Stock Car Mafia's '78 280z LS2 Build

[1969honda]

Oetiker clamps might be a good alternative

[Stock Car Mafia]

Oetiker clamps might be a good alternative

 

Thanks for the suggestion.  If these clamps don't work out, I don't mind trying something different.  

[Stock Car Mafia]

The girlfriend and I were able to get the stock U-joint axles out yesterday and put the Z31T shortened axles in.  I will have to say getting the differential stubs out of the diff really suck ass.  It took a large crow bar and a 2 lb. sledge to get them loose.  

 

The old nuts and companion flanges were taken off and the new ones put on.  I torqued the nuts down to 235 ft-lb.  

 

 

 

The hardest part was getting the right bolts for the axles.  I could not find it anywhere on the forums nor did Joe have the information handy when I called him.  The right size bolts are:

 

Class 10.9 Flange Bolts - M10-1.25 x 30mm

 

At this length it clears the strut and has enough threads for a locking washer and a hardened nut.

 

The axles went in extremely easy.  The bolts were tightened german style and same with the nuts.  I used blue locktite for it all as well.  

 

 

[Stock Car Mafia]

Boots are holding up after several test runs.  I think I should be ok with them.

 

I am working on the exhaust tonight and instead of scratching my head on paper doing all the geometry and measurements I am going with the ole' test fit and cut little by little.  I am working on mating the x pipe to the header extensions right now.  It sounds like I will be heading to Green Bay this week for work and have a wedding and family reunion this Friday and Saturday so time will be limited.  

[Stock Car Mafia]

Exhaust was slow but steady progress until about 8:30 last night.  I don't want to rush this and have a hack job exhaust with rough cuts and nasty bends.  I truly am trying to use the bend radius for pie cuts to keep everything as free flowing as possible.  And drip through will be smoothed out if possible.

 

I started with extending the piping off the collectors.  Straight piping worked for the driver side but not the passenger side.  I did cheat and angle cut the passenger side slightly and tacked them to the V bands.  That small of a pie cut would have been difficult.

 

 

The V bands were marked with a permanent marker to keep them in line as I was removing them quite a bit.  I placed the X-pipe against each side with it roughly centered to get an idea of what angles I would have to add.  

 

 

 

 

I don't have a compass, so of course test fitting and cutting little by little was my friend.  

 

After I made these measurements, I guestimated roughly how much I would have to extend the piping on the X-pipe to get it to the right width.  

 

 

I taped up the pieces and cut little by little til it was right.  Tacked them in place and went back to massaging the end with a grinder to get it just right.  

 

 

I got this pretty damn close and then sized it up again to measure for the pie cuts.  

 

 

I then made my cuts and tacked those pieces on to the collector extensions.  

 

 

All bolted up everything lined up well.  I went ahead and welded all of the tubes solid, then to for the final fitment of the X-pipe.  After welding everything still lined up REALLY well and quite level.  I tacked in about 6 spots on every joint.  I welded a 6th of the tube at a time and kept moving around to keep the heat down.  

 

 

This is where I decided to call it quits.  I didn't weld everything together as I want to clean up the small amount of drip through where I can reach yet. 

 

1.  I haven't determined how the piping will be hung yet.  I have some mounts but might go a different direction.

 

2.  The mufflers will be going under the diff and fit well between the front and rear diff mount.  I did fit the 90 bends between the back of the diff and the fuel cell cage and it will clear by 1/4" or so so I should be safe.  

 

3.  I will mock up the mufflers and measure the angles they are set at just like the collector extensions.  I'll then calculate how one bend on each side can be cut:  whether I have to remove some of the X-pipe or not.  

[RebekahsZ]

Looking great! My boots don't have that squished look at the clamp-I hope those don't leak. Also, my companion flanges are threaded so that I don't need a nut on the back side. I torque them to either 35# or 55#, I can't remember. I have to use a crowd foot on a 3/8" torque wrench. I fashioned a big crowd foot pry bar out of a 3" wide chisel to help pop the axles out-it really helps to pry evenly on 2 sides at the same time. It scars up the paint on the diff, but oh well.

[Stock Car Mafia]

I had to scoot the boots up about 1/8" more to make the boots stay on.  They are some cheap O'reilly boot.  I used the part number for the outer boot for both the inner and outer.  I drove probably 100 miles and checked and no leaks or ejected grease so far.  

 

The flanges I got are threaded as well.  I torqued them good and tight by hand, but wanted the extra precaution of a nut to keep them on.  I added blue loktite as well.  Maybe I am a little paranoid but it plays to be safe on a car that was just a shell a couple months ago.  lol

 

 

Looking great! My boots don't have that squished look at the clamp-I hope those don't leak. Also, my companion flanges are threaded so that I don't need a nut on the back side. I torque them to either 35# or 55#, I can't remember. I have to use a crowd foot on a 3/8" torque wrench. I fashioned a big crowd foot pry bar out of a 3" wide chisel to help pop the axles out-it really helps to pry evenly on 2 sides at the same time. It scars up the paint on the diff, but oh well.

