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"An improved car, with more horsepower, and better handling, and a box of stock parts in the corner of the garage (just in case). "

This seems perfectly reasonable. Enjoy it while you have it, and don't do anything that can't be undone. This is what I'm doing with mine.
 
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Discussion Starter #22
The search function on this website has been fantastic. Lots of great information.

Pretty quick here, I’m sure that I will have a few questions about your opinions and preferences on suspension improvements, bushing kits, struts and coils, Heads and headers, tires, wheels, offset etc... Stay tuned. And thanks for all the good input!
 

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The Cal 1980 car did not have an egr system, instead it had the O2 sensor. The federal 1980 had an EGR and no O2 system, so if yours has an egr then you don't have to worry about the O2. Sounds like you're on the right track for the most part. The 80 Ann car is worth a little bit more to the right person but if the car has floor pan issues it will never be in the #1 slot. Better to leave it in the #2 slot and make some improvements, or even the #3 slot. To simplify matters, what would make you the most satisfied with your 80 Ann? Personally I'd put more juice to the engine but then I'm a G force junkie and I love the sound of the bigger exhaust with a cam. There are certain things you can do to increase hp but there are also certain things that are just a waste of money. Put on a 2.25" or 2.5" exhaust system with a turbo muffler. If you can eliminate the cat that is good. If you can't then get a sport cat like you mentioned. That won't create extra back pressure with one of those. For the header there are issues. The 6 2 1 headers that are available for the zx's are not very efficient. They are ok down to where they neck down 2 into 1. Then they get inefficient and you loose a little ground clearance with them as well. You have a pair of 2" tubes going into a single 2" tube which cuts down the flow considerably. They're better than the stock manifold but not by much. I have modified those headers but the cost adds up real quick. I use a non coated header, cut it at the end of the 2 pipes where they start to merge into 1. They're a good header up to that point. Then I oval out one end of a 2.5'' piece of exhaust pipe and form it so that it will fit over the dual pipes and weld it all solid. It has to be angled at the proper angle so you won't loose any ground clearance. That pipe is about 8" long, and I weld a 3 bolt collector flange to it and have it ceramic coated. This ends up doubling the cost of the header vs. buying the initial header with ceramic coating. but it makes it very efficient and the exhaust system will now bolt to the header. As far as the extra unit on the exhaust for the 1980 cars all you have to do is cap the tube going to the air cleaner and remove the rest of the AIS items. It won't hurt anything. I modify the intake by cutting off the egr section and weld a plate over the hole. I have core manifolds I can do that to, or you can send me yours, the cost is the same either way. I can remove the BCDD system and weld it all closed as well. You can take out the vacuum hoses for the thermister valve on the t-stat housing as well, just leave the valve there to plug the hole. That's about all the emissions that you can remove. Any other system doesn't rob efficiency. Hogging out the intake is a waste of money on that year as is extra head work. To get more HP out of that engine you HAVE to raise the compression ratio. Change over to flat top pistons and add either a stage 2 or stage 3 cam. Don't bother changing out the throttle body or the air cleaner. They won't give you anymore HP vs. stock. I can sell you those items if you'd like, but they're a waste of money. Changing over to Megasquirt is always a good thing. If you do the bigger exhaust, header, flat tops, balancing, and cam that will give you a significant increase in HP and you can still burn premium pump gas. You'd be amazed at how much faster your zx is. That's enough to satisfy most people. Oh yeah, one more thing......when you do your exhaust, move your exhaust outlet over to the drivers side. There are a couple of different ways to do that, but by doing that you're eliminating a pair of 90 degree bends which cause back pressure. I can help you with the manifold and throttle body mods and all the parts I mentioned as well. If you're interested you'd have to contact me direct via e-mail or by phone at 360-668-2979 and be sure to let me know you use this forum. When you do there are automatic discounts I apply that will save you 5% to 30% off.
Z man of Washington
 

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Discussion Starter #24
Fantastic. Thanks ZmanOW, for the VERY SPECIFIC and detailed info! Just what I was looking for. We’ll be in contact.
 

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Discussion Starter #25
I want to thank everyone who has participated in this thread. I’ve gotten some amazingly good information from each one of you. Very good opinions, advice, and specific ideas. And please feel free, to chime in on anything that has already been covered with more specifics.

I would like to shift gears now, and get your advice on ENGINE IMPROVEMENTS, everything from mild to pretty good high horsepower, running premium pump gas.

I’d also like to get your opinions on the best SUSPENSION IMPROVEMENTS.

