Moved: Unsure which engine to use, asking for input/opinions

[Max_S]

Hi everyone

Even after spending a long time looking around this forum I'm still unsure what engine to pick for my project.
The main problem with that is that I can't buy the Z, import it, and then drive it while I figure stuff out.
I have to have a completed concept to present to the TÜV (the company in charge of approving modifications and imported cars for road use) before I turn a single screw on the car, and before it's first registered in Germany.
Also, logically, I like to know what I'm getting into from the start.
So I hope you don't mind me straight-out asking for input on a decision I'm sure many of you have had to make at some point.

What I'm looking for:
Since the 240/260Z is a very light car I'm looking for a relatively light fuel injected engine, preferably one that sits far back even without moving the firewall (so the balance isn't thrown off too much), and that will put out at least 300hp reliably (the car won't be abused, but it won't be completely "pampered" either, the car is a weekend-fun-toy for twisty country roads).
The car should have a usable powerband, not just produce big numbers on the dyno.

What I'm currently considering:
Mazda 13b: Awesome idea, but would require a lot of fabrication, so probably not a good first swap. Also, I've heard complains about lacking torque.
Chevy LS (Alloy block): Great power and torque, no lag, but I imagine it to be making the car a bit nose-heavy. Also, super-expensive to run (regarding taxes and insurance).
RB26/Toyota 2JZ: Great engines, lots of information, but, like the LS, I imagine them to make the car quite nose-heavy, with the engines being rather long and having iron blocks.
VQ35DE: Only seen relatively little of it, the big lump of plastic that seems to come with it is not really "up my alley", so that would probably have to go. Also, stock it falls short of the 300hp, and apart from twin-turbos I've seen little options in tuning.
Turbo-4-cylinders, like the SR20: Compact and good power, but I'm worried by hearing people in other places say they're disappointed in lacking torque and that the car "sounds like nothing". Also, to get my desired power-figure (talking wheel-horsepower here), how big/bad would the lag from a turbo be?

I'm still learning about Zs, and especially the 4-cylinders and V6s are "uncharted territory", so while I appreciate any input I'd especially appreciate input on the latter two.
What made you chose this or that engine?
What made you chose it instead of a different one?
Anything you regret/aren't happy with?

I got the whole concept pretty much worked out, except for the engine and things that depend on that (suspension, brakes).

Thanks in advance,

Max

[Neverdone]

Considering you're in Germany, you might want to give this thread a read.

 

http://forum.retro-rides.org/thread/139679/bmw-m3-powered-240z

[rturbo 930]

I saw in your other post you don't like the L28 turbo. Why not? Sounds like it'll do everything you want it to, and it'll be the easiest swap out of any of those.

 

Aside from that, what about a turbo BMW motor? An M52, M54, or if you want a challenge, N54. Should be easy to find any of those motors where you are.

[Gollum]

The DOHC I6's in the list will almost certainly add weight to the nose. An all aluminum BMW I6 might not be much gain, and you can bury them pretty deep into the bay which helps.

 

That said, an all allow LS will have LESS weight on the front wheels, by a lot. Not only is this because the engine's center of gravity is much further back because the overall length is shorter, but the engine itself is actually within the ballpark of the factory L engine. Which is lighter would depend more on specific accessories and add ons used. Where the REAL difference in weight is, and why most end up heavier after doing an LS swap, is in the transmission. The stock Nissan trans is only about 80lbs and doesn't like 300hp/tq. There's a reason Nissan put the T5 behind the L28ET in the 280ZX Turbo, and that wasn't even rated at 200hp...

 

I'm running a L28ET in my '75, and my reasons are as follows:

 

1. Any swap requires a lot of little bits to finish, it's not just mounts. It's mounts, driveshaft, throttle adaption, wiring, exhaust, etc. People often overlook just how much goes into a well engineered swap.

2. The L28ET can make enough power with relative ease that it can easily be "fun". 300hp is a well known recipe and a number many shoot for. And honestly, anything over 200hp in these cars is enough to have fun and also enough to be competitive in many forms of racing and starts being far more about the chassis setup/tuning than power.

3. The idea of chasing more power in the L28ET is entertaining for me. I know what it would take to push the limits and I enjoy the thought of the challenge.

