Subaru engines' weights

[Allch Chcar]

This isn't really to do with the FT-86/FR-S engine so I put it here.

The conversation:

Originally Posted by Allch Chcar

Yeah, nice catch BTW. Honestly it's stuff like this that makes me think what if they offer a FB16 later on and just launch it with the super special NA FB20 initially. How cool would that be? The FB16 should be 50lbs lighter than the FB20, even with boxers needing two heads. I know they're going to build a FB16 and it's going to be a turbo based variant. I'm going to have to start petitioning that we can at least special order the FB16 in the US when they start production .

Originally Posted by old greg

Unpossible. I'd be absolutely shocked if it was even 5 lbs lighter. The FB16 will be an FB20 with thicker cylinder walls and/or a shorter stroke crank. Odds are it will be the former, and even if it were exclusively the latter the FB20 crankshaft will only weigh ~20 lbs to begin with.

Originally Posted by Allch Chcar

Is that what Subaru does for their smaller displacements? That's shameful . Do you have a source? I'm actually very interested in that information.

Originally Posted by aliphian

Isn't the FB16 supposed to be boosted to the moon? If that's the case it would make sense to give it very thick cylinder walls. I would bet on that plan.

Originally Posted by old greg

It's pretty standard practice, really. Even Toyota does it, just look at the GR and UR engines. Changing the bore/stroke of an existing engine is much cheaper than developing something new from scratch. And keep in mind that Subaru is a comparatively low volume manufacturer (Toyota sells more Corollas than Subaru sells cars), yet it costs Subaru just as much to develop a new engine as anyone else. That's the reason they've been using the EJ for ~18 years now, and to be honest the FB seems to just be a modified EJ with a timing chain.

But look on the bright side. If the FT86 uses a standard FB20 shortblock with fancy Yamaha heads, you'll be able to upgrade to a 2.5L bottom end and lose a few pounds in the process.

PS: My source is 18 years of history.

Originally Posted by Exage

Sorry to disagree but the FB engine is very different from the EJ series.

Compare EJ25 Bore: 99.5mm Stroke: 79.0mm to the FB25 Bore: 94mm Stroke: 90mm

Fuji Heavy Industries has purposely gone from a over-square boxer to a more square boxer in the pursuit of better fuel economy (which they have achieved) (in the case of the FB20 it is under-square with a 84mm bore). The FB did incorporate the technologies of AVCS from the later EJ engines but it is however a brand new and redesigned engine down to the block, heads and internals!

With the same 90mm stroke I recon the crankshaft and connecting rods could be identical between FB20 and FB25. It might be slightly different but I've only seen one shot of the FB series connecting rod and crankshaft with no comparison shots between the two engines. It leads me to theorize that little gain if any at all would be made with a bottom end swap because they could be sharing the bottom end components.

Originally Posted by old greg

We'll just have to wait and see on that one.

I guess I should have said shortblock. Erroneous choice of words on my part.

Originally Posted by Exage

Fair enough. Here is Fuji's press release on the FB engine if you are interested. It goes over in better detail how the engine is somewhat different from the outgoing EJ. Better than I can explain, and it's official!

http://www.fhi.co.jp/english/news/pr...10_09_23e.html

Originally Posted by Allch Chcar

I don't think you understand what I'm saying here. Subaru already has smaller displacement engines. They used to sell an EJ18 in the states but they've been selling the EL15 overseas since 2006 and they had a EJ15 and EJ16 before that. I've been trying to get the engine weights for one of the 1.5/1.6 liter versions for awhile now. So if you know for a fact that Subaru reuses the same basic block then I'm looking for information that can be found by weighing any Subaru engine regardless of displacement! That's all I'm trying to clarify.

For example if Subaru builds a new FB16 it would undoubtedly be based on the EL15 not the FB20, in my mind. It would have changes similar to the FB20 but the EL15 already has some of the changes like being undersquare and having AVCS. Sorry if that does get my question across better, I'm very interested in this and I'd like to know what you know.

I found this from an aircraft engine supplier:
http://www.prekas.nl/subaru.htm

Originally Posted by http://www.prekas.nl/subaru.htm

The Subaru range of engines include:

EA-71: 1,6 liter, about 80 hp, about 78 kg(172lbs) dry weight
EA-81: 1,8 liter, 100 to 110 hp, about 85 kg(187lbs) dry weight
EJ-22: 2,2 liter, 130 to 160 hp, about 120 kg(265lbs) dry weight
EJ-25: 2,5 liter, 165 to 200 hp, about 135 kg(298lbs) dry weight
EJ-33: 3,3 liter, 225 to 275 hp, about 160 kg(353lbs) dry weight

I converted the numbers in bold to lbs. But I think this gives the idea that I really think they are different and not just a shared block with different bores and strokes. They're last generation engines, heck the 1.6L and 1.8L aren't even a part of the EJ series so maybe they're completely different. Needless to say the difference between the EJ22 and EJ25 is 33lbs. These numbers are unofficial and they're for complete engines w/o accessories like PS or AC too.

