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The ultimate grip ‘n drift Datsun on its wheels

260Z body, 350Z engine, 200SX suspension – does it add up to a 270SXZ?

29/06/2013 06:45 |  Comments: 

Contributing editor

One of the founders of our mother site, totalcar.hu. Quiet, self-restrained, self-taught car pro, who designed much of the mechanics in his Datsun 260Z track car, affectionately named ’Aardvark’. Karotta is one of the best-known car testers on TV in Hungary, a skilled drifter and the former managing director of Totalcar too. Now off to other, even more important duties within the big company, he still is a senior contributor to the mag when he can find the time.

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vehicles

  • Toyota Prius (2004)
  • Toyota Corolla AE86 (1985)
  • Datsun 260/350Z 'Aardvark' (1974)
  • Honda CBX 550F2 (1985)
People were drooling all over the Aardvark at the show, they thought that it would be ready real soon. Even me. But one tends to run into lots of dead-ends when making a race car from scratch.

Hello, ladies and gentlemen, this is our front end. The task: engineer and build a frame around that wheel, and a linkage to make it turn. Now, as sweet as it would've been to transplant an entire S13 front suspension under the Datsun, it was not meant to be. By this time I'd already bought the engine, a 3.5 litre V6 from a wrecked Nissan 350Z, to follow the Z-car blood line. The S13 steering rack would've never cleared the VQ35 sump. So we needed to source components that would allow us to run a front steer setup, where the steering rack is ahead of the axle line.

I'll spare you the details on how to design, engineer and build a tube frame and a front suspension that has decent roll center to go with the S13 rear end, proper steering geometry, nice camber gain in roll, low anti-dive and bump-steer and acceptable Ackermann, all the while staying true to the 260Z wheelbase and basic proportions. Let me just tell you that during those weeks I spent considerably more time sleeping on my keyboard than on my pillow.

So, what does remain of the original shell? Well, the sills, the pillars, some of the firewall, the whole roofline and the larger part of the rear unibody, minus the floor. The rest: custom tubing and a comprehensive roll cage, all covered with FRP panels.

This is how it looks painted and assembled, viewed from the front. You can see how the low sump forces us to use the BMW power steering rack and knuckles. Everything else are race-spec S13 items. The coilovers are from Driftworks, the brakes are Wilwood 4 pots at the front, Skylines at the rear. Note that the frame is ready for an aerodynamic flat bottom.

Interior view. Note the custom shorty propshaft, as the 350Z 6-speed tranny nearly reaches the S13 diff, so tiny is the Datsun chassis. Other features: adjustable steering column, pedal box, hydraulic handbrake.

Front Nissan S13/BMW E46 hybrid suspension. Note the yet unpainted front sub-structure supporting the radiators and the undertray. In the background you can see the exhaust primaries in black wrap.

Here's the rigidly mounted Nissan S13 rear end with Driftworks adjustable arms and Geomaster knuckles. You can also see the S13 diff with 2-way Kaaz mechanical LSD and safety fuel cell. Note the metal mesh protecting the FRP fenders from disintegrating tires.

Rolling chassis with engine block trial fitted. As you can probably tell, there is not much in front of the front axle. This is good for weight distribution and low polar moment of inertia, helping turn-in.

Beautifully gusseted ties between the A-pillars and the roll cage to enhance chassis rigidity.

Slightly upgraded Nissan 350Z engine. Why V6, I hear you ask? Firstly, because NA. For me, a classic should never be force-fed. The instant response, the induction noise, the tractability all favor atmospheric engines. Secondly, because of the stubbiness: it's roughly half the length of the original L6 iron block, or the venerable RB25/26/30, which is a huge help with weight distribution.

Now you probably understand my engine choice somewhat better. Yes, the VQ35 is actually in the car and I'm in the engine bay as well, sitting on the crossmember, looking silly. There's still room in front of me. That's how long the S30 engine bay is, and how short the VQ engine is.

Yes, ITBs, dammit! I've been a sucker for ITBs forever, as those are the closest you can get to carbs in feeling and sound, while giving you the tune-ability of modern fuel injection. The neck-snapping, violent response of a big-lunged, ITB NA engine is second to none. They also tend to emit a proper old-school bark and shriek under load, which is just priceless in a vintage recreation. Under those trumpets sits a set of C8 camshafts from Jim Wolf Technology and six forged Eagle conrods. We've also upgraded the oil pump to the later HR models.

Our custom primary exhaust pipes and the 3-1 collector. Most off-the shelf collectors for the 350Z engine are compromised in order to fit into the crammed engine bay or are meant to meet the factory exhaust components, which is just nonsense for us. Others are meant to hold and feed turbos, which I do not intend to do, ever. So after a lot of number crunching and some excellent fabrication by PWRacing in Hungary, here is a set of graceful long-tube headers, optimized for flow and harmonics in the 6500 RPM region.

Gases will leave through two black side pipes, as there was no way to fit the exhaust tubes under our flat underfloor, or indeed anywhere else. Believe me, they look rather hot.

A look at the pedal box and the brushed aluminum tranny-tunnel paneling.

The semi-finished interior with the dashboard recreated from fiberglass. In the end, it will be black. The gauges are analog-faceted but modern, digital Stack items. There's also an old-school Nardi wooden wheel from Japan, period correct toggle switches and warning lamps everywhere.

As you can see, both front and rear fenders had to be remade since the classics expo last year. As I've mentioned before, it's downright silly to finish the exterior before the mechanicals. It turned out that at the desired race ride height of 80 mm or 3.1″ there was no way to fit the wheels. So this time the fenders are wider and allow more wheel travel in bump. The ride height is not set, please ignore the high nose for now. Also note how the engine is pushed far back in the chassis.

A look at the trial-fitted underfloor with the venturi/diffuser. I'm not keen on mounting wings on a classic, yet we need to get rid of dangerous aerodynamic lift. We've made a fully functional flat composite underfloor, uninterrupted from splitter to diffuser. The venturi begins just in front of the rear axle line. Strakes are not installed yet. You can't see much of this from the outside, but you're sure as hell glad for it when traveling down a straight above 160 mph.

Aardvark nearing completion. We set it on corner scales, and the current wet weight with all fluids, excluding driver and around 30 kg or 60 lbs worth of miscellanea is 1,008 kg or 2,222 lbs. That's roughly 15% less than the original weight, with a significant increase in safety and rigidity, and more than twice the power. What's even better, the weight distribution turned out as 48/52% F/R, which means that we managed to build a very slightly rear heavy front-engined race car, without an exotic transaxle keeping all the Nissan parts. That's more than great.

And finally here's a graphic illustration of the soon-to-be finished car, created by a fan of the project in the style of the Japanese Tamiya scale model covers. If you want to hear the sound of the engine at the first start, or see the flames dancing in the ITBs throats, please check out the video.

Or, if you had enough of the old school, but would like to see me drift the new GT86 through Europe to finally pitch it against my old AE86, then head over to YouTube.

I really hope to get Aardvark race-ready by the coming season and to do some visual justice to the incredible amount of work that went into its creation by shooting the mother of all vintage Japanese driving action videos with it. Then another one, documenting its evolution from crude newborn to dialed-in racer. And another one. And then some more.

Thanks to:
My wife Diana for still not divorcing me
PWRacing for the build
OMG Visuals for the bodyshell and the forthcoming film
All the friends and supporters

Cheers,
Nino Karotta

https://www.facebook.com/ninokarotta.intl

Tags: 260z Datsun guest blog Mike Garrett Nino Karotta S30

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