Hey everyone.

I'm thinking bout building my A15 into a tough street motor, but as I've really only played around with rotors I don't have any idea where to start.

I'd be interested in hearing some of your ideas, things like what pistons i should use, cam, valves. Anything I can do to make it strong and fast.

BTW, I wanna keep it old school, so no injection or turbos

make it a 1600 by using mazda 1500 low compression pistons, with the high compression pistons you'll need to do head work, a high lifting cam, definately side draughts to fuel the bugger, a lighter fly wheel and if you can get a GX head else you'll have to flow the head and a bit of electronic ignition will spice up that engine quite nice

what comp do ya get with thoose pistons???

9.5:1 if you use the standard head else you can up the compression if you want to.

hmmm i want to build a low budget a15 with a couple of thoose diahatsu 1000cc diesel turbos of go the dattos

i want reasnoble off boost performance (not too far from stock drivability) but also a decent increase in power on boost

what is standard comp? and what sort of compression would be good for the style of engine charachteristics im after?

and then how is the best way to get this sort of compression, is it just a case of a fatter gasket or head/piston changing

cheers

I'd say standard compression for turbo without losing too much stock is 8:1 and you can run the turbo @ 6-10 psi without too many hiccups.
You can even go up on the compression to standard its the timing that creates the issues.
I know some mazdas had a vacuum advance and a pressure retard on some of their distributors which does a lot for what you want to do else you can build one
Fatter headgasket has it's pro's and con's with big boost, thus the piston change is a better solution

id say 10 psi is on the cards

one of those mazda dizzys sounds good, do you know what pistons/head combo could be use to get 8:1 and what is involved in getting em in

What i did to get the 8:1 compression was to use the A15 block with a A14 standard head, that solved my thicker headgasket problem, the boost was @ 10 psi.
What type of charging are you going to use? blow or draw and with what carbs or injection?

what comp would you get with a GX head on an a-15 block do you know???

i have a GX head and would like to use it if it would suit

id like to make up an injection setup but the price of the computer is gonna kill that one for at least a few months (im inpatient, i wont wait that long)

so its probably carbie with either a 32/36 weber or maybe some twin SU's if i can get em for the time being

i would like to run an intercooler so the turbo will come first, (making it suck through i think, i keep getting the names confused)

If I'm not mistaken the GX head will up your compresion to 8,5:1 which might make the 10 psi a bit tricky but using twin SU with an extra injector and boost sensor you can enrich the air/fuel under high boost which will solve some pre-ignition.
Oh and using the intercooler you'll use blow-through - it's quite easy the turbo either blows or sucs through the carb