So it's your turn Old Greg.

[old greg]

First, I just want to point out that the "EJ33" is actually the EG33 and is a very overweight flat six, just in case anyone may wonder in the future.

I counter with this:

As found here:
http://locostusa.com/forums/viewtopic.php?f=4&t=4299

It's impossible to make direct comparisons though.

PS. That includes the flywheel and engine mounts, which I'm not sure would be used on an airplane.

[old greg]

I'd also like to know exactly which versions of the EJ22 and EJ25 he weighed, as there have been quite a few. Assuming the engines were in a similar state, I'd say most of the difference in weight is in the heads. The common EJ22E (90-97) was SOHC, and the EJ25D (96-99) was DOHC. I believe theses are most likely what he was using.

PS: The EA71 and EA81 are carbed pushrod motors from the early 80's

EDIT:
EJ22E Heads
http://www.rs25.com/forums/f7/t14983...ification.html
EJ25D Heads
http://www.rs25.com/forums/f177/t117...ng-covers.html

[old greg]

Originally Posted by Allch Chcar

I don't think you understand what I'm saying here. Subaru already has smaller displacement engines. They used to sell an EJ18 in the states but they've been selling the EL15 overseas since 2006 and they had a EJ15 and EJ16 before that. I've been trying to get the engine weights for one of the 1.5/1.6 liter versions for awhile now. So if you know for a fact that Subaru reuses the same basic block then I'm looking for information that can be found by weighing any Subaru engine regardless of displacement! That's all I'm trying to clarify.

For example if Subaru builds a new FB16 it would undoubtedly be based on the EL15 not the FB20, in my mind. It would have changes similar to the FB20 but the EL15 already has some of the changes like being undersquare and having AVCS. Sorry if that does get my question across better, I'm very interested in this and I'd like to know what you know.

And since you snuck this in on me...

The EJ15/16/18 are just small bore and/or short stroke EJ motors, very little different from an EJ25. And the EL15 is heavily based on the EJ, heck it uses an EJ25 crankshaft. They're interchangeable.

The EJ is dead. The EL15 might stick around for another year or two until a small displacement FB comes along but it's fate is sealed, it's old tech.

[xantonin]

On a side note, self-moderated forums are pretty damn cool. Good job guys

[Dimman]

Old Greg, could you answer something for me? I've heard that the EJ series also varies as to whether it is a closed, semi-closed or open deck block.

What I've heard is the rather rare 1st Gen Turbo Legacy EJ22 is a closed deck, whereas the standard EJ22 is open, and that the EJ20(5?) WRX motor (North American) is open but that the EJ25(7?) STI motor is semi-closed.

Any truth to this?

And there was something about the FB having two cooling circuits, one for the head, and one for the block (I'll edit with a link when I find it). Do you know anything about this? Dry deck?

[ichitaka05]

Originally Posted by old greg

And since you snuck this in on me...

The EJ15/16/18 are just small bore and/or short stroke EJ motors, very little different from an EJ25. And the EL15 is heavily based on the EJ, heck it uses an EJ25 crankshaft. They're interchangeable.

The EJ is dead. The EL15 might stick around for another year or two until a small displacement FB comes along but it's fate is sealed, it's old tech.

Just one correction. EJ15/16/18 vs EJ25 have a lot of difference in heads & comp ratio too. EJ15/16/18 are single port exhaust while EJ25 are dual port exhaust. Comp ratio for EJ15/16/18 9.5~9.7:1 are common, while EJ25 (NA) 10.0:1 is common. EJ15/16/18 are more close to older EJ20/22 series.

EL series are a lot close to EZ series. EL comes w AVCS

[old greg]

Originally Posted by Dimman

Any truth to this?

All of that is correct to the best of my knowledge.

Originally Posted by ichitaka05

EJ15/16/18 vs EJ25 have a lot of difference in heads & comp ratio too.

EL series are a lot close to EZ series. EL comes w AVCS

I don't really consider the differences in head design to be "differences" in the context of the debate that Allch Chcar and I have been having. The EJ has had a wide variety of heads over the years, but the point that I was trying to get across to Allch Chcar is that EJ's use more or less the same block (I know there are differences) regardless of displacement.

[Exage]

Clearly I'm not as researched in the Subaru engine design over the years but I can see old gregs' point in them de-stroking a FB20 block to create a FB16. It is feasible because they've done that in the past after exhausting bore reduction.

Dimman I believe you posted this earlier but with a 72mm stroke FB20 block (bore 84mm) would result in a 1596.03cc FB engine. Coincidentally a 72mm stroke FB25 block (bore 94mm) results in a 1998.66cc FB engine.

