Getting the most power

[AndysPlit]

Eventually I would like to rebuild the stock L28 motor on my 78. There are some performance mods I would like to consider like a lighter flywheel, cams, maybe a bigger throtttle, headers, etc. However, I am trying to stay away from anything like throwing in a turbo, nitrous, or swapping out for a V8. Mind you, all those are exciting mods, but they are just not for me.

My attempt is to get the most power out of that staight-six without going over the top. I am asking 4 things:

1. What upgrades are recommended from you guys?

2. Is it possible to get the car in the 5 second range (0-60) by doing it this way?

3. What is the calculated top speed?

4. What's the most horsepower I could get?

Thanks!

[hls30.com]

1) You have limited your upgrades to those that are slightly effective(10% claimed increase), big bucks(head work aint cheep) or are trial and error for a diyer. After a used 4:11 swap, Nitrous is without a doubt the biggest bang for the buck at retail. I am sure some of the seriously into Engines/racing guys will chime in here with some viable upgrades for you.

2)With enough money and time, anything is possable.

3) Depends entirely on the tranny and differential you end up with-there is a link to a calc floating around somewhere-I'll post it when I find it, but top speed and low 0-60 figures are pretty well mutually exclusive unless you swap the 5th gear to something really really tall...

4) see number 2 and read it twice!

My answer isn't to be flippant, it is just to point out that almost everything in the automotive world is a trade off-you can't have a gain in one specification with out a loss somewhere else, and most of the time that translates to mean you can't have an older car that does everything well.
Will

[beandip]

I agree completely with what Will just said. If you do a rebuild , replace your dished pistons with flat. Have the head gone over , ported ,milled valve work and the compression raised to 9.5 - 10.0 to one or higher if racing is for the car. Install a cam with a grind suited to the sort of driving you intend for the car. Road racing then a hi-revving cam. Street use then one that will build power at lower revs like 2K to 5500. The 78z is a fairly heavy car compared to a series 1 so overcoming the power to weight ratio will come into this. Building the car for top speed will greatly impact the lower speed performance . As Will stated using a low rear end gearing will greatly improve the off the line performance but will lower the top end speed. Everything is a trade off, it all depends on how fast you want to SPEND . Gary

[Arne]

Is it possible to get the car in the 5 second range (0-60) by doing it this way?

However, I am trying to stay away from anything like throwing in a turbo, nitrous, or swapping out for a V8.

As Will said, anything is possible if you throw enough money at it, but I think it will be VERY difficult to achieve 0-60 in less than 6 seconds without the things you list as "not for you".

[240ZMan]

As someone who has a similar desire to keep the L6 and not go to forced intake or nitrous, I can relate to your goals. I've been gradually building up my L28 to the point where I now have:

N42 block bored .020 over
Flat top pistons
N42 head with mild porting
Header + 2.5" exhaust
Stage III-equivalent reground cam
Triple Webers
MSD ignition
Lightened flywheel
5 speed
4.11 LSD

The car is blast to drive and makes useful power up to 7k rpm. I'm in the process of converting to FI and will dyno it after that so can't tell you the power right now.

BUT....

If you want to build a reliable 5 second 0-60 car, then you should be looking at a V8 conversion or turbo L6. Assuming you don't want a turbo, then focus on a V8. Done right, the weight will be about the same and you'll spend about the same amount. Plus, if you want to go faster still, you'll have lots of options available to you.

I realize that what I'm saying could be considered blasphemy, and a few years ago I couldn't even imagine it. If you're like me and you like to wrench on your car and enjoy the learning that comes with it, then I'd definitely recommend going down the L6 route and enjoy the process. But if you want to straight to a 5 second car on a reasonable budget, then you should think about the V8.

Just my $.02.

[240ZMan]

Another thought: build a 3.1 stroker. It would let you keep the L6 and should get you to your performance goals.

BUT...

It's not cheap at all. In fact, from what I've read in multiple places, you'll likely spend MORE than a V8 conversion with comparable power.

