Changing to different catless DP with larger exhaust (already tuned)

[SavagePassenger]

I've been searching around trying to find an answer on this. I'm thinking about getting a different exhaust that has an option for 3.5" connection at the downpipe, so naturally looking at getting another downpipe I can have match that to eliminate the factory restriction there.

The car has a custom flex-fuel tune on Ecutek with catless dp currently (stock turbo). I can't imagine changing to a slightly different downpipe would matter much, but not sure about the 3.5" through exhaust part. Will this be something that needs a retune?

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[D3ad_Hand]

I've been searching around trying to find an answer on this. I'm thinking about getting a different exhaust that has an option for 3.5" connection at the downpipe, so naturally looking at getting another downpipe I can have match that to eliminate the factory restriction there.

The car has a custom flex-fuel tune on Ecutek with catless dp currently (stock turbo). I can't imagine changing to a slightly different downpipe would matter much, but not sure about the 3.5" through exhaust part. Will this be something that needs a retune?

Preferably yes. As flow of the whole exhaust will change. Also why would you want to eliminate the factory restriction. Unless you are pushing somewhere around 700+ then don't go out of your way to eliminate the restriction.

 

[SavagePassenger]

Preferably yes. As flow of the whole exhaust will change. Also why would you want to eliminate the factory restriction. Unless you are pushing somewhere around 700+ then don't go out of your way to eliminate the restriction.

That's what I was thinking, in order to get the most benefit it may need a retune. Really the only reason I'm considering it is the exhaust I was looking at has a 3.5" version, so it would be easy to do with switching out or modifying a downpipe.

 

[D3ad_Hand]

That's what I was thinking, in order to get the most benefit it may need a retune. Really the only reason I'm considering it is the exhaust I was looking at has a 3.5" version, so it would be easy to do with switching out or modifying a downpipe.

That's up to you. But speaking from perspective of people who actually had to face that issues where the factory restriction blocked them from getting more whp. They bassically delayed it until they needed to get the restriction out of the way. Had a dude push up to 800whp on an Fi exhaust. Then he switched for a full 4" exhaust. But if you think you would change the exhaust then get it retuned preferably.

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