EMK20a2

iTrader: (1)

Race season is over and now it is time to fix things that were broken and make improvements on things that did not work so well. Given that racing is not my life, I am trying to keep the rebuild to a reasonable budget and save my $ for tires and track time.

The single weakest link last season was the tranny. After 2 seasons I had toasted the 3rd gear syncros and mainshaft bearing. throughout the season, my car seemed to have a reasonably competative power to weight, but not being able to put the power down was just killing me against the AWD STIs and EVOs. So this offseason all of the problems will be fixed and improvements will be made.

To correct the third gear problem I picked up an entire Mainshaft from a K20a2 tranny that had around 17k miles on it. I was a bit scepitcal about installing a used part, but according to the seller everything was in perfect shape with little or no impression marks from the syncros. Not to mention I picked the entire mainshaft up for 3/4 of the cost of just a new third gear set and installation of the mainshaft is 100 times easier than installing a third gear. If upon inspection the mainshaft does not look good then it will be returned to the seller and I will be forced to buy a third gear set from Honda. I should have the mainshaft on Monday.

To correct the traction issue I picked up a ITR LSD, I debated the quaif, but I got a great deal on the ITR differential making it almost 1/2 the cost of what I could get a quaif for. Both the ITR differential and quaif are gear driven differentials with very similar performance. The big difference in the two is that the quaif is much more "beefy" and has a lifetime warranty. Based on my research the ITR differential is very reliable until around 350whp and seems to hold up very well for road race autox applications. The most power I think is necessary for what I want is around 270-280whp. If I wanted to spend more I would have went with the clutch type like an OS Giken, but remember this is under a budget.

I figured while I had the tranny off it would make sense to replace the heavy 19lb flywheel. For this I went with a ITR 11lb flywheel, I picked the one in the picture up with only 700km on it and got it reasonabally cheap and since Honda choose to put it on the Type R I figured it cannot be all that bad.

I don't yet have the tranny off so I have not looked at the clutch, but with less than 20k miles on it I would not anticipate it to be to bad and since the factory K20a2 clutch is an exeedy I will leave it go as long as it looks like it is in good shape.

Below are a couple of pics of the parts that I have now, I will update with addtional info and a step by step as I rebuild the tranny, including pics of the carnage that awaits inside .

Mr_Plenty

iTrader: (3)

nice...
so how did you do this season? any wins?

EMK20a2

iTrader: (1)

I did ok, did not win any there is one guy at every event who dominates and the rest of us fight it out for the top couple of positions. Street Modified is a difficult class, especially for our region. The guy who ALWAYS wins has a national level car, and there are a couple of other national level SM cars in surrounding regions who come out to play, including the Showcase Evo which took a third place finish in Nationals.

All and all for me to consitantly place top five or so out of 10-20 guys in such a competative class I felt was pretty good. I should do better with these modifications. Although I will be doing alot of NASA events next year, I am not sure how much autox I will do.

Da1lyDr1ver

iTrader: (6)

good luck on the build.

i read someone do a review of the ITR vs Quaif LSD (clutch type) for their car on honda-tech (not sure if it was a k series motor or a b series). but anyways, they said that the quaif LSD out performed the ITR one and felt that it put power down better. just throwing this in here incase you're interested.

Nameless

iTrader: (20)

I didnt know the stock clutch was made by exedy?

TRIZ

iTrader: (14)

Sounds like some cool projects you get to do that will really help you out. You should make the step by step into a diy. Good luck.

EMK20a2

iTrader: (1)

The quaif is not a clutch type it is actually a gear driven type just like the ITR except the design is slightly different. Yeah the quaif does work a bit better than the ITR, but is much more noticeable with higher hp applications. Both differentials are one way differentials and will go to open if one tire is lifted off of the ground. The quaif atleast $500 more than the ITR differential and there performances are so similar that I don't think it is worth the extra $. If I were going to spend more I would go with a clutch type, but the maintanance is kind of a turn off and they cost about $1000 more than the ITR.

In short, I don't think the ITR is the end all be all of differentials, but neither is the quaif. Everyone likes the quaif because it is build very well, has a warranty, and has low maintinance. Compared to a stock open differential, both will be such a huge improvement that I felt the slight improvment from the quaif would not be worth the extra $.

