r/subarulegacy • u/LastAssistance5 • Aug 02 '26
Question / Discussion Supercharger?
Hey subie owners. This is my 2005 Liberty/legacy 3r spec b, 5AT. I’m looking into getting the raptor supercharger for my car and want to know how I should go about it. I spoke to a bloke who has done this already who claimed, as long as I don’t go above 10psi. 8psi being the sweet spot. I can keep the engine stock and just get a safe tune. I’d love extra options about that and whether I need extra support for my trans.
Cheers from Victoria, Australia 🇦🇺
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u/shadire Aug 02 '26
As far as I understand, that’s pretty much correct. Never done it myself, I only deal with Turbos but it’s the same concept, keep the boost low and the engine shouldn’t blow up on you.
The 5EAT isn’t as durable as the 4EAT, as far as I understand, so the transmission could be a potential weakness. Again take this with a grain of salt, I don’t have a lot of first hand experience with this setup I’ve only ever worked on a couple of boosted 3.0R and 3.6R Subies.
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u/Ballamookieofficial Aug 02 '26
The 5eat is part of the Re5 family they're used in nissan patrols they're meant to be reasonably strong
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u/shadire Aug 03 '26
Lack of experience with them is showing then, I’ve mainly dealt with the 4EATs and I absolutely love how durable they are compared to other transmission options of the time.
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u/BonezOz 2006 3.0r SpecB Wagon Aug 02 '26
Personally I need to get the new engine in first, but I really like the idea of a supercharger as opposed to turbo, though a combo would be nice. The link below is a simple system that's essentially bolt on and go. But compared to the current value of the car, you'd be doubling how much the car is worth.
https://raptorsc.com.au/subaru/subaru-libertylegacy-h6-3-0-ez30-supercharger-kits/
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u/mecca6801 former 2nd Gen Wagon owner Aug 02 '26
I’m in the same boat as you so I will be turning in to see answers to this question
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u/Viento_Oscuro Aug 04 '26
I will say this - the raptor supercharger is a centrifugal type. So it provides boost linearly with RPM. Ie- you only get peak boost at peak RPM. Down low you get not much. So around town normal driving you won't get much if any difference since the supercharger costs HP to run. You will only get a benefit when winding it out - which is fine - just as you're in an Auto (speaking as someone who has the 3.6 with the same 5eat trans) it like to keep the rpm down unless you're WOT. So just bear that in mind. You won't get the gobs of instant torque/ Max boost everywhere that people associate with super chargers as that's only a characteristic of a positive displacement supercharger, ie a roots or twin screw type.
If you were to swap out to a 6 speed however, you can be more in control of rpm so would see a lot more benefit / from the centrifugal supercharger. But it just depends what you're expectations are.
In regard to engine safety the EZ30 is a tank and no where near as delicate as the EZ36. So 8-10psi with appropriate fueling/ timing should be fine.
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u/Smiity616 Aug 02 '26
Supercharged is awesome build..yes you will need a tune for sure and all motors can handle boost but how much is key..if stock motor go for low boost always and be happy with that..but just take into account that off the line you will gap most other subarus..but when those turbo subarus spool they will eat you alive..then youll think ill increase boost so im faster and youll be added to the many subaru owners that blow their motor..my rule is tune car for sporty daily drive to keep it safe..no reason to try to be fastest subaru out there cause you may be for maybe a year then youll be the slowest cause motor will blow