JimmyHat

My 12A is kinda boring me. What do u guys think about a 12A turbo Jspec? Will those just drop right in with all the stock stuff? Besides the ECU and harness. Ive been wanting to get a new engine, and it seems those jspec engines are alot cheaper. just wanting some of your advice on that.

BTW, all the talk about the ricer stuff, im only 19, and had my rx for 3 years, and my car is probably the ugliest car on the road. I dont plan to EVER rice my car out. I just like to pull up in my primered grey, dirty, melted rear bumper (from the DTM exhaust, that fell off one day on the highway and got banged up pretty bad), faded mesh wheels, bent up hood (flew off going 85mph. Some ******* took the hood bolts off), gutted *** interior, leaning to one side car that rattles and blow all those *fancy* hondas away. I love my car. Its a diamond in the rough, to me anyways.

Manntis

the Jspec 12A turbo is pretty neat. Puts out 165 HP, fuel injected (you'll need the ECU, air sensors, airbox, etc) A bit stressed, though, so be prepared for maintainance.

javypro

I got one for my RX3. Didn't have the ECU so I went with a pressurized Holley 650 and two extra 750 fuel injectors controled by a Haltec F1. How does it performs? I have Mustangs for breakfast, lunch and dinner. The factory turbo is kind of too small but the spool up is faaasst, now I choose to use a TO4 and other mods and it is kissing low 11's

diabolical1

iTrader: (3)

for the time, effort and cost-to-return ratio of a real, honest-to-goodness 12AT, i think you're much better off just turbocharging your stock engine.

and before we get to the next question ... HERE YOU GO! ... just do some research.

nevermind the flaming, there are some good links and there is some good information nonetheless.

if you have any questions afterwards, then feel free.

Directfreak

iTrader: (2)

Details and pics please

Manntis

hehehe Alex, you are SO into the engine ****, arencha

Directfreak

iTrader: (2)

Yes. I am. I need help. I will go to Rotaries Anonymous after I finish my project.

I got some more work on my car today, but I got a nice shiny new 4 Megapixel Camera which takes awesome pictures. I am just not in the mood to sit an shrink them down to 640x480 just so I can upload them to the forum.

Maybe tomorrow, as I a finally putting the finishing touches on the fuel system and down-pipe. The drive-shaft should be ready Tuesday too

White84SE

I was under the impression that the 12AT was at it's max power limits from the factory.. something about the intake ports being really small.. probably nothing that can't be cured with a port job, but just something to consider.. he he

--Danny

Adsy01

i got 220rwHP out my old 12aT the engine itself was stock as it came from the factory.. the turbo was "hi flowed" and i ran TII FMIC.. there was heap more in it if i added some extra injectors and a bigger FMIC, but i sold her
more on my old car here

a freind of mine who still has his 12aT is current modding the turbo ect... he want to see how much power he can get from those small ports!

stock 12aT port

i_piss_on_hondas

DO a search for 12 turbo... I have seen threads on the 12a turbo MANEY pages long before... on the forum...

MIKE-P-28

iTrader: (1)

Not to mention the newest version of that motor is 18 years old! Good luckfinding one you dont have to rebuild.

Manntis

as opposed to the non-turbo 12As?

MIKE-P-28

iTrader: (1)

As opposed to any 18 year old motor/car

peejay

At least you can get parts for non turbo 12As in the US... The center housing is 12AT-specific but a GSL-SE housing'd work (injector bungs) but the main problem is it's very difficult to find 12AT rotors. RB has a very limited supply.

The 12AT is a luxury car engine. It was designed to have smooth seamless torque from practically idle up to 6000-6500. It'd be less hassle/more reliable to put in a lightly modified 6-port 13B if you want a torquey engine with 165hp. If you must have a turbo, you can just whistle when you're at full throttle

If you'd heavily modify the 12AT for more power, it'd be better in the long run to (*gasp*!) start off with a more commonly available 13B block that was OE turbocharged. Remember, the 12AT had a simple analog fuel injection system, no intercooler, low boost, no knock control, and ignition timing was all done mechanically. If you're gonna mod it you'd want to get a bigger turbo, an intercooler, and a Haltech anyway...

