PineClone Posted May 22, 2018 Report Share Posted May 22, 2018 Okay so i have a '78 B210 with a stock A14, 5 speed (converted from automatic), with no tachometer. If i'm doing 50 on the highway and i want to pass the car in front of me, can i drop it into 3rd? So maybe the better question is, since i have no tach, what is the safe max mph in 3rd gear? Thanks! Quote Link to comment
Dolomite Posted May 22, 2018 Report Share Posted May 22, 2018 Listen to your engine, it’ll tell you when it needs to be upshifted. Quote Link to comment
PineClone Posted May 22, 2018 Author Report Share Posted May 22, 2018 Listen to your engine, it’ll tell you when it needs to be upshifted. That works if you assume all engines are the same. Quote Link to comment
metalmonkey47 Posted May 22, 2018 Report Share Posted May 22, 2018 What size tires? Quote Link to comment
Dolomite Posted May 22, 2018 Report Share Posted May 22, 2018 That works if you assume all engines are the same.I shift on feel more often than not. I have had two different l20b engines that tell you to shift at different rpms. One liked 7k rpm, one was happier shifted at 6500, same tachometer on both. Mph works if you assume all cars are the same. Quote Link to comment
datzenmike Posted May 23, 2018 Report Share Posted May 23, 2018 Should be 155/13 or about 22.5" diameter, let me know if different. A15? B-210 didn't have these so a 210 engine which begs the question.... what 5 speed is it 63 series dogleg or the 60 series I'll assume a 3.90 differential in your B210??? Top speed (engine red line @ 7,500) with that tire and differential in 3rd gear is 98 MPH with the B-210 dogleg. If using a 210 60 series transmission it's 93 MPH Quote Link to comment
Dguy210 Posted May 23, 2018 Report Share Posted May 23, 2018 Okay so i have a '78 B210 with a stock A15, 5 speed (converted from automatic), with no tachometer. If i'm doing 50 on the highway and i want to pass the car in front of me, can i drop it into 3rd? So maybe the better question is, since i have no tach, what is the safe max mph in 3rd gear? Thanks! If you are doing 50 on the freeway why would you be in 4th anyways, except climbing a hill. But yes you can drop it into 3rd, personally I'd drop it into 4th. Quote Link to comment
PineClone Posted May 23, 2018 Author Report Share Posted May 23, 2018 Should be 155/13 or about 22.5" diameter, let me know if different. A15? B-210 didn't have these so a 210 engine which begs the question.... what 5 speed is it 63 series dogleg or the 60 series I'll assume a 3.90 differential in your B210??? Top speed (engine red line @ 7,500) with that tire and differential in 3rd gear is 98 MPH with the B-210 dogleg. If using a 210 60 series transmission it's 93 MPH Sorry, typo. A14, 5-speed dogleg with 14" wheels. I don't think i'll try taking it up to 98 mph in 3rd gear! But it sounds like its safe to drop it into 3rd to get around someone on a 2-lane highway. Quote Link to comment
datzenmike Posted May 23, 2018 Report Share Posted May 23, 2018 You can have the same tire diameter with 13, 14 15 " rims. A14 red line is 8K so 104 MPH 1 Quote Link to comment
Dguy210 Posted May 24, 2018 Report Share Posted May 24, 2018 (edited) A14 red line is 8K so 104 MPH Oh you :lol: You can hit just shy of 130mph in 4th.... just saying. You shouldn't, but you can. Edit: Also, Pineclone you should get a tach even an aftermarket one. Edited May 24, 2018 by Dguy210 Quote Link to comment
0r0B210 Posted May 25, 2018 Report Share Posted May 25, 2018 To answer your posting question: yes, shift away. '76 B210, 4spd trans, stock carb, full air filter housing and intake tube and it reaches 70ish mph in 3rd gear(if you had a stock tach it'd be teasing the yellow mark). 1 Quote Link to comment
Tom1200 Posted May 28, 2018 Report Share Posted May 28, 2018 Just as an FYI. My A15 powered 1200 coupe using the 60 series (non dog-leg) 5 speed with short 13" Hoosier race tires 20.6 diameter will do 78 mph in third gear, it's turning 8000 rpm of course. With 14" tires I suspect the gearing is much taller than mine so 50 mph should not be an issue. A-series are non interference engines so even if you floated the valves it wouldn't be an issue. Of course if it did float the valves it would be rather pointless to down shift. A series engines rev like mad and usually need to have the living poo wound out of them to go anywhere. Read nothing happens below 4k. Quote Link to comment
Dguy210 Posted May 28, 2018 Report Share Posted May 28, 2018 Just as an FYI. My A15 powered 1200 coupe using the 60 series (non dog-leg) 5 speed with short 13" Hoosier race tires 20.6 diameter will do 78 mph in third gear, it's turning 8000 rpm of course. With 14" tires I suspect the gearing is much taller than mine so 50 mph should not be an issue. A-series are non interference engines so even if you floated the valves it wouldn't be an issue. Of course if it did float the valves it would be rather pointless to down shift. A series engines rev like mad and usually need to have the living poo wound out of them to go anywhere. Read nothing happens below 4k. Absolutely, rev the crap out of it. http://datsun1200.com/modules/mediawiki/index.php?title=Performance A12 vs A10 but it gives an idea of rpm vs power, similar curves for A14. Quote Link to comment
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