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Hey I have this header on my FB Rx-7 that collects two 1-7/8" id primarys in to a 2" id pipe that has been all cut up and bastardised. I want to cut off the 2" and collect them into .125 wall 2.25 id instead. I've got a new flange and I just need the 1/8" wall 2.25"id pipe. Anyone know where I could get about 1' of that pipe and anyone want to help me cut it up and weld it up? I know there are a few out here in WA that are quite crafty with a welder and your bad ass HMT cars. I'm in Seattle BTW. Cash in hand. Any help would be great.

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I can fix anything with some JB :y

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LOL Me too. There's more JB weld on my car then there is steel.

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run both of them all the way back right before the muffler, or just dont collect them at all. This is called a true duel setup. Its louder than a normal setup thats collected, but it frees up the most hp.

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Actually...A true dual setup is only when the primaries are not collected at all. True duals only work on stock ported engines. a stock rotary has huge amounts of over lap. A stock port has as much over lap as compairable to running 278 cams on a boinger. The bigger the ports the more potential power and the more overlap. My car has a fully built 13B with huge ports. When building a powerfull rotary you want to get the exhaust out as fast as possible. The best way to do this is with exhaust scavenging, in laymans turns a collected exhaust scavenges the exhaust pulses. You collect a rotaries exhaust depending on how big your ports are and where you want to have peak torque. Long primary exhausts as you suggested will make peak tq from 4-5K depending on port and where you collect. any where between 89 and 125 inches depenging on induction flow rates and port size. Short primary exhausts as I have usually make peak TQ from 6-10k again depenging on induction flow rates and port size and type. These short primary exhausts usually collect from 10 to 25 inches. The longer the primaries the lower Rpm the engine will make peak tq. Mine already collect at 25" and should be perfect for my port size and power goals, but it's just a shitty collector that needs to be redone. Sorry for the book but I know my rotors I've built plenty of very high HP rotaries throughout my years. I even have tought rotaries in auto engineering classes.

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yup.

i just read books and talk to jim downing. his shop is right down the street from my house.

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if you tickle my balls your car will gain 40hp

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If it wasnt a rx-7 u might be able to find someone to work on it.

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lol nice coments. This site is always good for the post -----s. Jim is a good guy, really knows his ----. I wish he'd get back into it like he was in the 80's. I'd love to see some new ---- from them.

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ok