BMW Engine Options

[daltmcintyre]

I'm in the very very early stages of planning a 818C build. I love my M3 so if possible, I would like to use a BMW engine to power the car. I know the M3 engines are not an option because they are either I6 or V8. There is a 2.0 turbo charged I4 that is used in the Z4 and 3 series cars. The problem I'm running into is determining what transaxle to use. If the Subaru transmission input shaft will mate with engine, I think I will be in business. With the ecoboost using an I4 configuration and Subaru transaxle, I don't think the frame will need any major modifications. If the two will not work, I would probably have to use a Porsche or VW transaxle. This may require more trial and error and frame mods to ensure the axles are located properly.

I've done a good bit of fab work on my FFR roadster, so I'm not intimidated by the challenge. It's just a bit harder to get some of the info and dimensions on what I need. I have only seen a couple of builds that have used anything other than the Subaru setup. If any of you guys could point me to any particular builds that may help or just provide any feedback on the concept, I would greatly appreciate it (specifically if someone could answer if the BMW engine would work with the Subaru transaxle).

Thanks in advance.

Joey

[Canadian818]

I don't know anything about BMW's, but I love it when people want to put something different in an 818. Check out Frank818's build thread, he's using a VW engine with a Porsche transaxle.

[Zach34]

If you want to do it, I say go for it. It'd be cool to see how it turns out.

That being said, the first question I would ask you is if you're sure the BMW 2.0 will be better than the Ford 2.3L Ecoboost, or even the Ford 2.0L Ecoboost. The Ford motors are already supported. I don't know where production stands on the transaxle adapter kit for the Ford engines, but FFR has already done all the fabrication work. You could end up spending 2 or 3 times as much money on a solution that only buys you a BMW badge when you lift the hatch. If you end up having to modify the frame forward of the engine, then the question is why not go for one of their larger motors, maybe even a V8? There is room if you want to go with a custom fuel tank and re-work the frame/firewall there.

As far as adapting to the transaxle, FFR would be your best resource since they already came up with the Ford solution. The variables are pilot bearing size in the crank, custom clutch disc source, and trans input shaft stick-out relating to how thick the adapter plate needs to be. I've seen the Ford Ecoboost motor in one of FFR's showroom 818's. There is zero extra room behind the trans. If your solution is a half inch longer than the Ford/Subaru combo, you will have to do some work on the rear bumper.

[wleehendrick]

That being said, the first question I would ask you is if you're sure the BMW 2.0 will be better than the Ford 2.3L Ecoboost, or even the Ford 2.0L Ecoboost.

If you end up having to modify the frame forward of the engine, then the question is why not go for one of their larger motors, maybe even a V8?

I agree with Zach; if considering a turbo I4, the groundwork from FFR is already there for the Ford EcoBoost. A modern BMW 2.0l turbo I4 would be perfect to transplant into a vintage BMW 2002 (that would be great), but I don't see the advantage it brings to an 818 over the EcoBoost, other than the badge on the engine cover and being different. It is their base/economy engine after all. I love the 3.0l turbo I6 in my wife's 135i; straight sixes are simply awesome, but unfortunately the wrong engine layout for an 818.

Before considering any non-factory supported drivetrain, I'd recommend reading through Frank's build thread and see all the challenges he's faced getting a VW VR6 into the 818. If you are up for the challenge, do something really unique... a V8 isn't totally out of the question, and nobody's done it before!

[FFRSpec72]

I agree with Zach; if considering a turbo I4, the groundwork from FFR is already there for the Ford EcoBoost. A modern BMW 2.0l turbo I4 would be perfect to transplant into a vintage BMW 2002 (that would be great), but I don't see the advantage it brings to an 818 over the EcoBoost, other than the badge on the engine cover and being different. It is their base/economy engine after all. I love the 3.0l turbo I6 in my wife's 135i; straight sixes are simply awesome, but unfortunately the wrong engine layout for an 818.

Before considering any non-factory supported drivetrain, I'd recommend reading through Frank's build thread and see all the challenges he's faced getting a VW VR6 into the 818. If you are up for the challenge, do something really unique... a V8 isn't totally out of the question, and nobody's done it before!

The long term cost of the Ford ecoboost is far less than the BMW, if I had to do this over it would be a ecoboost, but I would want to see the 2.3l ecoboost as there have been some great tunes on the Focus RS 2.3l

[GoDadGo]

I bet throwing a NORTHSTAR in an 818 would be cool too, but you'd be stuck with an automatic and the sucker sitting side saddle.
Went to a Rod Run this past weekend and a fellow stuck one in an old Fiero GT and he took me for a ride.
This little plastic car was Way, Way faster than I thought it would be and he said it was all stock.
Cadillac Deville's and DTS's are a dime a dozen down in Boca.
That car even had A/C and rode quite nice.

