spitflamesho

ok heres the deal.......i got a 87 base na with all bolt on's i could possibly bolt....what im gonna do next is port out the tb,black elbow,intake runners and remove six port sleeves....then im gonna take my motor and get it rebuilt with a monster street port...my question is being that my car is gonna be all top end can i up my motors redline to like 9 or 10 grand using the stock ecu.....right now im looking at 2 possibilities 1) use stock ecu with 550cc in secondary and use afc to control fuel or 2) spend more than enough money on a haltech.....being that the budget it tight would i really need the haltech....do i really need to raise the motors rev limiter being that the car is gonna be all top end power or stick to the stock 7rpm redline??? just wanna know which direction to follow plus i can get a good deal on an afc.....any help is greatly preciated

go_speed_go

With all those mods and money you're spending, it would be a shame not to go with an upgraded or stand-alone ECU to raise but no eliminate a fuel cut as well as take advantage of all the mods you have. Worked rotaries deliver very 'smooth' power to a point where if you're not careful, you can over-rev it.

If you're going to go with a big street port, make sure to have the rotors balanced. That should help keep you safe at higher revs.

BhamBill

Don't forget there are two other factors in making the engine safe at high revs - lightweight rotors and hardened gears. That's why the factory put those items in the 89-91 engines.

Good luck.

Blake

Well, first of all, there is no need to port the throttle body. Mazda's TBs are more than large enough for any NA, even with a "monster" street port. I wouldn't worry about that until you are actually getting a monster port, which is not any kind of streetport (it's an extreme bridgeport that goes all the way back into the water jacket). And if you were going that extreme, we wouldn't be taking about using any of the stock induction.

So, what have you done? You say "all the bolt ons". Care to list them? Are they all quality parts (Racing Beat, Mind Train, etc.) or cheepo Crap (Pacesetter, etc.)? What numbers are you puting down now (dyno or 1/4 mile times; not fantasy estimates)? What are your goals? What kind of power do you want and what kind of driveability do you need? Are you on juice? What's the budget?

If you are serious about the rebuild, then I would build everything else around what you are having done internally to the motor, such as the porting, the rotating mass, and the type of materials (stationary gears, bearing clearances, etc.). A good engine builder can build the engine to a specific redline and set the power peak with the size and shape of the ports. Stock ports run out of power long before redline. Even a large streetport is out of steam well before 9K. One thing you could do is simply upgrade to an 89+ setup. This is a PITA, due to all the wiring and stuff that must be swapped, but certainly less expensive than upgrading to a standalone setup. As for aftermarket systems, I would encourage you to check out SDS, which is a fuel-only system (you just use a distributor or separate ignition setup).

Just my $0.02....