Jab83 Posted October 18, 2011 Share Posted October 18, 2011 there for there is no real difference in the block. Only diff is internals heads and misc's Link to comment Share on other sites More sharing options...
subikid90 Posted October 18, 2011 Share Posted October 18, 2011 ^WRONG!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! EJ257 is a semi-closed deck block. BIG difference! -Subikid90 1997 Legacy GT 5spd & EJ251 w/EJ25D heads ~10.5CR 1998 Legacy GT Limited waiting for EJ22T hybrid swap Link to comment Share on other sites More sharing options...
Jab83 Posted October 18, 2011 Share Posted October 18, 2011 Ok. Oh well.... ej20r isn't closed. hmmm lots of subaru turbo engines are open deck.... So oh well i cant run 30+psi. I dont plan on it. Just making a one of a kind engine. Dont wanna have to swap in a sti or wrx engine to have a turbocharged subaru..... when i can look around and find used sti internals and make 300awhp. easy. only running like 15 psi Link to comment Share on other sites More sharing options...
SBT Posted October 18, 2011 Share Posted October 18, 2011 Believe the EJ20 DOHC Bugeye Rex is a semi-closed deck as are all of the EJ255 and 257s. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
Jab83 Posted October 18, 2011 Share Posted October 18, 2011 well I'll tell ya how it goes. If it blows OH well... lol I'm gonna get it done then prob grab a old svx and steal the engine out of it. lol. Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted October 19, 2011 I Donated Share Posted October 19, 2011 (edited) EJ205, EJ255, and EJ257 (current USDM turbo engines) are all open deck or semi - open. However, the JDM EJ20H and EJ20R (Legacy twin turbo) are fully open deck just like the EJ25D is...and are capable of 400 wheel horsepower on stock internals. Edited October 19, 2011 by broknindarkagain -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
lulzcow Posted October 19, 2011 Share Posted October 19, 2011 I'm with Jab on this. Although it probably won't be the most powerful, or take the most amount of boost. Link to comment Share on other sites More sharing options...
Jab83 Posted October 19, 2011 Share Posted October 19, 2011 I've seen some threads about it taking 30psi+ and go for a about 2 months then it threw stock sti rods. didn't bust the block though... sooooo. I think the block can take alot! Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 No open deck Subaru motor is going to take boosting above 5-6psi without head movement and other issues. And there's a large difference between semi-closed and open-deck Subaru EJ engines, both in the structural rigidity of the blocks, including BEB, and the cooling journals. And if I was going to run 30psi of boost, it would be on a 2.2T closed-deck block or a fully built Crawford 2.7T block. The EJ20R is the 2nd Gen JDM Legacy (low-pressure - < 10psi - twin- turbo) variant and is open deck. The other EJ25x models listed are all open deck and not worth boosting. EJ205, EJ255, and EJ257 (current USDM turbo engines) are all semi-closed deck with uprated internals in the EJ255 and EJ257 variants. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
jamaha51 Posted October 19, 2011 Share Posted October 19, 2011 There have been a few people that have boosted an ej25d with sti internals and they hold up fine. One guy finally cracked his cylinder at around 35psi and 600awp so I think they would last pretty good on lower boost but that is just me. Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 There's been countless hundreds more who tried and failed using the same approach. As always, there's an exception to every rule, and frankly I wouldn't pay that kind of money to find out whether my investment was the exception. I know I was "considering" boosting one of my 98 GTs back in early 2000-2001 and the numbers just wouldn't add up. YMMV I guess is the best caveat. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted October 19, 2011 I Donated Share Posted October 19, 2011 The EJ20R is the 2nd Gen JDM Legacy (low-pressure - < 10psi - twin- turbo) variant and is open deck. My EJ20R was tuned at 15psi on a single rotated TD04. The head gaskets eventually failed but I don't think this was due to boost. It had the same gasket design as the EJ25D and the same type of failure. IDK how strong the open deck blocks are. IDK ifthere is any difference between the EJ20 and EJ25 open deck blocks in strength either. -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 Typically, HGs are the first point of failure on boosted open-deck EJs, The cylinder walls have nothing to hold them firmly in-place, so the cylinder bores squirm under boost and that leads to misalignment at the head/block nexus and ultimately to HG failures. That is if the BE doesn't fail first. AFAIK, the EJ20 and EJ25 ODB are similarly constructed so would expect similar block structural strength block-to-block. The only difference between some of the variants is in the BE/CMB placement/construction - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
