L-Series Bench Racing

[kce]

So I recently bought a '73 240z which is basically my dream car. I've wanted one ever since I saw that youtube

of the 240 with supercharged SBC when I was like 16 or 17. However, because I am broke the only major work I can afford to do on the car is imaginary. So let the bench racing begin!

 

Now am I very much a chevy small block guy, not only do they fit my style but I've built a few of them. This makes the idea of a small block swap into my 240 a pretty attractive idea. Looking at some possible engine builds, I think I can put together a pretty stout (like 400-450hp) 383 for around 5K (my father and I have plenty of SBC parts... last I checked he's got like three blocks squirreled away in the garage!). That's a power-to-price ratio that's pretty hard to beat.

 

However, the L-Series engine is definitely cool too. The more I drive and fiddle with the car, the more I am learning to appreciate it. I've looked around but I haven't seen many engine builds so would anyone like share their favorite? I'm looking for something that is streetable, but that doesn't mean tame... so lumpy idle, long-warm up times, etc. not an issue.

 

My specific questions:

Is there anyway to beat (or break even) with the power-to-price ratio you get with an SBC using a L-Series?

What kind of horsepower, torque and engine profile (dyno maps be would sweet!) can you expect with a decently built NA L-Series, or a turbo-ed L-Series?

If you know the relative cost of your build, and you don't mind sharing I'd love to see it.

 

 

If any members have L-Series builds they'd like to share, I'd love to look at 'em.

 

Thanks!

[burninator]

I'll be the first to say this has been gone over 100s of times. Spend a little time searching. In particular read the faqs section.

[SleeperZ]

For $5k you can easily get that power out of an L28 turbo and still be reliable and keep good fuel mileage.

[kce]

I'll be the first to say this has been gone over 100s of times. Spend a little time searching. In particular read the faqs section.

 

My apologizes, there's so much information on this site it's a bit overwhelming. Thanks.

[Daeron]

I can't link you up to all that you want, but I can tell you right now that there are 120-140 free Nissan horses under the hood, and that price is mighty difficult to beat. Depending how much you put into it, a sturdy 140-150 can be had cheaply enough, and if you want to spend the cash to say, do a valve job and cam swap on a head, and get good SUs and electronic ignition, you'd be in for maybe 1500 (less if you can save on the "head job," but its a variable. I'll presume you understand how this cost thing plays out.)

 

My point is, you can then go about spending maybe up to the same amount on some suspension and brake upgrades (aftermarket springs/struts, replace bushings, continue on spiraling out the cost and performance gains but as always, the gains start becoming minimal for the cost eventually.. I'll leave you to discover) and get alot more fun out of the car. You'd need to put some work into the suspension to handle a 383 anyhow, right?

 

Like I said, there are at least 120 free ponies to use now, and you can't beat that cost/power ratio. Suspension upgrades first are the wise (if usually ignored) way to go with an old S30.

 

In terms of maximum NA power, for five grand you ought to be able to piece together a MegaSquirt system and some cheap ITBs or an aftermarket intake manifold. You'd want to do some pretty "real" head work if you are REALLY going after horses, and I don't know how much you'd spend and how much you would do yourself on that, but the 5K was just talking EFI. Stock internals are pretty stout, the reciprocating assembly is good to just about any NA power you're likely to make, and any RPM you're likely to hit, *in naturally aspirated trim.* The Pistons should be forged if you want to run the ragged edge of compression and push the power envelope, but if you can satisfy yourself with being a touch conservative stock pistons might even survive for a little while...

 

But, forged, full blown head, nice EFI and ITBs you're looking 10K for about 300 +/- 50 wheel horse. Forged, stock bottom, mild homebrew head, stock ported EFI manifold with the right cam, maybe a 3-6K job depending on what you can do, invent, and pull out of your arse and what you have to buy.. Maybe even 7K, but that motor would be looking like 220-240, 250 would be optimistic. If it was all done well, which can take a knack. You could put this $3-7K package together and land 165 WHP if you are seriously lacking in knack.

 

 

Now, ALL of that is total hogwash intended to give you a sense of where you are at in a murky sea!!! Every dollar figure and every power number, as well as every modification listed, is VERY subject to changing based on how the package is selected, (ie part matching on paper) assembled, (ie parts matching in reality) and the tune (ie computer fits with all the parts and spells out the power you want.) So, I hope it is useful, but to really understand how to summon power out of an L6 in NA trim is witchcraft of a capital order, and its a religion based on spending lots of money that could be FAR more efficiently spent on a turbo for the 6, or a V8. It is very very rewarding though.

