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There's been some discussion on bolt ons to give a few extra horsepower here and there. So, what are these and how much are they for say, a '79 ZX? The ones that come to mind for me are headers and bigger exhaust pipe. Thanks for the help.

-JB
 

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JB,
The first question that comes to mind is how much horsepower to you want to gain?
The second is are you going to use the car as a daily driver or primarily to race?
The third is how much money do you want to spend?
Remember, compared to the new engines on the market the L28 is, at best, an average size and has significantly less horsepower. Yours has a net HP of about 135. The new passenger car sixes are running 150-235HP and have more torque too. It's hard to get there with the L28 because of its older engine design and control technology without spending some serious money. Remember, the original reason for the popularity of the Z was its looks, affordability, and handling. Not its acceleration. The Nissan Maxima has the same 0-60 times as the old Z cars.
Phantom
 

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> There's been some discussion on bolt
> ons to give a few extra horsepower
> here and there. So, what are these and how
> much are they for say, a '79 ZX? The ones
> that come to mind for me are headers and
> bigger exhaust pipe. Thanks for the help.

> -JB

I'm not mechanic...but generally the thing you want to start off with to give yourself a bit more power is letting the engine breathe better.

Most of this stuff is pretty cheap compared to what you get back in terms of power.
And its fun to do!

If your exhaust is ready to be replaced--you might go to muffler shop that can fashion a new 2.25 inch exhaust from the catalytic converter back and a new free flow muffler....the difference in response was amazing for my 260z(which has no cat converter).

You get a bit more punch and it might even sound nicer(I recommend using a resonator though)

The next thing that is pretty cheap(or you could have done this first) is to replace upgrade the stock airfilter box setup. A couple guys here have fashioned some great K&N filters to replace the stock box. This allows the engine to get more fresh air.

The beauty of this stuff is that it pays for itself in terms of better gas mileage.
A couple more things--well I dunno about the ZX--but I've but a bigger coil on my Z.(A blaster coil) and some better wires and NGK spark plugs....)

Check out the Internet Z club....it has a bunch info that should be useful.
 

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Just for the sake of discussion...(long)

> JB,
> The first question that comes to mind is how
> much horsepower to you want to gain?
> The second is are you going to use the car
> as a daily driver or primarily to race?
> The third is how much money do you want to
> spend?
> Remember, compared to the new engines on the
> market the L28 is, at best, an average size
> and has significantly less horsepower. Yours
> has a net HP of about 135. The new passenger
> car sixes are running 150-235HP and have
> more torque too. It's hard to get there with
> the L28 because of its older engine design
> and control technology without spending some
> serious money. Remember, the original reason
> for the popularity of the Z was its looks,
> affordability, and handling. Not its
> acceleration. The Nissan Maxima has the same
> 0-60 times as the old Z cars.
> Phantom

It is true that the L series is somewhat of an antiquated design. Most of the flaws can be attributed to the head, not the block. The block has 7 main bearings (compared to 5 in others), and nitrided crankshafts (STOCK!!) which makes this block quite strong. I would argue that the design is very sturdy, and has great performance potential, if you can get to it.

The problem with the heads, is that it has only 2 valves/cylinder, is a side-flow design and most stock Z engines were built during the heyday of smog equipment. This meant that the cams were tuned down, and all kinds of useless and/or inefficient smog crap was bolted on to try and meet the new smog standards. Some used the old pellet style cats, power robbing smog pumps, restrictive exhaust size, etc....This is the same thing that killed the original beetle, VW just couldn't get all that crap to work and fit in the car.

There is a good side to this, in that if you improve the breathing capability of any Z engine, you will gain considerable 'hidden' hp. The repeal of smog laws opens up some doors, as well as advances in technology. It's just a matter of doing the right mods. Another problem for us Z fans, is that our cars are 20-29 years old! This means that we just can't bolt on new performance parts, without having to fix wiring problems, leaking hoses, worn engines, etc....
This makes it more expensive to modify, since you usually have to fix alot of stuff even before you get into the performance aspect of it.

My recommendations to getting more hp out of any Z are:(In order of importance IMO)

1. Fix/rebuild all broken/questionable parts first. This will give you a stable platform on which to build from. For example: If your original radiator is not up to snuff, replace it before you start messing with timing or adding a new cam, otherwise you will be compounding an already existing problem.

2. Install a 2.25-3.00 exhaust/muffler w/ header. I would recommend a 2.25 for 2.4L - mild 2.8L. 2.5-3.0 works great for built engines that can rev up to 7K. Either way, you will gain some considerable hp, and actually improve the efficiency of your engine.

3. Improve the intake with high flow filter. This works for either carbs or fuel injection. More air in = more hp.

4. Install a cam. This is somewhat more costly and complicated than the previous mods, but it works wonders on these engines. This is the 'Achilles heel' of stock Z engines in my mind. The Stock timing varies @250 duration with @.425 lift. This is VERY TAME for this size of engine, and just kills performance, especially after 5000rpm. Most performance cams range from @270-300 duration to .450-.600 lift. Installing even a mild cam with the aforementioned mods will bring the Z alive, you will be amazed at the new hp. Of course you don't want to install a cam on a worn head, so here we go again with having to fix other problems before we get hp.

Of course, you can keep going, adding on more stuff, increasing compression, etc.... but they are all more involved both monetarily and in complexity. With the above mods, you can probably get a net of at least 170+hp, depending on how radical you want to get.

240Dave
 
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