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Welcome to the 3500HD.com forum created October 2009

Author Topic: What RPM are you guys getting at 65MPH  (Read 2334 times)

ED-NY

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What RPM are you guys getting at 65MPH
« on: March 20, 2016, 08:58:17 AM »
Curious as to what RPM you folks are getting with the various 3500HD rear end ratios and man/auto transmissions.

In the 60-65 MPH range?

Organic Log Farmer

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Re: What RPM are you guys getting at 65MPH
« Reply #1 on: March 20, 2016, 01:22:27 PM »
'94 7.4L NV4500 4.63 Rear End Ratio, 2200-2500 RPM

I'd like to be @ 2000 RPM driving 60-65...

Born a Boomer.
Still Experiencing Childhood, Perhaps Entering Adolescence.
Still Learning...
Chronologically An Adult, The Jury Is
Still Out...

RPF207

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Re: What RPM are you guys getting at 65MPH
« Reply #2 on: March 20, 2016, 08:46:25 PM »
'99, 5.13s, nv4500, 2750 rpm's at 70 mph, 2550 rpm's at 65 mph, 2350 rpm's at 60 mph. Hoping to change to 4.10s someday. Only other combo that matches between D80 rear and D70 front.😎
1999 chevy HD 4x4 135.5" 6.5 nv4500 bw4470 Dana 70 HP 10 lug front

Due to recent budget cuts the light at the end of the tunnel has been turned off

ED-NY

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Re: What RPM are you guys getting at 65MPH
« Reply #3 on: March 21, 2016, 05:25:08 PM »
Thanks....don't know what rear ratio I have. Put this current 3500HD together from parts I had and will need to calibrate the DRAC once I get it on the road, now with the tach and a GPS I can determine what gears I have.

RPF207

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Re: What RPM are you guys getting at 65MPH
« Reply #4 on: March 21, 2016, 08:29:59 PM »
My rear diff cover has a small tag fastened by the diff cover bolts that states the ratio. There is also a B.O.M. Number on the axle
1999 chevy HD 4x4 135.5" 6.5 nv4500 bw4470 Dana 70 HP 10 lug front

Due to recent budget cuts the light at the end of the tunnel has been turned off

AZTimT

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Re: What RPM are you guys getting at 65MPH
« Reply #5 on: March 22, 2016, 12:49:54 AM »
nv4500, 3.73 thin (for use with 4.10 + down factory carrier and available for matching D70 front) runs as follows in 5th gear running 245's
2280 @ 80 ( MT & UT interstate limits 15mpg  in the mountains when 8500-10k empty/light :) )
2140 @ 75 15mpg
2000 @ 70 15-16mpg
1850 @ 65 16-17mpg
1710 @ 60 17-18mpg
1570 @ 55 18-19mpg on the flats
1430 @ 50 ?? too slow to bother with mpg
1280 @ 45 usually run 4th here unless empty on flat lands as it lugs the cummins more than I like.

The extended cab is most likely going to get 3.31 D80 fast guts front & rear since I found out D80 can stuff into D70 case with just a little bit of grinding. Search "Jana 87" before saying it can't be done. ;) This ratio with an rto-6610 and either a dt360 or 6bt should make a great interstate HD.
94 K3500HD (factory Monroe 4wd upfit) short wheel base 9' bed 454 no more/NV4500HD/NP261HD/D70 frt/D80 rear 5.13's Cummins powered with 3.73's.
93 C3500HD long wheel base parts truck 14' bed 6.5(gone)/NV4500HD/D80 4.63
95 C3500HD medium wheel base 11' bed 6.5/4L80E/D80 4.63
2000 C3500HD Monroe extended cab 9' bed, 6.5/4l80E/D80HD 4.63 will become 4wd with D70 front and repowered some day...

ED-NY

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Re: What RPM are you guys getting at 65MPH
« Reply #6 on: March 22, 2016, 07:36:28 AM »
AZTimT..wow..you did some research!

RPF207..looked the axle over real good, no tag and can't see any legible digits.

Thanks Guys
« Last Edit: March 25, 2016, 09:48:41 PM by ED-NY »

6669charger

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Re: What RPM are you guys getting at 65MPH
« Reply #7 on: March 25, 2016, 03:39:25 PM »
2000 7.4 auto 4:63  60mph  2000-2200 rpm

 


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