 

Two last points, then a treat from our resident Encyclopedia D. Turboing the 6 is a simple, fairly cheap way to get to 250-350 horsepower, even up to 400 with stock equipment plus bigger injectors and some computer upgrading. $1k added to the factory turbo system can net you 400 horsepower, and 250-300 should be easy to obtain spending that. (Turboing a non-turbo is a more complex affair obviously.) Secondly, as I said before, you'll get more fun out of tweaking the handling first.. and dont underestimate how much fun "only" 200 NA horsepower can be in the car with a good suspension!

 

Here is your treat... this is what CAN be done Naturally Aspirated:

[Tony D]

That's only a 205hp to the rear wheels L20A (1998CC's) with low compression. The L28 accelerates much faster.

instead of going the 1.3 miles in 53 seconds, it's more like 45. From a standing start, on dirt...

 

With the L28 and a four barrel manifold, running one time at Carlsbad we had no traction in first or second on street legal drag radials, and because of the 3.36 gearing you could count one...two...three before the cam came on in third and the car started accelerating to a 13.08 quarter mile...spinning the tires through the traps...

[T-Bone028]

I would agree with Daeron, get the current engine in solid running condition, spend a little money on the things that wont need to be changed after you settle on your power route (suspension, brakes, wheels/tires, RUST...Im sure you have some). Consider finding a R-200 and installing that as well.

 

In the meantime, pick up the book "Datsun Z car V-8 conversion manual" from JTR its about $15-$20 and will give you a good idea of what the swap involves. Search through numerous posts on this site, and start thinking about what direction you want to take your car...N/A, Turbo, HybridZ.

 

But to answer your question, horsepower/price...SBC V8 or L28ET will most likely be your most cost friendly route to more power.

[wigenOut-S30]

This thred might help with some L28 data.

 

http://forums.hybridz.org/index.php?/topic/68375-list-your-l28et-setup/

[kce]

First off, thanks for all the good replies. I certainly appreciate it.

 

Like I said, there are at least 120 free ponies to use now, and you can't beat that cost/power ratio. Suspension upgrades first are the wise (if usually ignored) way to go with an old S30.

 

I didn't quite look at it that way, but you make an excellent point. Any engine swap (especially a SBC) that includes a significant increase in horsepower is going to make suspension work necessary.

 

In terms of maximum NA power, for five grand you ought to be able to piece together a MegaSquirt system and some cheap ITBs or an aftermarket intake manifold. You'd want to do some pretty "real" head work if you are REALLY going after horses, and I don't know how much you'd spend and how much you would do yourself on that, but the 5K was just talking EFI.

 

At the risk of sounding like a newbie: What exactly is MegaSquirt, and ITBs? Google tells me MegaSquirt is a EFI engine managment computer system but I'm still in the dark exactly why I'd want one? You'll have to bear with me here, all my experience has been on carborated SBC or diesels. As for ITBs, I have no idea?

 

 

Stock internals are pretty stout, the reciprocating assembly is good to just about any NA power you're likely to make, and any RPM you're likely to hit, *in naturally aspirated trim.* The Pistons should be forged if you want to run the ragged edge of compression and push the power envelope, but if you can satisfy yourself with being a touch conservative stock pistons might even survive for a little while...

 

That's comforting to hear. I've heard that the rods on the L24s are forged? Is this true? If it is the case, getting them shot-peened and replacing the rod bolts with ARP hardware is probably the way to go. I'm betting a set of forged pistons are prohibitively expensive for the L6 engines (~$800 for a set? I am so spoiled by SBC prices), which is why you said I *could* get by using the stock ones...

 

 

So, I hope it is useful, but to really understand how to summon power out of an L6 in NA trim is witchcraft of a capital order, and its a religion based on spending lots of money that could be FAR more efficiently spent on a turbo for the 6, or a V8. It is very very rewarding though.

 

That almost sounds like a challenge! I've never owned or worked on a car with a turbo (well except a Cat engine) so building them and tuning them has always seemed like a black art to me. In fact, working with *any* electronic engine management has! However, the scream of any NA engine as rips to the top its powerband... sniff, it is a beautiful thing.