4. It sounds unique. If I wanted a great NA sound with similar power I'd strongly consider the BMW S54. Could I make good NA power with an L engine? Sure. Just not sure the build process interests me enough for the output. Once you've put in the effort to complete the S54 swap, a replacement engine is semi-readily available. Rebuilding a 250+ NA L engine wouldn't be something to just do casually. But all that to say, the turbo L engine sounds good and "uncommon". It's obviously not a V8 or a four cylinder to anyone who hears it, and it's not a boring V6 sound either.

 

Personally though, I find engine choice to be a very personal question and answer, and there's no right, and dare I say very few wrong. Nobody can answer if for you, but at least you know why I run what I run.

[Max_S]

For BMW-engines, I actually considered the S54 (E46 M3's inline-6).
It comes in about 20Kg under a 2JZ (around 215 Kilograms), and puts out 340hp give or take a few in stock form.
I can get one for around 4.5-5 thousand Euros, which already is more than I would pay for a 2JZ GTE, for example, and much more than an RB25DET costs (can't find an RB26 right now).
Also, they have their issues, and anything that breaks or that I want to improve comes at a premium (BMW-parts aren't cheap, M-parts even less).
I haven't considered the L28 because, to be honest, from the start I had a more modern engine in mind, so the only engine from the Z-line that was an option was the V6 from the 350Z, which I kicked mainly due to the big plastic intake (looks matter).
At this point I'm pretty sure I'll go for an inline-engine (rotary is too difficult to swap, V8 is very difficult to get TÜVed and very expensive to run (taxes are decided by displacement, and with no "exhaust norm" I'm already at a premium).

I like the idea of a more modern inline-6, but I'm unsure since I don't know what it does to handling if you throw over 20% of the weight to the front wheels (and further to the front).
That's why I started looking into inline4-engines as well.

But my focus is still on inline-6s, and I'll start looking into the L28 (turbo) after all, and also read up on the RBs apart from the 26DETT.
The main obstacle there is the balance.

Max

[Gollum]

Some weight placement and handling perspectives:

 

1. The 240Z won a lot of races with the factory engine, even in the factory engine location. The node weight didn't seem to hold it back much at all, and Pete Brock has mentioned that they could have likely gotten a lot more power out of the engine within regulation, but it wasn't exactly needed. Their largest obstacle was convincing Nissan to manufacture and send them a fully counter weighted crankshaft so they could get the RPMs up. Once they had that, and improved factory cam oiling, making the necessary power suddenly wasn't a big deal.

 

2. The factory engine can go back about 3" with almost zero change. The only thing of concern back there is the brake lines which can easily be remade to route elsewhere. Once further back, the engine can also go down a bit. Some hardcore racers have gone a lot further back than that, some with extensive firewall redesigning.

 

3. The factory engine is about 390 pounds in factory spec with flywheel bolted to it. An all aluminum BMW I6 will come in within 20+/-lbs of that. Which means the exact placement of the engine in the engine bay will matter for more than any potential added weight.

 

4. A vehicles ability to "turn in" has almost zero to do with how much weight is over the nose. The Integra Type R was something like 63% weight on the front tires, a lot of which was in the engine bay. That vehicle dominated autox and lower speed tracks in scca. Obviously it had no issue "turning in". A vehicles ability to readily change direction is all about chassis tuning. And I use the term chassis and not suspension because it's far more than just suspension. Yes, you need to have good suspension, but choosing the right tires, wheels, right height, and on and on all have an effect on turning performance.

 

5. A gas tank will affect weight balance from full to empty far more than any engine swap, yet we don't hear people getting all particular about gas tank weight and placement....

 

I'm just trying to drive home the idea that how well it's going to handle ultimately has almost nothing to do with engine choice.

 

 

Also, why is a rotary swap hard? It's actually relatively easy in my book. Just don't use the factory exhaust manifold if going turbo. 

[Max_S]

Downsides from the rotary are that there's nothing pre-fabricated I could use, and there's little knowledge since it's rarely been done.
That's why I don't think it's a good choice for a first-time swap.
Of course, weight and measures are pretty ideal, and it's certainly a nice idea.
A side-problem is that, to get them approved, I have to justify my engine-choice.
And the rotaries don't really have a good image (ineffective, oil-thirsty, etc).
I'm still keeping it in my plans, but I'm also looking for an alternative.

