'84 GS 4BL Nikki Carb Quick Question
#1
'84 GS
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'84 GS 4BL Nikki Carb Quick Question
What's the size of the stock carb in mm? I can't seem to find it anywhere.
I have a '73 VW Bug with a two barrel Weber 44mm Carb and because I know the size, I can buy a new carb that is slightly bigger, and I know what kind of power to expect from it.
But I can't do that with my RX7 because I don't know the size of the barrel. Anyone know offhand the size of a stock nikki?
I have a '73 VW Bug with a two barrel Weber 44mm Carb and because I know the size, I can buy a new carb that is slightly bigger, and I know what kind of power to expect from it.
But I can't do that with my RX7 because I don't know the size of the barrel. Anyone know offhand the size of a stock nikki?
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There's a lot more to airflow than just throttle bore. A stock Nikki flows 313 CFM according to Sterling and rx7carl. There's also a lot more involved in carb shopping for rotaries than just "bigger is better" (because it isn't). The three aftermarket carbs I would recommend are: Sterling Nikki, Weber 48 IDA, or Edelbrock 500 Thunder Series. The latter two require an aftermarket intake manifold with modifications for oil injection or premix.
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There's a lot more to airflow than just throttle bore. A stock Nikki flows 313 CFM according to Sterling and rx7carl. There's also a lot more involved in carb shopping for rotaries than just "bigger is better" (because it isn't). The three aftermarket carbs I would recommend are: Sterling Nikki, Weber 48 IDA, or Edelbrock 500 Thunder Series. The latter two require an aftermarket intake manifold with modifications for oil injection or premix.
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^ REPUs had Hitachis. And you can't use a 4-port manifold on a 6-port engine. As far as I know there was never a 6-port 13B intake manifold with a Nikki stud pattern. If there was one, that's news to me. Jeff20B has one that was made with a hacked-up 6-port 12A manifold.
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I should have been more clear. The Nikki and Hitachi stud patterns are the same, so you can use a Nikki carb on a Hitachi manifold or vice-versa. However, you can't use a 4-port manifold on a 6-port engine (at least, not without modification) because the bolt pattern is incompatible. And even if you managed to do it, it would flow like crap because the secondary runners are entirely the wrong size and shape to match up to the ports. Look at a 6-port engine and a 4-port engine side by side with the intake manifolds off and it becomes obvious why.
Now what you could do, possibly, is use an RB Holley intake manifold with an adapter plate, but I don't know how well that would work.
Now what you could do, possibly, is use an RB Holley intake manifold with an adapter plate, but I don't know how well that would work.
Last edited by PercentSevenC; 07-16-08 at 12:54 AM.
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To the top! I have to add a comment about the edelbrock. Thunder series is a good choice, but the performer is also just as good in my book.
I have a stock port 12a with an edelbrock performer 500 and the secondaries open up at around 3800 rpm. So if you want to have adjustable secondaries, spend the extra cash for a thunder series, otherwise for someone on a budget the performer works just fine.
I have a stock port 12a with an edelbrock performer 500 and the secondaries open up at around 3800 rpm. So if you want to have adjustable secondaries, spend the extra cash for a thunder series, otherwise for someone on a budget the performer works just fine.
#16
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Nikki actually did a lot of joint research and development with Hitachi; tight business partners. All the external electricals and pneumatics on the Nikki carb are Hitachi logoed.
Nikki history:
http://www.nikkinet.co.jp/english/co...e/history.html
Nikki history:
http://www.nikkinet.co.jp/english/co...e/history.html