout, it dangerously leaned out A LOT and I had to retune immediately. Luckily I tune it myself.

So you can deduce that if you tune it with just the downpipe and later add a restrictive exhaust like mine it will likely run much, much richer. The effect will be less I'm sure with a full 3".

Best advice is to finish the whole setup before getting it tuned.

 

+1

 

thanks so much guys. i decided to just go ahead and get exhaust and 3" downpipe before my tune this friday!