anyone had experience turning inlet manifold round on scooby ej20?
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projectgengar
- Posts: 17
- Joined: Mon Aug 02, 2010 11:06 am
anyone had experience turning inlet manifold round on scooby ej20?
any of you guys had any experience reversing the inlet manifold on an ej20 engine? going to do it on my legacy but would like advice first, always usefull to hear of others experience in the matter.
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ScoobieWRX
- Posts: 2136
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Any of the inlet manifolds on 4-pot turbo Subaru's will reverse. You will however have to lose your air-conditioning pump and either relocate the alternator or use phenolic spacers under the inlet manifold to raise it a centimeter or so, enough to clear the alternator. This also acts as a heat barrier so the inlet manifold soaks much less heat than when it's bolted directly to the block. All good stuff!!
Pro's for reverse inlet are less piping, neater install look, less uncooled piping routed over/around the engine soaking up less heat resulting in cooler charge air and less lag as there is less warm air to cause the lag and less volume of piping to fill again minimising lag. The less piping there is the smaller the pressure drop across the whole system. Pressure drop is the difference between the amount of boost at the turbo and resulting inlet manifold pressure. If you have an efficient intercooler and minimal pipework 30psi at the turbo might only see a pressure drop at the inlet manifold of maybe 2 or 3 psi, perhaps less. Less efficient sytems will see a much greater drop, perhaps 5,6 or 7+psi drop. I have seen from time to time this on badly thought out and put together installs.
What you're going to do is definately a DIY job if you're confident with a spanner and have a workshop manual to keep you on track and to provide proper re-tightening torque values, very important. If you haven't done this level of mod before or don't feel confident you're going to get it right give it to an experienced Subaru specialist or a mechanic you trust.
Pro's for reverse inlet are less piping, neater install look, less uncooled piping routed over/around the engine soaking up less heat resulting in cooler charge air and less lag as there is less warm air to cause the lag and less volume of piping to fill again minimising lag. The less piping there is the smaller the pressure drop across the whole system. Pressure drop is the difference between the amount of boost at the turbo and resulting inlet manifold pressure. If you have an efficient intercooler and minimal pipework 30psi at the turbo might only see a pressure drop at the inlet manifold of maybe 2 or 3 psi, perhaps less. Less efficient sytems will see a much greater drop, perhaps 5,6 or 7+psi drop. I have seen from time to time this on badly thought out and put together installs.
What you're going to do is definately a DIY job if you're confident with a spanner and have a workshop manual to keep you on track and to provide proper re-tightening torque values, very important. If you haven't done this level of mod before or don't feel confident you're going to get it right give it to an experienced Subaru specialist or a mechanic you trust.
Buggers cancelled my op just a couple of days before it was due. Inconsiderate barstewards!! 
Waiting now for another execution date!!:headhack:
Waiting now for another execution date!!:headhack:
If you plan on front mount turbo (which I wouldnt recommend) then you will need to reverse the manifold. As Francis says re the practicalities - also worth mentioning a distinct lack of space to go upwards and the angle of the throttle body hitting the bonnet.
Not worth it IMO when you can get 600bhp out of a standard fit bolt on turbo using non reversed manifold with minimal lag anyway.
Not worth it IMO when you can get 600bhp out of a standard fit bolt on turbo using non reversed manifold with minimal lag anyway.