Engine/drivetrain Selection for the 818

[16g-95gsx]

I will first start off by saying that I am very excited what is developing with the 818. Thank you very much to FFR for all that you've done so far, and what you do for the automotive enthusiast community.

One thing that I wanted to say, and I'd really like to hear some feedback regarding it, is the engine and transmission selection for this concept. Understandably the idea was to have a one-car donor for the components used in this platform, and therefore the engine and transmission selection comes naturally from a Subaru/WRX based vehicle. Without a doubt this car may very well be FFR's introduction into the younger crowd due to the price range and donor car choice. However, I am curious if FFR will allow other engine/drivetrain configurations as a possibility with this car? Understandably the WRX/EJ engine configurations would be the original intent, but due to the pricing and potentially "tuner" niche that this car may be able to cater to I am curious if the size constraints will allow for other options. I'm sure it's been addressed before, and everything is still in the design phase right now, but I'm curious what FFR's take on this idea is right now?

While the EJ engine series would be the original intent, other options such as Honda K20 series and Mitsubishi 4g63 options could provide even lighter, cheaper, and possibly better suited engine/transmission platforms for those that would WANT to have options. From my research so far it appears that an engine such as an EJ255 runs around 380lbs, vs an iron block 4g63 at around 300, or an aluminum K20A at around 280. The pricing of the iron block 4g63 is extremely cheap to most EJ engine applications, while the higher revving, lower torque K20 would possibly be another great choice for this type of a lightweight platform. Being that there are many fwd transmission options for these type of platforms, it would also keep the user from having to modify the awd Subaru transmission, potentially providing a stronger drivetrain and another lighter weight transmission option. Leaving other engine selections as options may very well allow even more development of this car, and possibly even further acceptance by potential buyers. Something that I noticed from the GTM was that the availability of the transmission selection which has increased the build cost tremendously as it was the sole option available for the platform.

Just curious what FFR's stance is at this point, and whether or not they will leave the spaceframe engine/transmission compartment spacing large enough for other non-boxer platforms? Obviously this wouldn't be the route that everyone would take, but since the spaceframe size constraints will ultimately limit the engine/transmission options for this car, I am curious if FFR is considering leaving these as "options".

[16g-95gsx]

Without trying to sound biased, I am very familiar with the 4g63/DSM engine and transmission setups. An iron block 4g63 can be had for easily under 1000 dollars, and handles far far more than 400awhp in factory form (I know of a number of them pushing 600awhp in completely stock form). With a "fwd" transmission setup this would prove to be an extremely reliable setup, while potentially reducing a solid 80lbs from the engine selection. FWD 4g63 transmissions are typically sold extremely cheaply as the AWD is the preferred setup, so the drivetrain selection would be extremely cheap, and LSD front differential options would be easily adapted. Additionally no transmission modification would be necessary to convert from AWD to "FWD". Additionally the AWD transmission could easily be modified in a similar manner to the subaru transmissions. Without knowing the total weight of a converted awd subaru transmission, you'd likely be looking at an additional 100lbs removed from the car, with a cheaper engine and transmission option, with equal power potential.

[BrandonDrums]

The rationale behind using Subaru running gear for this kit has been discussed at great length on these forums.

Just browse around a bit and pretty much every point you brought up has been shelled out specifically.

I would link the threads but I'm on an iPhone at the moment. That sounds like a cool engine but the Subaru platform is far more ideal for cost, availability, durability and support reasons. Cost being not only do or costs but design costs for the kit, Subaru packaging is easier to work around than a traverse fad setup.

Further, 380 lbs is about the weight of the full engine plus trasnmission of an ej motor. A bare ej longblock is about 180 lbs. I know because I just sold my old 2.0 and was able to pop it in and out of my car by myself.

[16g-95gsx]

If the EJ engine series is 180lbs for a longblock setup I would be impressed. From my research that isn't at all the case. Like I said, I may sound biased with my 4g63 comments, but I simply am doing preliminary research and it appears that the EJ engine series is surprisingly heavy for being all aluminum, and on a platform where every single pound should count, it seems non-ideal. I will do a bit of searching on this board specifically.

[Oppenheimer]

Other advantage of using Scooby is they are boxer motors, so the cg can be kept lower, improving handling. I think FFR was thinking of serious track handling with this car, more than ultimate power capability.