[RebekahsZ]

If the boots don't sling grease on a 20- minute track session you are golden. The lock nuts are a great idea, but way overkill. If you have it apart in the future, you can delete them. I've driven hard on mine for a couple of years with slicks, track days and LS2 4500 rpm clutch dumps and 1.4 60 foot times and never had one loosen up even without locktite. The old u-joint stubs used to take torque every third pass in the 1/8-mile with a 100hp L24.

[Stock Car Mafia]

I could possibly get some shorter bolts if i delete the nuts. Id probably still use loctite as i dont have the need to remove the axles often. I am very surprised at how the u joint half axles held up. I wasnt necessarily gentle with them but driving didnt include much drivetrain shock as i wasnt dumping the clutch.

 

Busy ass weekend so not much progress on the car. I realized i need to test fit the rear sway bar with the axles. Kind of struck me as im working on the x-pipe to muffler routing.

[RebekahsZ]

If you want, you can skip the rear bar. Most of us don't run it. Car is nice and neutral without it.

Edited June 20, 2016 by RebekahsZ

[Stock Car Mafia]

I've definitely read most people leave it off with no issues what so ever.  Maybe it is just me but I seems like the car does roll or lean quite a bit in the rear when turning.  But I am used to a solid axle so that could be why.  

 

I need to finish my fenders so I don't have any tire rubs.  I would like to test the car with and without it on.  Like most, it's probably not noticeable.  

[Stock Car Mafia]

The X-pipe is pretty close to being symmetrical under the car.  One side is maybe a tad bit lower.  The pipe is not entirely centered under the car but maybe it is just the location of the mufflers that make it seem that way.

 

 

The muffs tuck up really nice under the diff.  I am pretty sure ground clearance will be just fine.  I tacked on 6" extensions on the mufflers to get past the supposed location of my mystery sway bar. 

 

 

 

Another set of V-bands were added to the mufflers so the mid-pipe will be removable for tranny service.  We will see how often that is.  lol.

 

 

I didn't take any pictures last night, but I worked from the V-band back to the X-pip.  Since the mufflers are slightly angled I was going to add some pie cuts to get the straight tubing parallel.  The pie cuts were going to be so damn small again, I just ended up cutting the straight tubing at an angle...

 

The straight tubing ended up being 9 1/4" on on side and 7 1/2" on the other I believe.  The back portion of the X will be asymmetrical pass to driver side.   I think it will still look fine

[RebekahsZ]

Your tubing cuts look SO clean!

[Stock Car Mafia]

I wish I could say the same about my welds!  I guess they are ok but I am hoping for no leaks.  

 

As for the cuts, I've been using a Milwaukee chop saw.  For cuts other than straight tubing I am using a 4" cut off wheel and making sure it is as flush as possible.  Using a carbite bit to clean up the inside and outside of each cut really goes a long ways.  I will have to admit that I am going on the basis of cutting with some room for play and grinding away until it fits.  It has worked so far instead of doing all the intense math to figure out the bend radius of my turns.

 

Your tubing cuts look SO clean!

[bramagedained]

I wish I could say the same about my welds!  I guess they are ok but I am hoping for no leaks.  

 

A grinder can hide a lot.

[Stock Car Mafia]

I'd be crazy to get that elaborate with exhaust that is hanging under the car.  I'll live once it is coated in hi temp paint.  How'd the fishing go?  I made it to CnC and the turn out was pretty good.

 

A grinder can hide a lot.

[bramagedained]

Numbers were bad for fishing.  But, we did manage 26", 24" and a couple 22" walleyes.

 

Unless something catastrophic happens I'll be at the July C&C.  I should be taking my car for it's first drive this weekend or sooner.

[Stock Car Mafia]

Sounds like more drinking than fishing then.  

 

I am 75% sure I will be there, depending on how weekend plans unravel.  I might start my cam swap around that time so we will see.  

[Stock Car Mafia]

So toucing on where I left on for the exhaust build, I placed the mufflers where I wanted them positioned under the diff.  I then clamped up the mid pipe and measured the length of tubing I needed to connect the two.

 

 

I ended up welding the other side of the v band to the pipe and clamped them in place.  The hardest part is the x pipe isn't truly centered in comparison to the muffs so it took a little trickery.  I used the driveshaft as my "straight edge".  This worked out quite well.

 

 

After getting these close, I took the mid pipe out to angle cut the X for the pie cuts.  

 

 

 

 

Everything went back in and was measured for the pie cut.  This was the outcome.

 

[Stock Car Mafia]

I threw everything back in after it was tacked up and sized it again to make sure it was set.  Turned out PERFECT!

 

 

 

I used a square and measured the driver side exhaust cut out and replicated this on the passenger side.  I believe the cut is 2 3/4" in from the corner and the diameter of the cut out is 4 1/2", leaving me 1/4" of wiggle room with the tips.

 

Since the mufflers are angled a bit, I am trying to get the 2, 90 deg. bends to work out for the exhaust exits.  A little pursuation I should be ok.  I got one side tacked up last night and is looking alright.  I should have the exhaust complete and mounts welded prior to Sunday.  Tonight will be tough for time.