8100 Upgrades

gcope63 · November 25, 2003

Still debating whether to get an 8100 or a Duramax and was wondering what kind of performance upgrades were available for the 8100?? What are people using and what kind if results are you seeing??

I like the idea of the BBC, still trying to talk myself out of the mileage the Duramax has...

Thanks

Gary

Truckman031 · November 25, 2003

There are many upgrades for the 8.1. You can pretty much do anything( superchargers to minor mods like cold air intake). However, the Duramax has alot of upgrades too. Hypertech's Power Programmer does great with it, giving lots of power. Good luck with the buy.

Shaners · November 25, 2003

My buddy put a Westers PCM in his 8.1L Avalanche and it sure did pick it up. (He can show you the black marks on the road to prove it). He also picked up some MPG's too...

MCourson · November 25, 2003

Whipple super charger.

gunslinger45 · November 25, 2003

Ya, I've got the 8.1L in my Avalanche, and I have to say that I'm not overly impressed with the performance options available for it. Stock to stock, I would take the big gasser over the diesel any day, but the Duramax is really easy to mod to make serious power and torque for much lower cost. Quite honestly, I believe that the diesel will tolerate power upgrades a little better than the gasser just due to the inherent strength of the engine. But don't think there is a free lunch, you pump up your diesel by 100 hp or so and yes you are going to take some kind of hit in maintenance or durability of the engine or powertrain. Maybe it means you'll only get 175,000 miles instead of 200K, but there is a tradeoff. For the 8.1L, the only things that I have seen documented dyno runs for that make a difference are of course a supercharger kit (like $4K), quality headers made by really only one company (TOG about $700), and some variant of intake for about 10hp (Volant, procold, etc, ect for $250). Yes you can add the Wester's chip, but I am not a big fan of chipping modern day gassers for various reasons. There's a good reason why the computer is tuned the way it is at the factory, and being an engineer I can assure you its not always the default answer of the "beancounters."

So if you want to add 100 hp to your 8.1L, it'll cost you a pretty penny and the stress limits will be a bit higher I think. For the Dmax, you can make an extra 100hp for about 1/3 of the cost and have some stress margin. Of course, then you get into the initial cost of the diesel and all the other crap and discussions about maintenance etc vs the gasser. If the mileage thing is the only issue that stands in your way of the gas vs the diesel, than I can only suggest you do your own cost analysis. Everybody has their opinion on this, and when I did the analysis I will just tell you that is was a wash in the end. If you are going to tow a decent size load more than 5% of the time and you plan to keep your truck for a long time, than yes a diesel will yield a better cost basis, but don't go into the deal thinking it is going to be a slam dunk. Don't forget to figure in maintenance and some intangible factors like having to plug in the block at warmer temperatures than a gasser and worrying about jellied gasoline and bacteria in the fuel filters and such. Minor issues, maybe, but something to consider. My bottom line answer. If you're going to keep the motors basically stock and are not towing a 10,000 lb trailer around for 10,000 miles a year I just don't see the rationale for the diesel (macho factor asside). You want more power than stock and to maintain good durability, than go Dmax. Drive them both back to back in the city and on the freeway and I have not met many people who have not liked the feel and dribeability of the gasser a little better. Also, for the kind of money you're going to spend on this rig, make sure you get what makes you happy. Going with your brain yields one result, going with your heart may yield another. And, I have found that sometimes if you don't go with your heart, you'll end up paying alot more in the long run trading up anyway later on. Have fum, and enjoy purchasing your new rig.

Trev

gcope63 · November 25, 2003

Trey,

Thanks for the info, definately somethings to think about!!

One concern I have with the Duramax is the daily driving.. From what I have seen driving the diesel they do not warm up very quickly and with my drive to work being only 8 miles or about 12 minutes, I don't think it will reach normal temp unless I let it sit and warm up.. I have heard that if you don't let the diesel reach operating temperatures it will reduce the life of the motor... With the gas engine I don't see this being an issue since it seems to warm up quicker..

I am not looking for a large increase in horsepower.. I would like to help it breath better with a better intake and exhaust but a blower is a bit extreme and would have a definate reduction in the life of the motor....

Has anyone used the Banks Headers on their 8100?? It shows under the motorhome section but an 8100 should be an 8100 no matter what truck it is in ...