Jab83 Posted October 19, 2011 Share Posted October 19, 2011 damn I didn't understand a word of what you said.. LOL Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 Translation HG = head gaskets nexus = mating surface BE = bottom end ODB = open-deck block CMB = crank main bearings - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
Jab83 Posted October 19, 2011 Share Posted October 19, 2011 ahhhhhh Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted October 19, 2011 I Donated Share Posted October 19, 2011 My understanding was the EJ25D head gasket failure was due to a poor gasket design. The JDM EJ20 twin turbos use the same gasket...just thicker to lower the CR -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 EJ25D has a number of problems, chief among them is their propensity for blowing HGs. When you add boost, you further aggravate this situation due to the cylinder wall movement that I mentioned previously, which can lead to leaking HGs, misfires, and damage to the engine. Yes the HG failure on NA engines is due to poor gasket design and even manufacturing QC on some of the earlier Phase 1 blocks. But I find it also depends on how well the engine is maintained as well. Run it low on oil or coolant, or don't deal with a bad coil-pack/plug wire(s) or cracked/fouled plug(s), and your risk of HG failure goes up exponentially. Keep it tuned, regular OCIs and coolant change and you reduce the risk. One of my 98 BDs is still running on the original OEM head gaskets, the other I changed out as a precautionary measure. The closed deck and later semi-closed deck EJs were specifically designed to operate under the higher boost conditions, that make these engines shine, without compromising the head/cylinder mating surface integrity. Properly maintained, and under reasonable boost conditions, the EJ255 and EJ257 should not suffer the HG issues that plague the EJ20D. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
JAC Wagon Posted October 19, 2011 Share Posted October 19, 2011 Im just sitting here absorbing all this info like a damn sponge. SBT, what do you do for a living? Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 Program manager and long-time (over 37 years) Subaru owner, enthusiast and pro-active Subaru brand advocate. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
Jab83 Posted October 19, 2011 Share Posted October 19, 2011 nice... well... If i can find a 257 or any of those for a good price. local. I would get it. But Probably wont at all. I'm really wanting to find a old svx and steal the engine from it. and build a supercharged 3.0. Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 The EG33 SVX H6 would then be a supercharged 3.3L . Actually, you'd have a lot of fun with just putting a 5 or 6MT box behind it and letting the torque monster that is the EG33 rock your world without FI. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
JAC Wagon Posted October 19, 2011 Share Posted October 19, 2011 Supercharged H6 would be sick! Link to comment Share on other sites More sharing options...
Jab83 Posted October 19, 2011 Share Posted October 19, 2011 I thought it was 3.0... Damn it. my H6 knowledge is lacking.. But yes I'm gonna hook it up to my stock 4.11 5 speed that came with my car. I'm gonna have to get a new rad though. otherwise i think it'll bolt right up. Oh i also have to do a harness merge. would i be able to run the svx ecu? and be ok??? Link to comment Share on other sites More sharing options...
SBT Posted October 19, 2011 Share Posted October 19, 2011 You'd likely have to go to a Stage 4+ clutch to handle the massive HP and TQ numbers from an FI EG33. Have seriously considered picking up a 96-97 LSi SVX and putting an STI/Spec B 6MT box in it, likely go with an STI box for the FLSD and DCCD, and upgrade the R160 rear diff to the R180. But back OT... fitting an EG33 into 2nd gens is a challenge due to the length overall of the engine - you're added 2 more cylinders to a 2.2L engine and the TB cover sits really too close to the radiator and cooling fans. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
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