Hi everyone, I just bought a 81 ZXT. What should I do to improve performance?
04-08-2003, 04:20 PM
#1
Guest
Posts: n/a
Hi everyone, I just bought a 81 ZXT. What should I do to improve performance?
Hello all,
After long search, I finally got a 1981 280ZX Turbo automatic. The body seems to be okay and the interior is not so bad. But I could careless about these cosmetic upgrades now. I really want to make my ZX 300+ hp. I do know a bit about mechanic work. I used to own a Mustang myself. But "going Z" is another story. I'm not familiar how the Zs perform. I don't really know where should I start?
My stock engine is running perfectly fine. It's running a little rich right now. However, here is my plan and please correct me if I am going way over my head on this:
1) Swap 3 speed to 4 speed automatic
2) Port and polish intake/heads - how much should I overbore??
3) Install new rocker arms
4) Install new Cams
5) Install new Crankshaft
6) Install new headers
7) Change rear gear to 4.11 (new speedo ring)
Those as what I'm thinking when writing this right now. Please tell me will my plan work? How much should I anticipate to spend? And most importantly, where can I get these jobs/parts done?
I'm located in Souther California.
Thanks so much,
Nathan
P.S. I'm so glad that I found your forum. I'll be visiting this often now!
After long search, I finally got a 1981 280ZX Turbo automatic. The body seems to be okay and the interior is not so bad. But I could careless about these cosmetic upgrades now. I really want to make my ZX 300+ hp. I do know a bit about mechanic work. I used to own a Mustang myself. But "going Z" is another story. I'm not familiar how the Zs perform. I don't really know where should I start?
My stock engine is running perfectly fine. It's running a little rich right now. However, here is my plan and please correct me if I am going way over my head on this:
1) Swap 3 speed to 4 speed automatic
2) Port and polish intake/heads - how much should I overbore??
3) Install new rocker arms
4) Install new Cams
5) Install new Crankshaft
6) Install new headers
7) Change rear gear to 4.11 (new speedo ring)
Those as what I'm thinking when writing this right now. Please tell me will my plan work? How much should I anticipate to spend? And most importantly, where can I get these jobs/parts done?
I'm located in Souther California.
Thanks so much,
Nathan
P.S. I'm so glad that I found your forum. I'll be visiting this often now!
04-08-2003, 11:36 PM
#2
Externally Wastegated
Join Date: Oct 2001
Location: San Diego
Posts: 1,220
Wow, big goals there, but shouldn't be too hard except for the aftermarket exhaust manifold. Only company I know of that you might be able to get one from is Greddy and those suckers are expensive. 1500 bucks or so if I remember correctly, but worth it if you're going all out hp. Allows you to use their Mitsubishi TD series turbos. For the cam you can contact MSA, they have them, not sure what brand it is, the 3spd to 4spd swap is listed on the zcar.com site under articles, the port and polishing bit, I don't know, maybe extrude hone or someone can help you out. The rear end, if you can find a turbo Z31 with an LSD, it's a 3.7 and does a good job. I think a 4.11 would be too tight, but that's just me. Easiest way to 300 hp is to find a t3/t4 turbo, upgrade the injectors to either 370cc SVO Mustang or 420cc Mercedes 450 ones, a bigger pump, 3" exhaust/downpipe, and an i/c with the boost cranked up a bit.
Since you said you're in Southern Cali, check out the Z car show in Orange county on the 27th and you will see about 300 Z cars all with different setups. www.zcarparts.com has more info.
John
Since you said you're in Southern Cali, check out the Z car show in Orange county on the 27th and you will see about 300 Z cars all with different setups. www.zcarparts.com has more info.
John
04-09-2003, 01:14 AM
#3
Guest
Posts: n/a
Stay away from freaky gears in turbo cars, stick with a 3.54 or close to it, I wanted to find a 3.36 but they are RARE. You will not hit boost with a 4.11 like you will in a 3.54, plus the way they make these cars rev is freaking ridiculous IMO. You'd be at peak boost everywhere, freeway included, crappy MPG coming up.
I have a 3.90 in my car currently, and I do 3400-3800 on the freeway with my 195/60-15" and early 5 speed, it sucks.
I have a 3.90 in my car currently, and I do 3400-3800 on the freeway with my 195/60-15" and early 5 speed, it sucks.
04-09-2003, 11:45 AM
#4
Guest
Posts: n/a
Thanks!
I'm planning to have the motor bore out.
How much should I overbore?
And once after that, should I get a new crankshaft with new piston? LD28 crankshaft or something?
I've heard all these numbers 87mm, 87.5mm, for pistons. What are they?
I guess my whole question is that ... what's needed for a port/polishg an overbore to the engine?
Thanks for your replies.
I'm planning to have the motor bore out.
How much should I overbore?
And once after that, should I get a new crankshaft with new piston? LD28 crankshaft or something?
I've heard all these numbers 87mm, 87.5mm, for pistons. What are they?
I guess my whole question is that ... what's needed for a port/polishg an overbore to the engine?
Thanks for your replies.
04-22-2003, 10:52 AM
#6
Registered User
Join Date: Mar 2003
Location: WA
Posts: 373
If you have a ZX turbo and want to make more power you need to get out of the normally aspirated mindset. 4.11 gears are not good for turbo cars. Stock turbo Zs came with 3.54 and NA Zs had 3.90s so you would be going in the wrong direction. The reason you don't want the 4.11 for a turbo car is you won't be able to build full boost before shifting.
To get to 300hp you really don't need to do major headwork. Stick with the stock turbo cam unless you really know what you're doing. Start with a 3" exhaust and downpipe. Then get an efficient intercooler capable of supporting your hp goals and up the boost. You will then have the foundation for any additional upgrades to get you to 300 hp.
To get to 300hp you really don't need to do major headwork. Stick with the stock turbo cam unless you really know what you're doing. Start with a 3" exhaust and downpipe. Then get an efficient intercooler capable of supporting your hp goals and up the boost. You will then have the foundation for any additional upgrades to get you to 300 hp.
04-29-2003, 10:31 AM
#7
Guest
Posts: n/a
Dude you are way ahead of yourself...
I know you just got out of a Mustang and those cars need headwork and engine builds with cams to run hard. But this is not a stang. Don't jump the gun on pulling the motor out. First thing you should do is full exhuast from at least the cat back, gutting the cat. Then remove the air filter assembly replacing it with a cone filter. From there you can pick up a boost controller and set it to about 10-12psi. Those little things are going to make a big difference in how the car runs without blowing it up. If you really want to make big moves on that car buy a programable fuel computer. Having programablity will let you run much larger injectors and a safe ignition tune. You will also eliminate the restrictive air flow meter. Cams and engine build's will not help if you cant tune the car correctly and you wont be able to with a stock ECM. If you need options on fuel computers I can give you some suggestions. Good luck, and forget just about everything you learned with the Ford. Its a way different game on Z cars. Good luck.
Alex C
Alex C
04-30-2003, 12:10 PM
#8
Guest
Posts: n/a
I am running 3.90's right now in my turbo car, with the T5, and it dropped a tenth or two in the 1/4 mile on the old turbo versus the 3.54's. I have not been back to the track since the JWT sport 450 upgrade, but it feels plenty stout.
I expect it to run even better then the 12.6's before, and it is a rocket in 3rd and 4th.
I expect it to run even better then the 12.6's before, and it is a rocket in 3rd and 4th.
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