Rpm redline ? for 8.1 liter

[Chris]

OP has 3.73's

 

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[LongrangeLauber]

Yeah I just forgot to go back and read it.

 

That could be the reason you, @springfield5, don't hunt for gears. Cause it keeps those RPM's high enough to keep it pulling...

[Covehon]

Thanks. Right. I have a 3.73 rear end. I just got back from dumping the tanks. I was going up and down hills on the way. I put it in first gear and idled it up the grade to 4500 rpm. It pulled like the trailer wasn't there. Very nice.

Thanks, I appreciate your input.

[Covehon]

Springfield5,

I see your truck is very similar to mine only I have the 3.73 rear end. How high do you rev your engine? What kind of gas mileage are you getting?

Thanks

[springfield]

Covehon,

Yes I specifially searched for a 2500 Suburban with the 8.1l and the 4.10 rearend in order to get the 12,000lb towing capacity. The 3.73 is rated at 10,000lb. On the long pulls I usually keep it below 4000 RPM....that is just my comfort zone. If I need to pass slower traffic while pulling on a steep grade, I have no problem reving higher. I honestly keep a closer eye on the transmission temp rather than worry about the engin RPM. I have always assumed these engines were designed to haul. They have had many HD truck applications in the past so I figure my little Suburban shouldn't stress it too much.

 

As far as fuel economy goes I have a best of 14.5 and a worst of 8 while towing through the mountains. I usually average around 12.5.

 

Good luck with yours and let me know if you have any questions!

[Covehon]

Springfield,

Thanks for getting back to me.

I too watch the tranny temp. I think I'e been babying the engines although our driving styles sound about the same. I usually slow down so that my rpms stay less than 4000 on long pulls. I'm going to start pushing it a bit harder.

My fuel economy hasn't been quite that good. I only get 14 mpg going downhill. When I'm towing I've been getting just under 8 mpg. Although, I put regular with an octane rating of 85 and I generally pull well over 5000 ft elevation. Do you burn premium or reg?

J

[Jsdirt]

No need to run premium, unless your running a performance program, or have built the engine with high compression.

 

Using it in a stock truck, you might as well keep yourself warm by burning your money on the side of the road.

 

I do hear that there are some states that do not put ethanol in premium (MA ain't one of them, of course ...). In that case, it would be worth the extra.30 + cents per gallon to get pure gasoline. You'll save with an extra point, or 3 mpg, plus a few more ponies and ft.lbs.