Challenger Posted May 1, 2009 Share Posted May 1, 2009 So I imagine none of you guys have gone over 80 in your ZXs... so there wouldnt be any reason to have a speedo that goes past that. Anyways, what is a good way to know how fast you were going once you pass 80ish? I went out with a friend (5.0 mustang) and I was suprisingly able to keep up with him. We accelerated up to 80 and kept going. All I saw was that I was at about 5000 rpm in top gear (3rd). This was in my 81 280zx turbo automatic, all stock. So I assume a 3.54 rear end, and it has 195/70/14s. So anyone have an estimate on how fast I was going? Is it ok to assume 3rd on an auto is about a 1.308 ratio like the other manual transmissions? Thanks Quote Link to comment Share on other sites More sharing options...
Ferrariferg Posted May 1, 2009 Share Posted May 1, 2009 It should top out at 85, not 80. Damn government regulations. lol. Its definitely a pain to not know how fast you were going isn't it? I've clocked my NA auto at about 125 before by having my friend driving next to me. That was before I tuned it for better performance though so I'm sure its a bit faster now. If your gauges are analog then find a set from an early 79. They go up to 130 if I remember correctly. I'll find a link to a thread I started about the speedo problem. There are designs for making a separate digital speedo that registers as fast as you can go. I think I have the gear ratios for both transmissions somewhere. I'll try to find them in a little bit and post them here for you. I'm pretty sure they are different though. Quote Link to comment Share on other sites More sharing options...
DevilZX Posted May 1, 2009 Share Posted May 1, 2009 I've had my 130 speedo pegged at the top of 4th. Went to 5200 rpm in 5th and it no longer wanted to pull (also going uphill). 82 ZX-T 5-speed Quote Link to comment Share on other sites More sharing options...
Ferrariferg Posted May 1, 2009 Share Posted May 1, 2009 Here's my thread. http://forums.hybridz.org/showthread.php?t=138237 I couldn't find the gear ratios. I can't remember where I put them. Maybe they were in the service manual? hmmm. I'll look later when I can find it. Quote Link to comment Share on other sites More sharing options...
Kevin.pk Posted May 1, 2009 Share Posted May 1, 2009 time travel in only 3 more mph...... This should help if you can figure out the auto trans ratios...... http://www.geocities.com/z_design_studio/ Quote Link to comment Share on other sites More sharing options...
Challenger Posted May 1, 2009 Author Share Posted May 1, 2009 Yeah, Ive always loved that thing!^ Like you said, its just figuring out the ratio. If I remembered the exact rpm at 60mph in top gear I could figure out the ratio but its to late to go for a drive... Quote Link to comment Share on other sites More sharing options...
Ferrariferg Posted May 1, 2009 Share Posted May 1, 2009 I believe mine is around 3000 doing 60. Maybe a little above 3000. Quote Link to comment Share on other sites More sharing options...
Kevin.pk Posted May 1, 2009 Share Posted May 1, 2009 ratios...... http://www.datsuns.com/Tech/datsun_transmissions.htm looks like 3rd is a 1.00 ratio. Quote Link to comment Share on other sites More sharing options...
woldson Posted May 1, 2009 Share Posted May 1, 2009 So I imagine none of you guys have gone over 80 in your ZXs... so there wouldnt be any reason to have a speedo that goes past that. Anyways, what is a good way to know how fast you were going once you pass 80ish? I went out with a friend (5.0 mustang) and I was suprisingly able to keep up with him. We accelerated up to 80 and kept going. All I saw was that I was at about 5000 rpm in top gear (3rd). This was in my 81 280zx turbo automatic, all stock. So I assume a 3.54 rear end, and it has 195/70/14s. So anyone have an estimate on how fast I was going? Is it ok to assume 3rd on an auto is about a 1.308 ratio like the other manual transmissions? Thanks Years back there was a thread about How fast you have gone, or something like that.... I believe it was you that pointed me to a sight that allowed me to see how fast, at what RPM. It said 150. I'm still not saying that I got going that fast, but........................................ Quote Link to comment Share on other sites More sharing options...
Challenger Posted May 1, 2009 Author Share Posted May 1, 2009 Thanks for the ratios kevin. Turns out ~5000rpm will be approximately 105 mph which is reasonable. Although thats not "flying" it took about 10 times less time to get up to that speed compared to my rav4.. Yeah Marc that website is listed a few posts up. I dont believe you were going 150 either. Quote Link to comment Share on other sites More sharing options...
jc052685 Posted May 2, 2009 Share Posted May 2, 2009 back on my 79 280zx I could also peg 130 in 4th and 5th I went past 6500rpm several times. 195-60-14 tires. Quote Link to comment Share on other sites More sharing options...
Ineptitude01 Posted May 11, 2009 Share Posted May 11, 2009 Heh, this is sort of unrelated, but speaking of pegging speedometers... The one in my CRX goes up to 135, and believe it or not, that little Honda WILL go that fast. I was surprised, scared, and elated. Granted, I was on the freeway (duh) and had a long runup down one hill and up another. I don't think my ZX will go even close to that fast. I don't even know how I'd measure it, either. I'm using the NA rearend with the T-5, and I think I chickened out around 5000rpm when I tried to test the upper limit there. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.