Irace86.2.0's KPower Turbo K24 Swap

[RedReplicant]

I posted a video in my build thread of the issue, but basically 4th gear can move on the shaft and either the synchronizer ring breaks the three tangs off the synchronizer hub or 4th gear misaligns and blows up.

Carbon synchros won't solve this, unfortunately.

[Irace86.2.0]

Originally Posted by RedReplicant

I posted a video in my build thread of the issue, but basically 4th gear can move on the shaft and either the synchronizer ring breaks the three tangs off the synchronizer hub or 4th gear misaligns and blows up.

Carbon synchros won't solve this, unfortunately.

Maybe things were addressed or maybe not. I'm rolling the dice. I am going to go for it anyways. I can always sell what I buy if it doesn't explode and upgrade, but I want to do a transmission swap now on my break before next nursing semester starts, but I also just don't have it in me to do my own CD009 swap.

[Irace86.2.0]

I think while I tear apart the fuel system and tranny, I'll get in there and tackle the coolant hoses per the writeup by @captain awesome. I'll be drilling and tapping the water neck, so I'll need a 5/8 hose barb to 3/8 NPT, right captain, or is the NPT size 1/2? I bought the 5/8 thermostat adapter from TracTuff. I just need some 5/8 hose and clamps.

https://www.ft86club.com/forums/show...nt#post3511191


While I have the intake manifold off, I think I'll drill and tap some NPT fittings for the vacuum hoses. I am currently teeing into the side port, using the 3/8 barb Kpower supplied in the kit, but it is a little messy. I'm running the vacuum for the boost gauge and for the BOV off of those lines. I think I'll just add a fitting to that brass tee, and then I'll drill one or two ports in one/two of the three tap spots on the manifold, so I can run the boost reference lines for the fuel pressure regulator and fuel pulse damper.

[captain awesome]

1/2 NPT is what the Miata neck runs so that's what I went with.

[RedReplicant]

Originally Posted by Irace86.2.0

Maybe things were addressed or maybe not. I'm rolling the dice. I am going to go for it anyways. I can always sell what I buy if it doesn't explode and upgrade, but I want to do a transmission swap now on my break before next nursing semester starts, but I also just don't have it in me to do my own CD009 swap.

More data is always good, also I cannot blame you in the least. That setup looks like a process to try and rush.

[Irace86.2.0]

Originally Posted by RedReplicant

More data is always good, also I cannot blame you in the least. That setup looks like a process to try and rush.

Do you think the movement on 4th gear has anything to do with lateral G’s or improper engagement on behalf of the driver or too much torque or some combination? Track use seems to detonate these things at any torque, stock included, more than absolute torque levels, from my subjective perspective.

[captain awesome]

Originally Posted by Irace86.2.0

Do you think the movement on 4th gear has anything to do with lateral G’s or improper engagement on behalf of the driver or too much torque or some combination? Track use seems to detonate these things at any torque, stock included, more than absolute torque levels, from my subjective perspective.

Wondering the same thing myself. I doubt it's just user error but considering the lions share of failures are track specific there may be something to that environment loading 4th just wrong? Any data traces of when 4th gear went South would be neat to dissect.

[RedReplicant]

I'm not an engineer, but I suspect it has to do with track cars actually making grip, overly aggressive clutch setups, aggressive and much more frequent upshifts/downshifts, and probably a big part of it being sustained high gearbox temperatures.

There is another forum member that has run one of these things as a w2w car for a while, he told me he has been through over a dozen transmissions and said that once he added a transmission cooler it slowed their death significantly. I've been meaning to add a temp sensor to mine, as well as a cooler, just on the backburner.

I do have data from a spectacular 4th gear failure on the FA/Harrop setup, but the Jack's 4th gear failure was pretty silent and caught before a big bang.

There is another K swapped track car (this is not the same person that has been through transmissions mentioned previously) who found one of the three synchro hub pieces stuck to the drain magnet and sent me a picture a couple of weeks ago, so he caught that before the big bang too.



Basically, if the car is kind of difficult to get into 3rd or 4th drop the fluid. If you find one of these:



Pull the trans, it is done, you caught it before the big one.

[Irace86.2.0]

I picked up the transmission today. Clutch is ordered. I bought parts to do downpipe v3, so I can just do it all at once:

-Clutch and tranny
-Fuel system upgrade
-Add coolant line
-Reroute catch can lines
-Reroute vacuum lines
-Swap wastegate springs
-Redo downpipe
-Break in clutch
-Dyno tune

If there is time, I will get the stock driveshaft shortened and try to sell some parts. @captain awesome and @RedReplicant do I need to know anything? I figured I would just take both driveshafts to the shop and have them shorten the new ones. I will have to buy some spacers too. Captain, I'm trying to understand your first pic; why am I seeing three yokes and two driveshafts? Do I need to ask for a dust shield on the end or what? What is the thickness of the spacers and where could I find them?



https://www.ft86club.com/forums/show...&postcount=808

https://www.ft86club.com/forums/show...postcount=1252

[RedReplicant]

The deal is that the driveshaft shop might tell you that normally you don't want to just shorten the front section and that there may be vibrations because of doing this. They also might tell you that they don't know what they will find when they cut the DS open and don't know if it will work or not.

The stock front yoke is not reused, an aftermarket one is put in its place but unfortunately I don't have the part number off hand.

You're going to want to measure from the center of the center support bearing bolt holes to the output flange of the transmission and take that number to the driveshaft shop.

I used the following from McMaster Carr to shift the DS CSB down
2x M10 15mm spacers
2x M10x1.25-60 bolts
2x M10 split washers
2x M10 fender washers

[captain awesome]

Yeah I think the measurement I told my shop may have been on the short side for RedReplicant by a little bit so best to probably get that measurement for your application to be on the safe side. At best mine could have maybe been a 1/2 longer than what I got? I brought them the stock one and told them what the overall length I needed to be by removing X amount of material. Like said above the front yoke isn't serviceable so they will replace with aftermarket.

[Irace86.2.0]

Originally Posted by RedReplicant

The deal is that the driveshaft shop might tell you that normally you don't want to just shorten the front section and that there may be vibrations because of doing this. They also might tell you that they don't know what they will find when they cut the DS open and don't know if it will work or not.

The stock front yoke is not reused, an aftermarket one is put in its place but unfortunately I don't have the part number off hand.

You're going to want to measure from the center of the center support bearing bolt holes to the output flange of the transmission and take that number to the driveshaft shop.

I used the following from McMaster Carr to shift the DS CSB down
2x M10 15mm spacers
2x M10x1.25-60 bolts
2x M10 split washers
2x M10 fender washers

If I bring the Kpower aluminum driveshaft down and bring a stock driveshaft then can't they just measure off the aluminum driveshaft? Can't I just measure the aluminum shaft and provide that number? What am I missing.

[captain awesome]

Originally Posted by Irace86.2.0

If I bring the Kpower aluminum driveshaft down and bring a stock driveshaft then can't they just measure off the aluminum driveshaft? Can't I just measure the aluminum shaft and provide that number? What am I missing.

You can do that, I think the kink at the support bearing is where some dimension was lost or maybe the shop took just a smidge too much? If I remember correctly the length of the Kpower shaft is what I provided to the shop.

[Irace86.2.0]

Originally Posted by captain awesome

You can do that, I think the kink at the support bearing is where some dimension was lost or maybe the shop took just a smidge too much? If I remember correctly the length of the Kpower shaft is what I provided to the shop.

But you didn’t give them both shafts, right?