How much power can a 12a really take?? I have a drawthrough carbureted turbo setup on the stock 12a block, with water injection, and plan on 300 hp. Does everyone think it can take it? If it doesnt, I can use a rear cast plate from a 75 13b, which are supposed to be stronger.

 

It should take 300hp fine. Just make sure you do not let it detonate or run lean. I learned the hard way, and now my backplate is cracked and I have to take my car apart AGAIN.

 

Yep, 12A castings aren't the strongest Mazda ever made. They are lighter than the older castings though.

 

You can make over 300hp N/A.

Turbo engines depend on how much boost, and if you dowel or not. (see coldy13's recent thread)

 

i cracked my rear cast plate too by going lean and detonating. Thats why i am thinking about using a 75 rear plate

 

isnt there a way to braze the 12a ribbing to make it stronger?

 

dude you so got it. just make sure you NEVER RUN LEAN and do not detonate as said by coldy13. it's all in the tuning man. remember you can blow your motor on 6psi or 30 psi. T U N I N G! ! ! ! ! get it on a dyno with afr readings.

 

R5 plates have a small rib. Non nitrided plates have thick ribs.

 

My buddy has a wideband 02 sensor.
But, It was my dumbass using the stock fuel pump. When the float bowls went dry, i detonated. I got a holly fuel pump now, it should be ok.

 

I'm still amazed that you could run it how you did with the stock pump. I wouldn't have thought it would work at all.

 

its drawthrough, so it doesnt need the psi, it just needs to keep the floatbowls full

 

Yeah, but people run out of fuel with mildly modded n/a engines.

 

People run out of fuel with bone stock engines!

The stock fuel pump is complete garbage.

 

this is true, i would at the least use a gsl-se fuel pump. holleys only go to what, 15psi max?

 

If you use a GSL-SE fuel pump you *need* a bypass type fuel pressure regulator.

 

Even Facet pumps are too weak. I can't wait to run out of fuel in my 13B Midget. I'll probably parallel two Facet pumps now that I have a spare kickin' around.

 

Carb's don't need a ton of psi. But you want to look at the gph, that's the thing that'll keep the float bowls full.
I'd estimate maybe 7 psi at 20 gph? Someone tell me if I'm wrong. BTW, if it was me, I'd go with a blow through setup, and pressurize the carb. Jetting is so much easier.

 

it runs fine the way it is, plus, its already jetted correctly. The holley pump will easily supply enough fuel for the setup. I was able to go up to 140 mph before my floatbowls went dry, that was at 240 hp.

Anyway, i finished streetporting one of my cast plates today, it looks awesome!! I talked to some more people, and its not the webbing that strengthens the common braking area on the 12a's, its the thickness around the outside of the upper dowel pin. I am going to have it brazed to help with the strength.

 

actually it was running a bit rich, i have a wideband 02 sensor to make sure its still ok with the streetport and ported intake manifold.