2.5D swap or Franken motor

SILINC3R · Post by **SILINC3R** » Sat Jun 09, 2012 8:30 am

I have at least 5 hours on this so please don't give me the go search. So you are not sure which swap you want to do. What is your time frame for completion? What tools do you have access to and what parts. How much would you like to spend? How much knowledge do you have. Have you spent more time in the search bars of over 4 forums then me? This is mainly for people that are looking for a way to N/A happiness. This is for anyone trying to decide which route to go without being told to go turbo.

So reason for the Franken motor. I have seen talk about it but never much documentation complete with pics. Matt’s are kind of here and there. Not sure if Donovan did it to his FWD. Xephyer’s name popped up. It is a cheap build and not much is required beyond stock parts and a 25D block. Though not sure if the 1.8L ECU is advised or if that was because of the Impreza. The one downside I found is that MPG is reduced to low 20s to mid 20s if not dogged.

Reason for 2.5 swap. Still fairly cheap and about same horsepower but better fuel economy I assume than the Franken motor. Also the bottom end could be rebuilt for longevity sake not horsepower. Cams could be swapped in and exhaust for that. Should be able to retain higher MPG than Franken motor even with some aftermarket stuff. ECU does not get swapped

Questions for the board:
What do you do if you cannot acquire a Torque Chip? Would you still use the 1.8L ECU
On the 2.5 swap, wiring from the 25 is used or do you just swap the plugs for the coil pack and the canister purge control solenoid and use the 22 wiring?
On the 2.5 route EGR and block valve?
On the 2.5 swap use EJ22 TB?
Catch can on EJ25D due to PCV or use EJ20G intake manifold?

Quotes:
I repeat my mantra that I have said over and over around here: OEM IS BEST...-Matt Monson having a good time on NASIOC
This build isn't about revs it's about torque at the low RPM range- Greg Donovan in regards to franken motor

Notes:
If using Phase II EJ25D block use cometic head gaskets-Matt Monson
If using Phase I EJ25D block use OEM thicker (4layer) head gasket-Matt Monson
Fuel system capable of swap no upgrading necessary-Matt Monson
The 1.8L ECU has different timing maps that make it run much better up top than either an EJ25 or EJ22 ECU would allow. -Matt Monson
The 1.8l is pretty aggressive on timing advance up top and prevents it from running too rich and wasting potential power as compared to the 2.2 NA ECU- Matt Monson

Setups: Builder-block+heads+ECU+cams+Car
Matt Monson- EJ25D block+EJ22 N/A heads+ 1.8L chipped ECU+ 220 Delta cams+ 1.8L impreza
Xephyer- EJ25D engine+ 272 HKS STi V3 cams+ 1.8L chipped ECU+94 wagon
Greg Donovan- EJ25D block+EJ22 heads+EJ22 ECU?
Jason Grahn-Phase I EJ25D DOHC engine+2.2 ECU

Links:
DOHC Sticky
ChipTorque?
Hey Matt Moson AKA DR.
No more 2.2L
EJ22 N/A heads on EJ25 block
NASIOC high compression motor
EJ22/EJ25 valve size, head swap

There maybe others that have done these but these are the names I have seen over and over centered around these questions. It’s very late now as I submit this and have kind of forgotten where I was going. My hope is to bring all this info together so people will not have to search so much and give up and make so many threads about this. If this can be of any use I hope it can be stickied. I have it saved in Word so as things are addressed I can update it. Thanks in advance.

beatersubi · Post by **beatersubi** » Sat Jun 09, 2012 4:47 pm

I've been considering a 25D swap for a bit. This is good info. I think Ciper has done a similar swap also.

Post by **Legacy777** » Sat Jun 09, 2012 5:04 pm

Good info!

I added to the sticky compilation thread.

BoostedSubie · Post by **BoostedSubie** » Sat Jun 09, 2012 5:49 pm

I started building a Franken motor a couple weeks ago for a circle track car. My buddy races Mustangs in circle track and is always running his mouth about it, so I decided I wanted to build a cheap track car that could give him a run for his money. The rules are stingent though; no turbos, no DOHC, no engine management, no AWD, blah blah blah... So, I planned on picking up a 2 door Impreza, FWD it, 2.5 bottom end with 2.2 heads which I already have, then some delta cams, exhaust, intake, suspension, etc.. Then we'll see how it hangs with those Mustangs, lol. He says most of the cars in his Roadrunner class have around 180-200hp.

mike-tracy · Post by **mike-tracy** » Sun Jun 10, 2012 5:32 pm

If you just swap in an ej25d shortblock, won't you need to run midgrade fuel then due to higher compression? That to me would be enough to want to run a 100% ej25d setup.

I did swap in a complete ej25d into my 96 Legacy a few years back. I ran it on the stock ej22e ecu for about a month or so. Ran fine but the ecu took a little bit to learn the motor. No drivability issues or anything. Swapped in an ej25d ecu (obviously not possible for a 1st gen) and picked up 1-2 mpg (to 23-24 w/ a 4eat) and throttle was crisper. Overall a worthy upgrade imo.

