CIVIC SI FINAL DRIVE

[Only_Sonic.SI]

As much as I enjoy the gearing and auto rev-match features. It really annoys me going 75mph and already at 3,000 RPM
I feel like a 7-10% increase(taller gear) on the FINAL DRIVE would help it so much and not sacrifice so much enjoyment of going thru gears.

Does anybody has info on this ?

Sponsored

 

[OGGsr]

As much as I enjoy the gearing and auto rev-match features. It really annoys me going 75mph and already at 3,000 RPM
I feel like a 7-10% increase(taller gear) on the FINAL DRIVE would help it so much and not sacrifice so much enjoyment of going thru gears.

Does anybody has info on this ?

75 mph @ 3k rpm doesn't seem too high to me. I had an ITR transmission in my '97 GSr and at 75 the engine would turn 4000 rpm and would make quite a bit of engine noise. The Si's FD seems about right and a down shift is not really necessary to accelerate whereas a drop from 5th to 4th was in my old Integra.

 

[zeroptzero]

I do a ton of highway driving and I was concerned about this when I first got the car.

But my Si gets amazing fuel economy on the highway, 43-47 mpg's, I drive at 70 mph which gets me 2700 rpms. I don't find it noisy at all, the Goodyears drown out every other noise, lol. Acceleration on the highway is pretty good too.

Shifting to 3rd gear to get to 60 mph kills our reported 0-60 times but that is just a mental barrier, the car is not as slow as that statistic indicates.

I also had ITR trannies and motors in my old Civics and they revved pretty high on the highway, the Si is a better balance.

 

[Shankmeyster]

Try driving an S2K at 75-80 on the highway. Good god that thing is loud and runs high rpm's.

 

[zeroptzero]

Try driving an S2K at 75-80 on the highway. Good god that thing is loud and runs high rpm's.

I had an S2000 Ap1 for 9 years, I ran mine with a hardtop most of the time. The decibel reading of the S2000 in top down driving on the highway is above the level needed to cause hearing loss, it is that bad. Rpms were a bit high but on a 9000 rpm range well under the 50% capacity of that engine.

 

[PrayingForGrip]

Take a ride in an Evo with a tomei exhaust 80 mph at 4500 rpm

 

[CeeBee]

The final drive would mess with acceleration through all gears. The better option would be to move 6th gear from the .69 ratio to something a little numerically lower. My RSX (5 speed base) and my Accord both ran pretty high in the rev range and it wasn't ever an issue other than seeing those RPM's on the tach.

 

[SGSiSaajan]

Interesting, I was just thinking about this the other day. I drive a ton of highway and wondered if it would be possible to get a non-Si 6th gear somehow. Not sure the ratio difference but I bet it’s taller for MPG’s.

 

[CeeBee]

Looks like the Si has a numerically higher final drive but the same gear ratios in all 3 transmissions ( Hatch 2.0 MT / 1.5MT So 1.5MT)


Civic Hatch Sport and Civic Hatch Sport Touring

Civic Si

 

[Only_Sonic.SI]

I wonder if that 4.1 Final drive would fit in in the SI , it would help out so much on highway driving.

Damn that such good info, idk where you guys get all this from

I feel like that difference will impact acceleration but overall better since ur on boost more specially once tunes i feel like the gearing are so small. (Could be 100% wrong though)

 

[S2000toCivic]

I wonder if that 4.1 Final drive would fit in in the SI , it would help out so much on highway driving.

Damn that such good info, idk where you guys get all this from

It would theoretically negatively affect acceleration, though. As well as throw off the speedometer. But i’m curious to see how different final drives will impact how the car performs, in both MPGs and acceleration.

Back in my S2000 days, a lot of people opted to replace the OEM 4.1 final drive with 4.44 and 4.77 final drives to improve acceleration, but the MPGs and highway cruise RPM took a hit.

 

[DYI01]

Going to a larger diameter tire will essentially do the same thing as changing your final drive.

 

[Andrewb325]

I just picked up my 22 Si today (finally after a 4 month wait ). I was concerned about the higher highway RPMs but after taking an extra long drive home it is a non issue for me. 3000 seems like a nice comfortable speed for this engine to cruise at. It’s not too loud or buzzy and gives good roll on acceleration without a downshift. On a 55 mph road I kept it in 5th. I used to have a Focus ST which had slightly taller gearing (around 3000 at 80mph) and I considered that just about perfect. The Si isn’t too far off that and it’s redline is also higher than the Focus. For me it’s good to go.

 

[zeroptzero]

I just picked up my 22 Si today (finally after a 4 month wait ). I was concerned about the higher highway RPMs but after taking an extra long drive home it is a non issue for me. 3000 seems like a nice comfortable speed for this engine to cruise at. It’s not too loud or buzzy and gives good roll on acceleration without a downshift. On a 55 mph road I kept it in 5th. I used to have a Focus ST which had slightly taller gearing (around 3000 at 80mph) and I considered that just about perfect. The Si isn’t too far off that and it’s redline is also higher than the Focus. For me it’s good to go.

I pretty much peg my highway speed to 70 mph, where I get it at 2700 rpms. Higher speeds than that and my fuel economy gets worse, a bit slower would be even better for fuel economy but then it is too slow, lol.

At 55 mph I think I would put it in 6th gear, but I almost never drive roads with those speeds.

 

[axion_industries]

We are running the 2020 Si final drive in our Hatch with LSD, works great due to the longer PPG gears

Sponsored