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The Z31 Project - Race Car


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Big brake kit for both ends arrived, 330mm rear rotors, 355 front. Would the fronts clear 18" wheels, yes they would. Prior to purchase I received good advice that these Ceika kits are very heavy, I agree, they are. But aside from the calipers I can't see how they could be much lighter, the adaptors are steel not aluminium with the rears being minimumalistic but the fronts a bit beefy, a little bit to be saved there but not much. The calipers are radial mount and the rotors fully floating just like the pro stuff is. The calipers are massive, something like Wilwoods would be lighter but they won't be as stiff as these Ceika's, 8 cross bolts on the fronts and 7 on the rears, I expect excellent firm pedal feel from these. I also specified the optional stainless pistons, heavier than the standard aluminium ones but more serviceable and less heat conductive.

 

Time will tell if the decision to get these was the right one but they fit perfectly which is a good start and I can't fault the completeness and quality of the kit, the rest is up to the driver to gain something from them, late braking here we come :) Pics, the first two are of the rear.

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Edited by 260DET
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The weight thing was nagging me so I did some checks on rotor weights just to see. DBA advise that the average weight for a 300mm all iron rotor from your average car weighs 9.5kg. The outer ring from a 330mm StopTech rotor weighs 7.75 while the complete Ceika 355 inner and outer with hardware is 9.5. So that's OK, the nagging has gone away :)

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They came pretty quick too, glad it worked out for you. The brackets were the biggest gripe I had with them weight wise. Be interested to see how they go.

 

Ceika already had kits available for the Z31, given your warning I went through all the details with them to try to make sure that it fitted my '87 turbo. They said that they used to supply aluminium adaptors but changed to steel, presumably because customers were stripping threads. I honestly think that the components are excellent although time will tell how good the rotors are.

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Hi Richard,

 

Looks like an interesting build, the Gear Vendors unit will make it much more flexible - I assume you're running 3.7 or 3.9 diff ratio?

I was looking at your rear suspension setup and it seems to be a good solution to the dreaded camber and toe inducing trailing arm debarcle that was standard in these nuggets. There are a couple of things that you may want to revisit regarding your upper arm design though.

1) You'll end up with a roll centre well below your centre of mass which isn't ideal, I'd say somewhere about 120mm above ground level

2) I reckon you'll get some crazy camber gain on bump, perhaps you could drill some more mounting holes so that you can adjust the inboard mounting point up at say 25mm increments? It's going to squat pretty hard with a V8 in the front, so you want to get all of that rubber on the road!

 

Great build, nice to see something different.

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Thanks for the comments DatZed. Yes, getting the rear roll centre was up was a problem when running all the possibilities through the simulator, I don't have the figure to hand but it ended up higher than the front which was essential. A good thing is that it's very stable with suspension movement. 

 

Camber gain is designed in so static camber should be around neutral, I concentrated on getting both the inside and outside wheels right in a corner camber wise. There is no anti squat so hopefully she should put the power down OK with a little bit of squat that the springs should allow. There is a little bit of adjustment available using ride height, statically the lower link was designed parallel to the ground but height can be raised just a bit which will mean less camber change there from rest. Really looking forward to see how it all works on the track.

Edited by 260DET
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  • 2 weeks later...

Lots of little things getting done along with the usual transformation of details that are first thought of as straight forward but which turn into hair tearers, if you let them. Just one example, the brake booster. Given the new 6 piston front 4 piston rear brake setup a bigger master cylinder was obtained plus a Z32 na booster which needed longer attachment studs. Turns out no one in Brisbane including BHSS can recon it. After wearing out Google someone on the Z32 forum came up with a name so pics were emailed and he said he could do it. So it was posted off to Paul at Power Brakes (SA) P/L this arvo.

 

The project is nearly at the stage where things can be attached permanently, the big picture is looking great, some things are turning out nice like the Registered Design front guard vents, see pic. One of the basic things which is pretty cool I think is that 10" rears and 9" front wheels fit within the stock guards which on the S2 Z31 are already flared, obviously for that purpose :)

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Edited by 260DET
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One question Richard, why run a brake booster???

 

With all the mods being done, wouldn't it have been just as easy to run an adjustable balance bar and remote cylinder kit? 

 

You get much better pedal feel without a booster than with, well I do anyway, and I found it no problems in terms of effort to run a 1" unboosted master cylinder in teh green Zed, and will be running an unboosted 1.25" master in the S14. A proper adjustable twin cylinder system will be less effort with adjustable pedal ratios plus you have infinitely adjustable bias. PLus the cost of a decent pedal box isn't horribly expensive these days.

 

With the recent rule changes in ProdSports now making a full competition pedal box legal I may go to a full floor mounted set up with three remote master cylinders. 

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Manual setup would have been a lot cheaper and lighter but nothing is free including pedal pressure so for a car over say 8-900kg I think that a good boosted setup has advantages. The boosted setup on the 280ZX is great, nice feel and modulation, having to push too hard on the brake pedal dulls feel etc and is distracting. And all the new hi-po cars that can lap faster than I ever will have boosters. 

 

This is not to say that an unboosted system will not suit some, it gets to be a personal thing.

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A couple of things, firstly to keep the compound curved shape of the hatch glass I tried to get a replica moulded in acrylic over the glass like had been done with the 260. But no one would/could do it so I decided DIY. The pic shows the moulding setup, underneath the glass with the acrylic sheet on top was a gas space heater but without an enclosure it did not sufficiently heat all the acrylic evenly. With the help of a heat gun we did end up with the compound curved shape which ensures that the acrylic is permanently shaped and does not require support but it's not as nicely curved as it should be. Not up to my standards but it will work, just don't look at it closely.

