Datsun 280ZX IMSA GTU race car build...

Restores, Revamps and Repairs
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Grunzter
Posts: 508
Location: Epsom, Auckland

Re: Datsun 280ZX IMSA GTU race car build...

Post by Grunzter » Wed Dec 21, 2022 8:47 pm

Thanks guys, yeh it's down to weeks now rather than years...
It will miss out on Pukekohe but only just.

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1981 280ZX #33 IMSA GTU Race Car ...nearly done!
2012 Fairlady Z34 ST (For the son/wife...)
2007 Fairlady Z33 NISMO
(Sold) 1984 300ZX Z31 2+2 Turbo
(Sold) 1980 Datsun 280ZX 2+2

jdufour
Posts: 1

Post by jdufour » Wed Jan 11, 2023 1:54 pm

Hi,
We are considering build a 280Z race car for the ChampCar Endurance Series. It's amateur racing. We are concerned about the rear suspension. How did you configure your rear suspension? Is your rear suspension stock? Or are you using an aftermarket rear suspension? How large are your rear tires? Was your choice of tire size influenced by your rear suspension setup?

Thanks,

John

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Grunzter
Posts: 508
Location: Epsom, Auckland

Post by Grunzter » Thu Jan 12, 2023 4:43 pm

jdufour wrote: Wed Jan 11, 2023 1:54 pm Hi,
We are considering build a 280Z race car for the ChampCar Endurance Series. It's amateur racing. We are concerned about the rear suspension. How did you configure your rear suspension? Is your rear suspension stock? Or are you using an aftermarket rear suspension? How large are your rear tires? Was your choice of tire size influenced by your rear suspension setup?
Thanks,
John
Hi John,
My rear suspension uses the stock the components that have been heavily modified/strengthened.
- Rear crossmember has had inner mounts slotted vertically to allow camber adjustment.
- Rear crossmember bushes changed to solid/sleeved plastic ones.
- Rear arms were shortened and then rod ends added, so they can be adjusted in place, i.e. Left/right threaded. (in/out)... to adjust toe.
- Rear shocks/coil overs are from Koni Racing and are adjustable.
If I was to do it again, the APEX Eng. set is probably a cheaper way to go, and will offer similar adjustment. Though they did not exist when i started this project, and i wanted to keep it as close to the GTU car as possible.
If i didnt do the APEX thing, I would probably have gone complete custom rear like the GTO cars... but big bucks! :)
https://www.apexengineered.com/s130---280zx1.html

With the wide rear guards, I went with 11" wide wheels.
The original works GTU cars were running 16" x 12" wide wheels from memory.
Currently the car is fitted with 280 wide (300mm overall) x 650-18 slicks, but I will also use 295/30-18 Dot Semi-slicks (or 315/30-18).
My wheel offset is about 1/2" to far inwards, so I could have gone to a 12" wide rim, or at least 11.5"... but with two sets of wheels I'm not changing.
My tyre size is really influenced by the original car, and the amount of room I had under the guards.
Based on the average 8~10 lap race, the tyres are probably oversized for the car, but it looks cool!.
I'm only running 9" wide on the front (235 or 240 wide tyres) because my front guards are not as wide as the official GTU cars were.

We have done a few complete wheel alignments so far during the fabrication, and the front & rear camber/caster/toe all looks perfect to what you would expect (touch wood), though time well tell.

Photos below are before final powder coating.
Anything let me know, and good luck with your race car build!

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1981 280ZX #33 IMSA GTU Race Car ...nearly done!
2012 Fairlady Z34 ST (For the son/wife...)
2007 Fairlady Z33 NISMO
(Sold) 1984 300ZX Z31 2+2 Turbo
(Sold) 1980 Datsun 280ZX 2+2

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bernjean
Z Club Member
Posts: 1694

Post by bernjean » Sun Jan 15, 2023 2:25 pm

It just gets better and better.
Bernie Kant
Club President

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Grunzter
Posts: 508
Location: Epsom, Auckland

Post by Grunzter » Mon Apr 24, 2023 7:03 pm

In case you don't follow the FB page, here is a few recent updates.
A few pictures of a clean white interior...
Yes, it's back from the painters a few weeks ago.

The assembly has started. Today fitted the rear lights, fuel cell, dry brake, Diff cooler pump, rear brakes, and bits & pieces.
Also test fitted for a new driver side seat.
Clutch & flywheel all assembled, and new pilot bearing made to suit the Chev input shaft.
ARP Flywheel bolts used.
Little carbon protector for outside kill switch.

Engine bay ready for the engine & gearbox. They will go in later this week.
Engine & gearbox got a good clean, and hydraulic release bearing got plumbed up.
And eyes (headlights) fitted so car can see for the first time in 20 years.

Today we got the front brakes back on, fitted the small fire extinguisher as well as a few minor jobs.

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1981 280ZX #33 IMSA GTU Race Car ...nearly done!
2012 Fairlady Z34 ST (For the son/wife...)
2007 Fairlady Z33 NISMO
(Sold) 1984 300ZX Z31 2+2 Turbo
(Sold) 1980 Datsun 280ZX 2+2

mikec(nz)
Z Club Member
Posts: 181
Location: Tauranga, New Zealand

Post by mikec(nz) » Sat May 13, 2023 10:47 am

Love it, looking so good. This is really the fun part now, can't wait to see it on the track. You have inspired me ......

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