Project EJ Civic, Building the Drivetrain

By Mike Kojima

Annie’s Civic had seen tons of street and track miles, over 200,000 miles since she had completed her B series swap years ago.  Her clutch had begun to slip probably 3 years ago and she had been nursing it along for this long as she was too busy with other car projects to take care of it.  With this many miles we felt that it was probably prudent to open up the transmission just to inspect the insides and take care of any issues before bolting it up to her renewed engine pushing much more power.

We sent out our gears to WPC Treatment for friction reduction.  The lustrous WPC treated surface is very hard and slippery.

The transmission was left in the capable hands of Technosquare’s Howard Watanabe who disassembled it and found it to be in quite good condition with the exception of 1-2 and 2-3 syncros which had some wear.  Although the syncros were still serviceable, we replaced them anyway.  While we had the transmission apart, we sent the gears, syncros, hubs, sliders, shift forks, shift shafts and final drive gear for WPC Treatment.

Friction reduction and smooth shifting is the reason why we sent our shift shafts hub sliders and forks to WPC.

WPC treatment is a not a coating but a surface treatment that is similar to shotpeening but on a micro level.  You can read all about the science of WPC here.  In the case of Annie’s transmission we WPC’ed everything not so much for strength improvements as the B18 transmission is pretty strong for her planned amount of power, but for friction reduction and shifting smoothness.  The WPC process imparts a silky smoothness on the parts and greatly reduces friction and operating temperature.  We figure the latter is important when the car is track driven and the friction reduction may show up as a few more horsepower and better fuel economy.

Our ring and pinion also will benefit from WPC's low friction surface treatment.

The most important thing we are doing to the transmission is installing an M Factory limited slip differential.  The M Factory diff we used is a clutch type LSD.  M Factory also has helical gear type LSDs.  We chose the clutch type LSD because we wanted the more positive action of a clutch type LSD for our split track use.  The drawback to having a clutch type LSD on the street is it can be rougher in operation and chatter.  We did a few things to reduce this which we will discuss in a second.

We also WPC treated our syncros and balk rings to help smooth and speed shifting.  Several of the syncros in our 200,000 plus mile tranny needed replacing but it was in surprisingly good condition.


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Friday, March 02, 2012 1:32 AM
Love the flywheel, ACT prolites are what I've always lusted after for obvious reasons. That diff setup looks insane too!
Steve Choi
Steve Choilink
Sunday, March 04, 2012 10:36 PM
Was a heavier shot peening conducted prior to WPC? In some of those parts, a deeper compressive stress surface could be beneficial. I imagine you can WPC to achieve the surface quality after a heavier shot as well.

I love m factory and found it easy to order from and my torsen has seen years of service. I use the recommended torsen MTF though.
Steve Choi
Steve Choilink
Sunday, March 04, 2012 10:37 PM
I use torco* MTF ^
Mike Kojima
Mike Kojimalink
Sunday, March 04, 2012 10:39 PM
Since the Honda transmission is reliable at the power levels we are producing, we did not shot peen prior to WPC like we usually do.
Monday, March 05, 2012 5:53 AM
Honda transmissions are rock solid reliable if you treat them well. My first year Integra had 270K on the clock before the floors rusted out and the transmission never needed anything more than new oil. It shifted smooth as silk every single day.

Any plans for doing a budget Honda build? I'd love to see MotoIQ's take on penny pinching Honda.
Der Bruce
Der Brucelink
Monday, March 05, 2012 9:28 AM
I'm excited to see how this long rod build ends up! This car's probably going to end up being a blast to drive around, track or street.
Tuesday, March 06, 2012 12:45 PM
I had a Prolight flywheel on my 2000 Civic Si years ago. I loved having it on the car. Launching on the drag strip sucked, but I autocrossed the car more, and being able to let the motor rev was more important to me. The sad thing was, as pretty as it was to look at, I only ever saw it once.
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