Not much impact on the car although the mention about upsetting the car balance brings up a significant downside to not rev matching. Not rev matching certainly does have, will have, an impact and a lot on clutch and transmission life.
My Hellcat is an 8-speed automatic (and in using the paddles or just the lever to manually shift gears, on a downshift it looks like the engine control does some rev matching -- cool) but with my previous cars all manuals I always rev matched. One car I drove 317K miles and it was on its original clutch and transmission although it was clear from the pedal pressure required at the end the clutch was worn out -- but not slipping.
About the only time I don't rev match and this is often is when I'm rolling up to a stop. I leave the transmission in gear until RPMs get low enough I can select a lower gear with no real need to rev match or I can just shift into neutral and use just the brakes to bring the car to a stop. But if I'm on the open road and feel a need to downshift for passing or climbing a grade or descending a grade or any other reason I always rev match.
(As an aside, my 2018 Mini JCW is a 6-speed manual and it has rev matching when I downshift. At first I didn't know this but I finally got wise when I didn't do any rev matching and just selected a lower gear. Engine RPMs were raised as I moved the shifter into the lower gear. Now that I know the feature is there I rely upon and I've never down shifted a manual transmission so fast.)
I rev match all the time; I think it's really important especially when down shifting to accelerate i.e. when passing. Just hitting the lower gear puts a lot of stress on the drive train as the engine speed tries to slow the car. You get a a lot of upset as mentioned as well. For the remainder it's like Rockster mentioned removing the additional strain improves the life span of the clutch let alone the other components. When not on the track I just roll into the turns then rev-match into the gear I need entering or coming out of the turn so I don't have to heal-toe it. Kind of slacker mode.
As a racing driver I want to rev match all the time. However, I find rev matching in the challenger cumbersome (on regular public roads) because of the pedal position. Doing a proper heel-toe rev match at normal city speeds is almost impossible for me because the accelerator pedal is set further back than the brake pedal. Plus the pedal is so far to right, near the transmission area, that there isn't really any wiggle room for your heel. Anyone else have this problem or found a solution?
The only way to heel-toe properly is to slam the brakes and slow the car down from high speed very quickly which makes the brake pedal line up with the accelerator in a usable position. Perfect for racing situation but thats about it.
I've wondered if there would be a simple way to move the accelerator pedal up/forward just a little to make heel-to easier on the street...
I’m looking to do a conversion from 2013 to 2015^ I have bumper and hood coming in, now with the 2015 headlights will I need them to be modified ? And how ? Cut? Trim? And will I need just a wiring harness ?
I was washing my car today and to get it out if the sun I pulled the transmission override thing under the coin holder so I could go to neutral / push the car slightly.
It was tough to pull and now it's stuck upwards and won't push back down. Car tells me it's in transmission service mode.
I have some bubbles forming at the top of my 8.4 screen, like a separation or something. My car is a 2017 less than 2 years old. Has anybody else had this? Should I expect a new screen installed as a warranty replacement? I've never had a dealer repair on this car and wonder what to expect...
I have a 2015 SXT and everytime I try to do a burnout, I only spin one wheel. I understand that this is because the factory open diff within the SXT but my other v6 owner friends don't seem to have this problem. I was wondering if there is a way to change the diff or anyway to bypass this issue?