Sequential turbos4/30/2023 When the #1 turbo reaches 20psi, the #1 wastegate will start opening which will bypass exhaust gas to help spool the #2 turbo.Ĥ. When the #1 turbo reaches 2psi, the #3 wastegate will open which will bypass #2 turbo compressor flow to the #1 turbo inlet. Wastegates #1, #2 and #3 are closed and #4 WG is open.Ģ. When running off boost, the engine will draw airflow through the #1 turbo and the #2 turbo. The second wastegate (not shown in the pic above, but resides at the bottom left of the pic behind theĭown pipe) is my existing Turbosmart 60mm wastegate.ġ. To get maximum flow bypassing the first turbo. The first wastegate is a new Turbosmart 60 wastegate My design uses a 3.5" down pipe between the #1 and #2 turbo, a 4.0" down pipe for the #2 turbo. Here's a drawing I did to show how my sequential setup will be implemented in practice on my 2JZ-GTE Supra engine. My design uses a SPA manifold to keep it compact. When boost from the #2 turbo drops below that of the #1 turbo by 2 psi, the #4 WG automatically closes and the #3 wastegateĪutomatically opens, which resets it for the next cycle. #2 turbo pressure reaches within 2 psi of the #1 turbo, the #3 wastegate closes and the #4 WG automatically opens which allows boost from the This lets flow from the #2 turbo vent to the #1 turbo intake pipe. When the #1 turbo pressure reaches 2 psi boost, the #3 wastegate (used asĪn Intake Air Bypass Valve) opens against the 2 psi spring installed in it. When the manifold pressure reaches zero psi boost, the #4 WG automatically closes. The #4 WG lets flow from the #2 turbo through to the engine (like a One Way Valve) while the engine is under manifold vacuum as it cracks open with a 1 psi pressure difference. To control the merging of the flow of compressed air from the #2 turbo in to the intercooler. These act as an Intake Air Bypass Valve and as a One Way Valve and work together There are also two wastegates for controlling the compressor flow. The second turbos wastegate will be controlled via MAP and RPM using the ECU. Theįirst turbos wastegate uses spring pressure only to control it. There are two turbo control wastegates, one used for each turbo. This setup is simplier then any other sequential turbo setup I've seen. The second turbo quicker and instead of having a big dip in the torque curve when the second turbo comes on-line, there should be little to noĭip in the torque, resulting in a torque curve more like a large single turbo. Some exhaust gas diverted from going through the first turbo, as most other sequential turbo systems do. This means you get all the advantages of a compound turbo setup for spooling the turbos, but with none of the disadvantages of theĬompound setup such as the boost being too high for a gas engine.īy spooling the second turbo with the gas exiting from the first turbo, the second turbo will spool much quicker then if it was just recieving This sequential setup is basically a compound turbo setup on the exhaust side and a parallel sequential setup on the intake side. WG = Wastegate (number denotes size in mm) They say a picture is worth a thousand words, so here's a diagram of how it works. What I have come up with is, I believe far simplier, faster spooling and easier to control then any other sequential setup that I've seen. Therefore I decided to design my own sequential turbo system. To install in my own car due to various fitment, cost and complexity reasons. Having looked at every compound, sequential, and twin turbo setup that I could find on the net, there wasn't one of them that I was happy A lower stall will allow me to have a converter that holds more power and has lessĬonverter slippage, which results in more power to the rear wheels. I've been thinking of doing a sequential turbo setup for a while now as a means of getting more boost at lower rpm, so that IĬan run a lower stall in my TH400 converter. Kevin's Compound Sequential Twin Turbo Design Toyota Supra MKIV : Compound Sequential Twin Turbo Setup Toyota Supra mkiv
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