Free 7 Day Trial RV GPS App RV Trip Planner Campground Reviews RV Maintenance Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > TRAVEL TRAILER, 5th WHEEL & TRUCK CAMPER FORUMS > Trailer Towing and Tow Vehicles Discussion
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 10-23-2021, 04:02 PM   #1
Junior Member
 
Join Date: Sep 2021
Posts: 26
8.1 maximum extended rpm?

Hi all, I have a yukon xl with 8.1. I have an 11k camper...going up big hills/long grades I generally try not to hold the rpms past 4k (red line for the 8.1 big block is about 5k I think). 160k miles...engine is midly worked. Am I being overly cautious? I think on i70 in Colorado, I held it at 4k for like 30 minutes straight. Probably one of the more extreme examples. I'm not worried about overheating -- I'm worried about engine failure, especially the crank/rod bearings. I would like to push it 4500. At 4k in 2nd gear on the really big hills, I lose momentum. Perhaps at 4500 I could hold it. Idk. What do u guys think? How far do u Work Horse ppl push them?
Wanderer1 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 10-23-2021, 04:06 PM   #2
Senior Member
 
Join Date: Aug 2020
Location: Ohio
Posts: 1,023
What is your trans temp?
As always good luck and let us know what you did and maybe better members then me will help
__________________
2000 southwind storm, workhorse custom chassis with 7.4l vortec
donr103 is offline   Reply With Quote
Old 10-23-2021, 04:48 PM   #3
Junior Member
 
Join Date: Sep 2021
Posts: 26
Engine/Trans temps are fine...monitored in real time with digital aftermarket guages.
Wanderer1 is offline   Reply With Quote
Old 10-23-2021, 06:41 PM   #4
Senior Member
 
Arch Hoagland's Avatar
 
Monaco Owners Club
Workhorse Chassis Owner
Join Date: Aug 2002
Location: Clovis, CA, USA
Posts: 11,230
I don't run mine over 4,000 rpm. Max torque is around 3600 rpm.

I weigh in at 25,000 lb with my toad and climb lots of mountains.

At 95,000 miles now with no problems. I do change my oil about every 3,000 miles.

I like going slow up the mountains, gives me a chance to enjoy the scenery....lol
__________________
2004 Monaco La Palma 36DBD, W22, 8.1, 7.1 MPG
2000 LEXUS RX300 FWD 22MPG 4020 LBS
It's so weird being the same age as old people.
Arch Hoagland is offline   Reply With Quote
Old 10-23-2021, 06:47 PM   #5
Junior Member
 
Join Date: Sep 2021
Posts: 26
Thanks for your input arch.
Wanderer1 is offline   Reply With Quote
Old 10-23-2021, 08:32 PM   #6
Senior Member
 
tuffr2's Avatar
 
Join Date: Sep 2012
Location: Palm Coast Florida
Posts: 10,654
That engine is not designed to be a spinning engine like a 4 valve per cylinder with dual overhead cams.

I agree with 3,600 rpm as a better rpm to run that engine.
tuffr2 is offline   Reply With Quote
Old 10-23-2021, 08:50 PM   #7
Senior Member
 
mfire1339's Avatar


 
Monaco Owners Club
Workhorse Chassis Owner
Join Date: Jun 2008
Location: Glendora Ca.
Posts: 1,521
3,800-4,000 my max.



Mike
__________________
2004 Monaco Monarch
Blueox, SMI, 1990 Wrangler YJ
mfire1339 is offline   Reply With Quote
Old 10-23-2021, 10:14 PM   #8
Senior Member
 
Join Date: Mar 2019
Posts: 1,962
I can't speak much on the 8.1 as I have very little experience on them. As a general rule, you'd want to keep the engine running in the middle of it's max peak HO and max peak torque numbers. 4500 RPM for very long periods on an engine with heavy internals (pistons, rods and such) might be a lot.

I can run my 6.0 gas for 5 to 8 minutes at 5000 to 5500 RPM when climbing hills. Seriously though, unless you're trying to pierce the stratosphere I wonder why you'd be climbing at that speed for 30 minutes or more? As mentioned, the engine and trans would likely overheat at some point.
__________________
2011 GMC Sierra 3500HD dually gas 6.0

2006 Lakota 29RKT
kdauto is offline   Reply With Quote
Old 10-24-2021, 05:55 AM   #9
Senior Member
 
Bowtie Jim's Avatar
 
Join Date: Jun 2020
Location: Minnesota
Posts: 297
You can run it at 4000-4500 rpm all day long .
As long as you have plenty of air to cool it down. And fresh oil.
These 8.1 big block Chevys are stout.
The only downside is they like to suck the gas tank dry.
__________________
02 Keystone Hornet Lite 25 FL
18 Silverado Dbl.5.3 6sp 3.42 stock ( grunt truck)
18 Silverado Crew 5.3 6sp 3.42 9" lift 37's(fun truck)
Bowtie Jim is offline   Reply With Quote
Old 10-24-2021, 07:26 AM   #10
Senior Member
 