EMK20a2

iTrader: (1)

Yeah, if you pull the clutch off and look at it, it is just a Exedy Daikin clutch. I am not sure about the type S flywheel, but i know the type R flywheel is Exedy also. I guess I will find out what the type S flywheel is when I pull it off.

EMK20a2

iTrader: (1)

I will the tranny comes out after the 1st of the year. I am interested to see how bad it is screwed up or how obvious the damage is. I hope all that is screwed up is the mainshaft.

Da1lyDr1ver

iTrader: (6)

what do you mean by maintainence of the LSD? i thought it was just drop it in and no need to worry about it unless something breaks?

EMK20a2

iTrader: (1)

that is the case with the gear type such as the ITR and the quaif, but not the clutch types. As with a clutch on a car the clutches inside of these differentials wear out and need replaced.

EMK20a2

iTrader: (1)

Got the tranny pulled out and apart, the damage is not as severe as I had expected to find. It looked like someone poured fine gold glitter inside of the tranny case from the syncros and the magnent was completely full of metal shavings, which would explain why I was getting shavings when I changed the fluid. Third gear syncro is pretty worn and there are some serious impression marks on the syncro hub. The biggest thing is that the third gear syncro ring has a TON of play, indicating that it was likely broken loose from not matching when shifting.


Below is a pic of the tranny opened up before the removal of the internals



Below is a pic of the tranny after all of the internals, with the exception of the differential have been removed.


Below is a pick of the third gear syncro on the bad mainshaft, notice the wear of the syncro, and significant impression marks on the syncro hub. I tried to show how much play the syncro ring had by tipping it, it should have some play, but not nearly that much. I think that the play was the contributing factor to the syncro not functioning as the wear is not significant enough to cause the problems that I was having.


Below is a pic of the third gear syncro on the good mainshaft, notice how much nicer the teeth look on the syncro, and the lack of impression marks on the hub.

Civicman1988

iTrader: (24)

How hard is it to put an lsd in? Looks like a lot of wear on that ring

EMK20a2

iTrader: (1)

Not real hard at all, it just needs shimmed. Which ring has a lot of wear?? The one directly above is a suposidly good mainshaft with a good ring, the one above that is the bad one.

Yaj00003

Hi there well I know you know a lot more about transmission than me well I'm taking transmission class this winter and I wonder with the Quaife
LSD how do you break in the LSD? I heard you have to do some stunt with your car....Imma put it in my K20a3...

EMK20a2

iTrader: (1)

I don't think there is a break in period with the quaif because it is a gear driven type. Now with the clutch driven type I would say you should be easy on it for 500 miles, just like you would with a new clutch. The "stunt" may refer to a clutch type, maybe there is a certain way to do a series of turns that allows the differential to work at a desired level which aids in breaking the discs in.

HondaLuver

iTrader: (17)

nice, i have both the type R flywheel and qualif

RAZRBLD

iTrader: (2)

I also have a 12lb Flywheel and a Quaife LSD... Love them both... If you need a Clutch hit me up... I got connections with Competition clutch.

EMK20a2

iTrader: (1)

I bought a used Exedy stage II (sprung 3 puck) with 100-miles on it from a reputable member of K20a. I got it for $220 shipped with a new throwout bearing. What kind of deal could you have gotten me on a comp clutch or don't I want to know??

EMK20a2

iTrader: (1)

well my project took a turn for the worse . I noticed a bit of grinding in one of the bearings on the ITR differential and decided to have them replaced and this is what the shop found when they took one of the bearings off:




Since I have not touched the differential since I recieved it, it was broken when in the care of the previous owner. We came to the conclusion it must have been busted from excesive wheel hop, likely from drag radials on a drag strip. Luckly the seller is being really cool about it and is refunding my $ and I am sending him back the differential.

As for a replacement this finding has made me skeptical about the ITR differental, comparing it to a quaife the quaife has a ton more "beef" in the area where the ITR busted along with areas throughout the diff. So a Quaife is now going into the tranny.