KC98LS

A little over a week ago I filled up my car. I always go to the same exact gas station, and buy 91 octane.


Some time after that I noticed that under hard acceleration that my engine sounds a bit different. It has more of a throaty sound now, almost like a VTEC kind of sound.

I can't say that performance has been affected either way, it just sounds a bit different now.

Is this because of the switch from winter blend gas to summer blend?

Stroock639

the 98+ cars did have variable valve timing AND a variable length intake manifold... going from winter to summer blend shouldn't affect how it sounds or anything. with the JBrady intake the car sounds MAAAD throaty (in a good way) and at mid to high throttle you can hear the intake path shorten at 4900 rpm which sounds similar to vtec kicking in yo... that's my only guess is that there's some place in the intake path that sound is getting out from. maybe produce some audio of the sound? that'll help narrow it down... does it sound like this?

KC98LS

Mine usually sounds like that, sounds a bit different now.



Also for what it's worth, I checked the air intake, and didn't see any obstructions.

Car has K&N Air filter, cut out airbox, and Magnaflow catback Y-Pipe dual exhaust.

I'll try to get a video posted eventually.

Yamae

I would check the ACIS functioning correctly or not first.
Below might help you some.