X64v Posted August 17, 2008 Share Posted August 17, 2008 Even my brand new Autometer speedometer bounces when I get above 130. I've had several OEM guages up to that speed and beyond and they didn't bounce.... Apples need to be compared to apples. Was the Autometer speedo mechanical or electronic? If used in a Z, probably mechanical. The OEM gauges Gollum speaks of are most likely electronic. I have no first hand experience with one, but I'd lay down money that an Autometer electronic speedometer doesn't bounce... And I set a new personal record a few weeks ago, 154mph (5400rpm, 5th gear through an 81-83 5 speed, 3.364 r180, 225/50/ZR15 tires). Car felt fine, even took a slight bend at about 145. Quote Link to comment Share on other sites More sharing options...
Gollum Posted August 18, 2008 Share Posted August 18, 2008 The OEM gauges Gollum speaks of are most likely electronic. Cars Include: 93' Mustang Cobra 88' Mustang GT 98' WRX RS 89' CRX w/B16A 91' CRX w/B16A 03' Mustang Cobra 04' WRX STI 95' Mustang GT 97' Q45 I mean, the list goes on. I'm talking about OEM guages that never experieced ANY bounce other than maybe in 1st gear between 0-10mph, most notably the CRX OEM guage. Most of these cars had been over 100mph with no needle bounce and decent accuracy. I wouldn't trust them within 5% obviously, but not absurdly off. The only ones that I think might have been electronic on that list would be the 03' Cobra and the Q45. I'm not sure about those. Quote Link to comment Share on other sites More sharing options...
X64v Posted August 19, 2008 Share Posted August 19, 2008 Most of those cars have electric speedometers, but I do know one or two have mechanical ones, so you're correct. However, has anyone driven a car with an electric speedometer that bounced? Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted August 19, 2008 Share Posted August 19, 2008 I am going to go into another one of my somewhat long winded explanations here… The primary reason that mechanical speedometers bounce is due to a small leak in the transmission. What happens is the seal that keeps your gear oil from getting through the speedometer gear in the tail shaft starts to leak by, the speedometer cable is fully sheathed from end to end and the metal under the sheath is a coil or spiral shape. Since they do not pay particular attention to which end is which when the manufacture them some times the spiral runs clockwise and sometimes counterclockwise so as oil seeps into the cable it is either driven up the cable by the rotation of the cable or it is forced to stay in the gear (usually causing a oil spot to form on your driveway at that point), when the oil is forced up the cable it will eventually make its way into the speedometer. It takes a long time for this to happen because it is not an easy trip and every time you stop the oil drains back down… anyway when it finally gets inside the speedometer it ends up between the magnetic disk and the cup, this area should be very precisely spaced and have only air and the magnetic field in it. When the oil gets in there it creates a viscous bridge between the magnetic disk and the cup causing the needle to jump up then the bridge breaks and the needle drops back down because of the hair spring (tension spring that creates a known resistance to the movement of the needle and forces it back to zero when at rest), this will happen over and over usually in a very rapid fashion. If the problem is not fixed it will lead to the eventual destruction of the speedometer, the jumping is the first sign, the second is it stops jumping and just reads high all the time, the last is the failure of the hair spring which will cause the needle to just get stuck or go to zero and never move again. The only real way to fix this problem is to repair the speedometer gear in the transmission, replace the cable and replace the speedometer. You could repair the speedometer but I am not going to tell anyone how to take it apart, if you want to do that you are on your own. Dragonfly Quote Link to comment Share on other sites More sharing options...
frosty383 Posted August 19, 2008 Share Posted August 19, 2008 I think I hit a buck 60 on the highway while pacing, not racing quote un quote, two friends of mine who were racing a 2006 GTO and a 1997 cobra, I was well behind when they took off and I tried to stay even but my car said hell no lol. the goat let off at a little over 140 mph and I did as soon as I passed a rig. I hadnt shot 5th yet but the cobra owner decided to top out his car as you will see in the video. http://videos.streetfire.net/video/1997-cobra-vs-60-gto-for_176342.htm here is the car you see cruising in the far left By speed38374, shot with KODAK DX4530 ZOOM DIGITAL CAMERA at 2008-08-06 Quote Link to comment Share on other sites More sharing options...
blue72 Posted August 20, 2008 Share Posted August 20, 2008 I've experienced something similar in my Suburban. Perhaps that explains why the needle jumped off its peg while simultaneously the cable emitted a high pitched whine. Eh... I just drove it without a speedo for about a year. Quote Link to comment Share on other sites More sharing options...
datsun723 Posted August 20, 2008 Share Posted August 20, 2008 so far i've only done 110 while playing around with a WRX...still had plenty of room and power to have gone faster but traffic conditions did not permit....stupid traffic conditions Quote Link to comment Share on other sites More sharing options...
