I've got a 2002 Civic Si with the JRSC with 4.0" pulley and RC 440cc injectors. I also have a Quaife LSD in my otherwise stock tranny. When I really get on it 1st gear is gone almost faster than I can shift, and my 2nd gear is seriously worn also from the same grinding problems that seem to plauge all 02 Si's.

I'm thinking about doing something about both problems, and am looking for information. I know of one person on here with a boosted SI that has gotten the RSX base tranny for its taller gearing. (Steve you listening?)

Here is the question. Would I be better off going with a new tranny or would it be better to replace the worn 2nd gear, and just go with a taller final drive?

I am open to all information and suggestions.

Thanks,
Michael

 

Interested as well....

Subscribed.

 

Okay, I've done a little research, and found a neat little calculator that does some calculations to tell you what speed you will go in what gear, depending on the gear ratio and tire size. Here is the information I've found about the EP3 and RSX Transmissions.

EP3 Gear Ratios:
1st 3.062
2nd 1.769
3rd 1.212
4th 0.921
5th 0.738
Reverse 3.583
Final Drive 4.764

Base RSX Ratios:
1st 3.267
2nd 1.880
3rd 1.212
4th 0.921
5th 0.738
Reverse 3.583
Final 4.389

I need to give credit to Steve over at K-Series for the above info.

Here is the calculator I found
http://www.geocities.com/z_design_studio/

And here are the speeds I calculated with the different combinations. These are based on a fuel cutoff of 7300 RPM's (which is where mine is set) and tires sized 225/50/15. These should be actual ground speed, not indicated.

Stock EP Trans 1st 36, 2nd 61, 3rd 90, 4th 118, 5th 147
Base RSX Trans 1st 36, 2nd 63, 3rd 97, 4th 128, 5th 160
EP Trans with RSX Final Drive 1st 39, 2nd 67, 3rd 97, 4th 128, 5th 160
RSX Trans with EP Final Drive 1st 33, 2nd 58, 3rd 90, 4th 118, 5th 147

Does this additional information give anyone any ideas? I would love to hear them, but it looks to me like the EP tranny with the RSX final drive might be best for my application.

 

The USDM EP3 comes with the Type R final drive. To that you've added a Quaife differential, which is a Torsen axle better than the stock Honda/Acura units.

I dunno, bud...most of us would love to have that combination.

I love the USDM gear ratios and final drive.

I almost hate to say it, but I would really want to leave the ratios alone.

Depending on what I'm using the car for, the supercharger might make me want me to play with first gear and second gear ratio a little bit, but my instincts tell me I'd try to learn to shift faster or differently first.



Sorry if that sounds like I'm being a pain.

 

You are not being a pain. I know that I need to learn to drive better and maybe with a little more time with my current combo it won't seem like an issue to me. I'm just trying to explore all my options.