I am seriously considering a jspec 12A turbo swap and wold like to know everyones' opinions. Has anyone done this swap? Thanks.

 

yup ive done it into my old series 2 (1982 aussie model)
with a I/C and and a modded turbo i managed about 220HP at the rear wheels , i t was a lot of money for the power i got though....

the ports on the 12aT engines are tiny and so are the stock turbos....

i am about to make a 12a turbo using a mix of std12a and 12aT parts and a 13bt inlet, this would be a better option if big HP is your aim, but then again a 13bT is about the same cost(here in AUS at aleast) and you will have more potential for power.. but if you wanna be different go the 12a

there is more info on my 12aT on my WEBSITE
feel free to email me if you have more questions about it

 

Dont get the import 12A turbo. The ports are dinky, the throttle isnt much better and without custom mods to the inlet, you cant run an intercooler.

Your best option is to get a 12A from the last of the 1st gens and get a custom exhaust manifold and mount a T2 turbo on it. A custom inlet can be had for $1000AUS and then all you need is a log style plenum and a front mount and away you go!

Done properly, you should get close to 300rwhp!

 

heres some j-spec 12at ports..




this is a engine i bought cheap for the injectors, timing case, turbo and manifold...
as you can see the plates are in good nick though the ports are small. I will be using the side plates from my series 3 12a engine

 

i have the current NA 12a from my 83 that is in great shape...would you recommend using the sidewalls from it? would they work any better? also i was considering doing the custom job that AJC13B suggested, but I really dont need that kind of HP and I like the uniqueness of having a setup that few people in the US have. =)

 

well im semi thinking along the same lines which is why im going with a hybrid 12aT....

N/A 12a's have bigger ports, so will flow more ect....

im even thinking about extend porting my s3 plates. I dont know how big you can go before you start going backwards though..
my local rotor guru(Rohan Ambrose) is in the USA at the momemt, but ive got a few questions for him when he gets back to aus.....

AJC13B, what are your thoughts on porting for the 12aT?
are the std s3 ports plenty big enough or is a extend port job in order?
i will be running the 12aT hataich HT18S-BM turbo, but it will be running either a s4 13bt comp wheel & cover or a back cut set up (havent gotten that far into the planing just yet)

BTW my car isnt a daily driver if that has a influence on your response

 

not possible to go too big on the ports! remember you have a TURBO... you don't NEED any more low-end.

I shudder to say this, but I'd really like to do up the '85 to look like a turbo model. GSL-SE wheels, the special wing, air dam, white color. Maybe someday eh?

 

what if i took the low compression rotors from the turbo 12A and put them in the NA 12a housing? the ports are bigger right? would that even work?
btw...my car will be a daily driver so I don't want to do anything to crazy...

 

Yes it'd work just fine. You can do all sorts of mixing and matching. (I think it'd be neat to put a GSL-SE centerplate in a 12A for the fuel injector bungs) Make sure to use the counterweights as well - the counterweights are matched to the rotors. If you don't use the matching counterweights then you'll need to have the rotating assembly balanced.

 

the GSL-SE is efi right? thats why you suggeste using the centerplate? how much do you think it would be to put in larger injectors? would i need the new centerplate or could i just put the throttle body on my GS centerplate? BTW thanks for the help everyone everyday i'm a step closer it my turbo 12a hehe =)
Joe

 

I mean the GSL-SE centerplate in a carb 12A. Much easier to find a GSL-SE engine than it is to find a 12A Turbo engine in the US

 

dont forget if you do find a j-spec 12aT engine it will have 2 x 800cc injectors with it.....

i dont think i mentioned it before, but i am possibly going to use the N/A (higher comp) rotors, many people have done so before with good results

 

To AJC 13b, is there anywhere in Sydney which will do this wor? I was thinking of getting it done in Melbourne but the 700 km distance is a factor.

 

Adsy - The S3 plates are fine and would only require a clean up of the port runners themselves, the port timing doesn't need to be touched.

As for turbo, take a good long hard look at the std turbo from the 12AT, and throw it as far as you can and kick it some more Use a S5 turbo over a S4 turbo, the S5 are pretty close to a small T04/large T03. Its a better turbo overall and will make alot more power than a modifed 12AT.

Paul - Most of the shops in Sydney could do it. In Canberra though, I would go and see Jake Edwards. He has an LX Torana in the latest Zoom magazine. He did all the work on YES20B and he is a bit of a guru from all accounts. I would call him before anyone else.

 

thanks for that, i know what you mean mean about the 12a turbo, but its a cost thing at the moment ( plus i got the 12aT pretty cheap)...
I will run the hybrid setup for say 12 months while i sort out any thing that needs sorting..... then ill look at a bigger turbo...