Maybe I was taught wrong, but I learned that a sporty car handles well if it gets as close as possible to 50:50 balance, and that light cars suffer if you stick a heavy engine on/ahead of the front wheels (on a side-note, moving/drastically reshaping the firewall isn't an option, if the TÜV notices I might loose any chance at getting the car on the road).

Honestly, the L28ET is a bit "disadvantaged" because, for lack of better wording, it's "too close to stock" (regarding donor car, lineage and age).
What you wrote makes sense though, so (with the rotary "on the side") it's down to inline-6-engines, mainly the RBs or 2JZs.
Gonna have to look around more for experiences, and "on the side" I'm going to start putting together parts lists, reasoning and such for two concepts (rotary and piston-powered).

Max

[Zetsaz]

If you wanted to be REALLY out of the box and stay semi modern inline 6 you could always consider a Mercedes M104, but there are a lot of disadvantages it shares with other engines you've mentioned, and no significant advantages over a JZ or RB as far as I know

 

[Miles]

How will the car be driven?

• Street only?
• Race/autocross?

What are your constraints?

• Government regulations
• Experience
• Budget
• Parts availability
• Shop space

What are the  common 240Z engine swaps in Germany?

 

Are there 240Z clubs in Germany?   Clubs are good source of information

 

Engine swaps, and parts swaps in general,  tend to have a domino effect that adds complexity and cost.

 

 

 

[LLave]

GM Atlas Motors, I5 or I6. They are awesome and way under utilized. 

 

https://www.hotrod.com/articles/ccrp-1108-turbocharged-vortec-inline-six/

[Max_S]

@Zetsaz Around here, anything but engine-tuning or an L28 would be plenty unique.
 

38 minutes ago, Miles said:

How will the car be driven?

• Street only?
• Race/autocross?

Street.
"Weekend Warrior", so it'll be driven rather hard (but not abusive), mainly on twisty backroads.
Not looking for 1/4-mile acceleration or top-speed (Autobahn-driving is actually kinda boring), but for plenty of usable power (so a big turbo-lag is not really desired).
Racing/Autocross is far smaller in Germany compared to the states, outside of entering in some sort of touring-car-series there's almost no option for regular closed course track-use.
 

38 minutes ago, Miles said:

What are your constraints?

• Government regulations
• Experience
• Budget
• Parts availability
• Shop space

Government regulations are complicated and excessive.
Engine-swaps usually can't worsen a car's impact on nature (think, fuel-consumption and exhaust-gasses), but since the Z was made before the current norms were put in place I should be fine as long as there're no black clouds coming from the exhaust.
Also, fuel injection is a big plus in that field, making engines (seem) more effective (side note, I want fuel injection for simplicity's sake).
Over 40% more power than stock (although here the 260 and 280's might count) power opens up a list of hurdles, which I have to pass is down to the TÜV-engineer.
It's the advantage of a turbo-engine, I can run very low boost when they dyno the car, so the power-increase isn't too severe, (hopefully) giving me less hurdles to jump over.
Some I always have to pass (noise, brake-power appropriate to horse-power, weight per wheel, load-bearing capability of each wheel), some are optional (chassis-stiffness (a cage gives you a lot of bonus points there), speedometer-precision-test or 100/500/1000km test drive (the latter two are to be done on closed roads/tracks, making them quite expensive).
It helps to give the TÜV a completed concept to look at, so they see that it's a thought-through plan before you start working.
The biggest problem is that the TÜV makes it difficult to use certain parts (suspension, brakes, interior-bits), making it more expensive to change/upgrade those.
For a "rough idea", most wheels that aren't on the German market already aren't road-legal here (like Konig wheels, for example, or a lot of Volk ones).
For some reason (don't understand it myself) I have much better chances if I modify the car before it gets first registered for German roads, which is why I'm planning ahead so far.
Also, apart from all laws, each TÜV-engineer personally decides what modification he approves, so even fulfilling all legal requirements doesn't mean you get approval.
Which...kind of sucks.
Experience: First engine-swap, last project was a restoration which I started with little more knowledge than how to take the wheels off a car, so it's meant to be a learning experience.
Some bits (engine-tuning, working on the head/block, paint) will be done by experts, I'm probably going to learn how to weld.
Budget: I got a starting-budget, but no fixed limit (learned that that's not worth much on the restoration).
I'm not "made of money", so I'm not going to waste money (like buying a needlessly expensive engine or having a shop do ALL the work), but since I got no time-limit on the build and a garage to store the car I can go step by step with the project (worked fine on the restoration, took a while but got done without breaking my bank account).
Sounds stupid, but it actually worked out fine for me so far.
Parts... Most of them will be imported (car, engine, some tuning-bits).
A lot of Japanese cars in Germany are imports (from Japan/Britain in RHD or North America in LHD), either because the car was never sold here or because it's cheaper to import (yourself or through a dealership) than to buy a car that's already here for a bit.
I consider myself decently fluid in English and through my first project (MX5/Miata NA) I got some "contacts" I could, for example, ask to check out a car or to ship parts "via them" if a seller doesn't ship to Europe.
For Japan...I could build contacts there, over forums, too, I assume.
My Mazda is currently living in my parents 3-car garage, which has plenty of space (only being used with two cars) and soon it'll move into a different garage.
I got some basic tools, my father's got a bunch more I could use.
Only thing I'm lacking (for now) is a welder (didn't need one so far), lift (working with Jackstands/ramps) and engine-crane (which can literally be obtained in a few days).
Don't know exactly where I'm headed after graduation, but the weekend-car(s) are going to stay at my parent's place for the time being, until I figure out storage wherever I go after university.

