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Old 12-20-2012, 09:35 PM   #1
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Chipping a 2005 8.1L 454 gas engine

Hi I'm back,

I did buy a 2005 Newmar-Kountry Star Motorhome Class A with 12,000 miles on it. It does have a 8.1 liter 454 chevy engine in it, it has lots of power but only makes 7 miles to a gallon. I'm wondering if anyone has tried to chip a 454 chev engine and what they did to it, if it improved mileage or is it even worth it, also what did it cost?

and Merry Xmas to All

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Old 12-20-2012, 11:06 PM   #2
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Arch Hoagland's Avatar
Monaco Owners Club
Workhorse Chassis Owner
Join Date: Aug 2002
Location: Clovis, CA, USA
Posts: 6,500
Mine is the same engine, 8.1. I got 7.1 mpg over 60,000 miles average.

Couldn't tell you if chipping it will change it but I doubt it. Developing more power means more fuel used.

A 454 is an entirely different engine. A 454 in your coach would get you, at best, maybe 6 mpg on average.

2004 Monaco La Palma 36DBD, W22, 8.1, 7.1 MPG
2000 LEXUS RX300 FWD 22MPG 4020 LBS

Don't know where I'm going, spose I'll get there anyway.
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Old 12-20-2012, 11:31 PM   #3
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8100 Generation L18
The Vortec 8100 (RPO L18) is a V8 truck engine. It is a redesigned Chevrolet Big-Block engine and was introduced with the 2001 full-size pickup trucks. It is an all-iron engine (block and heads) with two valves per cylinder. It retains the same bore centers as the old 7.4 L big-blocks, but stroke was upped by 9.4 mm (0.4 in) to reach 8.1L (496cuin) for a total of 107.95 mm (4.3 in) bore and 111 mm (4.4 in) stroke. Power output ranges from 325 hp (242 kW) to 550 hp (410 kW) and torque from 455 lbft (617 Nm) to 690 lbft (936 Nm). Vortec 8100s were built in Tonawanda, New York. The Vortec 8100 is the engine used in the largest Uhaul, their 26-foot (7.9 m) truck. GM also sold the Vortec 8100 to Workhorse (now a division of Navistar) making it one of the most popular engine choices in gas powered Class A motorhomes during the first decade of this century. GM stopped installing big block V-8's in the Silverado HD trucks, when the GMT-800 series was discontinued in 2007. 8100 marine engines range from 400 to 600 hp (447 kW) and come with a stand-alone Engine Control Module (ECM). The last L18 was manufactured in December 2009.
Important differences between the Vortec 8100 and older big blocks include a changed firing order (1-8-7-2-6-5-4-3), a new 18-bolt head bolt pattern, different symmetrical intake ports, different oil pan rails and the use of metric threads throughout the engine. The fuel-injection system for the Vortec 8100 is nearly identical to that used on Gen III engines, right down to the fuel and spark tables in the ECU...
I think one of the best engines built for this application.
Dan Asbjornsen and Patty Chatman
This was replaced this year with a brand new 2017 Toyota Tundra and a 2018 FOREST RIVER WILDWOOD HERITAGE GLEN 24RLSHL
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Old 12-20-2012, 11:32 PM   #4
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8.1 is actually 496 cubic inches. Ultra Power will give you more HP and torque but MPG may go down if you use all of that extra HP.
Wayne & Roberta and Maggie the Miracle Dog
08 Winnebago Destination 39W Gas UFO Workhorse Chassis
Making the Journey in our Destination

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Old 12-21-2012, 06:49 AM   #5
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check out Brazel's RV for ideas for your Workhorse. Also Omey's web site will have ideas. You will have to decide if the money spent is worth the improved performance/gasmileage.
2004 National Sea Breeze LX8375, Towing a 2012 Liberty.
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Old 12-21-2012, 06:57 AM   #6
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I was told that they do not make chips" for ford 460's 0r Chevy 454's" gas enginess. Is that correct?
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Old 12-21-2012, 08:25 AM   #7
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The original poster has to clarify if they have a 8.1 or a 454, my guess is a 2005 would have a 8.1

With the price of UltraPower being around $800 and if you are looking for improved gas milage my recommendation is to go 5 MPG slower ! 0$ of initial cost and you should have a gain in gas milage.
Now if you are looking for improved performance the the UltraPower might be something to look into.

Best of luck with your findings.
Gene & Ginger
No RV at this time.
04 Winnebago Adventurer 33V, 05 Jayco 23B, 02 Coleman Cheyenne
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Old 12-21-2012, 08:48 AM   #8
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I have a 2008 Work Horse 8.1 L 38' MH pulling a 2 dr. Jeep Wrangler and as of yet I have not found a grade that I cant go up. So what is the need for more power? From what Ive read your gas mileage doesn't increase and I'm not drag racing anyone so what am I missing? From my experience any grade I have come upon I can run with the semi trucks with no problem.
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Old 12-21-2012, 09:01 AM   #9
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GM V8 spec's as installed in Motorhomes (from a few on-line brochures):

7.4 L, 454 CID:
290 HP
410 Lb/ft torque

8.1L, 496 CID
340 HP
455 Lb/ft torque

Regarding milage; we towed a 5000lb car trailer from KY to Lincoln Nebraska, and back, last year with our stock 454 powered TREK. I drove 60-62 MPH and got 8.1 MPG for the entire trip. As they say "Your mileage may vary"

Brazells has a reprogramming product for engine computers, and a neat spreadsheet to estimate any payback. You can enter:

Cost of gas
Miles driven per year
Assumed MPG improvement
And get estimated savings per year for comparison to cost of programming

Originally Posted by kb7uxe View Post
8100 Generation L18
The Vortec 8100... Power output ranges from 325 hp (242 kW) to 550 hp (410 kW) and torque from 455 lbft (617 Nm) to 690 lbft (936 Nm).
George Schweikle Lexington, KY
1999 Safari TREK 2830, FMCA 190830, Safari International chapter
1995 Safari TREK 2630, 1983 Winnebago Chieftain, 1976 Midas Mini
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Old 12-21-2012, 01:15 PM   #10
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THANKS for your replies they are very helpfull. I'll be checking other opitions .
I was thinking that the cost was probably not worth the hassel.
I love this unit very roomy and rides better than most cars.
2005 New-Mar kountry star with 12000 miles
Thanks biged49

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454, gas

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