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Dzimm

92 Turbo, Autocross MJ

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7 hours ago, ghetdjc320 said:

Going to use a turbo manifold or just put a flange on a stock manifold? Boostwerks is running a special on their manifold 

I've actually been thinking about running it remote.  Either on the passenger side or where the stock airbox goes, all depending on where I have room for piping.  I don't really want to fumble around with the manifold nor cut a hole in the hood.  Once I get the turbo I can figure out where it will fit and really get it planned out.  

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It's like Christmas here!  

 

I've been getting parts over the last week or so for the axle and filled a big box of parts that I can hardly lift.  Today though , the new tires and the LSD arrived!

 

The LSD is in really good shape, it's used out of a Liberty but was rebuilt by a performance shop with new clutches and Timken bearings.  I was going to get one eventually but I decided to pull the trigger on this one because it was only $300 and it came from a Liberty so it has the teeth on it for the speed sensor in the axle.  This speed sensor is for the Liberty ABS system but I wanted to maintain it just in case I need it for the turbo setup.  I really doubt that I'll need it but just in case I do, I'll have that option.  I've never seen a C8.25 trac lok that has the teeth so I felt I just had to buy it.

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The tires are freakin tiny.  They are 2.5" shorter than what's on the truck now which is perfect.  They should look decent as they still have some sidewall, but they will get the truck lower to the ground.  

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Contact patch is around 8" while the current tires is only 7".  

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Sidewall will have about 2.5" of exposed rubber.

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That setup is going to look good! I'm going to have to drive again so I can see it in person.

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That’s going to be a nice setup when it’s all done. For future reference I got a 8.25 lsd carrier for my tj from 2000 Dakota from the junkyard and it had the speed sensor gear too. 

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4 hours ago, JMO413 said:

That setup is going to look good! I'm going to have to drive again so I can see it in person.

We will definitely have to get together sometime this summer.  I'm hoping to be starting autocross this year since it will fit into the rules so maybe you could come out for that.  

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3 hours ago, onebigmj said:

That’s going to be a nice setup when it’s all done. For future reference I got a 8.25 lsd carrier for my tj from 2000 Dakota from the junkyard and it had the speed sensor gear too. 

Yeah I was surprised at how many other vehicles had the C8.25 in them in the early/mid 2000s.  Since the info on them is so limited, I don't know how similar they all are.  They are much more similar than I initially thought though.  Once I do my write-up on the swap it would be good if we can compile a list of what all has them so part searching can be easier.

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8 minutes ago, Dzimm said:

We will definitely have to get together sometime this summer.  I'm hoping to be starting autocross this year since it will fit into the rules so maybe you could come out for that.  

Sounds good to me.

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Just now, JMO413 said:

Sounds good to me.

Now that I think about it, I'm pretty sure there is a race or two at an airport out your way.  I'll message you when the time comes.

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I have an 8.25 in my Comanche and I’d really like a limited slip. I’m pretty set on a truetrac as it’s a clutchless limited slip, but I’ve never actually driven any limited slip that uses clutches. I’d love to know how it performs in your set up. Do you know what gear ratio you plan to run with that size tire? I have 29” tires, 3.55 and an ax-15 and it winds out pretty far on the highway.


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8 hours ago, SatiricalHen said:

I have an 8.25 in my Comanche and I’d really like a limited slip. I’m pretty set on a truetrac as it’s a clutchless limited slip, but I’ve never actually driven any limited slip that uses clutches. I’d love to know how it performs in your set up. Do you know what gear ratio you plan to run with that size tire? I have 29” tires, 3.55 and an ax-15 and it winds out pretty far on the highway.


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I've been reading that the clutchless designs are prone to breaking in a high torque/stress environment like autocross which is another big reason I went with Trac Lok.  The clutchless design lasts a lot longer so definitely a benefit if you won't be beating the crap out of it.

