Project FD RX7 Restomod: Part 27 – Fabricating the Exhaust with Vibrant Performance and SP Mufflers

FD RX7 wastegate and downpipeMounted on the car, we can see the front wastegate tube wraps around the rear wastegate.  For longevity of the diaphragm, it is really important to maximize the distance between any exhaust component and the wastegate.

Turbosmart Ven V CompGate 40 FD RX-7We mounted the Turbosmart GenV CompGate40 external wastegates onto the Turblown Engineering Investement Cast 347S FD3S Turbo Manifold.  The downpipe and wastegate tubes all fit perfectly with tons of clearance to the wastegates.

FD RX-7 Turbosmart GenV CompGate40 Vibrant Performance 4-inch downpipe and bellows, TSR Fabrication weldsWe were very happy with how well the wastegate tubes lined up with the wastegates.

FD RX-7 4-inch downpipe with recirculating wastegates Vibrant Performance tubes and bellows TSR Fabrication weldsThe complete 304 stainless steel Vibrant Performance downpipe starts off with a 3” V-band exiting the EFR turbine before expanding to 4” and making a turn down to go under the car.  On the way, both external wastegates are recirculated back into the exhaust and feature 1.75” Vibrant bellows.  After turning back horizontal, the exhaust reduces down to 3.5” to slightly increase velocity as the exhaust starts to cool.

We placed the lambda sensor roughly 10” from the turbine outlet in free stream and away from turbulence of the recirculated wastegates.  We also used a 4” Vibrant V-band on the downpipe to improve installation and serviceability of the engine.  This also enables us to test different A/R turbine housings without having to build an entirely new downpipe.

TSR Fabrication FD RX-7 DownpipeWith Mario Lozano of TSR Fabrication welding up the exhaust, we were extremely pleased with how well the downpipe looks and have a lot of confidence in its durability.

3 comments

    1. Thank you! I’m a bit behind on articles so there will be more updates that will come out soon. The car is close to firing up!

  1. I see you’re also a glutton for punishment wrenching on cars while laying on our backs, ha! Excited to see this up and running with all the extensive and detailed work on it.

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