GM 454 Vortec vs. 8.1 Workhorse

[Barbcollins1@yahoo.com]

OK, I'm just a girl but I am looking at a motorhome with this GM454 in it, a 2002 Winnebago. How does that engine differ from the newer 8.1 Workhorse engines that are on the newer models? I don't need a lot of detail because I wouldn't understand it. Is it a dinosaur? Will it pull the MH and tow vehicle? Only has 18,000 on it.

[hermanmullins]

Nurse Barbara, the 454 and the 8.1 are built on the same block. I am not sure but I beleive the 454 is a throttle body injection and the 8.1 is a multi port injection. And yes either one will do well on a coach up to 34 or 35 feet. more then that you not preform too well.

[Barbcollins1@yahoo.com]

Thank you for that reply. You are the only one who knew that much. The salesman says it's a tiny bit better on gas mileage than the newer ones. I don't always believe salesmen. Do you agree?

[dschmees@coxinet.net]

Hi Barb,

I chose to get the 8.1L because it has greater torque (torque is what turns the wheels, not HP) at a lower RPM. What that means is that you will not be downshifting every time you go up a small hill. I don't like a lot of downshifting because of the noise of a racing engine.

At 60mph the engine is running at about 2200 rpm. Then if it downshifts on a hill, it only goes up to 3300 rpm which is its best torque rpm.

Hope this helps.

[kalynzoo]

I've owned both, and I have very little technical background in engines. But I have RVed for over 30 years. Your profile does not give a location. So, if you live out West and need to travel over the mountain the newer Workhorse or Ford V10 give alot more power on the mountains. With my 454 in a Holiday Rambler 36ft, traveling over the Grapevine (a long hard mountain climb leaving Los Angeles on I-5) would drop us to 25 or 30 mph. With the previous Ford and the current Workhorse I can make the grade at 50 t0 55mph without difficulty.

Traveling on the flat midwestern plains, I don't think you will find much difference. Gas mileage is similar, seldom reaching 8mpg. Both will tow a light car without difficulty.

Things to think about. Even though the MH has very low mileage, it is still a 2002. The tires are probably original, and therefore way past the 5 to 6 year safe age. So plan on new tires right away. Also have a qualified mechanic check out the belts and hoses, all will age without regard of mileage. Also, check the generator, which may not have seen much use, but should have been run periodically. Just things to look out for, and all things that are expected.

Enjoy, and Happy Trails.

[pattexaco]

Hi Barb,

I chose to get the 8.1L because it has greater torque (torque is what turns the wheels, not HP) at a lower RPM. What that means is that you will not be downshifting every time you go up a small hill. I don't like a lot of downshifting because of the noise of a racing engine.

At 60mph the engine is running at about 2200 rpm. Then if it downshifts on a hill, it only goes up to 3300 rpm which is its best torque rpm.

Hope this helps.

I also have the 8.1 in a Winny '06, 33' Voyage, towing a '10 CRV.

Traveling 58 to 60 mph on flat highway getting about 7.5mpg. What is your average mpg @ 60?

Would appreciate your input.

[dickandlois]

Just some personal side notes on the 8.1 and 454's, They do use the same block,but that is where it ends.

The early 8.1 engines had an issues with Cam and Crank sensors. There was a recall from NTSB regarding these issues.Most where in the large work trucks and GM did not want to include engines that where outside there recalled VIN. numbers !! I have not heard of any problems with the engine with the up graded parts, because the sensors where improved.

The 8.1 will run well on Reg. gas, 454's like the middle grade,but will run on Reg. and they get about the same millage in regards to weight ratio.

The 454 engines tend to have more mechanically set ignition and timing then the 8.1. Just the difference in the level of ECM control on the newer engine.

The mechanical portion of the 8.1 was built to run 300,000 miles if all service intervals are met and the rpm's are not pushed. Deliver companies do run engines hard and long!

These engines are built for torque not high RPM numbers They are not warranted for 300,000 miles though!!!

There have been some check engine codes set,due to the O2 sensors, and it is an intermittent issue,that in most cases just requires removing the ECM code. The problem can pop up on any given day or even every other year.

The 8.1 oil capacity is seven quarts with filter change and there are two different sized filters for the engine if one prefers a larger filter. The change oil light will come on at different millage points depending on the driving conditions encountered between oil changes. Interesting point for one who keeps a maintenance log.

Also! like most Big Block engines, one should check the oil level at around 1500 miles. Big engines do use some oil and that is not really a bad issue, when one considers the heat generated. Oil and filters are cheap compared to what it cost the repair them.

R.M.

[Sundancer268]

For a Chevy, the 454 was not a bad engine. There was a lot of exhaust manifold problems in the class A motor homes with that engine and was probably due to the tight installations and heat build up. Father-in-law replaced two sets on his Bounder. Other than that, the engine performed quite well. Horse power is what you make of it. Some people can not stand to go one tenth of a mile per hour under the speed limit and no one makes enough horse power for them. Others like my self just get into the right hand lanes and let the world go by. If on a two lane road, just keep an eye on the traffic behind you and when three or four vehicles build up behind find a place to pull over and let them go by.

[LinRon]

Lynn

I am looking at a 2010 with Chevy Workhorse engine /Allison transmission. I need some feed back should I or should not.

[larrymitzi2014]

I just heard the same back fire noise in my 2003 pace arrow, 22000 miles, at the time I heard the noise I was pushing it pretty hard, steep hill, 4300rpms, air conditioning going full blast. I had new plug wires installed 3000 miles ago. Once I reached the top, the noise went away until the next day when traveling again, was pulling a slight hill, 3200 rpms, just cruising along and thought yesterday I had air conditioning on so I turned on the air and right away the back fire noise repeated so I turned off the air and after a minute the noise went away.

Can't believe the problem would be related but who knows?

What are your thoughts people?

Thanks

[zorro2kita]

I have the same coach - I've experienced "limp mode" several times and actually stalling on I-95 due to "vapor lock" - Yes it does happen on a FI engine - Have you had the Mass Air Flow sensor(MAF) cleaned or replaced?

Any error codes appear ? O2 sensors replaced ?

Sea Foam is a good product to use - do a search on this forum for recommendations re: Sea Foam - Give me more details of what you have experienced as I probably have had all these issues over the past 24 months.

Also, is the air filter and fuel filter new or replaced recently??