STI 2 and STI 2 RA same motor???????????
02 August 2001, 08:45 PM
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Pete is spot on... the RA heads are *VERY* special, they are very expensive to manufacture, and were used as the basis for the Group A rally cars, which ran 400BHP plus.I think they were a homologation special.
The fifth injector should be quite "prominent" on the intake manifold, right in the middle just after the throttle body. IIRC, this is used for background fuelling on high boost. This has the effect of balancing out the fuelmix between cylinders, as any "restriction" which could affect volumetric efficiency will be closer to the heads... No. 4 intake runner is restrictive, for example, so No. 4 runs rich normally, but becuase with the 5th injector *ALL* the intake air is subject to the same background fuelling any variation due to individual cylinder volumetric efficiency is reduced.
Also, the STi II Type RA has (should have) an EJ20G closed deck block, which is the strongest block that Subaru have ever made. With the STi II it's a bit of pot luck, you may end up with an open deck block. However, just to complicate the issue further, you may get forged pistons in the STi II engine and perhaps not in the type RA (theory being if you are gonna rally it, you'de replace them anyway... but you WOULD want a good block and heads). In neither do you get the very special STi con-rods, which I was foolish enough not to take a picture of.... they look very similar to the stock ones (to pass scrutineering) but have an oil feed up the centre to the little end bearing. They are almost indestructible and as rare as rocking horse dung.
Hope this helps,
Pat.
The fifth injector should be quite "prominent" on the intake manifold, right in the middle just after the throttle body. IIRC, this is used for background fuelling on high boost. This has the effect of balancing out the fuelmix between cylinders, as any "restriction" which could affect volumetric efficiency will be closer to the heads... No. 4 intake runner is restrictive, for example, so No. 4 runs rich normally, but becuase with the 5th injector *ALL* the intake air is subject to the same background fuelling any variation due to individual cylinder volumetric efficiency is reduced.
Also, the STi II Type RA has (should have) an EJ20G closed deck block, which is the strongest block that Subaru have ever made. With the STi II it's a bit of pot luck, you may end up with an open deck block. However, just to complicate the issue further, you may get forged pistons in the STi II engine and perhaps not in the type RA (theory being if you are gonna rally it, you'de replace them anyway... but you WOULD want a good block and heads). In neither do you get the very special STi con-rods, which I was foolish enough not to take a picture of.... they look very similar to the stock ones (to pass scrutineering) but have an oil feed up the centre to the little end bearing. They are almost indestructible and as rare as rocking horse dung.
Hope this helps,
Pat.
02 August 2001, 09:34 PM
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Some of the STI's came out with hepolyte pistons which are strength wise between the standard cast and forged pistons.
They are good for a car running no more than 18PSI continuos boost.
They are good for a car running no more than 18PSI continuos boost.
07 August 2001, 10:31 PM
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Awesome info guys....
that is why i came to this board no nonsense no bull**** good positive honest info
so thanks again
over here the subaru babies are just now getting the wrx and this "new car" they all think is the best thing since sliced bread but all the tuners know nothing about the early cars, engines, gb's etc.....and even less about how to rally one.
but they will learn and in 5 years time we will be up to speed i figure.....i cant wait that long.
BTW I finished 2nd in car class last weekend at a rallsprint type of event despite my Impreza'a weak 110hp 1.8L.
ONE EVENT TO GO THEN IT'S MOTOR CHANGING TIME!!!!!!
Gary
that is why i came to this board no nonsense no bull**** good positive honest info
so thanks again
over here the subaru babies are just now getting the wrx and this "new car" they all think is the best thing since sliced bread but all the tuners know nothing about the early cars, engines, gb's etc.....and even less about how to rally one.
but they will learn and in 5 years time we will be up to speed i figure.....i cant wait that long.
BTW I finished 2nd in car class last weekend at a rallsprint type of event despite my Impreza'a weak 110hp 1.8L.
ONE EVENT TO GO THEN IT'S MOTOR CHANGING TIME!!!!!!
Gary
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