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Raceboy Raceboy is offline
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Join Date: Jun 2009
Location: Estonia, Europe
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Very nice setup!
Though my point was that tuning primaries is not that important when using twin-scroll (equal length) compared to traditional turbine where pulses collide.

And twin turbos eliminate many problems by default (pulses are split, no restraints of header length etc).

Having tested both single and dual wastegates, I prefer single because there was no noticeable difference in spoolup and response. Since the pulse splitting is done to improve transient response, the wastegate is closed anyway during spoolup (at least when both chambers are controlled, the proper way). Plus single wastegate eliminates differences in wastegates.

But I think we do realise that we are talking about the last few percents of performance here, right? When you see some setups that look like they would never work, yet they do, it is clear that to have fun with the car (and that's why we do it, right?) one should not overcomplicate things.

Here's my favourite example: Old Soviet Moskvich, built by Finn Ville Oksanen, has original engine with 1500cc, factory Volvo pistons+rods, original head, crank, block and 800hp with two turbos (one feeding other, compund setup). Has driven for more than 10 years and not a single failure at the drag-races, best time so far is 8,8s @ 257 kph (1/4 mile of course). Everything is selfmade, only ECU (Hestec) and gearbox are bought items. Basically built from scrap, even turbine housing is self made of sheet metal. Though the guy is aeronautic engineer, that would explain things. He has videos in youtube also, do a search if interested.


Originally Posted by RarlyL8 View Post
Short un-equal twin scroll design will narrow the gap of effectiveness when compared to a tuned system but the tuned system still has each pulse arriving in order. The twin scroll turbo has only one common shaft so cannot act independent. Off-boost torque is also improved with a tuned system. You don't want to be on boost in a street car tooling around town as fuel mileage will be horrific. Race cars are a different story with different design constraints.
This system we put together combines all of the above, tuned primaries and secondaries, split plenum for use with twin scroll turbo and dual wast gates that isolate each bank of cylinders. Many applications and options, this is just one.
'83 924 (2.6 16v Turbo, 530hp),'67 911 hot-rod /2.4S, '78 924 Carrera GT project (2.0 turbo 340 hp), '84 928 S 4.7 Euro (VEMS PnP, 332 HP), '90 944 S2 Cabriolet
Old 06-10-2012, 10:33 PM
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