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Converting a Twin turbo to Single...

02-15-2008, 06:05 PM
hey there,

Am planning on converting my 1995 GT (BG5) Subaru Legacy Wagon which is a manual twin turbo into a single turbo :smooch: it worth the trouble??? can someone tell me about how it went for them if they did it?? Is it better to just getta whole new motor and go from there or pull what I've got out and change everything (inlet manifold, wiring etc) and just getta new computer?? Any ideas??? I'm just sikka the lag between turbos and all my mates hassling me to make it single lol

So is it worth it??


03-29-2008, 06:34 PM
In my research concerning the twin turbo Subaru engines, I have heard the 'lag between turbos' attributed to a variety of sources... some of it computer related, but another theory was that the factory blowoff valve is overcompensating for (or prematurely anticipating) the increase in pressure when the second turbo spools. This negates a pressure spike, but also causes a bit of a lull... where things should be the most exciting.

I do not have immediate access to the pages I had looked at... I'm using someone else's computer and thusly am separated from my bookmarks... :(

But that is one possible area to research before diving into a full engine swap or turbo system conversion. If I find the pages I had seen, I'll send them your way. If you change the blowoff valve and it improves or eliminates the ''dead zone'' let us know.

03-29-2008, 10:27 PM
Hi there psychopathisdude, cheers for your reply :) Yeah iv already changed the BOV, gta HKS Super SQV BOV (Super Sequential Blow Off Valve) and it goes a bit better with that but stil have major lag between the primary and the secondary - gotta front mount on it too which made it reaaal laggy down low but better once you reach about 3 and half/4 and it kicks in. Gunna cost me around $3,500 (labour + parts) to get it converted to a single (pulling out all the twin turbo stuff doesnt take long but doing all the wiring takes ages and is the expensive part) so yeah any info you've got on helping eliminate the lag further would be mint

03-30-2008, 01:20 AM
The RX7 uses a totally different sequential setup, the secondary turbo is powered via the primary turbo's wastegate.

I think it would be worth converting. I want to convert my BK to a single turbo EJ20R coupled to a V3/V4 STi tranny.

Twin turbo setups are so hard to tune, for one, making it worth it if you want to increase boost and WHP.

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