Rotortuner

If any one wants a 12a turbo exhaust manifold with a rajay turbo that is probably as core i have one. Its a BAE manifold with the external waste gate mount. hte rajay thats on it is almost as bnig as a to4. I am asking $200 That would be about 125 for the turbo core and 75 for the manifold. I wont brake them up. E mail me for pics if any one is interested. Sorry to edvertise on this thread. but it seams appropriate if any one is interested. Thanks

CJG Jaloy@tscnet.com

PaulFitzwarryne

The 12at is not a such a powerful motor only offering about 135-138 bhp. This level of power can be easily reached in a 12a with a good exhaust system and an upgraded carb.

The 12at has the potential for about 240bhp if you competely redesign the inlet system with a s5 turbo and intercooler and upgrade the ECU to a Haltec. This is still just a bolt-on modification stage.

However, the 12at is expensive to import and will be well worn. Uping the power will be a quick way to self destruction. If you want a 12at set-up then a full rebuild will be required. during the strip down a mild port job would be justified. Thus a $7,000 budget would not be unreasonable.

The alternative is to go for a blow through turbo system on your existing 12a, but while this is relatively cheap again the problem is will an old engine stand a major power increase. It quickly becomes an expensive exercise if you are wrong!

In reality a 13bt transplant would be cheaper and more reliable. See the threads on this subject. You will not get your money back, so its only worthwhile if you are planning to keep the car for 5 years. It will cost you $3000 to turn a $750 car into a $1500 car!

The engine is just the start, you have to match the increased power with upgraded tires, brakes and suspension. It cost me about a $1000 to up power from 110 to 155bhp, but the suspension mods of better shocks and coils[lowered], poly bushings and stronger struts cost more than that, add upgraded clutch, brake pads and tires was nearly a $1000. These are Aus $ but the cost in US$ would be relatively the same.

Remember there is more to life in a RX-7 than a 200 yard drag at the traffic lights, you may have to turn and stop!

Anyway, at 19 why waste your money attempting to out drag rice Hondas. Hav'nt you ever heard of wine, women and song? Keep your ugliest on the road primer grey car as it as- its unique!

Manntis

The Jspec 12a Turbo was rated at 165 HP @ 6500 RPM and 166 lb/ft @4000 RPM. With aftermarket mods it can go up from there, but it's scarce availability does drive up costs.

MIKE-P-28

iTrader: (1)

They tried to sell me one, and I was i want a newer motor. Not always is a older motor in more used conditon, but more often than not, they are plain wore out!

PaulFitzwarryne

I originally went along with the 165 figure but thought it very high in comparison with the 13BT which had a much better turbo and ecu at 180hp. However after research, now believe the rating of 165 hp for the 12AT is in JIS units not the commonly used SAE which is some 20% lower.

I have tried to get Japanese source technical specifications on the 12AT fitted in the RX-7, but the best available were for the Cosmo which appeared in 3 versions in the early 80s. The published data is:-

Model HB-SN2 engine 12A SPI 130hp@6000rpm
Model HB-SN2a engine 12AT 165@6500rpm
Model HB-3SE engine 13B RE-SE 160@6000rpm
These Japanese figures must be converted to SAE.

I can find no evidence that there is a difference in the 12At between the cosmo and the RX-7 produced a year later.

I think Manntis is quoting from Brian Long's excellent book on the RX-7. The figure given there is 160-165bhp depending on turbo, but at another point in the book he says this is 35% above the stock 12A. The 12A in the RX-7 for the US market was 100hp,

This all points to about 135-140bhp for the 12AT jspec.

Out of interest the 12A came out in a range of power configurations from 90 to 120 bhpSAE, nothing up to the 130bhp given above which was JIS units.

The 12A in the RX-7 came out in different configurations depending on the market. The Australian series 1 [SA in USA] produced103hp, while the series 3 [1985 FB in the USA] gave114hp or 86kw, nicely up on the North American model due primarily to porting improvements by about 10 degrees. Torque was also up at 113lb/ft. The Aussies always have to be one up!

Thus, I believe the 12AT jspec offers very little extre over the 12A until you make some expensive modifications.