[Dimman]

Originally Posted by Exage

Clearly I'm not as researched in the Subaru engine design over the years but I can see old gregs' point in them de-stroking a FB20 block to create a FB16. It is feasible because they've done that in the past after exhausting bore reduction.

Dimman I believe you posted this earlier but with a 72mm stroke FB20 block (bore 84mm) would result in a 1596.03cc FB engine. Coincidentally a 72mm stroke FB25 block (bore 94mm) results in a 1998.66cc FB engine.

I believe that was Old Greg as well, I expanded a bit on the AWESOME potential.

[Allch Chcar]

Originally Posted by old greg

And since you snuck this in on me...

The EJ15/16/18 are just small bore and/or short stroke EJ motors, very little different from an EJ25. And the EL15 is heavily based on the EJ, heck it uses an EJ25 crankshaft. They're interchangeable.

The EJ is dead. The EL15 might stick around for another year or two until a small displacement FB comes along but it's fate is sealed, it's old tech.

Sorry about that Old Greg . It was my last post and I just went ahead and moved it over with the whole topic.

I'm familiar with the EL15 a little bit and I don't disagree but I think there is enough evidence that your suggestion that the FB engines would be the same block/heads with different bores and strokes and even the same weight is if anything premature.

And those engine weights you linked to are woefully inconsistent, they even mentioned that they needed a consistent system for comparison. The engine weights I gave included were older engines like the EA series but they were dry longblocks w/o PS or AC and naturally aspirated. Plus the engine you listed was a newer one and it could have had anything or nothing on the serpentine belt.

Even if the EJ25 from the '06 forester are similar to the engines I listed I'd bet the EJ20 were at least 30lbs lighter .

Originally Posted by old greg

All of that is correct to the best of my knowledge.



I don't really consider the differences in head design to be "differences" in the context of the debate that Allch Chcar and I have been having. The EJ has had a wide variety of heads over the years, but the point that I was trying to get across to Allch Chcar is that EJ's use more or less the same block (I know there are differences) regardless of displacement.

I am arguing that they have enough of a difference in regard to the block and heads since there is significant weight differences. If the EA series were 1.6L-1.8L and they are almost 70lbs lighter than the EJ22 in older engines, why would the newer EL15 or the unknown FB16 be based on heavier engines like the EJ20 and FB20 respectively and weigh exactly the same?

If anything the weight difference between the EJ22 and EJ25 was enough to validate my point. And my point was that there were huge weight difference for engines that were similar (EJ22 and EJ25) therefore there is probably significant difference for the newer versions of the sub2L ones aswell. I admit I don't have weights for the EL15 for comparison but hopefully that gets my point across.

You are probably right about the differences or lack thereof in block and heads but I still kindly disagree that all EJs weigh the same .

[Dimman]

Originally Posted by Allch Chcar

Sorry about that Old Greg . It was my last post and I just went ahead and moved it over with the whole topic.

I'm familiar with the EL15 a little bit and I don't disagree but I think there is enough evidence that your suggestion that the FB engines would be the same block/heads with different bores and strokes and even the same weight is if anything premature.

And those engine weights you linked to are woefully inconsistent, they even mentioned that they needed a consistent system for comparison. The engine weights I gave included were older engines like the EA series but they were dry longblocks w/o PS or AC and naturally aspirated. Plus the engine you listed was a newer one and it could have had anything or nothing on the serpentine belt.

Even if the EJ25 from the '06 forester are similar to the engines I listed I'd bet the EJ20 were at least 30lbs lighter .



I am arguing that they have enough of a difference in regard to the block and heads since there is significant weight differences. If the EA series were 1.6L-1.8L and they are almost 70lbs lighter than the EJ22 in older engines, why would the newer EL15 or the unknown FB16 be based on heavier engines like the EJ20 and FB20 respectively and weigh exactly the same?

If anything the weight difference between the EJ22 and EJ25 was enough to validate my point. And my point was that there were huge weight difference for engines that were similar (EJ22 and EJ25) therefore there is probably significant difference for the newer versions of the sub2L ones aswell. I admit I don't have weights for the EL15 for comparison but hopefully that gets my point across.

You are probably right about the differences or lack thereof in block and heads but I still kindly disagree that all EJs weigh the same .

Remember too that the different strokes have different sized cranks and rods, which are steel unlike the aluminum blocks, so this could also be a contributing factor.

[old greg]

Originally Posted by Allch Chcar

And those engine weights you linked to are woefully inconsistent, they even mentioned that they needed a consistent system for comparison.
The engine weights I gave included were older engines like the EA series but they were dry longblocks w/o PS or AC and naturally aspirated. Plus the engine you listed was a newer one and it could have had anything or nothing on the serpentine belt.

The consistency of their testing is irrelevant to this discussion as I only used the weight from one engine. Furthermore, I myself said that there can be no direct comparison.