[16g-95gsx]

Certainly if the weight is kept low enough the center of grav of the boxer engine would be more idea. However, if my research proves correct in that the EJ25 is 380lbs, the total weight gain of this engine vs a comparible 4g63 or K20, etc, would destroy the COG advantage.

[bbjones121]

Nobody is forcing you to buy a FFR kit. It sounds like you might be more interested in a Superlite SL-R.


Certainly if the weight is kept low enough the center of grav of the boxer engine would be more idea. However, if my research proves correct in that the EJ25 is 380lbs, the total weight gain of this engine vs a comparible 4g63 or K20, etc, would destroy the COG advantage.

[16g-95gsx]

It's an open discussion about a new design, I don't see any harm in weighing the pro's and con's of various powerplant choices.

Like I said the boxer setup seems ideally if overall weight is held equal due to it's flat/ lower CG design. But if total weight is kept well over 300lbs then this benefit likely goes out the door.

[crackedcornish]

It's an open discussion about a new design, I don't see any harm in weighing the pro's and con's of various powerplant choices.

Like I said the boxer setup seems ideally if overall weight is held equal due to it's flat/ lower CG design. But if total weight is kept well over 300lbs then this benefit likely goes out the door.

read the link
http://www.factoryfive.com/whatsnew/update/nextcar/818intro.html

the donor car/drive train layout has already been decided, so discussing the pro's and cons of the Subaru boxer vs. other engine layouts at this point is mute

I think this thread was meant to focus on which Subaru engine/trans was the best selection for the car, not whether or not that a boxer type engine be used....but I could be wrong:)

[Someday I Suppose]

I am not sure if FFR will have a stance on it, they are supplying a frame with mounting points and maybe some exhaust components to support the subbie stuff, if you want to fabricate mounts and exhaust to fit something else in it, go for it. Knowing from the roadster, there are guys who have stuffed all sorts of things under the hood, if you can make it fit, have at it. That is part of the fun of building a car, deciding where you want to follow the book, and where you want to break new ground.

-Scott

[crobin4]

I am not sure if FFR will have a stance on it, they are supplying a frame with mounting points and maybe some exhaust components to support the subbie stuff, if you want to fabricate mounts and exhaust to fit something else in it, go for it. Knowing from the roadster, there are guys who have stuffed all sorts of things under the hood, if you can make it fit, have at it. That is part of the fun of building a car, deciding where you want to follow the book, and where you want to break new ground.

-Scott


+1 If a longitudinal Subaru engine and transaxle will fit, then you'll have plenty of room for virtually any transverse engine you like. Including some transverse v-6s I expect. That's the beauty of kit cars they are often a blank slate. A little measuring, cutting, welding you have whatever you want.

[16g-95gsx]

My thoughts exactly. This us without a doubt what keeps me excited about this concept. I'm used to tearing things down to the nuts and bolts in order to fight what the factory gives you.

The only concern I had is spacing, whether or not the body and spaceframe will be large enough to accomodate other choices.

[mn_vette]

On thing you have to remember is that with the subaru engine it is considered a "mid engine" car. If you were to put a mitsu engine in it with the transmission you have just moved the largest weight in the car back directly in line with the rear axle making it a rear engine car. Moving that 300+ pound mass 1 foot further back is going to make a large difference in the handling and dynamics of the vehicle.

[armstrom]

not to nit-pick (you're correct about the dynamics of the vehicle changing!) but it would still be a mid engined car. Many mid engine cars have this same configuration (toyota MR2/MR-S, Lotus Elise/Exige, Acura NSX to name a few) A rear engine car would place the engine fully behind the rear axle, like a Porsche 911 or a VW bug.
-Matt

[mn_vette]

not to nit-pick (you're correct about the dynamics of the vehicle changing!) but it would still be a mid engined car. Many mid engine cars have this same configuration (toyota MR2/MR-S, Lotus Elise/Exige, Acura NSX to name a few) A rear engine car would place the engine fully behind the rear axle, like a Porsche 911 or a VW bug.
-Matt

I stand corrected.