The rotary was the first idea, an engine that I quite like in a car that I quite like.
But because of its unique-ness and the downsides I saw (as mentioned above) I also went looking for an alternative.
The common LS (which is an attractive idea) is out because with the big displacement taxes get too expensive, BMW-engines are out for cost of parts/maintenance/repairs.
 

4 minutes ago, Miles said:

What are the  common 240Z engine swaps in Germany?

None.
A handful of SR20s and L28s are driving around, but most tuning is limited to different carbs, hotter camshafts, that sort of thing.
Tuning vintage cars is rather unusual around here (some people get the pitchforks out if they only see wrong-year wheels on a car), and the stuff that is done is 99% VAG.
 

4 minutes ago, Miles said:

Are there 240Z clubs in Germany?   Clubs are good source of information

Found two so far, both are more focused on preservation than modification.
One that mentions tuning is about period-correct modifications.
 

4 minutes ago, Miles said:

Engine swaps, and parts swaps in general,  tend to have a domino effect that adds complexity and cost.

I know that from the restoration, certainly doesn't scare me away from it.
I just want to make the right decisions so I don't sink money into something I won't like, which is why I'm asking so much.

Max

Edited September 19, 2018 by Max_S

[rturbo 930]

3 hours ago, Max_S said:

I like the idea of a more modern inline-6, but I'm unsure since I don't know what it does to handling if you throw over 20% of the weight to the front wheels (and further to the front).
That's why I started looking into inline4-engines as well.

I understand the weight issue, which is why I suggested the M54 and N54. M54 you would have to turbo yourself, N54 is already boosted from the factory (which I think would help the chances of a reliable swap), since both are aluminum block, and not too heavy as far as straight sixes go. If I were going to swap in a 4cyl, I think it would be a Honda K24. It wouldn't be a torque monster, but they're great motors. With the N54, you could convert to single turbo to drop some weight.

 

S54 is a heavy motor, which is why I didn't bring it up.

[rturbo 930]

1 hour ago, Max_S said:

Street.
"Weekend Warrior", so it'll be driven rather hard (but not abusive), mainly on twisty backroads.
Not looking for 1/4-mile acceleration or top-speed (Autobahn-driving is actually kinda boring), but for plenty of usable power (so a big turbo-lag is not really desired).
Racing/Autocross is far smaller in Germany compared to the states, outside of entering in some sort of touring-car-series there's almost no option for regular closed course track-use.

Max

I think you said you were going to cage the car? If this is going to be a street car, I think you need to rethink that idea, unless you were referring to a half cage with A pillar or roof bars. Zs are small cars, and a cage is not a good idea in anything but a track car. There's a lot you can do to stiffen the chassis without a full cage.

