PRODUCT DETAILS
MFactory Pro Series 1-4 Drag Gear Set - K-Series 6-Speed (MFT-TRS-01K20)
Factory gearing is a compromise between acceleration, cruising, and fuel economy. On a drag car none of those compromises are worth keeping. This MFactory set replaces first through fourth with a longer first for a better launch and tight ratios through second, third, and fourth so the engine barely drops out of its powerband between shifts. Your factory fifth and sixth stay in, so the car still cruises.
Why A Longer First Gear
Counterintuitive if you expect a drag gear set to be shorter everywhere, so worth explaining.
On a car making real power, the factory first gear is short enough that you're fighting for traction rather than accelerating. You spin, you shift almost immediately, and first gear does very little useful work.
A 2.313 first is considerably longer, which gives you more time in the gear and lets the tires actually put power down rather than lighting up. On a prepared surface with a sticky tire, that's where the launch comes from.
Close Ratios Are The Bigger Story
The 2-3-4 spacing is what separates this from just a taller first, and it's where the time actually is.
Every shift drops your engine speed. How far it drops depends on the gap between ratios, and how far it drops determines where in the powerband you land. Wide factory spacing means you shift at redline and come back well below peak power, then spend the first part of the next gear climbing back to where you were making the most.
These ratios run 1.650, 1.304, and 1.080, which are tight enough that the engine stays close to peak power through each change. Less rpm drop means less time spent accelerating back into the good part of the curve, and on a K-series that makes its power high, that matters a great deal.
Add it up across three shifts on a quarter mile pass and it's real time.
You Keep Fifth And Sixth
Worth calling out, because it separates this from a gear set that turns the car into a trailer queen.
The factory fifth and sixth gears carry over. That means the car still has usable highway gearing, so it can drive to the track, drive home, and be something other than dedicated race equipment between events.
It also keeps the cost down, since you're not replacing gears that were never the problem.
Hardened And Cryo Treated
These are hardened and then super sub-zero cryogenically treated, which is a genuine process rather than a marketing term.
Cryo treatment takes the metal well below freezing and holds it there, which refines the grain structure and converts retained austenite into martensite. In plain terms, more of the material ends up in its hardest, most stable form. The result is a gear that resists wear better and holds up to the shock loading a hard launch puts through a drivetrain.
On a part that fails catastrophically when it fails, that additional strength is what you're paying for.
While You're In There
Installing gears means the transmission is fully apart, which is nearly all the labor on this job. Use the access.
Inspect your synchros, sleeves, hubs, and bearings while everything is exposed and replace what's past spec. Anything that ran alongside a damaged gear has likely taken debris or abuse, and closing the case up with fresh gears next to worn synchros means doing this again sooner than you'd like.
If a shorter final drive is in your plans, this is also the moment for that, since both jobs require the same teardown.
Ratios
- 1st: 2.313
- 2nd: 1.650
- 3rd: 1.304
- 4th: 1.080
Fitment
2002-2006 Acura RSX Type-S (K20A2 / K20Z1)
2004-2008 Acura TSX (K24A2)
2006-2011 Honda Civic Si (K20Z3)
K20 and EP3 6-speed manual transmissions. Part number MFT-TRS-01K20. Covers gears 1 through 4, factory 5th and 6th are reused.
Who Should Run This Set
This is for the K-series drag build where the factory ratios have become the limiting factor, and for anyone who's found their launches are wheelspin rather than acceleration. Longer first to hook, tight spacing so the engine stays in its powerband, and hardened cryo treated gears to survive the loads. Keep your fifth and sixth, do the whole transmission properly while it's open, and go collect the time.
Fits: 2002-2006 Acura RSX Type-S, 2004-2008 Acura TSX, 2006-2011 Honda Civic Si, K20 and EP3 6-speed manual transmissions. Part number: MFT-TRS-01K20. Ratios: 2.313 first, 1.650 second, 1.304 third, 1.080 fourth. Covers: gears 1 through 4. Reuses: factory 5th and 6th gears. Treatment: hardened and super sub-zero cryogenically treated.
2002-2006 Acura RSX Type S
2006-2011 Honda Civic Si
2004-2008 Acura TSX