[wjfawb0]

not to nit-pick (you're correct about the dynamics of the vehicle changing!) but it would still be a mid engined car. Many mid engine cars have this same configuration (toyota MR2/MR-S, Lotus Elise/Exige, Acura NSX to name a few) A rear engine car would place the engine fully behind the rear axle, like a Porsche 911 or a VW bug.
-Matt

By that logic many current front engine rear wheel drives are mid engine then, right? If the engine is even with or behind the front axle? It's all semantics anyway I guess. :)

I'm not a FWD/transverse fan, so I'm not familiar with the mitsubishi and honda motors so much. How would you get the transmission outputs and axles to fit in a frame designed around the subaru symmetry without the weight of the motor being shifted to the left or right? The subaru transmission also is not much wider than a regular rear differential which leaves plenty of space for longer control arms, shock mounts, etc. I figure this has all already been discussed somehwere in this forum.

[16g-95gsx]

Why would engine choices like that place the engine further back? The engine itself is no deeper than the EJ series and most 4cyl fwd trans would be horizontal, making the bias of the weight go forward if anything.

I weighed a few EJ20 components yesterday FWIW, the heads without cams or valve covers came to around 20lbs each. The crank was around 21lbs, 4 OEM rods were around 5lbs. A 5spd trans came in around 130lbs with VC and center diff.

I'd really like to see a database on component weights start to be developed.

[Silvertop]

It's an open discussion about a new design, I don't see any harm in weighing the pro's and con's of various powerplant choices.

Like I said the boxer setup seems ideally if overall weight is held equal due to it's flat/ lower CG design. But if total weight is kept well over 300lbs then this benefit likely goes out the door.

Ultimately, the buyer can probably shoehorn any drivetrain into the 818 that he chooses, if he can make it work. However, I think it is unlikely that FFR is spending any time on engineering for other choices than Subaru, at least at this point in time.

What the prospective builder must remember is that the 818 uses a "donor car" concept, following the process of the 65 Roadster and Coupe, at least the earlier versions. (It has only recently become possible to buy a complete kit Roadster which includes everything BUT the drivetrain). But for now at least,for the 818 this means that much more than the drivetrain will be taken from Subaru. Included will likely be all suspension components, brakes, hubs, radiator, wiring harness, steering geometry, dashboard gauges (maybe the whole dashboard), fuel tank, and potentially even lights. And probably a bunch of stuff I haven't even thought of...... All of which means that you will be virtually required to buy a complete donor car - specifically a Subaru - to build the 818, at least at anywhere near the target price-point of 15K.

Based on what we know, this is likely to be a 2002-2007 WRX, although given the nature of Subaru model lines, it is likely that normally aspirated Subaru Imprezas of the same vintage could probably be substituted if one wants to save some money, and is willing to accept 170 horsepower rather than 225 + . The other parts should still fit.

If one does all this and still wants to try to fit an engine-transmission from another make of car, well -- go for it. But I personally think it is going to be more trouble than it's worth.

[bbjones121]

I think we need dimensions and axel locations just as much as we would need weights.



Why would engine choices like that place the engine further back? The engine itself is no deeper than the EJ series and most 4cyl fwd trans would be horizontal, making the bias of the weight go forward if anything.

I weighed a few EJ20 components yesterday FWIW, the heads without cams or valve covers came to around 20lbs each. The crank was around 21lbs, 4 OEM rods were around 5lbs. A 5spd trans came in around 130lbs with VC and center diff.

I'd really like to see a database on component weights start to be developed.

[armstrom]

By that logic many current front engine rear wheel drives are mid engine then, right? If the engine is even with or behind the front axle? It's all semantics anyway I guess. :)

I'm not a FWD/transverse fan, so I'm not familiar with the mitsubishi and honda motors so much. How would you get the transmission outputs and axles to fit in a frame designed around the subaru symmetry without the weight of the motor being shifted to the left or right? The subaru transmission also is not much wider than a regular rear differential which leaves plenty of space for longer control arms, shock mounts, etc. I figure this has all already been discussed somehwere in this forum.

Yes, this is correct. Many Front engined/RWD cars are mid-engined. Here's a list:

http://en.wikipedia.org/wiki/Mid-engined#FMR_layout_.E2.80.93_Front_Mid-engine_.2F_Rear-wheel_drive

I'm in no way arguing for the use of a transverse mid-engine setup. It does have drawbacks. The engines are usually mounted off-center in the car (as you point out) in order to make room for the transmission. Also, the use of an inline or V engine as opposed to a H4 will result in a higher center of gravity. Also, as was pointed out earlier, the longitudinal weight distribution is more rear-biased due to the engine being closer to the rear axle. Many of these transmissions also require the use of asymmetrical halfshafts which cause torque steer when used in a FWD setups but can also be problematic in M/R configurations. The shorter axle sees higher angular deflections when the suspension is loaded which can put additional stresses on the CV joints for that axle resulting in premature failure.... That, and you have two unique axles rather than one part that can be shared from side to side.. makes keeping a spare for track use cheaper and easier :)

