shifting RPMS and redline

Joined
Aug 15, 2005
Messages
5,175
Location
Lemoore, CA (south of Fresno) / Cortes Island, B.C
Ok so I finally got my 73 FJ40 with the 3 speed tranny, F engine, and 4.11 gears with 33s running and it is totally different than my old CJ. With the rig being new to me and the new sounds and unfamiliar engine, what is a good shifting RPM so that I do not rev out the engine? the engine is a lot louder (less insulation and noiser gears) than I am familiar with. I also need to set the redline ont he tach. I know when to shift to not lug, but how high could my RPMS go before I start to redline? Until I can do it by sound, I do not want to be off-road and shift with too high RPMs. With the CJ, I was safe shifitng up to around 3000-3500 RPMS, but the engine in the cruiser is different. So what is considered normal shifting RPMS for the straight six for my 73.

REdline is at 4000 but I do not what to get that high, but set my tach there.
 

HawkDriver

 
 
 
Joined
Feb 1, 2002
Messages
3,311
Location
No. Ogden, Utah
slickrock said:
Ok so I finally got my 73 FJ40 with the 3 speed tranny, F engine, and 4.11 gears with 33s running and it is totally different than my old CJ. With the rig being new to me and the new sounds and unfamiliar engine, what is a good shifting RPM so that I do not rev out the engine? the engine is a lot louder (less insulation and noiser gears) than I am familiar with. I also need to set the redline ont he tach. I know when to shift to not lug, but how high could my RPMS go before I start to redline? Until I can do it by sound, I do not want to be off-road and shift with too high RPMs. With the CJ, I was safe shifitng up to around 3000-3500 RPMS, but the engine in the cruiser is different. So what is considered normal shifting RPMS for the straight six for my 73.

Also, what would be considered redline for the old straight six? thanks.
One more time please not sure I understand what you're asking. ;p
 
Joined
Mar 27, 2003
Messages
6,169
Location
Georgia Tech
I don't have a tach.

The lower you shift, the better your gas mileage.

I've run my old F engine (what you have) for 3300 rpms for extended amounts of time.
 
Joined
Jan 26, 2005
Messages
5,522
Location
in the garage
shifting in town 2k
shifting to pass 2500-3k

redline on a f motor is 4k
but in reality, dont push it
make redline 3500
 

froggy

 
Joined
Jul 7, 2004
Messages
464
Location
Val-David
I shift mine around 2200.....If i'm in town, I keep it in second gear (3 speed tranny) most of the time. I do a complete stop only if I see a cop.....
 
Joined
Apr 24, 2003
Messages
2,212
i shift at 3700, peak power is at 3600 and it drops off dramatically from there so no point reving the rings out past that.

as for downshifting, these are big healthy manly motors... i'll lug mine along at 600rpms in 4th if i'm lazy.

and shifting early doesn't always = better gas milage, it all depends how your motor delivers it's power. if it struggles below 2500, and you shift at 2, it'll take alot longer to get to cruising speed, for example, with made up figures, 1 minute using 2 gallons of fuel an hour, or 5 minutes using 1.5 gallons of fuel an hour... which works out more efficient?

probably best bet is to shift before your peak horsepower, so that the next gear falls back just below the torque peak, as the torque peak is where the motor is using ing the most energy from the fuel to propel the car.
 
Top Bottom