[Greywulf73]

Hello all,

I've been playing around with the idea of an exhaust cut-out for many, many years.

My dad had a mechanical exhaust cut out on both his Renault 5 Hatch and his Renault 12 Wagon (yes, we're going waaaay back)...anyway, I remember the huge difference these cut-outs made in both noise and power on those N/A cars. I think the R5 had a 1.5 L and the R12 had either a 1.6L or a 1.8L . I mean, it was like hitting V-tech yo!

No, but seriously, I think that turbo vehicles benefit just as much if not more from something like this. Now-days, one can get kits with Y pipes with built-in cut-outs.

I was going to ask if anyone had done it but decided to search first and I found this on Google:

Veloster Turbo Variable Exhaust Sound ~ PartsKor

So, can we have a discussion on whether it would be best to do this or a simple but expensive exhaust swap.

 

[[email protected]]

Only problem with an exhaust cut out on newer cars... the PCM freaks out the first few full throttle applications/pulls. The adaptive's change to rapidly and it causes the PCM to run in semi-safe mode for a while until it realizes that a change was made. We have seen power loss as well when you open the dump on the dyno.

Thanks,

John

 

[Greywulf73]

Hmmmn...that's a bummer. I'm guessing the only way around this is an aftermarket PCM/tune?

 

[[email protected]]

Hmmmn...that's a bummer. I'm guessing the only way around this is an aftermarket PCM/tune?

Even with a tune, the adaptive strategy is still there. I don't know how the PCM knows when the thing is open but it normally takes 3 to 4 pulls on the dyno for it to adjust and the power gains to start showing up.

 

[bgenlvtex]

I'm not going to be surprised to find that the turbo prefers a reasonable amount of back pressure.

 

[swordfish]

I'm not going to be surprised to find that the turbo prefers a reasonable amount of back pressure.

:facepalm:

Hmmmn...that's a bummer. I'm guessing the only way around this is an aftermarket PCM/tune?

The possible work around would be to set-up a WOT switch, so that you would put the dump into the WOT fuel curve. But even that would need a tune to fully realize any actual gains.