The reason we've seen so many production mid-engined cars use FWD transverse engines over the years is simply a matter of economy. In most cases these engine and transmission combos are simply lifted from another (cheaper) production car already being made by the company in question. The whole system is simply pushed to the back of the car and boom, you have a sporty mid-engined car. Toyota did it with all three generations of the MR2.. They basically used the four-banger from the corola/celica models of the same generation (4A-G(Z)E, 5S-FE, 3S-G(T)E, 1ZZ-FED).

I still think the Subaru converted to "FWD" is probably the best engine/tranny combo for this type of car. If people are dead-set on an alternative drivetrain they could always look into the porsche boxter. it has a similar configuration to the subaru.. just be prepared to pay huge prices for any parts as well as having to source custom axles to fit the car. This assumes that FFR is planning to re-use the stock subaru front half-shafts and suspension uprights for the 818 (which would be a VERY good idea... nudge nudge)

-Matt

[forced4]

What the prospective builder must remember is that the 818 uses a "donor car" concept.....All of which means that you will be virtually required to buy a complete donor car - specifically a Subaru - to build the 818, at least at anywhere near the target price-point of 15K.

If one does all this and still wants to try to fit an engine-transmission from another make of car, well -- go for it. But I personally think it is going to be more trouble than it's worth.

16g-95gsx; if you want a Diamondstar powered kit car, I think you are on your own, at least with this option.

[bbjones121]

It seems like an NSX, Elise/Exige, MR-2 are more similar to a rear engined car? Despite this, reviews after reviews state the porsche boxter as being one of the best handling cars on the road, even better than the 911. So whatever the numbers on paper say, I image a Subaru drivetrain to handle far better than a transverse drivetrain.


not to nit-pick (you're correct about the dynamics of the vehicle changing!) but it would still be a mid engined car. Many mid engine cars have this same configuration (toyota MR2/MR-S, Lotus Elise/Exige, Acura NSX to name a few) A rear engine car would place the engine fully behind the rear axle, like a Porsche 911 or a VW bug.
-Matt

[PhyrraM]

Me thinks this is not the kit for you.

[Oppenheimer]

By that logic many current front engine rear wheel drives are mid engine then, right? If the engine is even with or behind the front axle?

Correct. When people talk about 'mid-engine', they often clarify by indicating if its mid engine with the engine in front or back, as in MR (Mid Rear), like the 818 will be.

An example of a Mid-Front is a Honda S2000. Its engine is fully behind the front axle (note the long hood).

[16g-95gsx]

The original purpose of the thread was long lost with these replies. I simply was asking to hopefully find out if the space constraints within the subframe would allow for other options. Jim had already mentioned that any spare inch of space would be saved for in the cockpit, so I was curious if there would be ANY room left available in the engine bay. Obviously any non-subaru powerplant selection would be up to the builder, but spaceframe constraints were my sole concern in making a thread like this. I don't "want" a diamondstar powered car, it was simply an example, and the comments about weight was simply to show the pro's and cons of potential powerplant choices. Again, I already specified that I fully understand FFR's original intent with the H4 engine choice.

At this point let this thread die off as it's not going anywhere near where I had intended.

[Oppenheimer]

What the prospective builder must remember is that the 818 uses a "donor car" concept, following the process of the 65 Roadster and Coupe, at least the earlier versions. (It has only recently become possible to buy a complete kit Roadster which includes everything BUT the drivetrain). But for now at least,for the 818 this means that much more than the drivetrain will be taken from Subaru. Included will likely be all suspension components, brakes, hubs, radiator, wiring harness, steering geometry, dashboard gauges (maybe the whole dashboard), fuel tank, and potentially even lights. And probably a bunch of stuff I haven't even thought of...... All of which means that you will be virtually required to buy a complete donor car - specifically a Subaru - to build the 818, at least at anywhere near the target price-point of 15K.

Which is a good thing of course. This keeps the kit price down (as well as overall cost to build), as there are less parts FFR has to source and supply, they get to leverage all the OEM quality engineering that went into all those pieces, its easier for you to find replacement parts (you don't a list of the 15 different cars that each componet came from just to do a repair).

