None.
I remember adding ECU or ignition (don't remember which) would change the pitch of the RB26 in FH3 but it was difficult to spot and probably an unintended effect.
It's very possible to change sounds by layering a more aggressive sound over the quieter stock one, but this requires work, and all the focus seems to be on adding cars to prolong the game's lifespan, so... not happening in FH4. We don't even have FM7's sound updates yet, all of which would be very welcome!
Originally Posted by: opencamswrx 
Originally Posted by: The Chugster 
Obviously changing the whole engine or the exhaust changes the engine sound but do any other upgrades change the sound?
What i want to know is how to boost the engine performance without changing the sound?
In real life, nearly every kind of upgrade changes the car notes in some way or the other. In Forza;
* Exhaust upgrades may or may not change the sound
* Cam updates with only make the revving sound higher (more high pitched)
* Forced induction upgrades will introduce new sounds
* Engine swaps will change the sound entirely
Think that's about it.
IRL you change the air filter and the sound changes. It's that sensitive.
Personally I want really loud turbos, superchargers, etc. I add forced induction and I want to hear it. Instead, I have to pay attention to hear my huge turbos spooling. That's something that could be improved.
I love driving cars with centrifugal supercharger upgrades like my 1993 Cobra R but all of my turbo cars have muted turbos and many cars with PDS have muted whines as well.
Edited by user Wednesday, November 20, 2019 12:13:19 AM(UTC)
| Reason: Not specified
May the forced induction be with you.
Alice >>>>>>>>>> Keira