I have no desire to lower the car, (at least not much) because of where I live.

Let me say that this will be a weekly driver, not necessarily a daily driver. And, For me to get from my house to a decent road, I have to drive a half a mile on a rough, white rock road, to then get to a pretty crummy asphalt road, to then get to the highway which is probably a 7 out of 10, as far as highways go.
So, with that said, I would love to hear all your ideas and opinions on a wonderful suspension package (not4x4stuff-haha).
Again, setting the bar pretty low: my comparison would be to have a significant improvement over my 1998 Honda Civic. The Z deserves better.
 

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I would keep ride height stock, and get some stock replacement springs, with some KYB shocks, or other gas shock/strut. If your existing springs are sagging, you might get a little lift going back to stock height.

Engine work depends on what your goals are. You could just have the head inspected, some new valve guides, and install an upgraded camshaft. There will probably be little "while you're in there" seals that may need replacing. If your cylinders still look good, no scoring on the cylinder walls, I'd leave the engine block alone.
 

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As far as suspension goes there are some variables. Most zx's (but not all) are starting to sag a little in the back end if the shocks are original, or if they were replaced with low quality soft shocks. With the car empty, park the car on flat cement or black top and take a framing square and place it up against the back tire at 6:00 to 12:00 with the bottom part of the square pointing straight out from the tire. Make sure the square touches the tire at the bottom. If the car is starting to sag then it produces negative camber. If that is the case you'll see a gap between the square and the tire at the top. That gap shows the average person what the camber situation is on your z. There shouldn't be any. Remember this for later.
Most of the time you should stick with KYB shocks unless you're going for the bigger bucks. There are 2 types of KYB shocks for the back. The low pressure which is what most places sell now, and the high pressure shocks which are fairly hard to find by comparison. I sell both models but the high pressure is definitely the better of the two. The HP's will also get rid of the squat on acceleration which most of them have. Z's are a sports car and need a little stiffer ride. It also makes them handle much better. If you want a soft ride go buy yourself a land yaucht. Anyhow, when you install the high pressure gas KYB"s it will usually raise the back end of the car up 1-2" depending on the springs and how saggy they are. A couple of the bushings in the car may or may not need to be replaced. If you do that, most of them need to be polyurethane EXCEPT for the TC rod bushings. Those have to be rubber or it will cause damage to your z. Then all you have to do is add a sway bar kit and you're done with the suspension. Most people don't need more than that.
Due to the roads you're having to drive, if your paint job is fair I'd suggest getting the bottom 12" of the outer sheet metal on the car sprayed with clear chip guard, along with the inside lip of the wheel wells, and the front valance as well. I do sell mud flaps that are recessed onto the wheel openings and they look very nice however they are made out of ABS plastic and won't take big impacts. They usually can handle road rocks especially at lower speeds like you'd be doing on the dirt road to your house. If you run over a small log it will break them of course. As usual I do sell all of these products and I'm not afraid to tell you the down side of anything I sell if there are any and do it before you buy it. Z man of Washington
 

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Discussion Starter #28
Once again, a very good and detailed description of where to go/what to do on the suspension. Thank you!

I had also been wondering about the polyurethane bushings vs rubber or other materials. You are the second guy to recommend KYB. I’ve heard about adjustable shocks... are these adjustable?

I’ll get out there tomorrow, with the square, and check the tires and camber. I’ll also bounce on the rear bumper to see how splashy it is.

Any thoughts/comments/opinions on 15” or 16” inch rims, offset and tire width? I would like to get the tires/rims to be a little closer to “flush”, with the fenders/wheel wells/body. I’m not looking for rubbing issues, or modifying the wheel wells.
(although some guys that have done some extensive work, on their suspensions/wheel wells and wider tires/rims/offset have come up with some beautiful results).
 

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[snip]
Most of the time you should stick with KYB shocks unless you're going for the bigger bucks. There are 2 types of A couple of the bushings in the car may or may not need to be replaced. If you do that, most of them need to be polyurethane EXCEPT for the TC rod bushings. Those have to be rubber or it will cause damage to your z.
[snip]
For clarity, what are "TC rod bushings?" I'm stumped as to the meaning. I'm sure that when you explain it, I'll realize it should have been obvious. :unsure:
 

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Torsion bar bushings is what I understand them to be.
 