[thebeerbaron]

The original purpose of the thread was long lost with these replies. I simply was asking to hopefully find out if the space constraints within the subframe would allow for other options. Jim had already mentioned that any spare inch of space would be saved for in the cockpit, so I was curious if there would be ANY room left available in the engine bay. Obviously any non-subaru powerplant selection would be up to the builder, but spaceframe constraints were my sole concern in making a thread like this. I don't "want" a diamondstar powered car, it was simply an example, and the comments about weight was simply to show the pro's and cons of potential powerplant choices. Again, I already specified that I fully understand FFR's original intent with the H4 engine choice.

At this point let this thread die off as it's not going anywhere near where I had intended.

I think so little is known about the frame at this point that it would be very hard to say. Doubly so because even if you snuck into R&D and looked over Jim's shoulder, the frame could change down the road to meet the body design needs. This thread would be a great one to ask down the road, once the frame and body design is finalized.

And, to continue the threadjack - as far as I know, Honda/Toyota etc power plants put the engine in front of the drive axles, so that when you put them in a rear-drive configuration, you end up with the engine in front of the drive axles, hence the rear-mid-engine designation.

[Silvertop]

Which is a good thing of course. This keeps the kit price down (as well as overall cost to build), as there are less parts FFR has to source and supply, they get to leverage all the OEM quality engineering that went into all those pieces, its easier for you to find replacement parts (you don't a list of the 15 different cars that each componet came from just to do a repair).

Precisely! This concept is one of the things that has allowed FFR to dominate the kit car industry. They have made it affordable for average humans. Of course, the fact that they make a really, really great product doesn't hurt either.............

[crackedcornish]

this is why I asked the question about the possibility of using removable subframes/engine cradles (which was never answered). It would allow the use of different engines/drivetrains, with the simple change of subframes without having to re engineer the rear of the frame later.

subframes would also allow the same car to be buildable using a choice of different engines without having to stock many different complete frames..you would get the standard front 2/3's of the chassis and then order the rear 1/3 that fit the drivetrain that you wanted to use

[Jmcd]

The suby engine "roughly" measures about 16" deep x 31" wide x 24" tall with manifolds minus tmic, the trans output shafts are about 6" back from the block and 4" down from crankshaft centerline.

Compare that to most transverse 4s (sixes?), and I think you will find that most will fit easily.

I also think that if FFR is designing for the ej, then that's what they should do, focus and optimize for that. Anybody who can weld or fabricate will find a way to fit whatever engine they want, and this community, as well as FFR will be stronger for that ingenuity.

[16g-95gsx]

The suby engine "roughly" measures about 16" deep x 31" wide x 24" tall with manifolds minus tmic, the trans output shafts are about 6" back from the block and 4" down from crankshaft centerline.

Compare that to most transverse 4s (sixes?), and I think you will find that most will fit easily.

I also think that if FFR is designing for the ej, then that's what they should do, focus and optimize for that. Anybody who can weld or fabricate will find a way to fit whatever engine they want, and this community, as well as FFR will be stronger for that ingenuity.

Thank you, that is usable info. I feel the same way about that this is the kind of car that embraces ingenuity and Im a bit surprised at some of the backlash comments that have been said in this thread.

[PhyrraM]

The narrowness of the Subaru transmission is what will keep the frame from being adaptable. If FFR uses the 'extra' width for longer than typical control arms, then pretty much any transverse option is out. Only time will tell at this point. FFR did take the time to model the Subaru front lower control arm, but if or where it is used is still unknown.

[Oppenheimer]

subframes would also allow the same car to be buildable using a choice of different engines without having to stock many different complete frames..you would get the standard front 2/3's of the chassis and then order the rear 1/3 that fit the drivetrain that you wanted to use

Or even build your own custom subframe. Of course, if you're going to build your own subframe, you could probably tackle modifying the (non-subframe) frame, but would be a lot easier of subframe concept was used. I think its a good idea for the future. Lets let them get version 1 done, and nail all the important stuff (performance, handling, weight, price, the top!), then later they can start engineering this stuff for 2.0

[Jmcd]

The trans output is no less narrow than some fwd setups I've seen, and it quickly widens towards the bellhousing side, but you're going to be welding either way.

