Topic: 300ZX Rear mounted rad?

We're building a Z31 300ZX that's a multi-Lemons, multi-Chump finisher in a past life. A few years ago, it blew the stock motor, and got crashed as well. Another friend took it in, fixed the crash damage, and dropped a small block V8 and a Hydramatic into it, then moved onto other cars. We inherited it last month, and need some radiator advice. Our goal is to make it incredibly reliable, and to get the rad out of the line of fire in case of a front end crumple.

The Z31 has a ton of room in the hatch area (and no windows intact), and I'd like to run the radiator/trans/oil cooler in the back with a pair of electric fans, and vent the hot air out the taillight panel (lots of room). Inlet air we will duct from the quarter windows with sheet metal. I understand that any coolant/oil lines coming into the drivers compartment need enclosed in conduit, but what about the rad/coolers themselves? Can they be mounted without a shield protecting the driver? The regs don't seem to address this.

Thanks

Re: 300ZX Rear mounted rad?

You will need to send a detailed description of what you have planned to John Pagel.  I'd even mock it up with cardboard or whatever.  The basic rule of thumb is that if a hot liquid can possibly get to a driver, a solid barrier needs to protect the driver.  My wild guess would be that a firewall of some sort would need to exist between the driver and radiator.

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Re: 300ZX Rear mounted rad?

What he said. I suspect a firewall will be needed. Other thoughts:

I used to work with a guy who had a similar idea to this. He wanted a 2JZ in his ‘87 4Runner and would stop at nothing to get there. He ended up with a huge radiator taking up most of the cargo area. Besides that making for an off-roader with no room for gear(not a concern here), the ducting and bleeding of that cooling system were, um, challenging. Like, are you always, always going to have a source of compressed air to run the suction tool needed to get the air out, any time you need to open the system?

I think it’s more trouble than it’s worth. Contact to the point of destroying the radiator, that’s pretty unusual. Contact that bends the suspension enough that you’re able to drive onto the trailer, but that’s all? That happens. I think you’re going to create more problems than solve them with this setup…

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Re: 300ZX Rear mounted rad?

Type44 wrote:

What he said. I suspect a firewall will be needed. Other thoughts:

I used to work with a guy who had a similar idea to this. He wanted a 2JZ in his ‘87 4Runner and would stop at nothing to get there. He ended up with a huge radiator taking up most of the cargo area. Besides that making for an off-roader with no room for gear(not a concern here), the ducting and bleeding of that cooling system were, um, challenging. Like, are you always, always going to have a source of compressed air to run the suction tool needed to get the air out, any time you need to open the system?

I think it’s more trouble than it’s worth. Contact to the point of destroying the radiator, that’s pretty unusual. Contact that bends the suspension enough that you’re able to drive onto the trailer, but that’s all? That happens. I think you’re going to create more problems than solve them with this setup…

/agree

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Re: 300ZX Rear mounted rad?

Will need a barrier for sure, and all lines have to be separated from the driver compartment too. Look up the eyesore miata, they have the radiator in the passenger seat area and have it all partitioned and ducted. So it can be done, but it might be more work than you originally planned.

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Re: 300ZX Rear mounted rad?

Have you considered routing under the car? I'm not sure if there is room to where you can route it where it isn't the lowest hanging item on the car (bad for when you go off) but IIRC when I was helping a buddy with his AW11 MR2 there was a long hard line that ran from the front radiator to the engine in the back. Total pain to bleed but had a huge thermal capacity.

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Re: 300ZX Rear mounted rad?

Hydramatic transmission? Like old school or are you talking about a turbo 350? As for the rad, as mentioned I think it will have to be isolated. I'd used exhaust tubing if you are going to run the coolant thru the cockpit. You'd probably toss a bunch of insolation on it too...otherwise it will get hot in there.

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Re: 300ZX Rear mounted rad?

Another vote for way too much work and so many failure points ONLY to protect it from a crash.

After its all done, you may find (for half a dozen engineering/aero reasons) it doesn't do anything but destroy engines.

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