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Ben280

280z FP Build

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the brake upgrade looks GREAT! would love a set of those hats or the cad file. How do you like the aluminum hubs? I have a set in a box. I even bought the bearing spacers (DPR). But I have some kinda mental hang-up about the use of aluminum there. I know It's not rational.    

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Off season 2019. I was going to keep it simple. I was planning to do new injectors, finish the E85 fuel system and might begin work on a new steering rack. I even posted here that I'd do such a thing! And then, as tends to happen, I used The Internet. 

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(WHAT'S IN THE BOX MAN?!)

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(Shiny!)

 

I'm not sure who to blame here, but I blame somebody! Troy Ermish was selling this Jerico 4sp on a facebook group, and I decided it would be mine. I've often thought about going to a dog box, there are a lot of advantages to them, and after driving a couple a few years ago, I knew it would be a significant speed advantage. One popped up on here years ago, right after I'd bought a new motor. Think it was a Quaife Sierra box. At any rate, this box had a lot of the main issues with a dogbox conversion sorted out. Namely the bellhousing. It also came with all the shifter parts, throw out bearing and a driveshaft (for a 510!) I think this has been the most complex task I've taken on in the car to date. After test fitting, a couple big problems became very apparent. I'd need to move a bunch of metal in the trans tunnel to clear the external shift rods. New crossmember, new driveshaft, new clutch and new pilot bearing would all have to be sourced. The shifter was positioned for a 510, so it was pretty far away in the Z. I'd need to move it back about 5" and then re-do all the shifter rods. All mostly doable, but the most stress inducing issue would be swapping out all the gear ratios. Since this thing was used for road racing, the gear ratios were super tight. Great for your high revving L16, but in my car, the 1.6:1 first gear would see me doing 92mph. Launching off the line would be impossible (1.6 is between 2nd and 3rd in the KA trans I was using) so I had some work in front of me. Luckily, these are still pretty well supported in the aftermarket community, and I was able to get ahold of a full second set of gears. Cue taking this whole thing apart. 

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(Oh dear....)

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(New gears!! Top set is the old super close ratio ones. Note the differences in sizes, 1st is on the left, 4th is on the right)

 

Ok, box back together with the new gears, and everything works. Great! Now for the rest of the parts.... Needed to source a new clutch. I wasn't super interested in getting a 5.5" or 7.25" clutch, since they have a really hard time slipping, and I like being able to drive this around the paddock and off the trailer without doing a hectic burnout and scaring dogs and children. The Jerico uses a Chevy fine spline input shaft, so I made a call to the local performance parts shop. 

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(Clutch Masters solid 6 puck clutch. Nissan diameter friction disk with a Chevy fine spline center. Also, resurfaced my 8 year old AZC flywheel)

 

Great! Another problem sorted out relatively painlessly. Last problem was the pilot bushing. Fortunately for me, the Chevy input shaft snout is smaller than the Nissan one, so I would be able to fabricate a custom piece out of an oversized GM bushing. Good thing I have a lathe in the garage...

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(Turned up an arbor to hold the GM bushing so I could turn the OD concentric to the ID and not have to hold the whole thing in a super terrifying way. The brass piece is just superglued to the aluminum here. Once done, I drilled the center of the aluminum out and then used a torch to break the superglue bond.)

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(Mmmmmmm custom. Plenty of meat left on the GM part, and I managed to keep the 0.001" oversized fit of the factory Z piece)

 

The parts for these shifters are all insanely expensive. I'm not sure why, they don't feel particularly well machined, or crazy toleranced, but the are $$$$. Back to the friends with CNC machines! One of my friends is starting up a general machining job shop, and I thought I'd see if he could make me a new plate for the shifter mount. I did all the measuring and CAD work, he made it look amazing! If you're in the PNW, check out Bigfoot Fabrication! Mike is a rad dude and knows his way around some machines. 

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(Shifter mounts to the top three holes, and the bottom 8 holes allow fore-aft adjustability in 1/2" increments. Once I had it placed correctly, I could measure for shift rods)

 

And that's about where everything sits now. Driveline is back from the shop and installed. Working on making a new front wiring harness for the new injectors (DW 660's) and plating over the huge hole in the trans tunnel from figuring out where the shifter goes. 

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36 minutes ago, luigi said:

the brake upgrade looks GREAT! would love a set of those hats or the cad file. How do you like the aluminum hubs? I have a set in a box. I even bought the bearing spacers (DPR). But I have some kinda mental hang-up about the use of aluminum there. I know It's not rational.    

 

Thanks! I'll have to see if the guy who made them wants to spin up another set.

 

The aluminum hubs are pretty good. I haven't noticed any odd behavior yet/flexing and I'm pretty hard on the front end of this thing! Bearings and grease looked good when I inspected them earlier this winter. I will say, having so much less thermal mass in the rotor means it's pretty easy to overheat the rotors if you're not thinking about them.

 

2 minutes ago, manninen said:

I dont know how much those discs can take heat for track use but i could take those on light street use. 

 

 

Oh you couldn't use these on track at all! Even with my car at 2100lbs you can get em smoking hot. I'm rebuilding my cast hubs and full disks for time trial events this summer. 

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Weekend update. No photos, but the modified fuel rail is in, lines are hooked up, trans is bolted in and new brakes are in. Switching from the DTC-30 to HP-Plus compounds, we'll see if they work better. The DTC-30's were great but made all the dust in the universe and didn't work until about 1/2 way through the first run. Hoping the HP-Plus is better on that front. 