[AndysPlit]

Right on. I will consult my garage (Sunrise Z) to see what we can do for my car in the future. Your recommendations sound quite similar to what they have mentioned. I really want to keep the straight-six, even if I I'll never get a 5-second or car without the turbo. Keeping with what came from Nissan will automatically override any lofy (maybe laughable) expectations I may have had.

Yeah, the V8 conversion can be cool, but I decided not to go down that route. I love my six! Maybe, I'll consider the turbo afterall. I guess I haven't really thought about what I am more willing to sacrafice: acceleration or top end...............As I have understood from other posts I need to think about that. Hmmm......I don't think top end will be my specific goal now that I think about it. I live a long distance from the Salt Flats anyhow!

So far all I have is a 2 1/2 turbo muffler as far as performance mods go. I have a ways to go, even after owning the Z for 10 years. How many horses would you estimate your car has?

Thanks guys. I'm open to more advice.

As someone who has a similar desire to keep the L6 and not go to forced intake or nitrous, I can relate to your goals. I've been gradually building up my L28 to the point where I now have:

N42 block bored .020 over
Flat top pistons
N42 head with mild porting
Header + 2.5" exhaust
Stage III-equivalent reground cam
Triple Webers
MSD ignition
Lightened flywheel
5 speed
4.11 LSD

The car is blast to drive and makes useful power up to 7k rpm. I'm in the process of converting to FI and will dyno it after that so can't tell you the power right now.

BUT....

If you want to build a reliable 5 second 0-60 car, then you should be looking at a V8 conversion or turbo L6. Assuming you don't want a turbo, then focus on a V8. Done right, the weight will be about the same and you'll spend about the same amount. Plus, if you want to go faster still, you'll have lots of options available to you.

I realize that what I'm saying could be considered blasphemy, and a few years ago I couldn't even imagine it. If you're like me and you like to wrench on your car and enjoy the learning that comes with it, then I'd definitely recommend going down the L6 route and enjoy the process. But if you want to straight to a 5 second car on a reasonable budget, then you should think about the V8.

Just my $.02.

[zbane]

I really want to keep the straight-six, even if I I'll never get a 5-second car without the turbo. Keeping with what came from Nissan...snip...
...I love my six! Maybe, I'll consider the turbo afterall.

How about this-find yourself an L28T from a later model year 280zx. Sure, it's a turbo, but it is a Nissan L28, and before you go and drop it in, you can do all the work you want to it, all the while driving your Z...

[AndysPlit]

I thought about that in the past....and it sounded like a cool idea. But for some reason I seem to be on this kick of keeping the original motor. Basically I want to finish the job Nissan started years ago with that very engine.

How about this-find yourself an L28T from a later model year 280zx. Sure, it's a turbo, but it is a Nissan L28, and before you go and drop it in, you can do all the work you want to it, all the while driving your Z...

[hls30.com]

I thought about that in the past....and it sounded like a cool idea. But for some reason I seem to be on this kick of keeping the original motor. Basically I want to finish the job Nissan started years ago with that very engine.

One more thought, the L28ET was the final evolution of the L24!
Granted it isn't your original engine, but it is in the original vein!

[240ZMan]

How do you define "that very engine"? At the risk of playing with semantics, if you define it as the block, pistons, and crank, you could swap to a P79 or P90 head, turbo it, and have a pretty robust engine as long as you didn't go crazy with the boost. Leave it at the factory levels of boost and that engine would live a long and happy life

Please keep in mind I'm not trying to push you into a turbo, just making sure you know what your options are. I'm not a fan of turbos for performance cars, although my daily driver is a turbo volvo. I don't like the delay between pressing the gas and feeling the torque. But that's just me. Lot's of people find the extra hp worth the slight lag.

Choices, choices, choices ...

[AndysPlit]

Yeah, tell me about choices. If only I had the budget to aquire a few Z's and try different things on each of them. At any rate, I suppose I would define "that very engine" as the block. The pistons and such I would like to upgrade. I'm still trying to decide if I want to bore out the cylinders.

