Subaru Frankenmotor for the Westy

[r39o]

[presslab]

[r39o]

[JeffRobenolt]

[presslab]

[kuleinc]

[r39o]

[JeffRobenolt]

Issues with the IAC added to a intake that didn't originally have one??

They do gum up and make the idle go all over the place.

Jeff
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[vinnyvango]

[r39o]

[JeffRobenolt]

vinnyvango wrote:

Why would the manifold be reversed? I'm REALLY interested in this since I have a Phase II DOHC on the engine stand with blown HGs. But I don't have the rest of the parts for a conversion. Thanks!

This is reversed to go in my bug.
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[JeffRobenolt]

r39o wrote:

Some IACs / throttle bodies may or may not work with the openings in some intake manifolds. That is what I read when some one mixed and matched to create another Frankenmotor on another forum.

All the IAC does is let air in at idle because the butterfly in the throttle body it closed.

As long as you add the IAC to the intake right after the throttle body I don't see any problems.

I don't know what is all different with the throttle body from a motor with an IAC vs one without. Just use the throttle body off the same intake that you take the IAC from.

Jeff
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[presslab]

I had a look at another recent frankenmotor conversion this past weekend, a member here. It has EJ22E heads that have had their CCs increased (to lower compression) and a phase 2 N/A EJ25 shortblock. Static compression ratio is unknown, but supposed to be "stock" which I would figure is 10:1 on an EJ251/3. Head gasket is Cometic with "stock" thickness. Cams were stock EJ22E.

Initially it had a 90-91 ECU with the red top injectors. It wouldn't idle right, the SSM cable showed that it was too lean for the ECU to adjust. He had an "F9" ECU so we stuck that on, because it should match the red tops. At first the ECU couldn't correct the idle mixture with just the short-term-fuel-trim. But after a bit of long-term-fuel-trim was learned the ECU could then control the idle mixture. There seemed to be a few problems with the IAC and TPS, so we cleaned/adjusted those. It now idles just fine and has good power.

Next we looked at the IAM to see if the ECU was pulling timing due to knock. Uh oh, the IAM was at "0" which means the ECU has pulled all the additional timing. The fuel was 87 octane in the tank; he's going to try 91 octane to see if the IAM can come up.

What this does confirm is my theory that the even with stock cams the frankenmotor (with OBD1 ECU) has too much timing advance, even at 10:1 CR.
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1986 Vanagon Westfalia EJ25
1988 Subaru GL-10 EJ20G --- 2000 Honda XR650L
2010 Titus El Guapo --- 2011 On-One 456 Ti

[Franklinstower]

And therefore,
We need you to make daughterboards and EPROMs for us Sambanistas!

My build had suddenly come to a halt, a little Beach time in El Salvador, but I am back and should have the pistons back in, plus I am waiting for my heads to get finished.

Hopefully by the end of the month I will have it together.

Paul
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug

[Franklinstower]

Small update to my build:

EJ25 Block - The VIN on the block has a "W" for the year; so I assume a '98 Phase 1 block, but I just noticed the 8 transmission mounting holes:

8 bolt blocks were Phase 2? Two knowledgeable Subaru gurus on the forums are conflicted whether it is Phase 2 or not: One says definitely, all 8 bolt blocks are Phase 2, another says not so fast; it is a Phase 1 odd ball block since the date code is 98. And others have said the factory warranty replacement blocks for Phase 1 EJ25's ('96-'98 ) used the stronger Phase 2 blocks with Phase 1 cylinder heads and pistons. Why do I care? The Phase 2 blocks are much stronger with larger rod bearings; 52mm versus 48mm and the thrust bearing was moved to the #5 journal to stop crank walking. So I would certainly prefer the Phase 2 block.

My EJ22 Cylinder heads are back from the machine shop and I assembled them on the coffee table last night will the wife is gone on a trip, hee hee!

I had the cylinder heads surfaced to ensure the Cometic MLS hybrid gasket has a perfectly flat and very smooth surface - This was recommended by my machine shop. They measured the cyl heads before machining: 3.870" is new; 3.860" is the limit. Mine wear just slightly under new so the took .003" taken off one and .004" off the other, my measurements are now 3.865" and 3.864". r39o says don’t machine the subie heads, but if you have a shop that does them all the time, it can be done successfully.

I ordered my Cometic Gasket in a thickness of .056". Stock I believe is .051" but again I can't get a confirmed answer on that. Others say .040" but I think that is for the SOHC 2.5's.

Regardless, using the TWE Compression calculator for Subies, my CR should be between 10.38:1 and 10.53:1.

Major work is now done. My HG's should be here on Monday and I hope to have the cylinder heads on by next week! I am getting excited to pull that 2.2 and have nice little power upgrade!

Besides my time, this is going to be a nice budget upgrade to my EJ22. My total cost so far is under $500!

Paul
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug

[syncrodoka]

The main bearings are a different size for phase 1 and phase 2. Different width and diameter, phase 2 is bigger on both IIRC.

[korkwood]

I found this old thread, perhaps someone will chime in
About to order Cometic headgaskets for my version of Frankenmotor
Brand new 2010 STI shortblock with 92 2.2 heads. had stock turbo headgaskets and ruined one trying to adjust water passages. Cometic does have right gaskets but they are confused about thickness, offered .051 thick mls gaskets knowing i got turbo block. Stock gaskets are .019. Their thinnest ones are .027, was ready to order but thought perhaps someone went same route and used different thickness. Just wanted to hear real info.
TIA
Leon

[Franklinstower]

[syncrodoka]

The shortblock deck volume and head CC need to be figured out first to get a grasp of what HG thickness is needed for your desired CR.
The wrist pin to piston top affects the deck volume of the shortblock. Since turbo motors are lower CR than NA motors some dimensions need to be confirmed before moving forward.

I am interested in what numbers that you come up with.

[syncrodoka]