 

The second job finalised is the front ARB, a straight hollow bar splined each end for the arms and running in bronze bushed brackets much stronger than stock. The car will have no rear ARB combined with a stiff front ARB setup just like the 280ZX's.

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Hear ye, hear ye, it is announced that the front end is completed, all the bits and tricks mentioned in past posts have finally come together to form a complete front end. When the brake booster comes back a start can be made on making up new brake lines. But for now the front guards can go on followed by the bonnet for latches and hinges and the custom aka home made nose for it's final shaping and fitting. 

 

Meanwhile the front end is celebrated with a pic. 

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  • 2 weeks later...

Little things starting to be attached permanently which is always good, an indicator of progress. Speaking of progress of the backward kind, went to start the V8 which is still in the 280ZX for this purpose but nothing happened except the dash light would go out. This 'nothing happening' began at Bathurst but the engine would always eventually turn over, I figure that the solenoid which is buried with the starter among the headers has been cooked, not my work, "it will be OK". Yeah.

 

To the project. Pic shows the new minimalist windscreen wiper, rescued from the back of a Suzuki. As usual with these sorts of jobs it had to be done several times but looks good now. It has three wires, +, - and park and I'm not sure what sort of switch is required. Would the + be permanent with - for on and park for off?

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So not planning to run in the wet then Richard, or you have plenty of rainex to go on the screen????????

 

A tad too small for me, I like to see where I am going in the wet, even if it is round and round and round at a great rate of knots.....

Edited by PZG302
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Fresh air vents from the front of the car straight to the screen demister outlets will keep the fog down in wet running, may need the window down to help too. The green car had the screen vents connected to ducting to the fresh air vents, worked well at speed.

 

The wiper being a rear wiper, may also lift at a decent speed. Even if its not raining it will be annoying if it is anywhere within your field of vision.

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If it's a nuisance then off comes the arm, it is a bit of an experiment but so is the whole project. Copying what everyone else does is boring. There is a fan forced ventilation system to come but that's mainly for driver comfort, basically if it rains then with semi slicks and V8 powah I'm out of there.

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One pic may not seem much but it shows the final part of the fuel system in the engine bay, the way things are going the car might get to Bathurst this year  ^-^  Brake pedal, booster and master cylinder are in so the next job is the new brake lines, this time the line will go through the firewall and run along the transmission tunnel inside the car, picking up the adjustable proportioning valve on the way. Also in the pic can be seen an adjustable master cylinder brace I made up which should help give a more direct brake pedal feel.

 

For engine bay cooling a couple of bonnet vents are needed but somewhere in the back of my mind is 'no bonnet vents allowed' rule but I can't find anything in the CAMS manual. Anyone know?

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Edited by 260DET
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  • 4 weeks later...

Yay, another milestone, the brakes are finished, new lines and all. A sparky from the club is making up a wiring diagram so work on the lectrics will start once that is to hand along with the dash. A display dash will be used and it will display everything except the fuel gauge and the rev lights, just a matter of connecting it up to the ECU, so they say. There has been a change of plan concerning the transmission, still auto of course but the Gear Vendors has been sold and the Powerglide will be once I get around to advertising it. The plan is to get the car on the track with the present 4L85E and then work towards changing to a 6L80E, not so much for the six speeds but because it's a bit lighter and has engine braking, a feature you don't appreciate until it's not available.

 

Pics. Brake MC and lines, driver's footwell and the final solution to operating the fuel cap latch, the knob is just inside the driver's door opening at the back. Nice and handy.

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Woohoo, another milestone, the new nose piece is bolted up. The total time involved in making this using the original soft plastic one as a starting point, don't want to think about that, from an aero point of view it had to be done and I'm sure it will do what it has been designed to do, reduce lift and increase downforce at the front. Needs some surface finishing and blending into the bodywork and that's it.

 

Pics, the inside one shows the top frame which attaches to the body with the two blue squares showing where the two lower supports fit against, the other two pics are self explanatory. 

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  • 3 weeks later...

Finally got the engine and transmission out of the 280ZX (don't ask), the engine will go into the Z31 while the excellent condition 4L90E is up for sale. At present a plan to operate a 6L80E auto behind the V8 is in progress, before the spending money phase begins I need to know all the practical details, with the proposed marriage of the two that is proving to be a bit complicated. Something that is relatively simple is get a bit more grunty cam and fit an aftermarket crank scraper and plate, LS lube systems need all the help they can get.

 

Otherwise it's been a bits and pieces time, pics show the composite roof panels I made now bonded in place, They will be finished off on top by spreading a glass balls filler bonder over it all to provide some additional strength and allow matching the panels to the rest of the roof.

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Something came up upon examining the transmission cooler hoses out of the 280ZX, the engine and transmission conversion being done by someone I won't name. Check out the first pic, see the wear mark on the fitting? It had been rubbing on the transmission tunnel and in time would have worn through or split, nice if it happened while tooling down Conrod. A few whacks on the tunnel with a ball pein hammer would have given clearance, sloppy work to say the least. For something more cheery, the first coat of polyester resin with Q cells has been put over the roof panels after some wire brush work to remove excess adhesive and paint, it looks good, about three coats will do it I think.

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