I was under the impression that an 92 SI tranny in a 93 DX hatchback would result in a lower overall gear ratio (higher RPM at a given speed in whatever gear). Therefore I put one in my DX. Now when I accelerate to the RPM I'm used to before shifting, the car is going much faster in all gears. Plus, the horsepower isn't really suited for the higher ratios. For example; when I'm ready to shift to 4th, the speed is around 80 to 85. The RPM is around 4000, maybe 4500 (no tach). If I want to shift to 5th, I need to be going 90 to 100 or there is no power. All the info I found indicates the opposite.
If the 1st gear ratio is 3.250 then 3.25 revolutions from the engine give one rev to the final drive? Right?
If the final drive ratio is 4.266 then 4.266 revs from the tranny gives one to the wheels? Right? 13.87 engine revs to one wheel rev.
My car seems to have an original FD ratio of 3.888 (12.64 to one in 1st)

So that's 12.64 vs 13.87. My old tranny/diff should be the higher geared one not lower? Right?
Anyone know why I'm wrong?


Modified by torturella at 10:17 AM 11/7/2006

 

replying now so I can reply later when I have a few mins

 

To add a little more to the question...
The wheels on the DX hatchback are smaller than other versions, Right? So, might that have anything to do with the situation?

Come on all you gear-heads. Please.....One of you must know the answer to this off the top of your head. For me it is not crucial, I'm certainly not going to change the trans again, I'm just curious.

 

gear connects to final drive, final drive connects to wheels.


d16z6 2nd gear of 1.9. d16z6 final drive of 4.25

4.25 times 1.9 = 8.075

8.075 engine rotations to equal one wheel rotation.


to find mph, you gotta find the circumference of the wheel and go from there.

 

Thank you for taking the time. However, I'm still without a clue.
According to one website, my original trans had a 3.888 final drive.
According to another website, it came with a 4.058. (P20/A000)
In either case, when you multiply any gear ratio times those final drives and compare to the P20/B000 trans from a 92-95 Civic SI... you get:
......Final Dr.......1st........2nd........3rd......4th....... .5th
DX (3.888)......12.64......6.85......4.56......3.53......2.73
DX (4.058)......13.19......7.15......4.76......3.69......2.85
SI (4.25)........13.81.....8.075.....5.31......3.86......3.19

In every gear.... more engine revolutions for one wheel rotation with the SI trans vs the DX. In my car, with the SI trans in a DX car, it takes fewer engine rotations per wheel rotation, not more. I can barely get into 5th and when I do I'm going at least 85. Shift any sooner & I have no power (Basically, I have no power in all gears compared to the old trans, but I'm getting better mileage now)


Modified by torturella at 3:11 PM 11/10/2006

 

what tranny do you have? I know they made i think like 3 different S20 trannys... you never know what yur gonna get unless it's from a good source. My friend had a VX hatch with an S20 tranny and those are LOOOONNNGGG gears! I would not be suprised if that is what you have. Another friend bought a used tranny from an import shop and got a DX tranny.. then I bought one from the same company and got an Si tranny haha.. I believe they all say S20 tho.. even the CX hatchs had S20's i think, which would mean there is a 4th one out there. btw my friend with the VX would always be in 4th on the freeway and only go into 5th for the mileage

 

the 3.8888 is a misprint in the 92-95 manual.

3.888 is the 1989-1991 DX final drive.

1992-1995 DX is 4.058

I am 100000% positive.

 

Thanks again Bense:

The receipt from the junk yard gives VIN # 2HGEH3385NH523326.
VIN translator websites list this as a 1992 Canadian Civic SI Hatchback, 1.6L. The description the junkyard wrote said "400-59765 1Y Transmiss/Transaxel stock # 040472 Y. 1995 Civic SI."

 

That sounds like me. 4th is like 5th used to be, maybe a tad higher. I don't normally shift at too high an RPM but now I've got to rev higher to have any power in the next gear.... (Like 5000) I could probably go 130 to 140 in 5th to bring the RPM up to 5000 but with my 180,000 mile old DX engine I would need a 45 degree slope downhill to get there.
The HX came with a higher ratio, right?

 

What is in the casting stamp by the fill plug? P20 A000 or P20 B000?

 

The casting reads:
P20
A000

There are 2 bar code tags; one near clutch slave & other above lower trans mount on passenger side of eng compartment.
The "slave one reads;
J8B ||||||||||||||||||||||||
<U>...............P20 .</U>

The other:
||||||||||||||||||||||||||||||
<U>S20............1060497 </U>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by torturella &raquo;</TD></TR><TR><TD CLASS="quote">The casting reads:
P20
A000

There are 2 bar code tags; one near clutch slave & other above lower trans mount on passenger side of eng compartment.
The "slave one reads;
J8B ||||||||||||||||||||||||
<U>...............P20 .</U>

The other:
||||||||||||||||||||||||||||||
<U>S20............1060497 </U></TD></TR></TABLE>

You do not have an Si or EX tranny. In fact, the last J8B tranny I had was from a VX. I pulled it myself from the original car. Si/EX are S20/P20 B000, and usually K4F or Y4F in my experience.

 

To anyone who is interested: it turns out that tranny was from a VX. It didn't take long for me to really like the high gear ratios. My daughter now drives that car and I bought a 92 VX with 100,000 miles a year and half ago... I just had the transmission replaced with a new rebuild and they put in a DX tranny; even after checking the VIN. Now the "shift-up" light goes on in 5th which it never did before.
Anyone have any idea why this would happen?