[daltmcintyre]

To be honest, the motivation behind using a BMW engine is to say it's BMW powered. If I had my choice, the NA 3.2 I6 in my M3 would be a perfect setup for this car. It has a base HP of 330 and likes to rev high. But obviously the problem is the length of the block. I haven't pulled a super accurate measurement yet but just off of the quick measurement I took it looks like the engine is over 25" from front of crank pulley to bell mount. I've only gotten about halfway through Frank's build and he noted 29.5" from pulley to axle centerline was absoulte max. This length includes his axles being installed at a slight angle. I would like to avoid the axles having any forward / rearward skew if at all possible. I'm going to try and finish his thread over the next couple of nights to see what frame modifications he made.

His thread may cover this, but has anyone done a fuel tank mounted forward of the cockpit? Although you would have to do frame mods, that would allow for more engine options.

I've always loved the BMW M1s but unfortunately those are outside my budget. That car is the reason why I would love to do a BMW powered mid engine car. Plus I enjoy the build process more than just buying a car.

Thanks for all of your input.

[Hindsight]

Several have done fuel tank forward of the cockpit, where the battery would normally go. Plenty of room up there if you move the battery elsewhere, and it's a good place for the weight. I think Bob did it, but not sure. I feel like I say, "I think Bob did that" in response to nearly all threads. Maybe it was Tamra and Andrew?

[GoDadGo]

To be honest, the motivation behind using a BMW engine is to say it's BMW powered. If I had my choice, the NA 3.2 I6 in my M3 would be a perfect setup for this car. It has a base HP of 330 and likes to rev high. But obviously the problem is the length of the block. I haven't pulled a super accurate measurement yet but just off of the quick measurement I took it looks like the engine is over 25" from front of crank pulley to bell mount. I've only gotten about halfway through Frank's build and he noted 29.5" from pulley to axle centerline was absoulte max. This length includes his axles being installed at a slight angle. I would like to avoid the axles having any forward / rearward skew if at all possible. I'm going to try and finish his thread over the next couple of nights to see what frame modifications he made.

His thread may cover this, but has anyone done a fuel tank mounted forward of the cockpit? Although you would have to do frame mods, that would allow for more engine options.

I've always loved the BMW M1s but unfortunately those are outside my budget. That car is the reason why I would love to do a BMW powered mid engine car. Plus I enjoy the build process more than just buying a car.

Thanks for all of your input.

I totally get the BMW engine because doing a Chevy in a Cobra to many is sacrilegious at the very least.
What impressed me is that this Crazy Fiero Impressed Me since it looked like a factory installation and was quite nice.
Going off the path most traveled is what everybody on this formum is doing because most folks don't buy their cars unassembled.

[DSR-3]

I have the Boyd tank and a close fitting firewall. At 6'+ tall, my seat (Sparco r100) will be fully back with the top at or almost-at the firewall/bulkhead, so moving the tank would have(almost?) no advantage for me. The center bulkhead to axles dim is the killer. If only they had designed in a few more inches, there might be more alternate engine options/installations. "Luckily" I only had to move 1 center bulkhead tube to fit an EZ30R, which hangs 3/4" into/over the 1.5" bulkhead tubes. I sure like that Canadian rotary install, but it looks tight too as I recall.

[Canadian818]

I sure like that Canadian rotary install, but it looks tight too as I recall.

Why thank you, and yes length-wise it's quite tight. Something to remember is the thickness of the adapter plate, mine is like 1.5" thick!

[RM1SepEx]

Several have done fuel tank forward of the cockpit, where the battery would normally go. Plenty of room up there if you move the battery elsewhere, and it's a good place for the weight. I think Bob did it, but not sure. I feel like I say, "I think Bob did that" in response to nearly all threads. Maybe it was Tamra and Andrew?

Bob and Tamra & Andrew have front tanks

[Frank818]

A lot has run on this thread already. loll

With the 29.5" measurement, that should be the one to look at IF you don't want to do any frame (or more) modifications. Yes it includes a 4" angle on the axles, usually cars have about 1". Also note that this measurement does not take into account the oil pan! If your oil pan takes the space of the perpendicular 1.5" tube (the one used for subie engine mounts) you're into frame modifications. Not a small one here cuz it will affect the fitting of the belly pan and rear diffuser.

