'78 280Z: N/A L28 - Best HP Increases W/O Turbo?

[OR-JO]

Hi gang,

 

New to the forum, just picked up a '78 280z for my wife's birthday. Here are some pix below.

 

 

 

 

 

 

This is a sweet 'lil car. I'm planning on body work and a white/black rustoleum paintjob soon.

 

Originally I started thinking about ZCars when the v8 blew some seals in my 1970 Chevy farm truck. I figured if I was to pull the motor, maybe I'd do something fun with it.

 

So then I bought the Z Car...

 

BUT - after scowering the forum, and driving the 280z for a few days, I'm pretty sure a v8 swap is not in the works for me.

 

In fact, I don't think a motor swap of any kind is in the works for me right now. The current L28 in the Z actually runs pretty nice. The car has some exhaust problems ( I think - doesn't sound great, fumes coming in under back hatch), and generally I'd say the car feels like it has more power than it can access.

 

I know stock these things are listed at 175hp.

 

The car came with some headers. Knowing the exhaust needed work, I thought I'd put those on in the process.

 

I've looked around a bit and seen mostly Turbo, Turbo, Turbo mods' hailed for pumping some more HP out of these engines.

 

I'd like for the car to be reliable (as it can be), but just crank out some more power. AS IS, it still squeels the tires from a stop and pinned from 4th to 5th. That's fun, it's a blast to drive.

 

But I know the car has some room to improve.

 

What are some non turbo, non v8 swap ideas you guys may have for improved HP? Think I could get in the 200-300HP range without a turbo (and without blowing up the motor)?

 

THX

[Challenger]

Looks good, I like the red and yellow for some reason. Im guessing someone is a photographer? I like the first one, maybe a little closer?

[75s30]

OR-JO Welcome,

 

First off if you are looking to improve your hp there is a lot of different combinations that you could go with. But if you are planning on staying N/A. Easiest way to do it is work on the head. Here are some possible ideas for head work:

 

1. Bore it out / re-machined

2. New Cam Shaft and kit

3. Tilt the valves (if you are going with a more aggressive cam shaft then go with a longer valve.)

4. Adjustable cam timing sprocket

 

If you are looking for throttle response look into getting a bigger throttle body if you are planning on boring out the head. Also a lighter flywheel will help with the rear end factor as well as an aluminum driveshaft (Quite pricey but helps reduce lag time to the rear wheels.) Since the motor will be taking a lot more air in you have to get that to come out. Since you got headers. Go with a straight pipe (Cat-back for some states). Free flowing air is better than back-pressure. Fuel pressure regulator is recommended by me. If you are looking for a little bit better gas mileage and a little bit more performance that's the way to go. There are some other things I am pretty sure I missed. But the best way to go is just increase your compression and you'll be fine.

 

-Brian

[JMortensen]

That is a pretty funky response that Brian gave you there. I'm guessing that he works on V8's. Never heard of "tilting the valves" on an L engine.

 

Take a look at the L engine forum and you'll find BRAAP's post on head modifications. Read the others there too, and between them and some more searching you should be able to figure out how to get more power out of your NA L6.

 

I think in addition to the headwork you'll have to do something about fuel management, as the factory computer doesn't deal with larger than stock cams very well, and that's going to be a must to get a significant amount of power out of the motor.

[slownrusty]

You bought "that" for your wife's birthday...then you are going to paint the car in Rustoleum....man, you REALLY know how to treat your lady!

 

There's an 8track on eBay right now that will be awesome in that 280Z, do you have a Wedding Anniversary coming-up per chance?

 

Yasin

[nismopick]

There's an 8track on eBay right now that will be awesome in that 280Z, do you have a Wedding Anniversary coming-up per chance?

 

 

Buahhaa.

 

When someone says "How much hp can I get?" I say... "How much money do you have?"

[OR-JO]

Looks good, I like the red and yellow for some reason. Im guessing someone is a photographer? I like the first one, maybe a little closer?

 

Yeah I know, I thought the car looked pretty cool too all painted funky.