By the way, does anyone know how far the cyliners can be bored to on an L28?

[e_racer1999]

to answer your last question, people bore out the L28 blocks to 89mm for the 3.1L motor. usually they use the F54 block because it is arguably a bit stronger.

but the setup that i'm going with is similar to daniel's, and i think it's a pretty darn nice, quick street setup.

i've got an F54 L28 block with flattop pistons
N42 head, milled slightly & mildly ported
stage III MSA cam with valvetrain
MSA 6-1 header into 2.5" exhaust

albiet i'm going through SUs, i think it's a good setup. i think that you can build something up pretty similar for around 1500 if you do the work yourself. stout combination, and you can use your same block and crank....

[240ZMan]

I'll just add to Jason's comments that if you're on a budget, you can have your current cam and followers reground/resurfaced. I did that with Delta Cam and spent around $125. I was able to keep my stock springs too. The cam has .488" lift and is spec'd at 284 degrees duration (don't know what it is at .050 lift). If you done your homework with the bottom end, and have the breathing in and out of the engine done right, the cam really wakes the engine up. Of course, this all assumes your head is in good condition, including the valves, seats, and springs.

Like I said, for that small amount of money, you get a lot of bang for the buck.

[AndysPlit]

Okay, so let's see here. An F54 head is from the last 280ZX motor, right?

Judging by the previous posts it seems that either way I'm going to have a different engine if I choose to upgrade in this vein. I suppose I'm being sentimental over the original motor. But if I want to build it up the right way, I am going to to be borrowing from various L-series engines?

Forgive me, while I digest this in. I think I have been under an illusion.


Thanks for the bore specs Jason!

to answer your last question, people bore out the L28 blocks to 89mm for the 3.1L motor. usually they use the F54 block because it is arguably a bit stronger.

but the setup that i'm going with is similar to daniel's, and i think it's a pretty darn nice, quick street setup.

i've got an F54 L28 block with flattop pistons
N42 head, milled slightly & mildly ported
stage III MSA cam with valvetrain
MSA 6-1 header into 2.5" exhaust

albiet i'm going through SUs, i think it's a good setup. i think that you can build something up pretty similar for around 1500 if you do the work yourself. stout combination, and you can use your same block and crank....

[AndysPlit]

I meant to regard the F54 as the block to clear that up.

[240ZMan]

If you are starting from scratch, then the F54 block is more desirable. But MANY people (yours truly included) have used the N42 block with excellent results. Unless you are going to go for outrageously high revs, or lots of boost with a turbo, you would be fine with your existing N42 block.

[AndysPlit]

OK, now that's a relief! I thought things were going to get more complicated than I imgained. Just for reference does anyone have a link or file that is a cutaway view of the L28 engine? That would be great.

Thanks!

If you are starting from scratch, then the F54 block is more desirable. But MANY people (yours truly included) have used the N42 block with excellent results. Unless you are going to go for outrageously high revs, or lots of boost with a turbo, you would be fine with your existing N42 block.

[mars23z]

Whats to say you cant just use what you have and get the big bore kit from msa? a little pricey but you keep the engine here is the link
http://www.thezstore.com/page/TZS/CTGY/PEM05

[e_racer1999]

just for personal reference (this also works into a recommendation for AndysPlit), would the KA24 pistons with the 240Z rods work without turning them down if the stroker crank isn't used? if so, that would certainly be an economical big bore upgrade.

[Curtis240Z]

Is laptop programmable triple throttle body fuel injection over the top? I have pictures in my gallery.

[GunnerRob]

Hi Andy,

I don't mean to throw a turd into your punch bowl, but how do you intend to pass smog with these modifications you are thinking about doing? Don't get me wrong, I feel you should be able to do whatever you want too your Z, I'd just hate to see you go through all this planning, financing, and building a hot car to find out you can't get California tags for it. Just a reality check.

