JDM 12A Turbo motor

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DeanRX7
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JDM 12A Turbo motor

Post by DeanRX7 »

Hey guys,

Putting the feelers out for a 12A Turbo which came in the Japanese models only. Very difficult to find i know but thought who better to as than you! Anyone know of a place to start the search? (Dont say ebay) ;)
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Re: JDM 12A Turbo motor

Post by gt_james »

There’s one in an escort van on eBay. Potentially will split engine and car.
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Re: JDM 12A Turbo motor

Post by DeanRX7 »

Contacted the ebay options, no luck yet. Will see what pops up over the coming months. Ta.
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Re: JDM 12A Turbo motor

Post by DeanRX7 »

I have spoken to a few experts (hello Era and Tool) if you read this regarding my 12a Turbo question. I have spoken to the owner of the motor on ebay which has been there for ages and seems like he knows what he is doing, he built the motor, with 40 years experience but is retired now. Problem, price is pretty much not negotiable. I also found the turbo bits to make the engine (sort of) complete. Again, pricey but rare.

So, if i did buy what i have found, I would have a 12at rotors and housing from one guy, plus the turbo, ecu, injectors to make the thing complete(ish).

What are your opinions on this? One day I wake up thinking that the SII Turbo,13B is the smarter option but then, making a JDM 1985 Turbo would also be cool. I cant lie, that the thought of opening the front and seeing the orange TURBO above the 12a does feel a little more tempting?

I guess the question is.....they would cost roughly the same......Buying a rusted out series 5 for the engine and bits, easier to get stuff and more power. 12AT, nostalgia as well as being a rarer beast on the road but a lot less power.

Thoughts?
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Re: JDM 12A Turbo motor

Post by danny »

Hi Dean, reading all this, i would go for the 12AT option. First of all it's very rare and secondary it will be a much better match with your car. And, of course that orange color under the hood...Do you realy need all that extra power for a road going car from a 13BT?
That is my opinion but hey, it's your car. g-l
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Re: JDM 12A Turbo motor

Post by DeanRX7 »

danny wrote: Sun Nov 22, 2020 9:16 am Hi Dean, reading all this, i would go for the 12AT option. First of all it's very rare and secondary it will be a much better match with your car. And, of course that orange color under the hood...Do you realy need all that extra power for a road going car from a 13BT?
That is my opinion but hey, it's your car. g-l
Opinions are what I asked for so thanks. As for the, do I need all that power, question, you are right.
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Re: JDM 12A Turbo motor

Post by DKWW2000 »

Hi Dean,
I would go for the JDM 12 AT. As Danny, all that power from a TII (I have a S5 TII) on the rear end of a light FB :o
Plus all the new electrics/gearbox/diff expense etc etc?
Probably cheaper buying a TII Vert & enjoy both!
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Re: JDM 12A Turbo motor

Post by ian65 »

Hi Dean,

a few more thoughts....

JDM 12AT

Pro's

Iconic
Sought after
Factory developed
Makes around 165 bhp

Con's

Extremely hard to find
Major parts are specific to this engine and very hard to find / expensive.... rebuilds cost ££££££'s
ECU is not tuneable so not easy to raise the power

Elford Turbo

Pro's


Simple draw through setup developed by car and motorcycle racing engineers back in the day
Nothing to go wrong except the occasional turbo / carb rebuild.
Bolts to a stock 12a in a weekend
Uses a stock 12a engine so more availability for replacement engines / spare parts......rebuilds cost ££££'s
Engine runs stock compression so good off boost drive-ability
Power can be upped to around 185-190 by increasing the boost. Boost was set to a conservative 6psi.... the stock 12a will handle up to 10psi.

Con's

Getting harder to find
Most 2nd hand kits will need the turbo rebuilding (£250) and the carb rebuilding ( £50)
A bit 'old school' and not as desirable as a JDM 12AT or a 13BT, particularly outside the UK
Can't be intercooled


TII 13BT

Pro's


Can make huge power
Extremely tuneable
Much easier to find
Parts to rebuild much easier to source
Can increase the value / desirability of the car depending on the quality of the install.

Con's

Higher purchase price
Higher costs to install including:
GSL-SE oil pan
12A or GSL-SE front cover
Turbo manifold
Intercooler and pipework
Modified mounting bracket
Standalone ECU & wiring
Gasket set to modify engine to work in FB (£150)
Downpipe / exhaust
Wideband
Uprated fuel system to run EFI..... fuel pump, fuel pressure regulator, swirl pot, lines.
Uprated transmission ( typically T11) inc clutch starter motor and custom made prop.
Needs expert mapping to set up properly.
Kit to re-locate battery.

This little lot can easily add up to 3 grand plus.....on top of the cost of the engine

Depends what you are looking for. The 12AT is iconic but pricey, the Elford is more user friendly, can make the same or slightly more power but is a bit 'old school', the 13BT can make a rapid car but initial costs can be very expensive and they can be temperamental in terms of reliability.

For me, I like the easy life and the simplicity of the Elford suits me. 180 -190 bhp is plenty in one of these little cars and way the turbo helps deliver the power suits me too. I'm currently driving a more or less stock 12a after 10 yrs in a turbo charged 12a and I can tell you that it just feels slowwwww!

A N/A engine can also make up to 200bhp with a good port and a good aftermarket carb but that's a whole different conversation.... N/A cars have totally different driving characteristics to turbo-charged cars... it isn't all about BHP.

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Re: JDM 12A Turbo motor

Post by DeanRX7 »

Ian, I have said it before and will say it again....your the best. The detail, knowledge and willingness to share your thoughts make this forum great. I will say you have definitely influenced my decision towards one of the options you gave, which one will of course depend on finding and getting the *** turbo motor.

'Long live the rx7 forum!"
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Re: JDM 12A Turbo motor

Post by Hobbawobba »

Yeah, I think Ian has said it all really aye! Good list there.

TII would be an easy decision to make. But major cool points on a JDM turbo setup aye! Or even the Elford ones :) Could run an aftermarket ECU on the JDM turbo? A cheap Megasquirt or something
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