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B20 Safe cruising/maintained RPM

vwbusman66

Stößelstange über alles
Joined
Oct 12, 2016
Location
SE MI
Can't find anything online that apply specifically to road going pushrod engines.
Boat sites are saying 4500RPM :wtf::wtf: sustained is good and safe/healthy for an AQ130!!
I'm trying to figure out if I can actually put the car on the highway and safely cruise at 72mph for four hours at a time.
Note: The car is a B20/M40 145 with a 4.10 rear end ratio. So far, my calculations have been 833 revolutions per mile (195/60R15 tires) X 4.10 X 1 (4th gear ratio) to give 3415 RPM at 60mph.
 
That's the same combo my 140 came with. Even with the W50 trans it would cruise around 3800 at 70-75 without any real issue other than the noise.
 
You will not be able to drive that 145 fast enough to hurt a stock B20.
Didn't they redline at 6500 rpm? I'd imagine 75 mph will be around 4K.
The only harm will be to your eardrums.
 
Pedal to the metal, don't stop till you get there.

122_wagon__90-1.jpg
 
In my experience driving many customers 1800E and 1800ES with automatics, the tachometer indicates around 5000 rpm while going 80 mph.

The automatics are 3 speeds with 3rd gear being 1 to 1 like 4th gear in a M40 or M41.

Now that is near the redline of 6500 rpm, but these engines, when in good condition, can run for days at 5000 rpm if you can handle the noise.

Some sound deadener and a good sound system will make the ride way more tolerable. :)
 
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In my experience driving many customers 1800E and 1800ES with automatics, the tachometer indicates around 5000 rpm while going 80 mph.

The automatics are 3 speeds with 3rd gear being 1 to 1 like 4th gear in a M40 or M41.

Now that is near the redline of 6500 rpm, but these engines, when in good condition, can run for days at 5000 rpm if you can handle the noise.

Some sound deadener and a good sound system will make the ride way more tolerable. :)

:nod:

Or take it down a big ass hill and bury the needle till the valves float at 120 and then when things level out everything's still going on as usual.

Who needs a rev limiter .?. they had it figured out....
 
I *really* like the M41 swap I did in my PV. But I think that's mostly for the reduction in NVH, I don't really think the engine cares all that much.
 
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