Or... Are you going to build a track car?

Rob

[Curtis240Z]

Won't next year be the magic year for Andy? His '78 will be 30 years old and his Z will be exempt from smog because of some CA historic rule?

[AndysPlit]

Unfortunately as it stands now, the California smog exemption stops at 1975 cars. I have heard that they do not plan to go beyond that year in the furture. I hope that the law will change, but as it stands now it doesn't look very good.

Maybe a 240 was the way to go.

Won't next year be the magic year for Andy? His '78 will be 30 years old and his Z will be exempt from smog because of some CA historic rule?

[AndysPlit]

It's cool. Ummm.......I plan to have this as a street-legal car. In the future, when I am ready for the rebuild and upgrades, this is something I will address with my garage. Great of you to still bring this up. Thank you.

Hi Andy,

I don't mean to throw a turd into your punch bowl, but how do you intend to pass smog with these modifications you are thinking about doing? Don't get me wrong, I feel you should be able to do whatever you want too your Z, I'd just hate to see you go through all this planning, financing, and building a hot car to find out you can't get California tags for it. Just a reality check.

Or... Are you going to build a track car?

Rob

[AndysPlit]

Yowsers!.......That is a lot, but I have seen this too in their catalogue. The thing is, I will not be performing the work on my own. But, perhaps I will keep this in mind if I decide to to increase my budget. Thanks for the link.

Whats to say you cant just use what you have and get the big bore kit from msa? a little pricey but you keep the engine here is the link
http://www.thezstore.com/page/TZS/CTGY/PEM05

[gnosez]

If you want big results from big bucks go look at the L-series motors Rebello Motors builds. He's right in CA too. How does 314hp@crank in an NA L28 sound? Brian510 made over that in his 3.2L. A turbo will get you much more, however.

[e_racer1999]

i completely forgot about the smog angle.

going turbo is THE WAY TO GO IMO.

you're not going to be able to get much more out of the engine NA and still have it pass emissions.

[dga]

Call Greg Whitehead at Whitehead Performance www.whiteheadperformance.com His team builds some of the best Z engines in North America, n/a and turbo, both for street and race applications. He has 30 yrs experience in L24-28 engines.

[AndysPlit]

Thanks. Further down the road I will add him to my list of places to consider.

Call Greg Whitehead at Whitehead Performance www.whiteheadperformance.com His team builds some of the best Z engines in North America, n/a and turbo, both for street and race applications. He has 30 yrs experience in L24-28 engines.

[Zs-ondabrain]

If you are still considering a cam for your engine build-up, I have a brand new Stage 2 cam for sale. It's a 480/280 grind.

Lift(In/Ex): .480/.480. Duration(In/Ex): 280/280. Characteristics: Good idle, power range 2000-6000 RPM. Great slalom grind, works well with stock carbs or triple Webers.

$100 plus USPS Priority (2-3 day) Mail (about $20)

Let me know if ya want it or know of someone interested. You or the buyer will still need new lash pads, and rocker arms but that's typical of any new cam installation. An oiler bar is not needed because this cam has the oil holes already, but keeping the stock oiler bar is never a bad idea.

MSA sells the same performance Cam for $179 plus shipping, ususally too much.

Dave.

[rdefabri]

If you want to try something (relatively) "cheap", check out the work Bryan Little did on his Z Car Garage site. He was quoting low 14 second 1/4 mile times, which translates into sub-6 second 0-60 times.

Note, he used a 240Z as a starting point (lighter), then swapped in a 280ZX motor and I believe a N42 head, which was "shaved" to boost compression. His cam grind is custom, but I think he gives a stock Crane grind as a reference.

FWIW, you could build a "junkyard" racer that would likely satify you and with some effort on your part be done cheaper than most options...FWIW

[AndysPlit]

Ah, decisions......I appreciate the offer, but all of my Z related funds are currently going into my 86 ZX. It'll be a while before I actually execute my plans to "get the most power" out of the straight six. Thanks though!