[Miles]

Given your constraints, and if I lived in Germany, my recommendation would be:

 

• Start with a rust free non-modified 240Z.
• Stock brakes are fine.  Rebuild the entire brake system.  If available use Carbotech AX6 pads and shoes.
• Replace all of the rubber suspension bushings with polyurethane
• Replace springs: Front 180 lb/in  Rear 220lb/in.  A Z car is low enough, so select springs that maintain stock ride height.
• Rebuild engine with modifications that meet local codes/rules. 
• Rebuild/upgrade clutch components
• If allowed, consider  a five speed transmission.  Research first as there are pros and cons and several transmissions to select from.
• Upgrade tires and wheels per local codes.
• Recommend installing the headlight relay harness available from one our members on HybridZ.  Your lights will be brighter and you can run higher wattage bulbs.  The harness is also available from MSA Motor Sports  Auto  (MSA).

This will give you a very comfortable daily driver that handles well under most driving conditions.

 

Brakes:  If you absolutely can't resist doing a "brake upgrade" install the Toyota 4x4 solid front calipers and stop there . The Toyota caliper is made by the same company that made the 240Z caliper so it might get a pass by your code guys.

[Ereschkigal]

There is a good Whatsapp Group... Want to get invited? Send me your phone number.

 

And you know what? 40% of 151 HP (211 HP) isn't much for your listed engines. If you can convince them the 240z has the same chassis as the 280z, else it would be 182 HP which is barely enough for a CA18DET.

[Gollum]

20 hours ago, Max_S said:

Maybe I was taught wrong, but I learned that a sporty car handles well if it gets as close as possible to 50:50 balance, and that light cars suffer if you stick a heavy engine on/ahead of the front wheels (on a side-note, moving/drastically reshaping the firewall isn't an option, if the TÜV notices I might loose any chance at getting the car on the road).

 

I was taught the same thing. Personally, I feel there's a lot of marketing BS that's created this stigma that 50/50 is "ideal". I will say, that a 50/50 balance is generally much easier to setup and tune, since you can put four identical tires on the car and then tune the suspension to balance out itself and the chassis and steering geometry.

 

That said, how many supercars do you think are 50/50? Almost no porsches, and they've never been poor handling cars. And in fact, Porsches generally dominate braking tests... Why? Because they can utilize a lot more rear brake and heat the tires more evenly during braking beccause that 40/60 split when tossing all it's G's at the front under braking retains more weight loading on the rear tire. A car like a FWD two door honda with 60% of it's weight on the front has almost no rear braking requirements, hence why they used drums for so long (and still do in some cases). In these cars, that rear car can't do much braking because there's no weight on the rear. Now, this also means the front has more weight on it and you can apply more braking force because there's more grip available. But tires respond differently at different temperatures. There's a lot of research you can do on coefficients of tire grip but the short of it (this is already long, sorry!) is that a perfect tire would grip the same at all temperatures but never do. With a perfect tire, a heavy car could handle every bit as well as a light car because the added weight would equate to more grip. Obviously well all know this isn't the case, though it's important to realize that "heavy" cars like the R35 GTR don't bend physics, they're surprisingly fast for their weight because they do a great job of spreading the heat between all the tires evenly.

 

And that's the key to all of it. Maximum grip is only attained when you can maintain consistent grip across a tire patch, and across all tire patches. Hot spots in a tire will deliver sub par performance, and having a cold or hot tire in the group will deliver sub par performance. That's the reality of what OEMs look at when engineering a car, as well as fine tuning it.

 

Also, what most people think of as "responsive and good handling" rarely has nothing to do with skidpad results. A car that's eager to turn in and feels stable and predictable have almost zero correlation to skidpad results or even ultimate slalom speed capabilities. If you want your car to "feel good" then spend time on ackerman angles, caster, toe, and scrub radius. Something I see a lot is people putting wire wheels on and then complaining about how "heavy these new wheels feel" when really the problem is that they gained a lot of positive scrub radius. The same problem exists with lowered cars and ackerman angles.

 

I say all this to showcase the reality that there's far too many variables at play to say that an engine is going to hurt your handling. In fact, I'd say that an engine should NEVER enter a discussion about handling, another common internet myth... Choose whatever engine you want, and then build/tune the suspension around THAT choice. Choosing an engine that fits your existing suspension is like choosing the flavor of pizza you want based upon the size of your plate...

[seattlejester]

I wouldn't get too caught up in 50/50. There are ways to get there in other ways to get there via moving things around and it also kind of depends on dynamic movement. You can have 2 cars with 50/50, but if one had the engine lifted a foot higher it would raise the center of gravity  and behave poorly etc. 

