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Anyone built a reverse frankenmotor?


ystrdyisgone
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Hey all, I've been digging and trying to find info on building a reverse frankenmotor. I have a supercharger kit, with brackets and much more, and it's ready to bolt onto an ej. I'm thinking of going the opposite route of a frankenmotor, and building one with an ej22 block and ej25d heads and intake to create a low compression engine. I have found a couple people that have done it, but there are no details whatsoever. I personally am doing a bunch of research, but I thought I would reach out and see what people's thoughts are on the idea, or if anyone here has done such a build (probably not the supercharger, but the motor itself?)

 

It will be going into a 99 outback which originally came with the 2.5.

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what are you planning for engine management?

 

I did some digging and found the specs on one I had that was build by Josh Long...

 

It appears that this is what the build consists of:
ej22t crank & rods
ej25 (NA) block halves.
ej25 DOHC heads ('96 with hydro adjusters)
newer EJ25 flat top pistons
ej20g intake manifold with 440cc injectors
vf8 turbo (ej20g)
ej22t exhaust (until I put the downpipe in)
ej22t fuel pump
2002 WRX top mount IC
ej22t bypass valve (I replaced with the TurboXS one)
ej22t ECU & wiring harness. original ej25 harness/ECU is gone, and the
ej22t ECU sits in it's place, and is all wired in, and I can check code like normal (ej22t way)


comes in around 2.4 liters with around 8:1 compression ratio

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There are all sorts of details on legacy central about building a dohc ej22. You're probably searching the wrong terms, dohc ej22 or ej22d would yield some results.

 

They aren't complicated really, if you can do head gaskets you can do this engine.

 

Things you need from the ej25d, heads(duh), intake manifold, oil pan, oil pickup tube, dipstick tube and dipstick, black metal coolant pipe from water pump to heater core. You also need to run either a pair of oem ej22t or cometic ej22t head gaskets. You cannot use ej22e head gaskets or you have a quick blown head gasket because the coolant ports in the head are different.

 

I've built a couple of these now, I can talk you through it.

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Thanks guys, that's very helpful.

 

@VaporTrail- I was planning on using the 2.5 ecu and "letting it learn" but that is not seeming like such a good idea anymore. (there's also a RRFPR and a voltage clamp involved)

 

I've decided I'm going to consider this adventure in the spring. Winter's coming, and I just want to have a running, newer gen car for the winter commute.

 

@86Bratman- I appreciate the offer, and will remember that if/when I decide to do this!

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Been done many times.....

 

 

Usually with a 2.2t block, but they're virtually identical (completely identical, as far as compatibility is concerned). Probably thousands of people putting WRX heads on the 2.2t block, which is almost as close. I've even seen the 25D heads drilled and tapped for oil feed and drain lines for a turbo.

 

I have seen several builds with a 22e block and 25d or 251/253 heads for a budget low-boost build. It seems to be a good way to go about it, puts the compression ratio right in the sweet spot of about 9:1, IIRC. 

 

 

Depending on how much boost you're looking at, the stock ECU might do alright. Those OBDII ECUs are surprisingly smart. I am not a fan of Rising Rate FPRs....I prefer to run 50-60 psi across the board. It's better for atomization, and IMHO gives you more consistent mixtures across the range. Also I'd recommend going to parallel fuel rails to keep your mixtures even across the 4 cylinders. Those 2 mods on a stock ECU should be good for 8ish psi, which will give you pretty respectable numbers.

 

 

If you're going for decent power, find someone parting out an early WRX, and get the wiring harness and ECU. With the open-source tuning that's available for it, it's almost as powerful as a standalone! Merging the wiring harness is a bit of a bear....but it's worth it!

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Thanks for the input Chux. When/If I do this, I don't expect to run too much boost. I prefer reliability over power. But I sure would like a mix of both! I'll have to look into parallel fuel rails, never heard of such a thing.

 

It is looking like a project for next year though. Time, money, and garage are all lacking.

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Do much research on a wrx ecu swap with a phase 1 motor, there is a lot more involved than Chux make it sound. You'd be better off stuffing an entire wrx swap in the car than trying to get all the little things needed to run the ecu correctly. To my knowledge there are only a handful of people who have done it.

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Do much research on a wrx ecu swap with a phase 1 motor, there is a lot more involved than Chux make it sound. You'd be better off stuffing an entire wrx swap in the car than trying to get all the little things needed to run the ecu correctly. To my knowledge there are only a handful of people who have done it.

 

It's identical to doing an entire WRX swap, just need to tune it for the different engine and suppress codes for the systems not present. It does require a full harness merge. But I bet there are literally thousands of people who have merged a GD WRX harness/ECU into the older chassis. I've done it a few times myself. I even wired a BD LGT for a Link Standalone ECU to run an EJ22t/EJ25d hybrid, we had a hell of a time getting that thing up and running, and a baseline tune done. We later swapped that same engine into a different chassis, and just merged in an '03 WRX harness/ECU. So much simpler....I wouldn't do an EJ Turbo for the street any other way.

 

 

 

I didn't get into the details of it because I wasn't sure what the OPs goals were, since they are more modest, it's not really relevant

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