Was there a post or info that said 4x double wishbones/konis? At that point, the rear suspension is scrap, and i would expect the whole FS to be migrated rearward, although I would wonder about the ebrake setup.

[Oppenheimer]

Thank you, that is usable info. I feel the same way about that this is the kind of car that embraces ingenuity and Im a bit surprised at some of the backlash comments that have been said in this thread.

I think some of the backlash is against people seeming to froth over about how they want to get all this HP into this car (Subaru or otherwise). How much power you think you are gonna even want or be able to control in an 1800 lb car? I think backlashers are seeing that you can get tons of cheap HP from the target donor (2.0 or 2.5 WRX), so why go crazy redesigning to try and fit more HP potential when all the potential you could use is already in the base 818. To each his own, obviously, but if you're gonna do heavy mods, do ones that are really cool or make a big performance difference, not just mods for mods sake (so say the backlashers).

Lets not lose sight that we're talking about what mods to do on a car that doesn't even exist yet. IMO lets see how the 818 turns out before we spend too much time talkng about how to mod it into something else.

[bbjones121]

I don't think there is any backlash. No matter what excuse is used to cover it up, it is pretty easy to tell that you want a different drivetrain than what has already been decided on. There are other kit options out there for you. If you think this deters from your thread topic, then the thread should have been labeled something else maybe? Something like, "Alternative drivetrain options", because i think the selection has been made.


Thank you, that is usable info. I feel the same way about that this is the kind of car that embraces ingenuity and Im a bit surprised at some of the backlash comments that have been said in this thread.

[crobin4]

I don't think there is any backlash. No matter what excuse is used to cover it up, it is pretty easy to tell that you want a different drivetrain than what has already been decided on. There are other kit options out there for you. If you think this deters from your thread topic, then the thread should have been labeled something else maybe? Something like, "Alternative drivetrain options", because i think the selection has been made.
+1 Agreed

[16g-95gsx]

I don't think I mentioned concern over power output anywhere? My comments were entirely directed at weight and drivetrain selection.

[Evan78]

Choice is good. I've owned a few turbo Subarus and would be perfectly happy to run the recommended setup in the 818, but it would be nice to have other choices as well. I don't see a need for the "if you don't like it go find something else" attitude. Most people like to stick with what they know, so if you know 4g motors, you'd like that, if you know LS engines, you'll want one of those, it's all perfectly understandable.

Personally, I'd like the option to run an LS setup with a G50 trans like the GTM. I wonder how long it will take someone to say "Well, they already sell a kit for you..." without acknowledging the weight and price difference.

With that being said, 16g-95gsx, I wonder if you are getting accurate weights for a true apples to apples comparison. Perhaps the EJ weight you got was complete with accessories, exhaust manifold, and turbo versus a more bare 4g63 weight? Given the same materials, I would expect the flat 4 to weight a bit more than a similar displacement I4, but not 80 lbs heavier than an iron block I4.

[bbjones121]

I don't know if it is so much of a, "if you don't like it go find something else," it is more like observations that this might not be the right kit for some people. Having said that, I will state again more generally instead of specifically to one person, I think people looking for a more customized setup should look into a superlite roadster(sl-r) instead.

Just an FYI about that though, read a bit about the SL-R and changes they are making to it. You will be interested to know that they are trying to take away the many engine options because so many people are having problems and probably overloading the manufacturer on configuration issues. FFR should stick to supporting one configuration or risk struggling with it just as other kit car manufactures seem to.


Choice is good. I've owned a few turbo Subarus and would be perfectly happy to run the recommended setup in the 818, but it would be nice to have other choices as well. I don't see a need for the "if you don't like it go find something else" attitude. Most people like to stick with what they know, so if you know 4g motors, you'd like that, if you know LS engines, you'll want one of those, it's all perfectly understandable.

Personally, I'd like the option to run an LS setup with a G50 trans like the GTM. I wonder how long it will take someone to say "Well, they already sell a kit for you..." without acknowledging the weight and price difference.

With that being said, 16g-95gsx, I wonder if you are getting accurate weights for a true apples to apples comparison. Perhaps the EJ weight you got was complete with accessories, exhaust manifold, and turbo versus a more bare 4g63 weight? Given the same materials, I would expect the flat 4 to weight a bit more than a similar displacement I4, but not 80 lbs heavier than an iron block I4.

