johnj92131 Posted January 8, 2016 Share Posted January 8, 2016 And I'm sure all these interstate speed readings were taken on calibrated speedometers. :rotfl2: Huh? What's that? Don, I use a GPS app on my phone to check speed and distance calibration of the speedometers on all my cars. During a short period between the rain yesterday, I checked the Comanche speedometer. It was between 2 and 3 mph high at 70/75. My tires are stock 225/75 x 15 Kumho Solis SR21. The phone app is so easy to use, I have not bothered to install the calibrated speedometer I pick up in Las Vegas 3 or 4 years ago. Link to comment Share on other sites More sharing options...
johnj92131 Posted January 8, 2016 Share Posted January 8, 2016 I took a nice long drive this last weekend and noticed things got a little scary after 75MPH on my Comanche, I know these trucks are not designed for high speeds so I was curious as to how fast you guys have driven your rigs? . :MJ 1: . If things are getting a little scary after 75 mph on the truck, then there are some things wrong with your tires/suspension that your really need to fix on your truck. I have had to do quite a bit of work on the front end over the years. Still a bit more work needed. My rational is that the truck is mostly used for Home Depot type runs (except for now, because my other car is in the paint shop). The best MJ I have ever driven was an 88 that a fellow was selling. He had gone completely thru the front suspension and rebuilt everything. It was amazingly tight and drove very well. Link to comment Share on other sites More sharing options...
big66440 Posted January 8, 2016 Author Share Posted January 8, 2016 Back when the speedometer still read about 9% low I pegged the 85mph speedometer on an empty road (actual speed ~93ish). Nothing scary happened and if anything it smoothed out a bit. Of course, my front end has quite a few new parts sprinkled in, but if a stock MJ doesn't feel stable at ~75 something is quite wrong IMO. Also, :agree: It was stable, It was just vibrating a lot like many others have said and the fact that my door seals aren't sealing real well doesn't help. Link to comment Share on other sites More sharing options...
gogmorgo Posted January 9, 2016 Share Posted January 9, 2016 ^^That. Mine wasn't going to throw me off the road or anything. It just didn't seem particularly happy to be doing 75mph. It also seemed to get better after that. Link to comment Share on other sites More sharing options...
outlaw star Posted January 9, 2016 Share Posted January 9, 2016 My old Xj I never took over 75mph and it was only on 31" tires. As for my Mj, it'll only see the same. As for the 88mph comment, anyone else think of Back to the Future? "When this baby hits 88mph, you're gonna see some serious s#!t" Link to comment Share on other sites More sharing options...
Lee21490 Posted January 9, 2016 Share Posted January 9, 2016 I've done 85+ On 33's. Coming back from the mountain, Downhill lol Link to comment Share on other sites More sharing options...
glundblad Posted January 10, 2016 Share Posted January 10, 2016 I am sure I have hit 70mph in mine. The question was how fast have you driven it. Not how fast can it go. Right? Regarding how fast it can go, its a stock '87 with 85k miles. The engine is like new. So whatever those are rated at... Driving an mj fast is not high on my bucket list. Link to comment Share on other sites More sharing options...
gogmorgo Posted January 10, 2016 Share Posted January 10, 2016 Well, when someone says they went a certain speed, and someone else calls it impossible, suddenly the top speed possible becomes relevant. A couple of us younger and foolisher types have actually managed to get them to where they won't go faster. I think that's about top speed, yes? Mine would go no faster than what I believe to be about 105 mph, (educated guess based on known speedometer error and indicated speed) but that was before I was able to gps verify it. I'm not going to do it again... I have no interest in swapping out another motor until I have my stroker built. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 10, 2016 Share Posted January 10, 2016 I might as well jump in too. :yes: Specs: 31" Michelins, 4.10 gears, AW4, 2WD. Everything is new in the front end (except ball joints) and drive train including wheels and tires within the last five years, ~2.5" lift. The dash speedo is calibrated, verified, and dead-on. I normally cruise the interstate at 75MPH / 2500RPM. At 85MPH the speedo's pegged and I'm right at ~3000RPM. It will climb w/o protest to 3600 RPM, but beyond that the rear end starts feeling light and I chicken out. The engine wants to keep going higher, and runs fine on the dyno up to 4800RPM. I don't have GPS, but calculating the 3600RPM speed using ratio and proportion comes out to ~110MPH. The longer LWB with a heavy shell on the back helps out I think. Link to comment Share on other sites More sharing options...
cruiser54 Posted January 10, 2016 Share Posted January 10, 2016 Needle pointed straight down and it felt great. Link to comment Share on other sites More sharing options...
fiatslug87 Posted January 11, 2016 Share Posted January 11, 2016 150 mph... in my dreams. Link to comment Share on other sites More sharing options...
rmoore1031 Posted January 11, 2016 Share Posted January 11, 2016 ^cruiser has huge balls. Biggest balls of them all. Link to comment Share on other sites More sharing options...
cruiser54 Posted January 11, 2016 Share Posted January 11, 2016 ^cruiser has huge balls. Biggest balls of them all. Had fast cars all my life. MJ felt great at that speed. They can do it. I take no credit. Just reporting what I experienced. Link to comment Share on other sites More sharing options...