D1CNAR Posted August 20, 2008 Share Posted August 20, 2008 my rb26dett in a 1974 260 ive hit 174 at 4500rpm in 5th it has a rearend that noone has ever heard of its out of a 1970 nissan prototype lemans style race car where it came from i have no idea i found the motor tranny and rear end from that proto in a 1981 300zx fairlady that was wrecked in a junk yard the motor is a r30i nissan motor 3.0 liter inline 6 carbarted that motor was in my car before the rb and i was told to put it in storage and never look at it again its for sale to the right buyer for the right price Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 20, 2008 Share Posted August 20, 2008 174 at 4500? I know with a 3.70 and .74 O.D. 4700 is 125... So that's a 2.65 Differential or thereabouts. Given the same .74 O.D. It would be a 2.31 if it's a .85 O.D....or thereabouts... Who is 'noone' that you've spoken to about the differential. My bud just moved here from NY (Buffalo) and from his exhortations, there is a dearth of knowledge. Have you posted inquiries here about the pieces? I'm sure some here (including HS30-H) would have knowledge of the parts used in lemans-style racing packages from the early 70's. Quote Link to comment Share on other sites More sharing options...
kam Posted August 21, 2008 Share Posted August 21, 2008 my car maxed out the speedo, all the way around, in the desert in nevada. It has a carburated 383 sbc, 700r4 with 3000rpm stall, r-200 with 3.90 gears ..... my speedo may be off ...... Its still fast Quote Link to comment Share on other sites More sharing options...
kam Posted August 21, 2008 Share Posted August 21, 2008 my car maxed out the speedo, all the way around, in the desert in nevada. It has a carburated 383 sbc, 700r4 with 3000rpm stall, r-200 with 3.90 gears ..... my speedo may be off ...... Its still fast Quote Link to comment Share on other sites More sharing options...
stprasinz Posted August 21, 2008 Share Posted August 21, 2008 That's 180mph according to the sources I checked....... How many miles did it take you to reach that speed? Calculated here: http://www.f-body.org/gears/ Ratio's here: http://www.zhome.com/ZCMnL/tech/GearRatios.html no lie palot less than 1 mile probably less than a 1/2..... look at the mods.... on pump gas 93..... Quote Link to comment Share on other sites More sharing options...
Mikelly Posted August 21, 2008 Share Posted August 21, 2008 I'm starting to smell some BS in this thread... Better put my boots on... Mike Quote Link to comment Share on other sites More sharing options...
woldson Posted August 21, 2008 Share Posted August 21, 2008 That viedo made my buthole pucker, traffic? Quote Link to comment Share on other sites More sharing options...
stprasinz Posted August 22, 2008 Share Posted August 22, 2008 I'm starting to smell some BS in this thread... Better put my boots on... Mike Ok then gobore your l28 40 over, install a stage 2 cam (recomended for 15 psi plus), get undercut valvestems(ferrea), potred and polished head, a turbonetics 60-1 turbo, run 24 psi of boost, act 4 puck clutch, full 3" manderal exhaust, fidanza alluminum flywheel, 440cc injectors, gut the ever living crap out of it(including but not lilited to the heater assembly., etc), lexan hatch glass, even the dash is only the metal carcass with autometer aftermarket gauges, light weight headlights, and roll it on the stock 14" tires....... so you better go to your thinking place . go find a car in your area running 24 pounds even in a honda..... or an sr20...... 24 pounds is impressive... and out of our larger 6's..... I smoked a honda civic that was dynoed to 276 hp running 15 psi while I was at a mere 8.... I beat my buddies sr20 who was dynoed to 37x hp when I stayed in 5th gear and floored it from a 75 mile an hour cruise...... he did pull his nose from my back bumper to my door before I got the full 24 psi built up the I slowly pulled inch x inch....... but now its toat.... 12 psi plus 125 shot anyway... no bs here.... real deals all the way around.... Quote Link to comment Share on other sites More sharing options...
johnc Posted August 22, 2008 Share Posted August 22, 2008 Now that you've listed your mods, we know your 180mph claim is BS. Keep digging the hole. Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 22, 2008 Share Posted August 22, 2008 180 mph from 37X HP? I'm assuming "lightweight headlights" refers to the G-Nose? Aero advantage comes from said lightweight headlight modification. In 1 mile, or half that distance? Sounds like you should make a run to Maxton and get some trophies with that screamer, they have a 1 mile runup to speed contest... Certification will put all aspersion casters aside... But for me... 180mph with under 400HP in a Stock Bodied S30, in less then a mile? I'm with John C on this one: "Keep Digging that Hole" Quote Link to comment Share on other sites More sharing options...
Gollum Posted August 22, 2008 Share Posted August 22, 2008 oh come on guys, he hasn't even mentioned the 200hp shot of NOZZZ yet. Keep digging, and make you'll put a hole through the earth. Then drop the Z through it. It'll hit 180mph for sure! and will less than 400 HP! Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted August 22, 2008 Share Posted August 22, 2008 Yeah....I think to run 180mph it takes what, 500-600+ hp in a stock bodied Z? hmm...I remember a website there's a guy with the world land speed record on a 1500cc engine. it took over 600hp in a 1991 mr2 body, to go 205mph. considering how much more aerodynamic an mr2 is, I think it would take quite a bit more power to get a Z up to the same speed http://www.bobnorwood.com/The%20Fastest%20Little%20Sports%20Car%20in%20Utah.htm there it is. It's a really good read too. Quote Link to comment Share on other sites More sharing options...
AutoX_Z Posted August 22, 2008 Share Posted August 22, 2008 Actually, stprasinz tells the truth. I raced him with my stock 86 300ZX n/a and he beat me! So then I put in a mild set of cams and we raced again. I almost had him but I blew the welds on my intake so i figured I better shut it down. Quote Link to comment Share on other sites More sharing options...
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