 

I've never driven a limited slip vehicle at all to my knowledge so it will be interesting to see what this is like.  The conversion math says my tire is about 24.8" with 3.73 and ax-15.  Should be pretty quick to get to speed.  I'll definitely be posting about the results when it's all in the truck.

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Took measurements before removing everything and found the original backlash to be about .006-.007 which is right where it should be.  Pattern was also right in the middle of the teeth.  I took plenty of pictures so I can reference back during reassembly.

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Was able to get the ring gear bolts off and knocked the ring gear off.  

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Got the ring gear on the new carrier and torqued up to 55ft/lbs but need to go to 70ft/lbs I learned after finding a Liberty FSM with the info.  Many places I read it to be 55 but the FSM says 70ft/lbs so I'm going to go with that.  I will also need to get a vise to finish torquing them, I can't get any higher than 55ft/lbs on the bench.  I also sliced my hand open when the gear slipped, turns out they are really sharp.

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It currently sits in the axle as I took a stab at setting backlash but was having some issue, turns out because the FSM had some key info everyone else misses in their "tutorials".  Once this is all done, I will do a thorough write-up on the diff swap and setting up the backlash per the FSM.  I will also be doing a separate write-up on putting a Liberty C8.25 in the MJ.

 

One other thing I learned from the FSM is that you need to replace the ring gear bolts.  After reading into it more, it's like anything else, people say it's fine to reuse them, others say don't because they can back out or break.  I even came across some pictures and video of pretty catastrophic damage done from broken ring gear bolts.  Since this will be beaten on pretty hard, I am opting to take the safe route and replace them.  I ordered a set of Yukon bolts and they should be here by Thursday. 

 

I also need to find a vise so I can actually torque these bolts down.  I need a vise real bad but can't bring myself to buy one because I always seem to find a way to make due without. 

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Progress was made today.  Everything is now painted and clear coated except for the wheels.  I found the Rust-Oleum enamel clear coat isn't playing nice with the Rust-Oleum enamel paint on the wheels.. I luckily only did one wheel and it only cracked a little bit so refinish will be easy.  The other parts took it without issue but the wheels didn't like it.

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I pulled the spare tire carrier off because I won't need it and shedding the weight will be nice.  I also pulled off the rear most exhaust hangar because I'm not using it.  I am posting them up in the classifieds if anyone wants them.  Much cleaner in the rear end now.

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I also got the new spring perches tacked in place.  Need to find somewhere near by that has a capable welder and can run the beads for me.

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I also decided to take the bumper end caps off and set the airdam in place.  It currently sits 11" off the ground.  After tires and suspension it should be closer to 7"-8" from the ground.  Need to figure out something for the license plate and I need to decide, black airdam to match the pretty nice black trim, or paint everything red?

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Realized my fabricator buddy is only 30mins from me so he picked up the axle tonight.  I'll be picking it up from home either tomorrow or Wednesday so this weekend I should be tearing the rear end out of the truck!!  

 

On a less than thrilling note, I figured I'd have to have my driveshaft shortened a couple inches but realized it's got the double walled driveshaft so I may need to have a new shaft built.  I'm going to talk to the driveshaft shop and see if they can do anything with it and what a new shaft would cost.

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48 minutes ago, Dzimm said:

Realized my fabricator buddy is only 30mins from me so he picked up the axle tonight.  I'll be picking it up from home either tomorrow or Wednesday so this weekend I should be tearing the rear end out of the truck!!  

 

On a less than thrilling note, I figured I'd have to have my driveshaft shortened a couple inches but realized it's got the double walled driveshaft so I may need to have a new shaft built.  I'm going to talk to the driveshaft shop and see if they can do anything with it and what a new shaft would cost.

I have the two piece style driveshaft as well. Place by me was able to cut it down and balance no issues. Charged 150

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1 minute ago, 70barracuda said:

I have the two piece style driveshaft as well. Place by me was able to cut it down and balance no issues. Charged 150

Thanks, that's reassuring!  I never looked into it but remember reading somewhere that those can't be cut down.

