epic thread revival! Took a while to find it I can tell ya

6 weeks ago I bought another Datsun, a 720 King Cab that was just too good not to buy when I saw it. Thought it might be a good way of satisfying my Datsun urges with something I wouldn't be tempted to race! lol And utes are always very handy - I've done heaps of runs to the tip since I've had it!

But all it really did was make the desire to own a cool old school Datsun even stronger. So I started looking for another 120Y coupe, which are really my favourite old Dattos...

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1st round of the hillclimb series was last weekend. Brendan knocked another 7 tenths off his PB I think with a 50.4, and half a second faster than I went :) Good stuff! Nice to see it improving. I'm really liking watching it go around too

I think there's a new exhaust on it as well, and he's currently making a new turbo manifold to replace the ugly manifold me and Nev whacked together.

no idea if they're ADR approved. The welded diff isn't exactly ADR approved either ;)

oh yeah, he polished it too! It almost looks like a different colour now lol
and straightened the front bumper.

And a couple of Action shots -

First one from the final hillclimb of last year with the gas shocks I bought just before selling it. That seemed to have stiffened up the rear enough to stop it from getting up on 2 wheels.

Second one is from the test and tune day last weekend, trying out the new brakes. He's getting up to speed pretty well now too. Only a couple of tenths off my best time, and this time he was 2 wheeling again by the last couple of runs, but it doesn't do it as badly as it used to. The photographers missed that unfortunately

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Thought I'd post some updates of what Brendan's been up to with the Y.

Wilwood front brake upgrade. Should be slightly better! Has to use min 15" wheels now but. The old 250mm Silvia discs didn't have to braking power to lock the wheels when the semi slicks were on - I called it Datsun ABS :P The new brake combo is lighter too, despite the larger disc. So that should be a very useful upgrade.

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Yep, oil sealing under vacuum is the issue requiring the carbon seal. You could still get that to an extent with the CD type carb as the carb piston is still in front of the compressor. A BOV recirculating the pressure from in front of the closing throttle plate to the intake side of the turbo can only help. The sooner the pressure gets ahead of the compressor, the less chance oil will get sucked past the seal. Although you might actually want that pressure reversion to hit the compressor and stall it instead of letting it recirculate though the BOV, because slowing the compressor would also stop the vacuum being created... hmmm...

It's going to be overly rich when the throttle's reopened anyway - you've already got a bunch of metered fuel through when it was on boost, waiting to be ingested when the throttle's reopened. Which is why you'd want the throttle plate as close to the turbo as possible to minimise the amount of excess fuel you've closed the throttle on.

Old school draw through setups pretty much negate the ball bearing advantage anyway. The advantage of BB cores is the speed of spool up. A draw through setup with the throttle plate upstream of the turbo does not slow the turbine when it's shut. In fact it creates a vacuum for the turbo to spin freely in. When the throttle's re-opened after the gear change the turbo has not lost speed like it does in a modern setup with the throttle plate after the turbo, which sends a reversion pressure wave back to the compressor, stalling it. Putting a throttle plate after the turbo just so you can use a BB turbo is pretty much self-defeating imo.

Useful if you had a turbo for which carbon seals weren't available, but otherwise it's probably easier and better to just carbon seal the turbo, and make sure the rest of it is in good condition at the same time. That way you keep the draw through advantage of not slowing the turbo speed on gear changes.

I'd say you'd need to have the throttle body as near after the turbo as possible to make it work, and a BOV recirculating that pressure back to the front of the turbo would be a good idea too.

Would run nice an rich on the overrun - might get some cool flame-outs too :)

Stumbled across this article in my search for another Datsun, now that I've sold the camper trailer and have room in the garage :) I know Murph's been mentioned here before as a 1200 SSS owner - well here it is! Pretty cool :)

http://www.tradeuniquecars.com.au/readers-rides/1507/1974-datsun-1200-sss-reader-ride/

For those on the other side of the pond, Greg Murphy is a retired professional racer. One of the fastest V8 Supercar (our premier motorsport category) drivers we've seen.