[OR-JO]

You bought "that" for your wife's birthday...then you are going to paint the car in Rustoleum....man, you REALLY know how to treat your lady!

 

There's an 8track on eBay right now that will be awesome in that 280Z, do you have a Wedding Anniversary coming-up per chance?

 

Yasin

 

When we pulled up to the previous owner's house, the first words out of my wife's mouth were, "Oh, that thing is sweet.....I hope it has an 8 track, and if it does, we can't tear it out."

 

My wife is cool like that.

 

No stereo to speak of anyhow.

[OR-JO]

Buahhaa.

 

When someone says "How much hp can I get?" I say... "How much money do you have?"

 

I guess what I'm looking for more of here are ideas with tightening up/ cleaning up the performance of the car. I already ruled out an engine swap, now just trying to figure some DIY tuning (for a n00b).

 

Thoughts I had along with the headers and exhaust fix were stuff I felt confident I could do myself like:

- lighter fly wheel

- cold air intake

- performance ignition

- remove junk from car (old AC compressor)

- and very literally "tighten up" the gearshift. It's pretty sloppy; old owner said I could replace the bushings or whatnot.

 

As much fun as it would be to hit a specific HP goal, the car is much more fun for us while its RUNNING as opposed to scattered in pieces or running like crap as I try to figure out if I've got wastegates properly aligned.

 

What are some things I could do to add performance w/o too much destruction involved?

 

This is our weekend street/fun/smile mobile. I'm not really a car guy - no racing aspirations, but this Z car is a fun project for me. I'd like to learn as much as I can, but start a bit slower than BRAAP's post on head modifications. That made my brain explode.

[Gollum]

but start a bit slower than BRAAP's post on head modifications. That made my brain explode.

 

I've been reading his posts for a long time now, and his write up STILL make my brain explode.

 

 

It's hard to say there's any easy DIY power in the L28E (e for EFI). There's guys here than know a lot more than me, that's for sure, but IF you know how to tune a carb you're probably better off ditching the efi from some carbs. There's several options that you can research on this site.

 

Something to consider though is that the L28E was only rated at around 135hp, and the origonal 2.4 liter version was rated at 110 (might be off, someone correct me if I'm wrong). Going to just a well tuned carb could get you up to as high as 160hp, plus a bit more with supporting mods like full exhaust and a camshaft.

 

The nice thing is that these motors create decent amounts of torque and will move the car quite nicely.

 

Though honestly if you wait long enough and keep hunting a turbo conversion might be just as affordable for the HP per dollor. But it really depends on how deep you want to get in mods and how comfortable you are with mods and such.

 

Example: A completely stock turbo L28 is gonna produce about 180hp, but a COMPLETELY stock L38ET using megasquirt instead of the stock computer, with raise fuel pressure, and raised PSI from the turbo will be able to reach about 210 wheel HP (remember that the stock 180 I reffered to was crank, which would be about 155 or less wheel HP). At that point you're gonna want an intercooler because your air charge will be getting too hot from the turbo, add an intercooler and raise the boost and now you're at 250 wheel HP, all on a 90% stock motor and very low investment costs.

 

But that's also very DIY and can be a headache if you don't know what you're doing (might even be a headache for some that DO know what they're doing).

 

So for the sake of simplicity it might be wise to just carb the ol' L28E, do some small bolt on stuff and be happy with around 200 crank HP.

 

Braap hails from the northwest up there and has some very affordable pricing on headwork if I recall correctly. I'm not sure where his prices start for mild work, but I remember his high end stuff was pretty decent in price and he's an honorable guy from everything I've seen.

 

But even some basic headwork combined with well tuned carbs would make for one quick little Z.

[MrFancypants]

Personally I think the first two things that should be addressed on any S30 are brakes and suspension. Adding power is not only a waste but dangerous until you do those two first. I would hope that header will make a difference, plus it's free.

 

 

 

- Greg -

[BRAAP]

..... I'd like to learn as much as I can, but start a bit slower than BRAAP's post on head modifications. That made my brain explode.

 

 

 

 

 

I've been reading his posts for a long time now, and his write up STILL make my brain explode.....

