LS1Formulation

iTrader: (13)

I'm having a custom exhaust built, and I'm wondering if there's any design specifications to follow when routing a pipe for the wastegate dump. I have a Huronspeed V1 truck manifold kit, and my dump pipe goes right above the wastegate. It would be super easy to have a V-band welded to the dump so the wastegate could feed into it, but I'm concerned that dumping it into the pipe right next to the turbine outlet ( within 6" ) might disrupt turbo operation. I'm not venting it to atmosphere, as this car is supposed to be sleeper-ish, so can I route it there? Or should I have a length of pipe added and route it into the exhaust system?

rpturbo

iTrader: (47)

I don't think even at full tilt, there would be any problems caused from putting it there, unless the downpipe was dramatically undersized. I have a twin turbo setup, and mine are also dumped in that same kind of position. I would recommend using a bellows on it so it has some room to move around with the heat difference.

Ls1Rx-7

iTrader: (4)

its better for flow if you have the wastegate pipe follow your downpipe for 18-24” before dumping back into it. I dont have the thread but they did alot of dyno testing on evolutionm.net about recirculated wastegates vs vent to atmosphere setups and found that if you need to recirulate it then you need some distance between the turbine and where the wg enters.

LS1Formulation

iTrader: (13)

That makes sense. However, my exhaust set-up is going to be pretty odd, so I may have to figure something else out. Basically, I want this car to be stealthy at idle and cruising around. My fab guy is building me a 4" dump that is going to exit adjacent to my passenger front tire, as stuffing it out the fender/bumper will ruin the sleeper effect. The dump will have a boost activated flapper valve that will open at 5-7 lbs. of boost. Fishmouthed into the dump is going to be a 2.25" pipe that will turn and travel back on the same path as the Huronspeed downpipe did. It will then attach to a stock style exhaust. So at low speeds and cruising, the flapper stays shut and all the exhaust is routed into the stock size tubing. This should make it as quiet as it was factory. Then when I get on it, the valve opens up and I get all the benefits of a 4" pipe with none of the annoyances. It almost seems like the best routing path for the wastegate would be into the stock size exhaust tubing running out the back of the car, but I'm not sure if it would cause any flow problems. RPTurbo, your point on the bellows is well taken, and I'm realizing that routing it directly into the pipe would be a no-go, as the distance between the wastegate exit and the dump is around an inch. Setting it up that way is bound to crack something. And if I did route it into the dump further down, it's going to have to backflow when the flapper is shut - not an ideal situation.