2020 Civic Si Reviews Compilation

[amirza786]

Yes, I understand that...this is the impact a final drive change should have on the gearing (better acceleration/penalty at top end, and associated mpg considerations). But I'm wondering about actual impact/numbers. Nobody has published 0-60 for the 2020?

O to 60 should not change much

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[amirza786]

I feel like the difference in RPM is being exaggerated, although I don't mean to downplay the negative effect of an extra 100-200 rpm at cruising speed.

The 17-19 Si sits at ~2,250 RPM at 60 mph. With the 6% ratio change the 2020 will sit at ~2,380 RPM at 60.

This translates to the 17-19 sitting at ~3,000 at 80, and the 2020 sitting at ~3,175 at 80.

Not even a 200 RPM difference, whoever the reviewer was that said it sits at 3,500 RPM at 75 needs to go for an eye appointment..... Or upshift to 6th instead of cruising in 5th.

Several members on this forum report that at 70 mph they are near or at 3000 RPM. Maybe after break-in that will change

 

[amirza786]

ya mine dosent sit at 3500 that would be annoying but i never seem to really need to downshift into 5th to pass anyone thou 6th gear can pull just takes a second it seems

If I was at 70 or above I never needed to downshift as well for passing or accelerating. Just slowly went down and I would be at 80 before I realized it

 

[JT Si]

Several members on this forum report that at 70 mph they are near or at 3000 RPM. Maybe after break-in that will change

Gear ratios don't change with break in. These people are wrong.

 

[rhino]

If I was at 70 or above I never needed to downshift as well for passing or accelerating. Just slowly went down and I would be at 80 before I realized it

ya now my truck is a different story lol she is a bit on the hefty side lol

 

[EdwarDallas]

Making the gearing shorter will definitely increase acceleration, but will affect top speed. Many 2020 owners are reporting that at 70 mph their rpms are are nearly at 3000 while 2017-2019 don't see this rpm until around 80 mph. They will also see more power at cruising speeds because of the smaller gearing

Yeah, I can pass in 6th with no problems, but I wish 6th gear was taller.

 

[EdwinDrn]

Hmmm, I've got a '19 also at usually sit at around 3k RPM @ 70 MPH. I am however, only at 3,6xx miles.

 

[Siiick]

I drove the Si on the turnpike this morning and found I was turning 2500 RPM @ 60mph and about 2900 RPM @ 70mph. Not bad if you ask me.

 

[Maroco]

Hmmm, I've got a '19 also at usually sit at around 3k RPM @ 70 MPH. I am however, only at 3,6xx miles.

Your 19 should be around 2700rpm at 70mph. Gearing doesnt change with break in. Check closely next time you are on the highway.

 

[JT Si]

A 17-19 will sit at 2,700 RPM at 70.

Here are the 2019 Si transmission gearing and tire revolutions specifications.

70 MPH / 60 Minutes = 1.1666~ miles per minute

1.1666~ * 823 revolutions per mile = 960.1666~ revolutions per minute

960.1666~ revolutions per minute * 4.105 final drive = 3941.484 revolutions per minute

3941.484 revolutions per minute * 0.686 6th gear ratio = 2703.858 RPM.

If we do the same calculation for a 2020 we see 2,865 RPM, still over 100 under 3k.

There may be some small variance due to these gear ratios being approximations, not exact. Also due to manufacturing tolerances. If they individually calibrate and test the vehicle speedometers instead of blanket programming them, that would also lead to some variance. None of this would add up to even 100 RPM, though.

 

[Seth_FC3]

Making the gearing shorter will definitely increase acceleration, but will affect top speed. Many 2020 owners are reporting that at 70 mph their rpms are are nearly at 3000 while 2017-2019 don't see this rpm until around 80 mph. They will also see more power at cruising speeds because of the smaller gearing

This I can confirm on. Cruising 70 mph im at around 3k. The shorter gearing has it's advantages and disadvantages.. Acceleration is very quick, power band is almost always there in any gear (if not in low RPM ofc)

 

[amirza786]

Yeah, I can pass in 6th with no problems, but I wish 6th gear was taller.

You actually don't want a taller gear due to the engine size. You need the shorter gearing to keep you in the rpm range (and the proper power band) while at cruising speed or you would be downshifting every time you accelerate. Cars with bigger engines that are designed to be quiet a cruising speeds (family or luxury cars) usually have taller gearing, but cars that are more performance oriented would have shorter gearing. For example, My 2013 Sienna has a 3.5L 266 HP V6 that cruises around 2200 rpm at 80 mph (6 speed auto), and my 2010 Lexus IS 350 has pretty much the same 3.5L V6 which has 306 HP and a 6 speed auto, but cruises at the same speed at 2400 rpm due to shorter gearing. When I need to quickly pass, the Sienna will drop 2 gears while the Lexus will only need to drop 1 gear or sometimes it just stays in the final drive much longer before dropping any gears.

Anyway the smaller gearing is to your advantage

 

[Sal Bandini]

A 17-19 will sit at 2,700 RPM at 70.

Here are the 2019 Si transmission gearing and tire revolutions specifications.

70 MPH / 60 Minutes = 1.1666~ miles per minute

1.1666~ * 823 revolutions per mile = 960.1666~ revolutions per minute

960.1666~ revolutions per minute * 4.105 final drive = 3941.484 revolutions per minute

3941.484 revolutions per minute * 0.686 6th gear ratio = 2703.858 RPM.

If we do the same calculation for a 2020 we see 2,865 RPM, still over 100 under 3k.

There may be some small variance due to these gear ratios being approximations, not exact. Also due to manufacturing tolerances. If they individually calibrate and test the vehicle speedometers instead of blanket programming them, that would also lead to some variance. None of this would add up to even 100 RPM, though.

Good overall summary, but one small note. Gear ratios are not approximations. Gear ratio is the ratio of one gear to another. It is an exact number. If you have 40 tooth gear to 10 tooth gear it is 4:1 ratio. There are no variances or manufacturing tolerances on the number of teeth each gear has.

 

[JT Si]

Good overall summary, but one small note. Gear ratios are not approximations. Gear ratio is the ratio of one gear to another. It is an exact number. If you have 40 tooth gear to 10 tooth gear it is 4:1 ratio. There are no variances or manufacturing tolerances on the number of teeth each gear has.

The fact that we don't know the tooth count in addition to the fact that they are maintaining 3 significant figures despite having a trailing 0 leads me to believe the numbers are not exact but are rounded.

The tooth count would be the only exact way to express all the gear ratios.

For example, maybe 6th gear is 35:51 gear ratio, which calculates to 0.68627450980. Or maybe it's a 24:35 gear ratio, which calculates to 0.68571428571.

0.686 is obviously a valid approximation of these ratios, not an exact expression.

 

[Sal Bandini]

The fact that we don't know the tooth count in addition to the fact that they are maintaining 3 significant figures despite having a trailing 0 leads me to believe the numbers are not exact but are rounded.

The tooth count would be the only exact way to express all the gear ratios.

For example, maybe 6th gear is 35:51 gear ratio, which calculates to 0.68627450980. Or maybe it's a 24:35 gear ratio, which calculates to 0.68571428571.

0.686 is obviously a valid approximation of these ratios, not an exact expression.

You don't need to know the exact tooth count. If 3 significant digits isn't enough precision for you then your head will explode once you factor in tire expansion at higher speeds.

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