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Max_S

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

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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

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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.

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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.

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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

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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. 

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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

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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

 

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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.

 

 

 

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@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 by Max_S

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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.

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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.

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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.

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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.

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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...

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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.

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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:  

 

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@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

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I went with the LS swap mainly because of the weight.  A fully dressed LS1/T56 is only 30lbs (13.6kg) more than the stock 2.8 liter with the T5 trans and the weight is centered more because it’s the transmission that is actually heavier. And with the quality of Hoke Performance LS swap kits it looks and fits like a factory made V8.  The aluminum 5.3 can easily make 300hp at the wheels.  I don’t know how easy it is to get LS1 parts in Germany but here they are everywhere here and they are cheap!  I couldn’t get the power I have with a 1 or 2 JZ or RB without spending at least twice as much as I did.  

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The S30 engine bay is quite a bit larger than an E30. I used to be able to stand inside the engine bay in front of my engine with my 7mgte. In my friend's E30 I think part of his accessory drive sits offset of the fan because they are so close.

 

If you are precluding an engine choice based on a removable-nonfunctinoal cover than I think aesthetics are a higher priority than performance. It seems maybe ease of install would be a close second over performance as well. Might be worth sitting down and thinking about what is the highest priority and making a list in order. An L28ET seems to be the easiest, aesthetically it is pretty much stock, it is dirt easy to install, and it can definitely make over 300hp. If that is not on the top of your list than you have another priority like wanting a swapped car, or street cred, etc. Hard for us to play the game without you giving us your list of priorities. You mention sound, aesthetics, hp, ease of swap, torque, turbo lag, insurance, tax, etc. Make a list in order of priority. If an engine is suggested that meets the criteria and you still don't like it than you definitely have a different priority order, adjust until it accurately reflects what you want.

 

To start for me my priority was:

Ease of install

 

So I went with an L28E that I converted to carbs. That was the easiest to do. 

 

Then it switched:

Turbo (preferably factory)

Cross flow head (preferably with intake on driver side)

Similar displacement or larger (I had a 2.8L in my 240z)

Ease of service (parts available in the parts store)

Low modification (keep factory mounts to make it reversible)

 

That precluded the RB's, SR's, german engines, etc, even the turbo JZ's. Basically left me with the 7mgte. That is what I did.

 

When the 7mgte let go, my priority shifted:

Ease of install

Turbo

R154 compatible

 

That meant either staying with a 7mgte or swapping to a 2jz, or going to a 4g63 with an adapter. Since I still wanted turbo, but I didn't want to have to rely on importing parts or dealing with a new platform, my priority switched with ease of finding parts taking over factory turbo charged so I went with 2jz-ge na-t.

 

Then I decided to swap in a stronger and smoother transmission, priorities were:

cheap

strong

not visible under from the side

 

So low modification fell off the list and cheap while not visible meant I had to do the work and spend a lot of time with getting the fitment right. 

 

At each point the priority changes, but looking back I know exactly why I picked each one. There really are no regrets as at the time it made justifiable sense, granted in hindsight I would have done some things different as options weren't available or affordable at the time.

 

Some things to consider:

 

Transmission:

Any engine with a decent horsepower output is going to use a bigger transmission. LS, JZ, RB, VQ. They all have fairly big transmissions especially for their strong transmission option. The VQ transmission is I believe the biggest next to the the T56, but the benefit is that all of those mentioned above actually can run the CD009 transmission as it is strong, cheap, and plentiful. You can cut down quite a bit on bulk using the newer adapter plates the require bell housing cutting but it still is large. Even at that large a size with an early Z 70-72, you can probably fit it without any drastic changes other then removing the mounts. The later years you have to remove the whole trans tunnel brace type situation. With that said the R154 from the JZ can fit with custom mounts on the factory points in the early years, I still have my "kit" if you want measurements.

 

Rear end:

You are planning on putting out more than double the power the axles are used to seeing if you want the earlier cars you are also going to have the weaker stub axles. That means you need to factor in stronger axles, rear end, etc etc. This can end up costing as much as the engine itself so keep that in mind.

 

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My priorities have almost been opposite direction lately. The more I drove my daily (a G37S), the more I realized that I didn't even take advantage of the top end of that car. I quickly realized that anything near 200whp in the S30 would match the power to weight ratio of the G37s.... sounds fun enough for me and easy enough to do with a very mild turbo L28, or some extensive work on the L28 with fuel injection. 

 

300hp is a common goal for a lot of people, and really you can hit it with almost any of the popular swaps. For your goals I really think the turbo L28 would be a solid option. It'll hit the numbers. fitment will be easy, will be lighter than a 2jz or an RB, turbo will let you adjust how much power you're making to meet regulations when you need to. 

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@30 ounce
There is no defined "threshold", as far as I know it's "fluid".
The bigger the displacement, the more expensive the taxes.
It's why a VR6-Golf is much more expensive than a 1.8T, because while they can put out the same power and can have the same equipment the VR has more displacement.
It's meant to discourage using big thirsty engines, unless it's for certified vintage cars (which my Z won't be).
Those who run LS-cars (or any American V8) usually just ship (parts for) them in from the US, either through the manufacturer or themselves (same goes for a lot of cars, by the way).

