Kaosone

Hello ,

Could someone explain the in’s & out’s of why a 2.35 engine is so special about it please?

I get that it’s a stroked EJ22 crankcase which is rare & therefore an expensive start point. Is that it or is it down to characteristics of this engine or is there something more to it?

Thanks

Henrik

iTrader: (5)

it's also a closed deck as standard, but is centre thrust so needs machining to fit the longer throw crank of the ej257 (which is rear thrust, i.e. thrust bearing for the crank sits on the journal closest to the crank).

They do seem to end up super expensive when built up. Just the blocks seem to be 2k+ nowadays + a couple of hundred at least for machine work etc, but on the other hand they also seem to be "the daddy" when it comes to high power and reliability (or at least were, back in the day).

Kaosone

They do seem that way, but why is the question?

What does it do that a 2.1 stroker or 2.5 can’t

Alyn can closed deck you a 2.5 & convent it to 14mm headstuds & you’d think it’d spool a turbo faster than a 2.35 & produce more torque? (Granted it may not “Rev” as well).

matt-c

iTrader: (5)

2.2 block is solid though, rather than just an insert at the top.

So in theory, no problem with bore's flexing.

Kaosone

What power & / or boost levels do you have to run for that to be an issue?

Henrik

iTrader: (5)

yeah i've been toying with the ideas of stupid builds lately, and i would dearly like a 2.35, but my wallet winces every time i look at the costs

@matt-c i don't think the walls of the cylinder bores are "fully closed" (i.e. the shape you see at the top of the block doesn't go all the way down, i think), but the cylinder walls are probably still much thicker than the 2.5

I see importcarparts (and probably others) have thick wall ej20 blocks too - might be an alternative to ej22, but of course spool would be worse on a stroked ej20 than an ej22.

motors-gt mentioned on some other post somewhere that he'd seen some ej22 blocks crack by the bellhousing bolts, and (from memory) the hypothesis was that the ej22 + earlier CDB ej20 have fewer bolts holding the block+box together, which allowed the block to flex and crack, but this was on race cars, so maybe not applicable to us normal mortals.

Tidgy

Build spec depends on what you want to achieve, higher the power, less life span and bigger the cost.

Road use is different to race use and drag use

Drag use is different to race and road use

etc etc

Basicly it isn't simply a case of saying 2.35 is best option becuase above the 2.35 is a 6 pot.

So you need to come up with what you want to achieve before you spec the engine and what will be a long list of supporting mods as were talking big builds.

matt-c

iTrader: (5)

Henrik, you may well be right, there needs to be some coolant flow.

There is a video somewhere (can't currently find it) which details how the closed deck blocks are made, IIRC it's a much longer and difficult process and that's one reason why they cost more.

Kaosone

The question was what’s so special about the 2.35, none of that statement is relevant to this post.


This one?

If I am not mistaken Alyn will closed deck & rehone an open block for £500? The EJ22 is cast as one piece with support for the cylinder walls (which may allegedly make it stronger).


Calling for assistance...

@stonejedi & @IainMilford

Help!!!

stonejedi

iTrader: (51)

EJ22T had a different casting process,closed deck,under piston squirters...A much stronger block,that was given more thought.SJ.

Kaosone

Is that it?

Nothing to do with the balance of torque & revs from the capacity?

Literally it’s just the strongest foundation to build upon

lockheed

iTrader: (1)

Here's mine , with the Arrow crank along side

Picture taken at Finch Motor Sports work shop , A.K.A Motors GT on here , Alyn some years ago did vertical cut thru of the differences in the blocks the results were , well not what i ever thought . Perhaps he will share

Kaosone

Arrow crank saves 1kg of rotating mass

stonejedi

iTrader: (51)

What was you expecting?A coffee machine and free cable!...Lol,in my opinion its the best out of the bunch definitely for holding big power!Before i built my engine i had done lots of research talking to all the Subaru specialist at the time from Ollie and Matt Clark to Mark of lateral performance etc etc etc... and all recommended going the 2.2 block stroked to a 2.35,expensive build but once built right are very tough engines that last and can take a beating.SJ.

