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frankenmotor worth it?


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4 replies to this topic

#1 peacewize

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Posted 30 January 2013 - 12:28 AM

My apologies if this has already been asked. Currently i run a very underpowered ea82 cover less, so naturally my next step is to ej swap it. This car is my dd so i want to keep it reliable. I know quite a few people have done frankenmotors but the most ive seen posted so far is 10k on one. The other thing is that Im pretty hard on cars, I once jumped a celebrity station wagon over an entire street at 55mph, are these motors ok with some abuse? Price wise its going to cost similar to swap either so I want to know if the hp/tq gains in the frankenmotor are noticeable enough to make it worth it. Also if i do frankenmotor swap which ecu do i use? ive read some say 2.2 and some say 2.5 ecu so im a bit confused.

#2 grossgary

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Posted 30 January 2013 - 07:41 AM

ECU doesn't matter - EJ22 and EJ25 ECU's are interchangeable.
match the displacement to be precise - so EJ25.

As to reliability - there's no concern. It's just an EJ head bolted to an EJ engine. It's the same Subaru head, headgasket, and block...just different bores, no big deal. So it's no different than any other Subaru EJ engine.

It's usually an economic decision.

EJ25's are far more expensive and harder to find in known excellent condition than EJ22's. EJ25's easily sell for $1,000. Ej22's are easily had for $300.

EJ25 are not the most reliable or easy to find for cheap in known, excellent condition. You can google "EJ25 headgasket" and read for an entire year if you're not familiar with their propensity to eat headgaskets and lower end bearings.

There's a million ways in which either way is a good fit though...based on cost, ease of maintenance, easy upgrade for a bit of power...etc.

I'm practical so I'd go for the EJ22 swap. It's cheap and a HUGE upgrade from an EA82, I don't need more than that. Heck I'd probably install an EJ18. You sound like you want more out of your Subaru's so you might like the 20 (EJ25) or more (FM) hp bump, go for the frankenmotor!:headbang:

#3 cal_look_zero

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Posted 30 January 2013 - 04:10 PM

I'm a proponent for the FM, but all told, it's been a trying 8 months for me in terms of getting it to run proper. The idea is that it's a cheap way for EJ22 cars to make good HP, I failed at that. All told, I'll be about $2000 into my build (Brand new, from the ground up mind you) and be making very close to stock WRX hp.

If you do the basic 22 heads on a 25 block and leave it at that, you should be happy with it.

I have cams, injectors, piggyback ecu, intake spacers, oversize valves, pnp, and etc... and will just be getting around to getting it tuned in February.

Keep it simple.

#4 Fairtax4me

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Posted 02 February 2013 - 11:26 PM

For an EA car, you're going to notice a huge increase in power just with an EJ22.
A 90-96 ej22 you can continue to run naked. Any EJ25 you will need to run covers because of the interference design of the block.
Franken motor offers about 30 more HP, but you pretty much have to use premium fuel or it will ping.

#5 monstaru

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Posted 11 October 2013 - 01:15 AM

For an EA car, you're going to notice a huge increase in power just with an EJ22.
A 90-96 ej22 you can continue to run naked. Any EJ25 you will need to run covers because of the interference design of the block.
Franken motor offers about 30 more HP, but you pretty much have to use premium fuel or it will ping.

Gonna bring this one up to the top.

My engine is at about 18k, and I have not used premium but a handful of times. No ping.

I am pretty rough on my junk. And this engine is no different.

 

THe funny thing though, is that I have broken a couple starter snouts now .The high compression is pretty crazy sometimes.

Overall, since I have had it in a lifted automatic on 235's, and a street 5spd with like 195's, I gotta say I love this motor. Yeah , she has an ugly deadspot sometimes from the IAC not working right. , But I think when the engine goes in my truck it will get a reworked IAC.

 

cheers






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