 

 

But, forged, full blown head, nice EFI and ITBs you're looking 10K for about 300 +/- 50 wheel horse. Forged, stock bottom, mild homebrew head, stock ported EFI manifold with the right cam, maybe a 3-6K job depending on what you can do, invent, and pull out of your arse and what you have to buy.. Maybe even 7K, but that motor would be looking like 220-240, 250 would be optimistic. If it was all done well, which can take a knack. You could put this $3-7K package together and land 165 WHP if you are seriously lacking in knack.

 

I'm assuming these numbers are on top of the L24's stock "200hp" (I doubt mine makes close to that). Pulling another 220hp out of my current L24 is definitely an option I'll consider. Getting something like 350-375 hp total out of it would be amazing.

 

The only thing I'd like to mention is that my off-the-top-of-my-head guess is that an EFI conversion (tank, pump, regulator, lines, manifold, injectors, etc.) comes close to $5K with everything all said and done and we haven't even started talking about cam swaps, head work (some of which I can probably do... although head-porting is the blackest of black arts), and new pistons (presumably to raise the compression level)... so $10-12K said and done? For that price, I could just go with something top shelf like an LS6 and have plently left over for that badly needed limited slip differential (and other suspension work).

 

 

 

Secondly, as I said before, you'll get more fun out of tweaking the handling first.. and dont underestimate how much fun "only" 200 NA horsepower can be in the car with a good suspension!

 

With the added bonus that I can actually drive the car instead of spend 6-8 months building an engine!

Edited March 11, 2010 by kce

[wondersparrow]

Megasquirt for all intents and purposes is a standalone aftermarket ecu. Do a little research. I haven't done an efi conversion yet, but I will be as soon as funds allow.

 

http://www.diyautotune.com/faq/faq.htm#whatheckms

 

ITB - individual throttle bodies. There are lots out there, these are the ones I have my eye on.

 

http://extrudabody.com/Products/ITBs.html

 

Having a completely stripped track car, I am not concerned with any of the stock electrics or gauges. For me to make the switch, those two items are the biggest costs involved. I have triple webers and a fuel cell installed already, so again no worries about stock gas tank or intake mani. Unless I am mistaken, injectors, wiring, fuel pump and lines would be all that remains for a basic setup. Oh, and the ford edis 6 system if you want to get rid of the distributor.

 

There is tons of info on this site, poke around.

Edited March 11, 2010 by wondersparrow

[Leon]

Daeron is talking actual power, not differences from stock. And BTW, an L24 does not make near 200hp stock! It's closer to about 120-130whp (150bhp). You'd have to put in a considerable effort to get to 200whp.

 

I agree that tackling the (likely poorly maintained) suspension first is the way to go. Do that and then drive it with a stock engine. You don't need 300hp to have fun! When my 240Z was on the road it ran pretty badly, partly because it was a $400 240Z. It very likely had under 100hp, and I had plenty of fun!

[Daeron]

I completely ignored carburetion, and that was NOT fair of me to do... but it was already a book of a post.

 

You asked a couple good questions.. MS (megasquirt) you've got figured out, but the reason it would be needed is tied intimately into the point I made about ignoring the possibility of using carbs. The piston issue also comes into play.

 

We all know the formula for making a powerful engine; more fuel, plus more air, plus more compression. The L6, unfortunately, CAN have troublesome detonation characteristics when you boost compression over 9:1. This threshold runs from 9:1-10.x:1, but compared to many other motors the threshold is pretty low. There are workarounds (a very lengthy thread involving cooling modification between cyl #5 and #6 in the head, among others) and there is an "open chambered head" camp versus a "high quench head" camp, but my point is the ceiling is there.

 

If you build a longblock with 9.5:1 compression and a mild NA cam the right way, you can run properly set up SU's (not a difficult task) and get away with it on pump gas; maybe not even high octane. If you do it the wrong way, you can't dial in enough timing to avoid pinging on low octane fuel.

 

The "right" and "wrong" ways are not my point; nor am *I* the one to explain. (I'm really more of a talked than a Do-er. Gotta make that clear, all this knowledge is obtained by oZmosis and through living my 29 years of life in and around these cars. Haven't built an engine myself yet, but two brothers co own an ITS racecar, there are 4 Z's currently owned by my immediate family, and 6 datsun Roadsters.)