[daltmcintyre]

I've been brainstorming this today and I think the simplest solution would be to extend the frame from the bulkhead back. Setting the frame on a chassis jig and "sliding" the rear portion of the frame back would be fairly straight forward. The biggest hurdle would be splicing the quarters to have a seamless transition. If I go forward with the build I would build a couple and after staring at pictures, my eye can't see the cut line to splice it. If you can figure that out, the hatch could remain the same and create something similar to a small decklid between the hatch and spoiler. I'm not scared of fiberglass work, but I don't look forward to it. One of the guys who works for me is a guru at photoshop. He's also interested in a build so I may have him try to doctor some photos up to see how the car would look if it were stretched.

I know absolutely nothing about turbo cars. This car would be used in some autocross / TT events. If I understand correctly the turbos are not good for this. If that's the case, I think the NA I6 engine would be a great fit. I'm going to research some more tomorrow about some of the early I4 engines and see what the power to weight ratios look like. If I remember correctly, the early 1.8L used in the E30 BMWs was a decent setup for autocross. If that's the case, it may be decent on this lightweight platform.

[codename Bil Doe]

Modern turbo cars are fine if tuned properly, especially with a twin scroll turbo. I autox'd and road raced GM's 2.0T. It makes 390whp on 110 octane with just a tune. The ecu was extremely hard to learn because it's torque based. But, after learning to tune it I could have the turbo spool from 0-20psi in .458 sec. This turned out to be pretty uncontrollable outside of drag racing. Had to back off spool to 0.7-0.8sec.

There are other tricks where you can maintain boost at part throttle and bleed off the extra boost in a factory recirc setup for quick response. You can also make the pedal linear in response versus the ramped exponently power application a lot of factory tunes come with. It's all in the tune.

Do what you want to do.

[wleehendrick]

I know absolutely nothing about turbo cars. This car would be used in some autocross / TT events. If I understand correctly the turbos are not good for this. If that's the case, I think the NA I6 engine would be a great fit. I'm going to research some more tomorrow about some of the early I4 engines and see what the power to weight ratios look like. If I remember correctly, the early 1.8L used in the E30 BMWs was a decent setup for autocross. If that's the case, it may be decent on this lightweight platform.

Lots of turbo 818's are autocrossing. A big disadvantage of turbos can be heatsoak, but that's not nearly as big a deal on single lap events as it is for a roadcourse.

I love me some E30's, but the most potent 'normal' 4-banger, from the E30 318is only had about 130HP (at the crank, when new) IIRC. That would be a lot of work for less power and arguably worse CG than you'd get from a basic Imprezza build (NA 2.5l flat 4). Even the iconic E30 M3 had less than 200HP from it's 2.3l NA I4 in US spec (and that motor would be too valuable to use in an 818).

If you're contemplating stretching the 818, I'd really see if the straight six can fit and bolt up to an appropriate trans-axle. Almost all car manufacturers have gone to V6's over I6; BMW is the only car manufacturer left still carrying the silky smooth I6 torch and you want an 818 "powered by BMW" that's the 'logical' choice IMHO.

[Maximus]

If you want to do it, I say go for it. It'd be cool to see how it turns out.

That being said, the first question I would ask you is if you're sure the BMW 2.0 will be better than the Ford 2.3L Ecoboost, or even the Ford 2.0L Ecoboost. The Ford motors are already supported. I don't know where production stands on the transaxle adapter kit for the Ford engines, but FFR has already done all the fabrication work. You could end up spending 2 or 3 times as much money on a solution that only buys you a BMW badge when you lift the hatch. If you end up having to modify the frame forward of the engine, then the question is why not go for one of their larger motors, maybe even a V8? There is room if you want to go with a custom fuel tank and re-work the frame/firewall there.

As far as adapting to the transaxle, FFR would be your best resource since they already came up with the Ford solution. The variables are pilot bearing size in the crank, custom clutch disc source, and trans input shaft stick-out relating to how thick the adapter plate needs to be. I've seen the Ford Ecoboost motor in one of FFR's showroom 818's. There is zero extra room behind the trans. If your solution is a half inch longer than the Ford/Subaru combo, you will have to do some work on the rear bumper.

What do you mean that the ford motors are already supported? I've been trying to keep up with the official integration of the 2.3L ecoboost into the 818, but until I see it on the order sheet as an option I am a bit skeptical.

[flynntuna]

Check out FFR's Facebook page , the snap on 818c video. They are building one with the 2.3 ecoboost .

[Maximus]

Yeah, I had seen that. Just thought he was referring to something a bit more ready-to-market. Waiting sucks.

[flynntuna]

I wouldn't be surprised if they announced it as an option officially at SEMA this year.

