My first 7!!!
When I open my 20B up I'm going to match its primaries to a GSL-SE so they open at the same time. There will still be plenty of velocity at GSL-SE port spec. Heck they did it with only two 680 injectors back then! Or maybe I'll go slightly bigger. I don't need a smooth idle at 600 RPM or whatever a stock 20B can do. 850 RPM idle is good enough for me. 
The secondaries will be ported a bit too I'm sure. I'll just work out a good opening and closing timing. They don't have to be huge but bigger than stock to get me to 300HP.
The exhaust port sleeves should be changed but I'll cross that when I come to it. The stock 20B sleeves are weird and sort of close the port earlier than the actual shape of the port in the housing. You see Mazda kept the same port timing from '86 to '02 and just had various sleeves for turbo or NA. A sleeve a cheaper to produce than having different tooling to make different port timings in the housings. Therefore I could install a set of T2 sleeves and port match the housings if I wanted to.
The secondaries will be ported a bit too I'm sure. I'll just work out a good opening and closing timing. They don't have to be huge but bigger than stock to get me to 300HP.
The exhaust port sleeves should be changed but I'll cross that when I come to it. The stock 20B sleeves are weird and sort of close the port earlier than the actual shape of the port in the housing. You see Mazda kept the same port timing from '86 to '02 and just had various sleeves for turbo or NA. A sleeve a cheaper to produce than having different tooling to make different port timings in the housings. Therefore I could install a set of T2 sleeves and port match the housings if I wanted to.
Thread Starter
Environmentally-Hostile
Joined: Sep 2005
Posts: 1,662
Likes: 3
From: Ennis/Arlington Texas
When I open my 20B up I'm going to match its primaries to a GSL-SE so they open at the same time. There will still be plenty of velocity at GSL-SE port spec. Heck they did it with only two 680 injectors back then! Or maybe I'll go slightly bigger. I don't need a smooth idle at 600 RPM or whatever a stock 20B can do. 850 RPM idle is good enough for me.
The secondaries will be ported a bit too I'm sure. I'll just work out a good opening and closing timing. They don't have to be huge but bigger than stock to get me to 300HP.
The exhaust port sleeves should be changed but I'll cross that when I come to it. The stock 20B sleeves are weird and sort of close the port earlier than the actual shape of the port in the housing. You see Mazda kept the same port timing from '86 to '02 and just had various sleeves for turbo or NA. A sleeve a cheaper to produce than having different tooling to make different port timings in the housings. Therefore I could install a set of T2 sleeves and port match the housings if I wanted to.
The secondaries will be ported a bit too I'm sure. I'll just work out a good opening and closing timing. They don't have to be huge but bigger than stock to get me to 300HP.
The exhaust port sleeves should be changed but I'll cross that when I come to it. The stock 20B sleeves are weird and sort of close the port earlier than the actual shape of the port in the housing. You see Mazda kept the same port timing from '86 to '02 and just had various sleeves for turbo or NA. A sleeve a cheaper to produce than having different tooling to make different port timings in the housings. Therefore I could install a set of T2 sleeves and port match the housings if I wanted to.
Thread Starter
Environmentally-Hostile
Joined: Sep 2005
Posts: 1,662
Likes: 3
From: Ennis/Arlington Texas
Well today I'm embarking on a entirely new chapter in my life. Moving out of my house into an apartment for college, and my RX7 that I've owned for just 2 days is taking me there. Wish me luck!
Wish me luck!
Thread Starter
Environmentally-Hostile
Joined: Sep 2005
Posts: 1,662
Likes: 3
From: Ennis/Arlington Texas