 

 

 

 

 

Oooops... Sorry.

 

Keep reading...

 

 

BTW, nice photography.

[JSM]

I think Gollum advice about the carbs is very good. If you want good fuel injection, dump the stock computer and go aftermarket.

 

Simplicity, performance and cost switch to SU's. If you go the SU route, get the Ztherapy video.

[OR-JO]

Thanks for those tips gents. I'll keep trolling the board for more specific info and post pix of my progress.

 

Who knows Paul, maybe you'll hear from me one day. I'm only about 20 miles away in Oregon City.

 

Rad.

[X64v]

Personally I think the first two things that should be addressed on any S30 are brakes and suspension. Adding power is not only a waste but dangerous until you do those two first.

 

Greg's got it right on. Get that thing handling and stopping correctly before doing anything else. I got my 240 running reliably on SU carbs, did my suspension and brakes (not huge upgrades, just lowered with good bushings, and properly set up stock brakes) and then got into the addiction that is boost. But if you're just looking for a little umph, and not looking to turbocharge the engine anytime in the future, I highly recommend carbs over fuel injection. They're simple, reliable, and they just work. The only reason I went F.I. is to run a turbo.

 

I think sometimes the big numbers of the turbo crowd can make people overlook the N/A crowd on here. N/A z's can still be fast, and can certainly be a blast to drive. If your goal is not to race or have an über-super-duper fast street machine, but simply to have a fun car to drive, and not have many problems with it or any down time, a nice N/A l28 would certainly be my vote.

[roughridin89]

id say add a stroker with a racing cam, possibly add a rising rate fuel pressure regulator, performance throttle body, and a cold air intake would all together add almost enough horsepower to reach between 250-300

[Globerunner513]

why do people keep talking about cold air intakes, when the intake location can't get any colder? just a pet peeve....

 

if you are looking to break the bank, check out Kameari Engine Works. They're a japanese company but have branched out into the US aswell. But that kind of stuff probably is more for the 400+ hp crowd...

[Tony D]

Example: A completely stock turbo L28 is gonna produce about 180hp, but a COMPLETELY stock L28ET using megasquirt instead of the stock computer, with raise fuel pressure, and raised PSI from the turbo will be able to reach about 210 wheel HP (remember that the stock 180 I reffered to was crank, which would be about 155 or less wheel HP).

 

Just as a note, the Eurospec L28ET's run a .82 A/R exhaust turbine, and a simpler EFI system that utilizes a standard E12-80 Distributor fitted with a Pneumatic Retard Cannister....and it was rated at 200HP.

 

So yeah, pretty much you remap a stock turbo and a 20hp bump is the minimum to be expected when you put the fueling in line with the Eurospec version. A good downpipe and exhaust can add 20HP on a stock setup without the remapping. So without an I/C and only fuel remapping and a good exhaust 220 should be available at the crank.

 

That's plenty fast for an S30 with a stock suspension as stated above. Make it handle first, learn to drive it to 10/10ths' second, and then start adding power to the chassis as by then you will know what you have to tweak to keep it all hooked up. Not what most want to hear, but the biggest item holding a Z-Car back is usually found behind the wheel, not under the bonnet!

[Gollum]

Ahh, good point tony. Didn't know that about the eurospec models.

 

Regarless of what they were rated at though, there's lots of power lying in ALL the EFI motors if they're equiped with a modern ECS system.

 

MrFancypants also brings up a good point. As far as actual racing goes you'd be better off working on the suspension and brakes before the engine, and in the name of safety on the street, it's still a wise choice. There's tons of good info on those topics here, and if you just want something mild for the street it shouldn't cost much either.

[Ratsun]

I'm all for starting with suspension and brakes. I had a harder time enjoying my first Z with problems in both areas (especially since the car had been sitting for a year before I'd gotten it). Once that was done, it felt worlds better.

 

With my current Z, I think all I'll do for a while is refresh the brakes and suspension and possibly a MSA limited slip differential. Eventually, I'd like to work the head and possibly ITBs...That may complete my dream engine right there:)