[Bob_n_Cincy]

Here is a picture of an ecoboost in an 818 frame back in January.
Looks like the top of the engine is too high for the 818s hump engine cover.
Bob

57257

[DodgyTim]

Here is a picture of an ecoboost in an 818 frame back in January.
Looks like the top of the engine is too high for the 818s hump engine cover.
Bob

57257
Doesn't look like a subie transaxle, that will add to the $$$$

[Bob_n_Cincy]

Doesn't look like a subie transaxle, that will add to the $$$$
That is a Subaru STI 6 speed transmission. I suspect double the Subaru MT5
Bob

[phil1734]

The 5MT has enough problems handling stock horsepower/weight in the WRX.

So now you'll need:
A FFR 818 Kit for $10K
A 02-07 impreza for suspension $2K
A 04-07 STI transmission $3k
A brand new ecoboost motor/ECU $5k

Total just for the major parts: $20,000.

And you'll still have to figure out how to spice together a subaru wiring harness into a CAN-based Ford unit, just to end up with a car that has as much power a lightly tuned wrx based car. Someone remind me again why FFR is wasting time on this?

[Bob_n_Cincy]

The 5MT has enough problems handling stock horsepower/weight in the WRX.

So now you'll need:
A FFR 818 Kit for $10K
A 02-07 impreza for suspension $2K
A 04-07 STI transmission $3k
A brand new ecoboost motor/ECU $5k

Total just for the major parts: $20,000.

And you'll still have to figure out how to spice together a subaru wiring harness into a CAN-based Ford unit, just to end up with a car that has as much power a lightly tuned wrx based car. Someone remind me again why FFR is wasting time on this?

I feel that the 5mt is strong enough for road racing or street use. Launching in drag racing or autrocross broke axles and CV's for me.

The 6 speed and ecoboost are just options. you can still go cheap if you want to.

I would say most of FFR customer base is 45 plus year old and have disposable income to take on projects like this.
The Subaru kit appealed to the younger tuner generation to expand the FFR customer for the future.
The ford or gm engine would be my choice in a heart beat. (I'm 57)
I'm part of the Midwest "buy American generation" that grew up building Chevelles, Camaros and Mustangs.
Bob

[wleehendrick]

just to end up with a car that has as much power a lightly tuned wrx based car.

To be fair, you need to compare apples to apples. The Eco-boost makes more power in stock trim, and all else being equal, it will make much more power than an similar "lightly tuned" EJ. With direct injection, it is simply a more modern platform, and I can see the desire some may have for that. Not worth the effort to me, since I'll be content with the build based on an 06 WRX drivetrain, but with FFR's relationship with Ford, and their customer's demographics, I understand why the desire to offer a domestic option for the motor.

[FFRSpec72]

The 5MT has enough problems handling stock horsepower/weight in the WRX.

So now you'll need:
A FFR 818 Kit for $10K
A 02-07 impreza for suspension $2K
A 04-07 STI transmission $3k
A brand new ecoboost motor/ECU $5k

Total just for the major parts: $20,000.

And you'll still have to figure out how to spice together a subaru wiring harness into a CAN-based Ford unit, just to end up with a car that has as much power a lightly tuned wrx based car. Someone remind me again why FFR is wasting time on this?

From the R version view, the ecoboost engine a far far more reliable road race engine, the Subaru platform is a good street platform but not a road race platform

[Zach34]

What do you mean that the ford motors are already supported? I've been trying to keep up with the official integration of the 2.3L ecoboost into the 818, but until I see it on the order sheet as an option I am a bit skeptical.

"Supported" may have been a strong word. I'm alluding to the fact that FFR has built one. I don't know where they are as far as offering it as an option yet. In terms of the kit, it's engine mount locations and an adapter plate for the transmission. If dashboard electronics integration is the concern, that's probably why they don't list it as a kit option yet. You'd have to figure that out.

[Zach34]

From the R version view, the ecoboost engine a far far more reliable road race engine, the Subaru platform is a good street platform but not a road race platform

Retro and I obviously still have hopes for the Subaru motor for road racing. It may very well turn out to not work, we'll see. Chad Plavan's motor did eventually work, remember. He put a lot of laps on it, with oil that was nearly overheating and possibly aerated, and it didn't blow up. There was a lot in question about that motor, too, revolving around how it was built. FFR's motor blew for correctable issues. We know that a dry sump and at least an AWIC (we'll see how Retro's top mount with the scoop works) are definitely requirements. A breakthrough air-to-air intercooler solution could be all we need for real viability. It's still an expensive motor to race, though. The Ford motors could win out among future builders by virtue of affordability assuming you don't have to blow too much money on adapting a transmission.