[BrandonDrums]

If the EJ engine series is 180lbs for a longblock setup I would be impressed. From my research that isn't at all the case. Like I said, I may sound biased with my 4g63 comments, but I simply am doing preliminary research and it appears that the EJ engine series is surprisingly heavy for being all aluminum, and on a platform where every single pound should count, it seems non-ideal. I will do a bit of searching on this board specifically.

To be sure we're talking about the same thing. It's about 180 or so for just the engine, no intake, exhaust accessories, oil pan etc. Just Heads+block and internals. Having JUST sold my EJ207 3 weeks ago I can confirm that the engine is pretty light.

Further to prove my point, here's the webstore page for a built Cosworth EJ257 (the 2.5) http://www.flatironstuning.com/p-1900-cosworth-high-performance-sti-ej257-long-block-assemblies.aspx

Note the weight they list on the page: 160 lbs.

The 5mt transmission is about 135 bare http://www.clubwrx.net/forums/transmission-awd/134295332-transmission-weight.html

The only confirmation I have found for that is shipping weights people have posted.

Assuming the Ej207 weighs 180, the total weight not including accessories is 315. Depending on what you include as engine+transmission weight the number can vary from 360lbs up to near 500 lbs.

I guess the more traditional assessment for what a WRX engine includes in being part of the engine assembly are the accessories, intake, oil pan+oil, headers, exhaust manifold turbo and intercooler along with the longblock and transmission is probably more like 400-450 lbs.

Still pretty light. But again, the rationale is not just weight but to optimize cost/performance+availability. I'm sure there are lighter engines and transmissions out there but not in the same quantity with the same aftermarket support and interchangeability. Using Subaru stuff just makes sense for a donor-car based kit intended for high volume sales.

And even if you disagree, it's pretty much set in stone that this car will use Subaru stuff only, at least in the beginning.

So I'm with many of the other guys, I just don't think it would make too much sense to spend time shoehorning another engine in the car to save weight. The idea that the Subaru stuff is heavy seems to be pretty inaccurate. No offense.

[16g-95gsx]

After weighing the few EJ components that I did, I am starting to believe your 180lb figure. At this point I wish I had simply started a thread asking for EJ engine weights as there is so little information available online. If the longblock weighs in at only 180lbs, give or take a bit, then I agree, there is likely little reason to switch to anything else.

40lbs for both heads, 20lbs for the crank, 5lbs for the rods. That adds up to only 65lbs, for what would be basically a longblock minus pistons, the block itself (aluminum), cams, valve covers, and an oil pan. Granted there are other small components added in there, but I definately see all of it weighing in closer to the 180lb mark than the original 380lb mark that I found online. The 130lb mark for the trans can also be immediately reduced due to the 2wd configuration.

Not bad at all.

[Jmcd]

I just tore down an ej20/trans.

the center diff/rear output combo is heavy! maybe 25 pounds or so

I will throw all of this stuff on a bathroom scale and get a better idea of what the whole thing weighs, sometime this week.

I think some components may be heavier because of the non-inline configuration, but nowhere near an iron block.

[PhyrraM]

Use your body as ballast. In general, bathroom scalse are not very accurate under 50 pounds or so. Weight yourself holding the part, and then again without it. Subtract the difference. It should be more accurate and easier than propping oddly shaped items on the scale.

[crobin4]

Use your body as ballast. In general, bathroom scalse are not very accurate under 50 pounds or so. Weight yourself holding the part, and then again without it. Subtract the difference. It should be more accurate and easier than propping oddly shaped items on the scale.

+1 Thats how I weigh stuff. Seems to well

[Jmcd]

Posted weights in new post, comparing these to what a k20 weighs (same ballpark, IMO): http://www.midlana.com/Diaries/Old%20Diaries/2009June_Dec/ I think you are going to be hard pressed to justify any common aluminum i4, much less an iron one in the name of lighter weight, but for being different and ingenuous-go for it!

[16g-95gsx]

Just as an FWIW adding up the weights of the individual components of the iron block 4g63 the weight comes to around 189lbs without manifolds, this includes all internals, timing components, oil pan, etc. Of course there is an error that is generated from weighing each and every single part individually, but it gives a very close estimate. Just thought it was interesting to note since you would naturally expect an aluminum block to weigh far far less. In the end I suppose there is a lot of extra aluminum mass that must be used just as reinforcement, and with the iron block itself weighing in at around 85lbs, there is likely only but so much weight loss that is generated from using an aluminum counterpart when that is taken into account.