@seattlejester
Early on I read somewhere (don't remember where exactly) that a big downside of the 350Z's engine is "the big plastic intake, which can't really be skipped".
I've seen one swap throw an R35 GT-R's cover on there, but it was just a photo, I don't know if it even works.

Priorities:
Looks aren't the main priority, but they are still very "high up on the list" since I'll spend a lot more time looking at the car than looking out of it.
The original idea was to get a classic car, put in relatively modern technology, and throw around 260hp at the rear wheels (in Europe WHP is pretty much all that matters, almost nobody measures or mentions crank-hp).
My first car ever made 68hp, the MX5 makes 131, it just seemed "neat" to double that again with the next project.
And then that "little child in my head" went "why not make it 300, nice even number?"
So I guess that's where I went off-track a bit, partly my own fault, partly that of seeing all kinds of crazy engine swaps from the states.
And when I looked around the first thing that came up was the 2JZ, followed by LS-swaps.
I have to admit, a big part of the rotary-swap idea was the uniqueness of that combination, which is why I also went and put together a "plan b" with a piston-engine.
My main priority is to have "250+" horsepower at the wheels, and that in a useable way, meaning not just having power at the very end of the rev-band.
Great for the dyno and the 1/4-mile, but not very good for my kind of driving, where plenty of time is spent at as (relatively) low as 3-4k rpm.
The power is supposed to be actually usable for more than bragging.
Maybe I should tell, the first turbo-car I ever drove was the Opel Speedster Turbo, it had a whole lot of nothing coming from the engine, with the turbo kicking in rough and VERY late, I don't want that.
300hp is perfection/ideal, but I would probably be just fine if the car falls just short of it.
I guess number two is performance-feel (that was the problem-point with weight-distribution, in my mind a car wants to corner less happily the more weight I throw onto or past the front wheels), and also things like the engine being rev-happy and having a nice-shifting gearbox, no "pudding bag" or even automatic).
I've had quite a few people say "take any turbocharged engine, and just slap the biggest turbo on there you can find".
Yeah...no.
Might get my target-hp, or more, but as I said, I want a car with a usable power-range, so while a turbo is an option supercharging or NA-tuning is also.
Number three is looks, four is ease of install (I can get some custom mounts, I can't construct a pipe-frame to put the whole body on, I can expand the front of the tunnel a bit, I can't move the firewall entirely or create a new underside).
I'm not going to do a completely "tucked" engine bay (because that's impractical), and I might not get something super-mega-clean like the famous FuguZ, but it should still be nice to look at.
Summed up, with the hood closed it's supposed to look like a 240/260 that could be taken to the track, with a few updated details (seats, brakes, wheels, etc, but, for example, no rocket-bunny-stuff or huge wing), with the hood open I don't want carbs but also don't want a whole lot of plastic or a chaotic snake-pit of wires and hoses.
That look is also where my plan for a cage comes in, serving "tripple-duty".
1st, a cage improves safety, even a roadcar can go shiny side down.
Second, it improves stiffness, which is good for handling and for the approval-process.
Third, I think it would look good.
Parts-availability is low on the list, I don't care if a part takes two weeks from the states or Japan, as long as I can get the parts to keep the engine/drivetrain running.
A big bonus if the engine came with a five or six-speed manual, eases approval for road-use.
Fuel-consumption doesn't matter, as long as it is fuel (and not diesel, I've had someone recommend a cummins-swap), I plan on a fuel-cell (goes for the racecar-style) so I should be able to haul some fuel if necessary.
Cost isn't really on the "priority-list", I don't want to waste money but also not cut corners or safe a tiny bit of money but be unhappy with the result.

Limitations:
Fuel injection, 6 cylinders (decided I don't really want a 4-banger after all), 3 (3.5 at most) liters of displacement in stock form (the TÜV doesn't see if the displacement was enlarged as part of tuning), ideally an engine I can run on a custom ECU (haltech, motech, that sort of thing, so I have more freedom in programming (with safety-measures, for example, or a low-power-lean-run "TÜV"-setting, that sort of thing).
Also, some space left in the engine-bay to run power brakes, sufficient (or over-build) cooling, an A/C-system (on the engine or electrical), because I need heating by law so I already got to have the vents and such, and maybe a power steering kit.
Oh, and the whole package has to fit a stock hood, if I get an intake sticking out the hood, or even just a scoop, chances at road-legal approval go down DRASTICALLY (pedestrian safety is seen as compromised with anything bulging/sticking out of the hood).

Gearboxes:
Manual, five or six-speed, no straight-cut gears (it's still a roadcar, and the straight-cut-gear-whine gets on my nerve even if I only watch videos).
Nice if it fits with just a "massaged"/widened tunnel, even better if it fits (towards the interior) with the stock center console.
Big bonus if I can use the donor car's gearbox (stock or if necessary with stronger gears), makes the approval-process A LOT cheaper.
Fabricating new mounts/having someone fabricate them is perfectly okay.

Drivetrain:
I'm already factoring in a new driveshaft, so if I find a place that'll make those I should be able to find a source for stronger axles if needed.
New/stronger differential is already on the list too, definitive decision there depends on the engine/gearbox I end up choosing.

Max

Edited by Max_S

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