SILINC3R · Post by **SILINC3R** » Sun Jun 10, 2012 6:31 pm

Yes mike you would want to run about 91 to 93 if you can with the franken motor but again this is what I found out, its not an economy build. It's a torque fun engine.

beatersubi · Post by **beatersubi** » Tue Jun 12, 2012 2:01 am

mike-tracy wrote:Swapped in an ej25d ecu (obviously not possible for a 1st gen) and picked up 1-2 mpg (to 23-24 w/ a 4eat) and throttle was crisper. Overall a worthy upgrade imo.

Thats not great mileage. I was considering this swap for better economy than my turbo.

No longer.

mike-tracy · Post by **mike-tracy** » Tue Jun 12, 2012 2:07 am

Well with a 3.9 FD 5mt, or in tony's case a 3.7 fd, I'd imagine better mileage to be had. And it doesn't require premium (as a complete ej25d).

scuba steve · Post by **scuba steve** » Sat Aug 25, 2012 7:15 pm

Just a note about fuel economy. My frankenmotor got me about 2 more miles per gallon than the stock EJ22E. I tried the motor in both my cars at the time. My 94 sedan 4eat was about 1.5 mpg increase and the and 92 wagon 5spd was about 2.5). The low end torque was so solid, I could slip the clutch at idle to take off in first. This was with the Delta Cams torque grind, stock 22e ECU and 87 octane gas.

I'm looking for a block to do another one, but I'm likely going the EG33 route this time.

kimokalihi · Post by **kimokalihi** » Sat Aug 25, 2012 8:31 pm

beatersubi wrote:
mike-tracy wrote:Swapped in an ej25d ecu (obviously not possible for a 1st gen) and picked up 1-2 mpg (to 23-24 w/ a 4eat) and throttle was crisper. Overall a worthy upgrade imo.
Thats not great mileage. I was considering this swap for better economy than my turbo. No longer.

Yeah my ss with 4.444 gets 23-24 mpg on the regular and if I really grandma drove it and stayed off the freeway I'm sure I could hit 26+.

entirelyturbo · Post by **entirelyturbo** » Sat Aug 25, 2012 9:23 pm

One thing from when I was planning on doing the same thing:

I talked with Matt Monson about the EJ18 ECU as to why it's a good idea. We both posited that, because the EJ18 never had a knock sensor, that the ECU actually uses a fairly static timing map, to err on the side of safety since it couldn't measure knock. That won't help it make any more power, but with the risk of detonation being so high in a Frankenmotor with high compression, an EJ18 ECU was the safest bet in terms of engine longevity.

Also, all EJ25D engines are Phase I.

Sent from my iPhone using Tapatalk

mike-tracy · Post by **mike-tracy** » Mon Aug 27, 2012 6:04 am

Not all ej25d's were phase I.

No, not talking about the JDM ones either.

entirelyturbo · Post by **entirelyturbo** » Tue Aug 28, 2012 4:43 am

When were there Phase II EJ25Ds? The EJ25D was replaced by the Phase II SOHC EJ253 in the Impreza 2.5RS and Forester in 1999, and the Legacy and Outback carried over the EJ25D until 2000, when it was replaced by the Phase II SOHC EJ251.

mike-tracy · Post by **mike-tracy** » Tue Aug 28, 2012 10:58 pm

I guess I should be more specific.

In 1999, certain ej25d engined Legacys received the new phase 2 block halves, with the updated crank, pistons, and rods, compression ratio, etc. The heads remained the same as 97-98. The 4eat on my 99 is also a phase II, mechanically and electronically.

About half of the ej25d's from 99 that I've worked on were phase II. If you'd like to see my vin# I'll PM it to you.

entirelyturbo · Post by **entirelyturbo** » Wed Sep 19, 2012 3:47 am

I don't work at the Subaru dealer anymore, so your VIN won't help me much. But that's interesting, like a factory Franken-motor from Subaru themselves

That kinda fits into the theory that me and my parts manager used to have though... that some Subarus occasionally get blessed with goodies from the factory that they normally wouldn't have gotten just as a means to get rid of surplus (in this case, extra EJ25D heads). We actually theorized that the Baja existed just to get rid of spare BE-BH Legacy parts

Correct me if I'm wrong, as, again, I've been out of it for a little while now. But Phase II bellhousings are 8-bolt instead of 4-bolt, aren't they? That's another way to see what you're working on without tearing the bottom end apart.

Post by **Legacy777** » Wed Sep 19, 2012 6:01 pm

Are all the new bell housings an 8 bolt bell housing? For some reason I had though they were 6 at some point...

zeke · Post by **zeke** » Thu Oct 11, 2012 7:13 am

i just got done swapping a ej25d into my buddies 91 wagon i wanted to do the franken motor but he didnt want to spend money on new head gaskets quite yet its a really straight forward swap you have to use the harness from the 2.2 the part that runs under the intake and the only things that you need to take from the 2.2 are the crank position sensor, cam position sensor, knock sensor and the throttle body because the tps is different we also deleted the egr and the charcoal canister you also have to use the power steering bracket off the 2.2 because the bolts are more spaced out on the 2.5 i guess when he blows the head gaskets on it we will put the 2.2 heads back on i would like to do a eg33 swap on my wagon

legacycentral bbs

A forum for 89-94 BC-BF(BJ) Legacy Owners and Fans