12AT question
04-10-05, 02:58 PM
#1
Royale with cheese
Thread Starter
Join Date: Jan 2004
Location: Las Vegas, by way of Poulsbo, WA
Posts: 1,256
Likes: 0
Received 0 Likes
on
0 Posts
12AT question
OK. Is the 12at from japan, injected, or carburated? Cause Ive heard that its powered by a "modded nikki", but Ive been findind things like computers and injectors for "12at"s. So, is the nikki modded so its just like a throttle body, or what?
04-10-05, 03:05 PM
#2
Old [Sch|F]ool
Nikki made the carburetors and the throttle bodies for Mazda.
The 12AT is fuel injected (two 800cc/min injectors), non-intercooled, fuel-control-only computer. It has a "mechanical" distributor with centrifugal advance and vacuum advance/boost retard, similar to the B6T setup.
The 12AT intake manifold is great for people doing a turbo conversion, since it is really "pinched" at the bottom for turbo clearance, so you can use a 12AT manifold or a suitably modified 13BT manifold. Plus, the throttle body mounts vertically and has the same bolt pattern as the common carbutetor, so you can use the manifold to do a carbureted turbo setup using a suitably modified Nikki carb.
The 12AT is fuel injected (two 800cc/min injectors), non-intercooled, fuel-control-only computer. It has a "mechanical" distributor with centrifugal advance and vacuum advance/boost retard, similar to the B6T setup.
The 12AT intake manifold is great for people doing a turbo conversion, since it is really "pinched" at the bottom for turbo clearance, so you can use a 12AT manifold or a suitably modified 13BT manifold. Plus, the throttle body mounts vertically and has the same bolt pattern as the common carbutetor, so you can use the manifold to do a carbureted turbo setup using a suitably modified Nikki carb.
04-10-05, 05:16 PM
#4
Apprentice Guru
Join Date: Oct 2001
Location: Cloud Nine and Peak of God
Posts: 1,425
Likes: 0
Received 0 Likes
on
0 Posts
As Peejay said the 12A T is efi, it uses a Nippondenso fuel only analogue computer and had low compression rotors. It was installed in Japanese only models, in the RX-7 performance was 145mph, 15.3 second 1/4 mile making it the best stock 1 gen produced.
The confusion arises when people add a turbo to a carby 12A engine with normal NA rotors, and call it a 12AT. The Nikki has to be modified to suit. However a Webber carb is often the carb used in the add on turbo modification.
Mazda never used the 12A T designation, but in Japanese literature said 12A turbocharged engine. In fact 12A is the only designation on the engine but there is a turbo symbol on the body plate. There is no lower case in Japanese so there never was a 12a engine, like cast on the engine it is 12A.
In the case of the 13B, they called it a 13B Turbo 11. Owners often simplified this to 13bt so some people adding a turbo to a 12A started using 12at as an unofficial designation.
The confusion arises when people add a turbo to a carby 12A engine with normal NA rotors, and call it a 12AT. The Nikki has to be modified to suit. However a Webber carb is often the carb used in the add on turbo modification.
Mazda never used the 12A T designation, but in Japanese literature said 12A turbocharged engine. In fact 12A is the only designation on the engine but there is a turbo symbol on the body plate. There is no lower case in Japanese so there never was a 12a engine, like cast on the engine it is 12A.
In the case of the 13B, they called it a 13B Turbo 11. Owners often simplified this to 13bt so some people adding a turbo to a 12A started using 12at as an unofficial designation.
Last edited by PaulFitzwarryne; 04-10-05 at 05:39 PM.
Thread
Thread Starter
Forum
Replies
Last Post
Nosferatu
2nd Generation Specific (1986-1992)
7
09-05-15 02:13 PM