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T/C rod bushings actually stands for tension/compression. These cars don't have torsion bars. KYB's are not adjustable. The only shocks that are adjustable now are the Koni's and they're significantly more expensive. Having an adjustable shock isn't a bad thing, it's just not necessary for most people. Most people don't need to go with them. If you have a high horsepower engine and like to grab gears with that HP, or if you're a very aggressive driver in the corners, AND you want to spend twice as much on your shocks and struts then use Koni's. Otherwise use the KYB's. The high pressure KYB"s will give the back end a little bit more lift than what you have now so if you're riding an inch low that is usually taken care of with them. Stay away from other brands of shocks or struts for these cars, they are inferior, at least for these cars. As far as wheels go 15's are great, 16's will give you a little bit more stability in the corners by comparison. Stay away from the bicycle tires, they're not forgiving on the street driven vehicles. They will not only pound your car more, you're way more likely to bend a rim. A little sidewall flex is a good thing on the street with "Little" being the definitive word. Bicycle tires on cars don't have any sidewall flex at all. The offset of the rim is critical, as is the back spacing. The mated surface on the wheel where it contacts the hub is A. The spring perch on the strut is B. On the stock style suspension you want 114mm max from point A to B. The amount the tire overhangs the rim on the inboard side is also critical because if it does that too much even on the perfectly matched wheel, the tire can hit the spring perch and cut right through the tire. When it comes to actual tire sizes you need to use a tape measure on the height and width. The stock tire height on the 75-83 cars is about 25". You can use 6" wide or 7" wide in most cases AS LONG AS you use the proper rim size to go with your tires. I've seen tires marked the same size and one tire is taller and narrower than the other comparing manufacturers. Notice I'm not mentioning any specific sized tires or rims for that matter because there are so many variables. I've seen some wheel manufacturers that claim there wheel fits perfectly and it doesn't and I've seen some that claim they won't fit and they do. If you get rims and tires that need to get away from the spring perch a little more then you can put in longer studs and spacers from 1/8" thick to 3/4" thick as long as your studs are long enough to be safe. Example: If you're using 3/4" spacers then you should increase your stud length by at least 3/4". ZMOW
 

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Discussion Starter #32
Very good stuff guys! Details! I love the details. Thank you.
By the way, I went out to the shop the other day, and put the carpenter’s square down on the flat concrete, and up against my rear tire and it looks like I’ve got about a half an inch of camber. In other words, the square is flat on the concrete, and the top of the tire is inboard about a half an inch away from the top vertical component of the carpenter’s square.
 

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Very good stuff guys! Details! I love the details. Thank you.
By the way, I went out to the shop the other day, and put the carpenter’s square down on the flat concrete, and up against my rear tire and it looks like I’ve got about a half an inch of camber. In other words, the square is flat on the concrete, and the top of the tire is inboard about a half an inch away from the top vertical component of the carpenter’s square.
You might want to put a level on the concrete where you did that measurement to see if it's actually level or not.....
 

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Discussion Starter #35
Question: when you buy a “complete” urethane, (or polyurethane) bushing kit, does the manufacturer know to make the T/C bushing set come in rubber as ZMOW indicated in his previous message about suspensions/KYB’s and bushings...? Or, Will I need to separately by the T/C bushings in rubber? I know that you can’t answer the question for every bushing kit out there, but generally speaking...?
 

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I'd be surprised if you didn't have to buy a separate set of rubber bushings for the T/C
 

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Hey GoldZX, I had the same decision to make and am also in Texas. (Houston area) I have a 1981 280ZX Black and Gold edition Turbo. It was bought new by my wifes Aunt. It has about 36K on it but was stored in a garage in North Dakota for about 13 years. Fuel system was a mess, tires, brakes and even the radiator gave out. I have it running good and drivable so now am working to get the interior and exterior back in shape. It's not bad but lots of dings and scratches as well as it was in a minor fender bender once upon a time. I'm going more restomod direction. I put on the Koni suspencion and Eibach springs and really like how it rides. The interior is well, yellowish-tan so it is getting redone in mostly all black. I will keep the exterior black as well. Biggest downer is the automatic trans. I am on the list for the adapters to go to a CD009 out of a 350Z. Then a few engine mods and she will be fun to drive and yet dependable. Good luck with whatever you decide.
 

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Discussion Starter #38
Hey BlackShirl, it sounds like our cars are almost identical... and the direction that your heading sounds good. I've decided to keep the paint, body, and interior stock, but seriously upgrade the suspension and engine... but keep all the old stock parts around (in a box in the corner) just incase somebody shows some interest in buying it someday in the future.
 
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