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Yeah the guys by me gave it a weird look and said ' I don't know if we can do this. Well have to check it out'. Hour later they said it was good to go 

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25 minutes ago, Dzimm said:

Thanks, that's reassuring!  I never looked into it but remember reading somewhere that those can't be cut down.

 

yeah, just have them cut down the non-isolator end. :L:   but this is ONLY if the rubber bit is in good shape.  the rubber goes bad over time.

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7 hours ago, Pete M said:

 

yeah, just have them cut down the non-isolator end. :L:   but this is ONLY if the rubber bit is in good shape.  the rubber goes bad over time.

Looking in from the rear side it looked good. Solid with no cracking so fingers crossed.

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I just had my double wall shaft shortened for my 4wd swap.

I asked if it would be a problem, guy said nah, if the rubbers good, it's no problem. It cost $148 to shorten, balance and new U joints

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I had a new shaft with new joints made for my Comanche for $200. Are you planning to drive down the highway much? Sounds like it’ll be screaming with 3.73 and 26” tires. Oh and the only experience I have with clutchless limited slips are my miata buddies that beat the snot out of them. One of them is running 12 pounds of boost on his 1.6 and the other is waiting for his turbo manifold to come in for his 1.8.

 

Edit: My butt dyno says there’s actually a slight improvement going from the double wall heavy rubber shaft to a normal steel shaft. There’s a sizeable weight difference between the two.

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2 hours ago, SatiricalHen said:

Are you planning to drive down the highway much? Sounds like it’ll be screaming with 3.73 and 26” tires. 

At 65mph in 5th gear it'll be running right around 2600rpm according to the math. 

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2 hours ago, SatiricalHen said:

Sounds like it’ll be screaming with 3.73 and 26” tires.

 

my Dakota RT had 3.92s and ~27" tires and could max out the speedo limiter with rpms to spare.  he'll be ok. :D   

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Went and picked up the axle tonight.  Perches are all welded, hopefully will get paint on it and start installing if all goes well this weekend.

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Things have been pretty busy and cold/rainy so I couldn't get much progress done as I needed to paint some stuff.  Last weekend I finally got the carrier in and setup properly as far as I can tell.  First time I've ever setup anything with the gears themselves so hopefully all works out well.

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I got tired of waiting and it was in the 40s today so I painted what I needed and did some assembly.

 

Axle seals

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Backing plates, caliper brackets, parking brakes, and axle shafts painted and installed.  Had a little trouble with the carrier side axle shaft not sliding in quite far enough to get the C-clip in.  It was so incredibly close but the clip just wouldn't drop in.  From what I could find was that the shaft bottomed out against the brake hardware.  I finally decided to just tap the C-clip in.  After some in and out and working at it, I got things freed up enough I can get it in and out easy.  I think my issue was a combination of the brakes not being perfectly centered and the carrier side of the limited slip diff being slightly deeper than the other side.  Everything moved freely and seems to be functional so we'll see if I have any issues.

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Put the calipers on to start roughing in the brake lines.  I realized that the brackets for the softlines bolted to the old coil pads so I'll have to find a way to mount those.  Don't really want to weld them to the axle so I'm thinking about using a stainless band clamp.

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Also painted the diff cover.  I kept it black but am contemplating doing a color.  I'm liking the gray calipers but I think that would be too much for the whole cover.  I may paint the cover bolts gray to do something a little different with it.

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Worked on the axle for a little bit before coming to a standstill again. 

 

Found a way to use the original brake hose brackets, I'm going to get some exhaust clamps to hold them to the axle so I can take them off if needed.  The hose clamp is just proof of concept.  Just a snug hose clamp I can't even budge the bracket so I have no worries an exhaust clamp will hold it fine.

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Turns out the main brakeline block requires metric fittings so I need to go pick some up before getting the hardlines on.  

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