 

Going through and making the adjustments for the E-85 tune, going into the shop on Thursday for pre-race dyno, alignment and balance work! 

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Car is out of the garage for the first time in a few months, getting aligned, corner balanced and a new tune for ethanol. Hoping for some positive numbers, we'll see what happens! I try to do most of the work on this car myself, I really enjoy the fab, design and implementation. But you gotta know when a job is over your head! I'm always happy to have the pro's do what they do best! 

 

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(On the rack, getting weighed)

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(Pre balancing. This is with 235# of ballast and 5 gallons of fuel on board. No driver)

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(Dyno time!)

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Time to move the radiator back to the hole you have there :-)  I'm sure you've probably already been thinking about that given some of the FB threads.  Great to see all the updates.  Two things I'd add in case they aren't done.  Run a brace from your rear diff mount down to the transverse link,  The will help flex that does lead to rear toe changes.  Also make sure to inspect those two bits of medal as you have enough tire to crack them.  I went through a few sets before adding the braces and never had a problem after.  You also need to put bolts into the ebrake bracket that is on the strut.  Those little threaded holes can lead to cracking the rear struts if you don't.

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Thanks guys! Tube80z, been thinking about how best to clean up that whole area for more strength. You have any photos of the braces you made? I boxed the factory body-tranverse link mounts, that seemed to help, but integrating that into the mustache bar seems like the actual solution. I'll put some bolts back into those holes in the struts too. I figured since they were blind it didn't much matter, but it's an easy fix for a potential catastrophic failure!

 

Radiator was going to go into the rear this winter, but I got distracted with Jerico mods. Next year probably, I'll run a scirocco size radiator or something to help keep the weight in line. The to-do list is getting ever shorter, but at the moment it looks like:

 

-Rear suspension re-fit: I'd like to do something with modern wheel bearings/axles, both to add strength and loose some weight. The factory rear knuckles are HEAVY!

-Radiator relocate: smaller size, and add an electric water pump

-Woodward steering rack

-Aero? rule change might happen where we can finally add functional aero to the car. Full front end splitter with canards and end plates along with a big dual element rear wing. Auto-X speeds mean bigger is better. Would be cool to bolt on about 500lbs of function downforce at 60mph. 

 

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What you want to do for the rear brace is triangulate the lower pickup point with the rear diff stud (orange line).  Somewhere I have a picture of this but I can't find it so I used a random image that's in my downloads folder.  Not my car or a friends in case you're wondering.  Some company in the UK that does rebuilds.  Another item to add to your list are toe-link rear arms if you don't already have them.  This helps reduce side loads on the strut from alignment changes, which reduces friction.

 

On my street car I've been looking at a bracket that bolts under the normal spindle pin location that allows a control arm using rod ends to be mounted in double shear.  And that's lead to more rat holes and I think I'm leaning towards a fabricating housing that uses nothing Datsun on the outer end to keep costs down.  Somewhat similar to the Apex Engineering stuff but different outer mounting and a simple bolt-on hub assembly.

 

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Other easy items to think about.

1.  Droop limiters

2. Hanging ARBs from rod ends (lowers friction)

 

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On the front you can do something similar to the yellow and orange lines in the attached image that helps stiffen the suspension mounting points.  Rather than bolt things to the TC cup those could be welded and the tubes could mount as plates under the mount.  They would stack and be bolted in a sandwich from the bottom.  There's a lot of things you could do for engine bay bracing between the strut towers.  BMW touring cars had this cool tubular structure that was connected to the strut towers, frame rales, and lower crossmember.  It looks like a truss in the engine bay and you could easily hang your motor from it.  That would allow you to ditch the normal motor mounts.  And if you pick up the bellhousing with mounts you can get rid of the transmission mount.  My old race car ran solid mounted this way and it worked really well.

 

Hope that helps,

Cary

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Hi Luigi, it allows the strut another axis of movement that isn't putting bind on the strut insert.  If you have stock rubber bushings those probably allow enough movement this doesn't matter.  WHen you take apart the rear struts and try to line them back up to go on the upper mount you often see how small changes to the pickup points (toe/camber) make it really hard to get back where it needs to go.  The stiffer you make the bushings (poly, rod ends, or sphericals) there's less give needed to follow the path laid out by the upper mounts.  There's a lot of good info in the suspension section stickies that discusses in deeper detail.

 

I'd recommend the brace for any V8 or higher powered street car.  Years ago I was sitting in a friends V8 car and he tells me to watch the tire from the side mirror.  He proceeds to power brake and I see the rear tires toe out and not a small amount.  Even on a lower powered car if you corner really hard I'd expect this isn't helpful.  The brace helps to reduce this.

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That flex on rear might be from bushing, i dont think that moustache bar to transverse link support change a thing. Only helps if you drift mad with wide tyres. 

I have incoming watercut part which replaces transverse links and moustache bar to one part and uses same hooking points. Other post its said catastrofic failure, havent heard none of stock tranverselinks ripping out of body, even on 1000hp have been ok. 

 

I thought that front supports too but i have no room on front, 4" downpipe and gearbox blocks everything

Edited by manninen

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11 hours ago, manninen said:

That flex on rear might be from bushing, i dont think that moustache bar to transverse link support change a thing. Only helps if you drift mad with wide tyres.

 

It's very believable to me that this piece would flex and crack. It's a pretty poor design with very little lateral stability. Adding the drop bars as Tube80z mentioned would really alleviate stress in the system. 

 

Doing it in one piece as you're planning is probably better but might run afoul of some of the rules I'm constrained by. 

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