Something else that is interesting is that an Evo 3 16g with oil lines and water lines weighs in around 9.8lbs. Thats not bad at all for a turbo that is as cheap as it is (500 bucks or less most of the time), and yet has been proven to over 400awhp. If I recall the stock WRX turbo was around 13.Xlbs. On a EJ25 it would prove to be one hell of a torquey setup as 2.0L's typically see 20psi by 3000rpm assuming a full weight (3200lb).

[bbjones121]

Just thought it was interesting to note since you would naturally expect an aluminum block to weigh far far less. In the end I suppose there is a lot of extra aluminum mass that must be used just as reinforcement...

That is great to know. Looks like it might just be a made up rumor that the mitsubishi block is more bulletproof than the Subaru. So if the Subaru block is designed to be as strong as an iron block by adding more reinforcement structure, than it has the bigger advantage since it has a way lower cg over the mitsubishi.

[16g-95gsx]

Not sure what you're saying about a strength rumor, I was talking about iron naturally being a stronger metal than aluminum and therefore all designs being equal there would need to be more aluminum added in to make it strong enough. Similar concept to why aluminum driveshafts are larger diameters than steel. In the end the weights are very similar, and a far cry from the 380lbs that I originally thought of for the EJ. As far as the CG comment though, remember that 150 or the 180lbs of the 4g63 is located entirely in the shortblock, so I really don't think there is that much of a CG difference. I would say that the overall heigh/space requirements are going to be different for sure with EJ's being far wider and deeper with their transmissions.

[BrandonDrums]

That is great to know. Looks like it might just be a made up rumor that the mitsubishi block is more bulletproof than the Subaru. So if the Subaru block is designed to be as strong as an iron block by adding more reinforcement structure, than it has the bigger advantage since it has a way lower cg over the mitsubishi.

From what I've heard, it's not exactly a rumor but it is misleading. Subaru's do have a higher failure rate than Mitsubishi's at high HP numbers but not because of the block material or really even the block itself. The Evo engine has a more ideal bore/stroke ratio being in a vertical inline configuration. The 2.5L subaru engine is flat and because there's only so much room in the engine bay, EJ engines are rather stubby and are limited on how much stroke you can run to up displacement numbers. This isn't the case with a 2.0L wrx engine but it has other issues with oiling which can be fixed with a better oil pump.

To get the displacement on the 2.5 Subaru had to max out bore and stroke on a short block which results in an "over square" engine. They should have decreased stroke and put larger pistons in the engine but that would result in a very top-end power band.

The pistons will fail in a Subaru 2.5L more often than any failure in an Evo engine with the same numbers stock for stock. Either it's because of the oversquare engine and weak pistons or there are just more guys with subarus out there and it's a "tragedy of the commons" where more Subarus fall into the hands of guys who just over boost and under-tune their cars because they don't care.

However, the gray area is that additional HP on a Subaru engine is harder to get because of the location of the turbo and and less than ideal header/manifold flow. On an Evo, you can run lower boost and make higher numbers because of a more efficient manifold given an equal sized turbo (not to mention the evo has a front mount IC with very little piping). If you just run equal length headers, have an appropriate turbo and a quality tune I imagine the actual rate of engine failure on a Subaru wrx/sti vs. Evo would be the same if not less and the power output potential would be rather close.

So it's not really the engine in my opinion that causes Subaru's to get the bad rap for the most part. It's just the configuration of things that puts EJ motors through more stress to get the power output.

[bbjones121]

That is great info. Thanks. So it means that the subaru power plant in the 818 might not have the configuration restrictions the led to some of the limitations it faced when previously compared to the 4g63.

[16g-95gsx]

I dont see these cars running imense power levels anyway. I've seen plenty of 600awhp stock longblock evo's and DSMs to know the engines are fully capable of tremendous power in factory form, but ultimately none of that will be usable on the 818 while keeping with the spirit of a drivable car. I think weight and size restrictions are really the goal here.

[BrandonDrums]

That is great info. Thanks. So it means that the subaru power plant in the 818 might not have the configuration restrictions the led to some of the limitations it faced when previously compared to the 4g63.

Pretty much what I'm thinking. What's more important is that if you're smart enough to build a whole car, your going to be smart enough to just mainatin the car to begin with.

Good tune, good oil, good owner...these engines will last