Originally Posted by old greg

It's impossible to make direct comparisons though.

Originally Posted by Allch Chcar

I am arguing that they have enough of a difference in regard to the block and heads since there is significant weight differences. If the EA series were 1.6L-1.8L and they are almost 70lbs lighter than the EJ22 in older engines, why would the newer EL15 or the unknown FB16 be based on heavier engines like the EJ20 and FB20 respectively and weigh exactly the same?

The EA motors have nothing in common with the EJ motors aside from both being Subaru flat fours. In addition to having tiny OHV heads, they undoubtedly have a shorter deck height and a smaller bore pitch. They are not comparable.

It is illogical to argue that a small displacement FB will be lighter because the EJ22E had dinky little SOHC heads. You yourself say:

Originally Posted by Allch Chcar

I know they're going to build a FB16 and it's going to be a turbo based variant.

Such an engine would need all the breathing ability it could get. It would not have heads significantly different from an FB20/25. They would be large complicated DOHC heads, with variable vale timing and lift.

The EL is based on the EJ because it is, this is a known fact. Your hypothetical FB16 would be based on the FB20/25 because it's an FB16. If it were an XYZ16 then it could be anything you wanted it to be and I would gladly agree that such an engine could be 50 lb lighter.

Originally Posted by Allch Chcar

If anything the weight difference between the EJ22 and EJ25 was enough to validate my point

The difference in weight comes almost entirely from the heads. See this discussion as evidence:
http://groups.yahoo.com/group/AirSoob/message/39751
In which the weight of an SOHC EJ22 longblock is given as 182lbs, and that of an SOHC EJ25 is given as 186lbs. Another poster claims to have weighed his DOHC EJ25 longblock at 202 lbs. Further a third party is claimed to have found the DOHC heads to weigh ~15.5 lbs more than the SOHC heads. According to these guys then, there is approximately a 4 lb difference between the EJ22 and EJ25 shortblocks.

As I've previously said, a turbo FB16 would use the same heads (or bigger,to be honest) as an FB20. There would be a negligible weight difference in the shortblock. Both would use plastic intake manifolds which hardly weigh anything, and both would use the same accessories. The weight difference would be negligible, and that's before you consider the weight of a turbocharger, intercooler and heavy duty exhaust manifolds.

[Allch Chcar]

Originally Posted by old greg

The consistency of their testing is irrelevant to this discussion as I only used the weight from one engine. Furthermore, I myself said that there can be no direct comparison.

No argument there, I just thought it was worthy of note, nothing else.

Originally Posted by old greg

The EA motors have nothing in common with the EJ motors aside from both being Subaru flat fours. In addition to having tiny OHV heads, they undoubtedly have a shorter deck height and a smaller bore pitch. They are not comparable.

The EJs are both SOHC and I thought that was interesting enough how big of a weight differences they had. The fact that Subaru had separate engines for the smaller displacements that were much lighter than the bigger displacement EJ series was what I was pointing out though.

Originally Posted by old greg

It is illogical to argue that a small displacement FB will be lighter because the EJ22E had dinky little SOHC heads. You yourself say:

Such an engine would need all the breathing ability it could get. It would not have heads significantly different from an FB20/25. They would be large complicated DOHC heads, with variable vale timing and lift.

The EL is based on the EJ because it is, this is a known fact. Your hypothetical FB16 would be based on the FB20/25 because it's an FB16. If it were an XYZ16 then it could be anything you wanted it to be and I would gladly agree that such an engine could be 50 lb lighter.

Even if you add 20lbs to it for heads and then add whatever the thicker sidewalls would add and reinforcing the block, an aluminum 1.6L shouldn't weigh 200lbs+. Remember also it's going to be specially built by Subaru/Cosworth for their reintroduction into rallying. I doubt they'll use a heavier engine and just debore/destroke it. Plus do you know what an EJ15/16 weighs?

Originally Posted by old greg

The difference in weight comes almost entirely from the heads. See this discussion as evidence:
http://groups.yahoo.com/group/AirSoob/message/39751
In which the weight of an SOHC EJ22 longblock is given as 182lbs, and that of an SOHC EJ25 is given as 186lbs. Another poster claims to have weighed his DOHC EJ25 longblock at 202 lbs. Further a third party is claimed to have found the DOHC heads to weigh ~15.5 lbs more than the SOHC heads. According to these guys then, there is approximately a 4 lb difference between the EJ22 and EJ25 shortblocks.

As I've previously said, a turbo FB16 would use the same heads (or bigger,to be honest) as an FB20. There would be a negligible weight difference in the shortblock. Both would use plastic intake manifolds which hardly weigh anything, and both would use the same accessories. The weight difference would be negligible, and that's before you consider the weight of a turbocharger, intercooler and heavy duty exhaust manifolds.

Certainly, if you say so.