Mechanical Secondaries On Factory Carb...
 

This is a 1st gen question, to be completely specific it is for a 1985 Base model Rx-7

Well I am sure you know what I am asking, do the pros outweigh the cons? Who has converted their vacuum secondaries over to mechanical? What advantages, disadvantages do you notice? I am debating over doing this, I just dont know for sure what I am going to do. I hear some good things and some bad things. Let me know what you think, and I only want to hear from those with experience with this mod. All opinions are welcome, but please be honest if you have never done this or driven a car with it....

Chris

you should take this over to the 1st gen section and talk to Rx7carl or sterling

i have run mech secondaries on my nikki carbs for years. you can get the same MPG as before if you learn to feel where the secondaries start opening. a lot of people complain about the abrupt opening, and a bit of lag when they first open, but with a few runs down the block you can get the opening start point to a smooth transition by varying the length of wire/ziptie/whatever that is holding the secondary arm to the primary.


isaac

If you lengthen the wire, then the secondaries wont be 100% open at WOT. I have noticed that for best performance, you need to "slam it to the floor" slower than normal. I personally like the idea of being able to open the secs before 4K (closer to 3K for me).

mechanical secondaries actually makes the car alittle more fun, IMO. when u put ur foot on the floor all 4 bbls r open, no gradual opening as when the vac pulls them open. makes the engine come to life much quicker. but if u don't like it u can always cut off what u used to tie them together with and ur back to vac sec again.