hey everyone. first off i searched! i couldnt search for key words such as six, four, 6, 4- so it ended up with alot of stuff about port jobs.

this summer i want to attempt to build myself a motor and i was curious on the best way to go about building an NA. ive done a few nights research and found that the weber IDA carb sounds like fun, but the trade off is carbs generally dont run as well as an EFI EMS system can. then i got to thinking if i'd want to go 4 port NA or 6 port NA. its my guess that you can only go 4 port if your going carb, though, as i couldnt imagine which combination of manifolds would acheive 4 port EFI NA.

can anyone lay out which port configuration i should use to acheive good power for an autocross/track car? the car isnt trailered yet, but it should be- and its on the list of things to do. basically its got a plate, still...

also- i want to go streetport, if that makes any difference. thanks for all your help!

 

There's no reason you can't use a carb if you have a 6 port engine. Mazdatrix sells appropriate manifolds I believe, but they do defeat the operation of the 5th and 6th port actuators.

If you want the broadest torque curve, then working 6 ports with EFI is a good starting point. Some will argue but if you have to ask it's far easier to set up, especially since Mazda has already done it.

 

that helps alot. anyone have a take on 4 port vs 6 port NA (for carb applications)? id like to get a EMS that eliminates the MAF, and easy to set up and get to work. im lazy to a point =P

 

Easy is subjective. I can do a manual transmission easy enough, but an automatic kicks my *** for exampe, so there is my point of view.

Microtech, Megasquirt, Haltech, and Wolf3D can be all installed and tuned but with a good knowledge of the vehicle and a dyno or wideband (perferably dyno).

 

it comes down to how much power you want and as always how much money you have in your budget. If you were after say 175 hp to the wheels and wanted it fairly inexpensive, thatn a 6 port with a holley would make some nice power for you. If you are after more power, I would suggest making a 4 port with full bridgeports, and than run IDA carb or fuel injection. Alot of info out there on arbs is negative, people will say they never start in cold, they dont make good mileage or power, whatevr, its all relative. Carbs can work great and make awesome power, and are a little cheaper than doing a full EMS system. On the same note though, EMS with a good tune will alnmost always make more power, a smoother band ,a dn better mileage. But it takes longer to get it all set up.