 

What I wanted to make clearer was this: the more precisely controlled your fuel and spark is, the further you can push the compression envelope with stock pistons. Everything is really contained within that sentence.. The MS helps get fueling and ignition *just* right, at every combination of RPM, throttle position, and load level possible... Carbs will never be as precise as the MS, but you can certainly tune them to be "safe" at the expense of fuel economy. (And THAT issue isn't just as simple as "Oh, sure, whats 1-3 mpg?)

 

If you know 4 barrels well, and have a 390-650CFM Holley in good shape, then a cam and a 4 barrel, along with an electronic ignition setup, might be your best bet engine-wise. I have to say frankly that the 4-bbl is at the bottom of my personal list, but there is no factual reason for that, merely taste and experience. My dad ran a 4bbl in his 240 ratrod-racecar and friggin loved it (and he is the one I got the prejudice from in the first place.) Whether I like them or not, I can't deny that they are a valid, easy, cheap, and potent way that many people have no regrets over.

 

 

Edit-- I forgot to mention that the Stock EFI system is an antiquated computer. It functions well, and is well worth maintaining and using within a certain limited power demand, but upgrading the car is virtually impossible. Methods were worked out through the 70s and 80s, but they all involved richening the mixture through band-aid means and "fooling" the computer one way or another. There is no way to properly re-tune the stock EFI if you change a cam, or injector size, or anything like that... so if you wanted to go EFI, it would be nearly pointless to consider using a stock system/computer/sensors. Stock EFI intake manifolds are not the biggest breathers in the world, which is why ITB's were suggested... but this is something of a lark. The stock manifolds don't flow as much as the engine could use, but they are certainly adequate for up to 350-400 turbocharged horsepower. An NA engine is going to be limited in a different way, though, and if you built a mean NA monster longblock/computer, and put a stock (even stock +ported) EFI manifold, chances are that mani would be a bottleneck.

Edited March 12, 2010 by Daeron

[pcakes55]

Just my .02 if you go L28et and you're trying to be on a budget, buy ALL the supporting mods first before doing any motor work. I planned about $2k in all on my swap, and before I knew it I'm up to $2500 on building the longblock alone.

 

Buy things like a suspension, brakes, front mount, good ECU, etc. and drive as is; Build the block down the road. It really sucks that I'm going to have a brand new motor and won't be able to drive the car until july-ish.

[Tony D]

You'd have to put in a considerable effort to get to 200whp.

 

As has been posted here, the ITS cars are close to that with an L24 and SU's, unported head, stock Nissan cam, stock cast pistons...

 

L24's in RACING trim (forged pistons, or hell, MONZSTER's Car...) can be closer to 300HP using forged pistons, worked head, cam, etc...

 

Not saying it doesn't take effort to get 300HP, but using alternate induction, porting, and a cam getting 200HP from an L24 is easier than trying to get it from the stock pieces (and it CAN be done!)

[Daeron]

One final note to add:

 

As you play with your L24 whilst getting to know your Z-car, pay attention to the sounds of the valvetrain. I was about 16 when I finally learned how much of the sound that I love comes from the valvetrain of these cars, and through that how much the noise is addictive to me.

 

If it weren't for that problem, I would be one of "the turbo guys" in an instant, but the noisy valvetrain being the chief high percussive note of the underhood sound really really gets my gears going in a way that keeps me on the fence. Decisions.....

[TimZ]

One final note to add:

 

As you play with your L24 whilst getting to know your Z-car, pay attention to the sounds of the valvetrain. I was about 16 when I finally learned how much of the sound that I love comes from the valvetrain of these cars, and through that how much the noise is addictive to me.

 

If it weren't for that problem, I would be one of "the turbo guys" in an instant, but the noisy valvetrain being the chief high percussive note of the underhood sound really really gets my gears going in a way that keeps me on the fence. Decisions.....

 

You are talking about valvetrain noise and not induction noise, right? How does the turbo affect that? I can hear my valvetrain just fine...

Edited March 12, 2010 by TimZ

[Daeron]

I dont care for the turbo sound drowning out the valvetrain sound... A clutch fan doesn't "drown out" the valvetrain any more than a turbo does, but it still takes away from the sound in a way that triples do NOT. I'm not saying I don't like turbo whine, but.....

 

Sorry, I was trying for once to keep a post short, so I failed to wax poetic about my beloved valvetrain noise properly; I just wanted to point out one of the features *I* find most attractive (in a subconscious way) about the engine.