Hi guys, as you can tell I'm going to be building my tranny over the winter for next season. I lap and time attack frequently, about twice a month. Been using my current vehicle setup for 2 years now, and I feel that I have maxed out my potential (yes I know I can learn more as a driver).

Either way, my DC2 - which some of you have seen at Expo10 this year, needs some help. It has a K20A2 swapped in, pretty much stock, not even running KPRO. Runs great, keeps up to many cars, but I know it is lacking. Why? First off, no LSD.

What I'm planning to do to my STOCK 6-speed tranny, is replace the clutch, replace the flywheel with a slightly lighter one, install an LSD, and also change the final drive.

So I'm looking for input on two parts to this, the flywheel - definitely beneficial or waste of time? How light would you recommend? The second is the final drive. Everyone seems to be throwing in 5.1's into the K tranny's. Is this really necessary since the wheels I run are smaller anyway? Keep in mind, the tracks I frequent are mainly 3rd gear corners, with the few 2nd gear hairpins, and the 5th gear back/front straights.

I just want a proven setup to lower my time attack times next season.

Thanks in advance to any inputs and comments

...I know you all like pics so here's what she looks like

 

Nice ITR btw.

I havent tracked an ITR with a k20 before, but I have driven one that had the 5.1 final drive and those gears were extremely close. 1st and 2nd were useless for daily driving. If you are seeing only those gears with your current ratio, I would stick with that final drive imo. Saves you the extra time shifting...

Besides when you get that motor properly tuned it will surely be a different car to deal with.

Dont forget the key iss to keep your runs as smooth as possible...

 

What size tires and rev limit? I can set you up with something better than the FD.

 

Stock ITR 15", so 205/50/15 with a limiter at 8250

 

These are you stock top speeds and RPM drop.

1 - 40 / xxx
2 - 61 / 5,446
3 - 85 / 5,915
4 - 113 / 6,232
5 - 140 / 6,653
6 - 175 / 6,605

These are with an MFactory close gear set and OEM 4.764 FD (stock 4.389 FD). RPM drops don't change between the two as FD doesn't affect that. Stock 6th can be used if you need a higher top speed without making 1-5 longer by using the stock 4.3 FD.

1 - 51 / xxx (56)
2 - 72 / 5,839 (78)
3 - 91 / 6,514 (99)
4 - 110 / 6,819 (120)
5 - 124 / 7,312 (135)
6 - 140 / 7,322 (152)

Now your trans with an MFactory 5.46 final drive and (MFactory 5.08 final drive)

1 - 32 / xxx (34)
2 - 49 / 5,446 (52)
3 - 68 / 5,915 (74)
4 - 90 / 6,232 (97)
5 - 113 / 6,653 (121)
6 - 141 / 6,605 (151)

 

the 5.08 looks close to what i would want...currently, i seem to be around 4000-4500rpm on corner exit, which i wish was a little higher to im more in the power band. so a 5.1 is probably what im looking for right?

any input on flywheel changes? or no need to do it?

 

Although I don't have a K20, I can chime in with some experience from my motor. I've had good success with the Fidanza/Clutchmaster aluminium flywheel. It's 7lbs and I've used them in both my 230whp all motor setup and now my turbo setup with great success.

When I was all motor the flywheel really helped get the car moving from a lower RPMs and the car was much more responsive at higher RPMS. One thing that does suck about having a lighter flywheel is daily driving, you really have to keep the revs up so that the car doesn't stall.

Which LSD were you thinking of running? If you're planning on doing a lot of tracking I'd definitely recommend something like the MFactory Clutch Type LSD.

 

The 5.08 would work well for you.

I always use the lightest flywheel possible. I use the Fidanza 7.5lb in my daily/track car without issue.

 

I have been seeing all kinds of problems with aftermarket flywheels,I personally have been running a ITR DC5 flywheel for 3 years. Its strong and lighter.

I wouldnt stretch to the 5.1 final just yet. If you say you want to exit the corners a little better,try investing in K-Pro with a nice tune. Maybe if your wanting to freshen up the transmission anyway,you could try a 4.7 ITR final.