I'm new so please help.

1) Will '98 DOHC heads bolt on to the stronger Phase II block?

2) Is it possible to run low impedance injectors, with ballast resistors, and the stock '98 MAF / ECU?



Thanks

You guys are bums!

I'm assuming that you are referring to the Cobb Tuning Stage II Short Block. Your best answer for this is to contact Cobb Tuning, but they do make a short block specifically for the 98RS.

If you are upgrading the block, remember that without doing anything to the heads (using the stock DOHC) will leave untapped potential in the motor.

I think he's refering to subaru's second release (known as Phase II) of the 2.5L block.

I don't know...
but I really doubt it because Cobb Tuning has different blocks for 98 than they do for the 00.

uh.... yeah, actually a lot of the '98 2.5 DOHC engines came with a phase II block. It was one of those mid year-random changes. (not really mid-year, build date doesn't mean you have one or the other)

I just got a phase II block in my '98 RS due to blown headgaskets. My DOHC's bolted up just fine.

mike

Thanks Mike! Is there a way to determine which block I have in the car now? Was there a specific date of manufacture for the changeover, or serial/vin # number series?

Also, do you know the specific differences between the phase I and phase II blocks? I've read that they may have extra, or thicker main bearing webs/supports. Since you've had yours apart; are there added cylinder deck attachment points? The pictures I've seen of the Phase I show 2 (one on each end) plus the center between the two cylinders. I've also seen some pictures of a new WRX/STi block that has 4 attachment points + the center one. And, one of the Cobb Phase II blocks has 4. In both cases I think it's referred to as a "semi-closed deck".

As an aside, is it a simple process to drop a 2.5 crank assembly into the 2.2 turbo block? Are special pistons/pin heights, or rods required? And just how far can you bore the iron liner in a 2.2 block?

As for the rest of you out there; no takers on the injector question?

Thanks again Mike. There is nothing like real hands on info.

clairify please.... By phase II are you refering to the second revision of the 2.5DOHC block, or this WRX/2.2 thing you mentioned. My experience is with the '98 2.5 DOHC engine with two versions of the block. The differences between the two are slight, but the second revision is definatly more reliable. IIRC the Phase II uses a more robust ?Thrust Bearing? . They are both open deck designs. The semi-closed deck stuff you saw was the result of some hard work by someone other than FHI.

There is no way to tell the block version from the VIN# etc... You may have to do some research, but there's a thread out there that shows a picture of the two and the differences. The Phase I block has two ridges when looking down beside the alternator from above, The Phase II has only one ridge (or vice-versa, it's been a while :blush: )

As for the 2.2 liter engine, I'll just keep my mouth shut 'cause I don't know a thing first hand.

....and just as a side note.... HOW the heck am I a junior member?!!!! I've been on here since it all started. I was mad when I got bumped down to member #292 or whatever... Now I'm number 219384 or something ridiculus (not as bad as my spelling though :) )

Thanks for pointing out what Fletcher actually needed infowise.

Just goes to show that assumption is the mother of all f-ups.