 

I would put the VQ back on the table with that kind of power restriction, there are aftermarket intakes available which you may even need to flip the intakes towards the front. It would be torquey, reliable, and be brand loyal if that mattered. Plus the transmission option is really fantastic for that latter years, it really has a lot going for it.

[Miles]

5 hours ago, seattlejester said:

I wouldn't get too caught up in 50/50. There are ways to get there in other ways to get there via moving things around and it also kind of depends on dynamic movement. You can have 2 cars with 50/50, but if one had the engine lifted a foot higher it would raise the center of gravity  and behave poorly etc. 

 

I would put the VQ back on the table with that kind of power restriction, there are aftermarket intakes available which you may even need to flip the intakes towards the front. It would be torquey, reliable, and be brand loyal if that mattered. Plus the transmission option is really fantastic for that latter years, it really has a lot going for it.

 

 

VQ pioneer:  

 

[Max_S]

@rturbo 930
The plan in it current version holds a half-cage (look at a Porsche 911 GT3/GT2), with bars running around the doors too.
Door bars...undecided.
The car won't be a track-car, but "track-ish" if that makes sense.
Also, I like the added security (same reason I'm dropping a roll bar in my MX5, which will NEVER see a racetrack or be driven at the limits), and it's well known that the TÜV is more forgiving with power-increases if they see a properly done, preferably welded-in bar/cage that "connects" from the rear strut-towers to the front footwell (front towers are often no-go-extensions, for worries that it might "impale" the other car in a crash).
Also, to be honest, I kinda like the look of it, and although the focus is on function looks still matter.
 

@Miles
The concept started with "modern tech in an old shell" before the Z was picked, so, at least for this project, working off the stock drivetrain is no option.
I'm still going to copy the notes from your reply, who knows, maybe I'll have two Zs one day
The car won't be a daily driver, I got a cheap and robust Golf for that for the foreseeable future.
Like my MX5, the Z would be a "weekend warrior", just a different kind of car than the MX.
I want a nice sporty car for the weekends.
Not too extreme (so...no straight-cut gears, for example), or no completely back-breaking seats and all solid mounts/bushings, but among other idea's I've been playing around ideas of harnesses (quite like that idea) or a larger fuel-cell than the stock tank (undecided, main downside is that as far as I know that would "kill" any fuel-gauge).

I'll keep the Toyota 4x4 brakes in mind.
Brakes are not the biggest problem with the TÜV,  since those guys tend to be a bit forgiving when it evidently improves safety (a lot of old BMWs and Volkswagens with more power run Porsche-bits or complete aftermarket setups, no problem there).

@Ereschkigal
The 40% increase isn't a solid ceiling, it's a hurdle/expense.
If all else fails, I found a company who claim they can get stuff approved much easier than individual people.
There's a ton of cars running more than 140% stock power, so while it's annoying that there's that hurdle, it doesn't mean I can't go past it.

@seattlejester
I have to look into that more.
I was...hesitant with V-engines because, from other engine-swap stories (V8 E30s, for example), I've heard of having to basically build a new front end, or...brave patching-together of custom steering-assemblies, which NEVER sits well with the TÜV if your steering-colum consists of countless joints.
So I kind of disadvantaged the V from the start.
As for the VQ, I'll have to look into that further.
Not only into tuning, but also in the looks-department.
Because, as I said above, while function has the priority on this build, I still want it to look good.
And the stock plastic lump on these engines does not fit that plan.
Torquey and reliable sounds good, brand loyalty doesn't really matter.
What would be helpful is if the stock transmission could be bolted into the Z without needing a complete new underside (some widening/raising of the tunnel is fine), because that makes a few of the hurdles easier to pass if the donor and the swapped car have the same gearbox with the same ratios.

For now I'm "saddling the horse from the rear", making decision on other bits, while the engine is undecided.
I still got the "A-plan" with the rotary, Plan B would be a six-cylinder for sure, either V from the newer Zs or a 2JZ/RB.
A big question mark is still a place to get those engines, apart from the scarce offerings on the German market (and I don't speak/read Japanese).

Max

[Ereschkigal]

You mean there is a ton of german cars doing more than 140%.

I know it isn't solid but 10.000 € is a big hurdle.