IainMilford

iTrader: (15)

In my experience the 2.35 is generally classed as the best of both worlds, more torque and earlier spool than a 2.1 and more revvy than a 2.5, all of that and having a strong, closed deck block make it an ideal platform for high power builds.

Kaosone

Actually something along the lines of what Iain just said

Cheers


So as well as the previously mentioned strength advantages the final configuration of the stroked out 2.2L offers what’s probably the best balance of revs & torque


So I guess the next question for poor people (me) is do they (I) stroke an EJ20 to a 2.1 or build an EJ25 for the additional torque & spool.....?

Hmmmmmm

IainMilford

iTrader: (15)

that really depends what you are aiming for, 2.5’s are known to be fragile above 450bhp (rule of thumb safe limit) but do make an excellent road engine based on torque and drive ability. Personally I wouldn’t track a 2.5.

if you’re building for track then 2.1 or 2.35, plenty of big power 2.1’s about if you don’t want the cost of the EJ22T block. The block in my car is a 22b block so was already Rear thrust converted and had the oil squirters blanked off.

stonejedi

iTrader: (51)

I wont reply next time then!....He’s all yours Iain.SJ.

lockheed

iTrader: (1)

And a larger and superior oiling system, never mind the strength of it ......

Kaosone

2.1 probably sounds like the best bet, however I may compare 2.1 & 2.5 dyno charts when I am bored at work next (just because).

I take it that 450BHP limit is based on an open deck EJ25 with forged rods & pistons?


Now now, I said “cheers” & gave you a thumbs up as I am nice & value your input (even if Iain's is better).




The stock 79mm crank seems ample for most, what are you planning?

IainMilford

iTrader: (15)

Yes, I know you can pin the block and many have done it successfully particularly in the states but I have seen too many fail to want to take the risk.

lockheed

iTrader: (1)

RCM runs the 2 litre block and a 2 litre crank so ive read with all the bells and whistles

Kaosone

Interesting... That takes us full circle back to choosing an EJ22 over a closed deck converted 2.5
​​​​​​​

IainMilford

iTrader: (15)

I think they also run O rings instead of head gaskets so it’s safer at high boost, I think this is only possible on the EJ20

Again depends on what you’re building the car for, if you’re planning regular track use then I’d avoid the 2.5 block.

Tidgy

actualy it is very relevant, the point im making is if you dont have the right spec/budget 2.35 isnt special at all. If budget allows a 2.35 will be pretty crap compared to a 6 pot meaning 2.35 is total crap.

For example your now talking about 2.1 vs 2.5, for road use, closed deck converted 2.5 at 500bhp will prob be about as good as it gets cost vs reliability vs road performance due to the low down grunt. But it comes back to what your trying to do with it, if its track use the 2.1 may well be better as it can be based on a true closed deck block as it revs better compared to a 2.5, which even closed deck has thnner liners in stock form.

So as said it isn't as simple as saying what is special about the 2.35, what your are trying to achieve with it is the starting point.

lockheed

iTrader: (1)

Im not sure im able to help you decide giving my limited knowledge , but the 2.35 with a big gtx35.82 on the road is laggy unless your in the zone and i have found the top speed in higher gears is out of this world (licence loser)particularly in the manner it gets there , however if had my time again i would have to think very hard and would probably opt for the 2.5 cdb for the road with a smaller rotated set up .

Kaosone

Yes, you're exactly right. I appreciate the detailed specifics you’ve offered with regards to the 2.35 engine configuration, we'd be lost here without your input.

Thank you.

Henrik

iTrader: (5)

A completely different option to get to 2.35 was something i read about years back - someone took a 2.0 CDB, bored it out enormously (maybe even enough to get rid of all the cylinder wall), and replaced them with thick liners in steel. I can't remember who it was, and it might be something I've just made up, but if not, it would maybe also be an option.
Not sure it'd work out cheaper than an ej22 block, however, and there's the risk of liners dropping etc etc, so maybe not a worthwhile avenue.

Kaosone

That is very interesting & honest feedback as well as food for thought.

Kaosone

I am surprised no one has sleeved a 2.5 down to 2.2?

Thicker cylinder walls for added strength & 2.35’s for everyone