running at 70 mph at 3k rpm, what is a ok or safe rpm (Page 1/3) georgie FEB 09, 06:14 PM My car is a 85gt 2.8 an run's strong with a 4 speed man. I run down the freeway at 60 to 70mph at 60 my rpm is 2500 an at 70mph it's 3k give or take 100rpm. What id like to know is what is a safe cruzing rpm an what is starting to be to much for the motor when freeway driveing. I understand not to red line but is 3 to 3500 to much? olejoedad FEB 09, 06:41 PM You're good. georgie FEB 09, 07:22 PM Great. It run's an sound's ok at 3k+ rpm, an dosent make like it's over reved an still has plenty of trottel left. Im going on a 3k mile trip from Cal to fla an don't want to blow, or over work my motor! 82-T/A [At Work] FEB 09, 07:45 PM 3k is fine... the only thing is, your fuel economy will stink. You really want to keep it around 2,500 to get decent fuel economy. But... this engine really is safe to 6,000 rpms (and somewhat beyond as well). But cruising at 3k is not bad. rogergarrison FEB 09, 07:55 PM My V6, 4 spd also ran that fast on the freeway. In fact my Mercedes SLs do the same thing. Id say its just typical. My old 60s cars lumbered down the freeway at 1500-2000 rpms. georgie FEB 09, 08:02 PM Ya.. I do see my gas milage drop when over 2500 rpm. But here in california if you drive under 65/70 you will get ran over.... thank's for the info. jim94 FEB 09, 08:42 PM I have an 87 GT v-6 70=2,500 100=3,500. I have not went any faster Bloozberry FEB 09, 09:29 PM quote Originally posted by jim94: I have an 87 GT v-6 70=2,500 100=3,500. I have not went any faster You have a different transmission than the OP. quote Originally posted by 82-T/A[At Work]: ...this engine really is safe to 6,000 rpms (and somewhat beyond as well). I disagree. The '85 - '86 V6's didn't have the same improved-design oil galleries that the later blocks did. Sustained high revs will shorten the life of the crank, cam, and bearings due to poor lubrication. You won't run into problems at the 3000 - 3500 range in my opinion though. armos FEB 10, 12:41 AM The last ~500rpm of many 1980s GM tachs are shaded in yellow. I've often wondered - does that actually mean anything, or is it just for looks? Is the "yellow zone" only rated for split-second excursions, versus running continuously? I don't know what GM's standards were/are for deciding where an engine's rev limit is. carbon FEB 10, 08:42 AM The yellow area was for the area where GM pushrod engines make no power so there is no point in revving into that range of RPM.