M1A1TankerTom Posted January 13, 2016 Share Posted January 13, 2016 I have gotten my MJ up to 75mph before, it does fine. It's definitely more comfortable at 65mph. No real need to go faster than that. I got in a vehicle pursuit (I'm a police officer) with a motor cycle the other day. I was driving a new ford explorer with the twin turbo motor and got up to 132 mph........and yes, I caught him! Link to comment Share on other sites More sharing options...
Lee21490 Posted January 13, 2016 Share Posted January 13, 2016 I have gotten my MJ up to 75mph before, it does fine. It's definitely more comfortable at 65mph. No real need to go faster than that. I got in a vehicle pursuit (I'm a police officer) with a motor cycle the other day. I was driving a new ford explorer with the twin turbo motor and got up to 132 mph........and yes, I caught him! Don't taze me bro. Link to comment Share on other sites More sharing options...
Minuit Posted January 14, 2016 Share Posted January 14, 2016 I believe the factory top speed of an MJ is something like 116 mph (don't quote me on it, read it somewhere) Mine's a short bed and I don't normally run a topper so my rear end is lighter than some, but I don't think even with the totally unrebuilt 25 year old drivetrain it would have any problem reaching that speed. At my estimated high score of 93, the truck didn't feel like it was even trying. Just a slightly louder buzzy straight 6 sound than normal. Link to comment Share on other sites More sharing options...
Dirteatr717 Posted January 23, 2016 Share Posted January 23, 2016 107mph in my 89 pioneer and according to the NYS highway patrol 89mph in my 87 4cyl :D Link to comment Share on other sites More sharing options...
AMCJeepMJ Posted January 26, 2016 Share Posted January 26, 2016 I hit 70-75 on accident coming down a long hill form a mountain pass the first year I owned it, but usually its rare to get over 55 for fuel economy's sake during daily driving. The Benz, I may have had it to 110 passing a long line of trucks on a 2 lane highway this summer on the drive from TX to OR, but nobody can prove I did it (except the black box). Link to comment Share on other sites More sharing options...
64 Cheyenne Posted January 26, 2016 Share Posted January 26, 2016 They all smooth out past 90....well at least mine do jks. Link to comment Share on other sites More sharing options...
Jackrabbit41 Posted January 27, 2016 Share Posted January 27, 2016 Mine wouldn't go past 88 and that was a gps speed reading. That was back when I had 3.08s and 31s. It was scary Link to comment Share on other sites More sharing options...
FrankTheDog Posted January 29, 2016 Share Posted January 29, 2016 Stock 92 4.0 stick 2wd on 205/75/15's I had the needle past straight down and on its way up to 0 post. It was running really smooth with no shakes. That was when I first bought it 5 years ago. Since then it has gotten a D44 with a not quite stock drive shaft that vibrates. Also has been converted to 4wd. I don't think it'll ever go that fast again. Link to comment Share on other sites More sharing options...
Crash Posted February 1, 2016 Share Posted February 1, 2016 I've had the needle buried a couple times. I would say probably 90-95ish. Didn't have a tach at the time so not sure what the engine was running. With the 3.73's and 31.5" tires I can cruise at 70-75 all day long. @70mph I'm running 2k RPM Link to comment Share on other sites More sharing options...
Incommando Posted February 1, 2016 Share Posted February 1, 2016 80. After the SOA & lift Link to comment Share on other sites More sharing options...
Incommando Posted February 1, 2016 Share Posted February 1, 2016 I can barely get my MJ up to 85 with 32s and 3:55s. 105.6 on 35s... I don't think so. Not unless there was some serious gear changing. I am on 32's with 3.55's as well and 80-ish is about all she has Link to comment Share on other sites More sharing options...
HOrnbrod Posted February 1, 2016 Share Posted February 1, 2016 The flag has officially been raised on this entire thread. :rotfl2: Link to comment Share on other sites More sharing options...
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