Join Date: May 2013
Location: SW Louisiana
Posts: 433
GM 8.1L Vortec L18 V-8 Specs and Information
Attached Thumbnails
Click image for larger version

Name:	w8om.png
Views:	18
Size:	80.2 KB
ID:	346999   Click image for larger version

Name:	r5tb.png
Views:	17
Size:	91.7 KB
ID:	347000  

__________________
A bunch of salvage title junk I rebuilt
Boogie_ is offline   Reply With Quote
Old 10-24-2021, 07:29 AM   #11
Senior Member
 
Join Date: Nov 2013
Location: Elko, Nv
Posts: 1,797
I never had an issue spinning mine that high for long grades other than what was just mentioned mpg. On one trip with a headwind i got 4mpg.
NevadaNick is offline   Reply With Quote
Old 10-24-2021, 08:26 AM   #12
Senior Member
 
yeloduster's Avatar
 
Workhorse Chassis Owner
Join Date: Sep 2017
Posts: 1,083
I live in Colorado and get a chance to do a horsepower check every time I go out! I'm not shy to run it hard...but...on the up hill I leave the transmission in Drive and place the throttle on the floor and let the transmission, the grade and the engine decide what gear it should be in. On grades like Floyd Hill climbing out of Denver on I70 most of the time my speed is `~32-35 MPH and RPM is ~3500 RPM in 2nd gear. Some parts of the hill are steeper and the speed will fall to ~25 MPH and the transmission will shift to 1st and RPM's jump to ~4500 RPM. When the grade becomes a little less sleep RPM's climb to 4600 RPM and the transmission shifts back into 2nd gear. All the time the throttle is on the floor.

I think your Yukon with its 4L80E transmission is a different animal. 4L80E gear spacing is different than our Allisons. But I think I would do it the same way. You might go up the hill a little slower than holding the RPM's at 4500 but it will be easier on your engine. I wouldn't hesitate to let the engine RPM go to the transmission shift point but I wouldn't hold it there.

I had a Ford F250 with a built 390 CI engine. I didn't hesitate to take it up those mountains at 60 MPH and 5000 RPM in 2nd gear. I was younger then but I never broke it!
__________________
2003 34' Georgetown on W20 Workhorse Chassis. UltraRV power mods. Front Sumo Springs, Rear P32 Sumo Springs, UltraRV Track Bar.
1998 Jeep Toad.
yeloduster is offline   Reply With Quote
Old 10-24-2021, 08:39 AM   #13
Junior Member
 
Join Date: Sep 2021
Posts: 26
Quote:
Seriously though, unless you're trying to pierce the stratosphere I wonder why you'd be climbing at that speed for 30 minutes or more
...40mph for 30 mins is only 20 miles. That's not at all unusual for a mountain pass to be 15 or 20 miles long. And as fuel economy...yeah, I only average 5 or 6 mpg. 37 gallon tank though! So, some of u seem to be concerned about overheating. However, if cooling was not an issue, u still wouldnt recommend pinning it at redline for 30 mins, right? In other words, what else besides cooling/lubrication should be my concern? A friend of mine who had an 8.1 would just hold it to the floor over the mountain passes...no care in the world. Never had a problem. But then another friend said to be careful of spinning a rod bearing above 4k. To be honest, that's really the only thing I'm concerned about... that's why I started this tread. I'm really looking for technical specs of the 8.1 --with assumed perfect maintenance/cooling/lubrication, what breaks when and how under extreme conditions.
Wanderer1 is offline   Reply With Quote
Old 10-24-2021, 09:00 AM   #14
Junior Member
 
Join Date: Sep 2021
Posts: 26
yeloduster, thanks...and yes, 4l80e. Wish I had the Allison! At 4k in first gear I'm about 40 mph. Back in the day when she was stock with 3.73's, I would be maxed out at 25mph on some of the passes too. I thought I was killing it. But after switching to 410's and the engine mods, I have been able to take it to redline in 1st gear on every grade so far...but I just can't get the upshift due the Trans spacing.
Wanderer1 is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 2 (0 members and 2 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Redline and Maximum RPM? RVLiberator Ford Motorhome Chassis Forum 2 02-05-2008 08:31 AM
maximum water pressure gator67 Alpine Coach Owner's Forum 12 04-09-2006 04:50 PM
40' coach & maximum tow trailer lenght?? Lucchese1 Toads and Motorhome Related Towing 6 03-28-2006 02:46 PM
Maximum RV Height? MojaveJoe iRV2.com General Discussion 10 03-31-2005 07:33 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 12:04 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.