Frankenmotor questions

[torxxx]

read this thread http://www.ultimatesubaru.org/forum/topic/125377-ej25-with-ej22-heads/

 

and started thinking about what else could be done to that setup.  What compression ratio does the engine end up at with 22 heads on it?

 

How much can or has someone taken off the heads?  local machine shop said 95 22 heads the max is .05 but they've done .08 before.    0.1 possible?

 

Basically what I'm getting at is how close can we get the valves to the block deck?  I should know where the pistons sit @ TDC on a EJ25D block but I've never paid attention when doing HG's because I never turn the crank once the belts off.   And I'm guessing I would use 22T headgaskets?

 

And from what I've gathered it ends up being ~180 hp?    So compression ratio is gonna go up so Its going to need higher octane fuel and maybe water injection?  Kinda would like to see what could be gotten out of one of these setups with out a turbo or supercharger.   Its going in an offroad rig so I dont need all the extra bs that goes with forced induction

Edited May 1, 2013 by torxxx

[idosubaru]

I attached an excel spreadsheet of a Phase I EJ CR calculator.  Phase II EJ heads are 50cc head combustion chamber i think.

I suppose you can adjust the headgasket thickness to mimic shaving the heads, or attempt to calculate it out of the head CC's?  I never thought about head resurfacing reducing those numbers.

 

 

 

The standard height of the head is 3.839", so if you end up measuring anything less than 3.827"

 

A machine shop "inadvertently" resurfaced some Phase II heads to 3.81 which is 0.029 below stock (quoted above) or 0.017 below the lowest limit per the FSM.  They were bolted to a DOHC EJ25 and I used a thicker headgasket to make up some of that difference but it ran fine.   be advised that when resurfaced that low the valves protrude above the surface of the head and may strike the resurfacing device if not accounted for.

 

DOHC EJ25 pistons will strike Phase II heads when running if you use thin headgaskets, though it doesn't do it if you simply turn the crank by hand.  not sure if that matters in your work.

 

I'm sure you already know it but shaving the heads impacts timing belt geometry.  not sure if that theory has any practical implications though.

[torxxx]

well ya pistons hitting heads aint good, thats why I figured I'd ask here first.  I'm not trying to make a non interference engine.   I want this motor to be close enough tolerance that belt breaks @ high RPM, valves go thru pistons. 

 

Idea basically is max power output 

 

 

 

When you say the valve will protrude above the surface you mean at fully open correct?   Got I wish there was a way to get a cutaway design on these engines, or a computer simulator to play with to see just how far we can go with these engines.  

 

I have access to a 99 2.2L  but iirc they used oddball pistons in those, which makes me wonder if the valve quench area is different?

[chaz345]

What compression ratio does the engine end up at with 22 heads on it?

Disclaimer: I've not built or owned any sort of Frankenmotor. I have picked up a fair bit of information about them from shooting the breeze with my mechanic who has built many frankens.

 

Is not a simple question with a single answer due to different pistons and different head volumes having been used on different years. There's quite a range of possible compression ratios that you can end up with. I know at the higher end of the spectrum, the computer gets very unhappy as it's not capable of adjusting the timing enough to prevent detonation, even on high octane fuel. My mechanic and a friend built one of the highest possible compression ratio combinations and were having major issues with the ECU being unhappy. Their eventual solution was to get a tuneable ECU and run the  thing on E85.  Probably ended up with some of the highest possible output from a frankenmotor but I'm not sure the additional few HP was worth all the extra expense. You sould be able to get close to 180hp out of one that has a more manageable compression ratio.

[86BRATMAN]

Highest ratio of all stock parts combined is right about 12:1, that is with 96 ej25d bottom end and ej22 heads.  The 96's are a unique piston to the ej25d because they used the large combustion chamber hears with the bucket hla's.  If you don't know what the design is I'm talking about I can snap a picture when I get home.

[cal_look_zero]

So I ran a 98 EJ25D block with 97 22E heads. Standard resurfacing on the block and heads; no milling down. .040 Cometic MLS head gaskets. My original plan was a nasty CR with wiseco pistons and such, but I realized that I couldn't get too much more power from a little more CR, and it would probably cause more headaches anyways. Delta cams, 370cc injectors, PP6 tune, PnP on the heads, I/H/E (stock cats) and I made a little bit under a stock 2.0 WRX. Estimated to be about 200hp/220tq at the crank.

tl;dr: Power adders and a tune are more beneficial than >12:1 CR

[torxxx]

Megasquirt as a stand alone system?   Would stop the issue with the factory ECU trying to readjust everything.  I was thinking Delta low end cams, and PnP the heads before they goto the machine shop to get surfaced and cleaned.   I've got a buddy thats made an airplane run on Megasquirt, I'm sure we can make something use-able for a subaru

 

200hp @ the crank with an N/A motor is kind of my goal.  I'd like more use-able power, (dont get me wrong I love my EJ25D above 4k rpms.  Just sucks the TQ doesn't start til 3k or so)  

[flight_of_pain]

I just rolled over 20k mi on my frankenmotor. It is a phase 1 ej25d bottom end, single year '99 phase 2 ej223 heads, and ej25d headgaskets. The heads appeared milled, but I never measured them. This motor has significantly more low end torque than the ej22 that came out (and it was the pinnacle of ej22s, a '99 phase 2) I am constantly surprised by how well it moves my boat of a legwag around.

 

Isaac

 

edit: Mine is also run on the stock '99 ecu, and it works beautifully, although 99 was a MAP based setup so I imagine it is significantly more versatile than the earlier MAF ecus.

Edited May 2, 2013 by flight_of_pain

[chaz345]

Megasquirt as a stand alone system?   Would stop the issue with the factory ECU trying to readjust everything.  I was thinking Delta low end cams, and PnP the heads before they goto the machine shop to get surfaced and cleaned.   I've got a buddy thats made an airplane run on Megasquirt, I'm sure we can make something use-able for a subaru

 

200hp @ the crank with an N/A motor is kind of my goal.  I'd like more use-able power, (dont get me wrong I love my EJ25D above 4k rpms.  Just sucks the TQ doesn't start til 3k or so)  

I believe that Megasquirt is what they went with on the very high CR frankenmotor I was talking about but I may be mistaken. I do know that a Subie can be made to run quite well with a Megasquirt though.

[torxxx]

yea I checked with the megasquirt guru in town and he said no problem.  Order the kit, help him on his 5.3L twin turbo El Camino project and he will do all the wiring and tuning for me.