Thanks

Gary

gunslinger45 · November 25, 2003

Its funny you mention Banks. I have a friend who is a project manager there and when I first got my truck he was the first person I wrote to. Now I know that everyone has their favorite aftermarket companies, but from what I have seen of Banks and the robustness of their testing and documenting process for all of their products, not to mention their warranty, I think they are the best out there for the big engines, both Diesel and Gas. So I talk to my friend and the bottom line is that the 8.1 kit they have for the Workhorse 8.1 in motorhomes and is not tuned properly for the trucks, Avies, or Subs, let alone engineered to fit into the chassis of those vehicles. So even though a kit is available for the engine, it is not applicable to our vehicles. I asked him about their development plans for a system and he said they were in the middle of doing the business case to see if it made sense and if they did commence, the product would not be available until sometime in mid to late 2004. The issue is that when stacked up to the Vortec 5.3, 6.0, Dmax, New Dodge Hemi, Ford PSD, the 8.1 is at the bottom of the pack when it comes to numbers sold, so like any company, they're trying to priortize their business plan, which sucks for us, but I guess makes sense.

I also talked to my friend about what kind of potential power and pricing a Power Pack kit would be speced at when it hit the market and tried to compare it to their kit for the old 2000 7.4 engine which advertises 70 hp and 85 lft-lbs for around $1500 or so. He said that the price would comparable, but the consensus there is that the kit would not produce those kind of numbers due to the increased design eficiency of the 8.1L from the factory. There would still be substantial gains, but probably in the neighborhood of 45 to 50 hp or so, but this is speculation until they actually start doing some buildups. But yes, should Banks come out with the kit, I think it would be a slam dunk for the 8.1L from a value, quality, and performance perspective.

About your thermal issue with the Diesel, although I think it may be important, I'm not sure its that big of an issue. One of the big factors of metal fatigue (in engines or any other application) is number of thermal cycles. This can be reflected in a large sense by an engine coming up to operating temperature, and a smaller sense by each combustion stroke of the piston. If you drive your vehicle to work and back each day, that is two of the "larger" thermal cycles whether it gets to operating temperature or not. Heck, one may argue that by not achieving the highest temperature, the metal will undergo less stress. If you would agree that a gas engine goes through this as well, then it too would show the same degree of stress. The Diesel takes longer to warm up because it has more metal, needed because of the higher internal stresses of the engine. I think the issue of not coming up to operating temperature had more to do with life of exhaust systems in both Diesel and Gas applications. There is condensation that forms in the system and if it is not evaporated off completely, it can lead to premature rust. You've probably seen water dripping out of a cold car as it idles at a stop light. So, ya, not warming up and being in the "zone" may contribute some extra stress to the diesel but I don't know that it would manifest itself in any appreciable problems, but that's just my opinion. The daily driver issue you mentioned was an issue for me, just because I thought the diesel was constantly rowing through gears on the city streets trying stay in its sweet spot. Diesels enjoy constant RPMs, gassers are designed over a wider powerband, which I think makes them better on the street, but obviously less so on the freeway. Anyway, sorry for the rambling, but darn it, talking trucks is awesome!! Have fun.

Trev

Rippem · November 25, 2003

gunslinger45 that is one HELL of a synopsis in just two posts!! I drive an 8.1 and enjoy it over the 'MAX for exactly the drivability ++'s you mention above. My Wester's works well, though it is a tradeoff...premium fuel and probably worse mileage, because I can't stay out of it! I'll tell 'ya though...it does run GOOD

k1500chevy97 · November 26, 2003

whole lotta upgrades for the 8.1 at our prefered vendor tbyrne

422 SS · November 26, 2003

All the mods mentioned except for the supercharger will net very little gain for the dollars spent.I have a Dmax and it daily drives just fine.Contrary to belief around here a Dmax does'nt need to be plugged in unless its colder than -30 deg.I have had mine a year and have never plugged it in,no problems with fuel jelling either.I live in Ohio and its been down to -15 degrees and my Dmax started on the first try.Having owned both a 8.1 and Dmax there is really no debate when it comes to performance.The Dmax is quicker stock to stock and with a $800.00 programmer I run times a 8.1 owner would have to spend 10k to achieve.I use regular ol #2 diesel and get close to 20mpg on the freeway while the 8.1 owners are sipping premium at 9mpg.Remember all these costs when you make your decision.The diesel has a 100,000 mile warranty to boot.

HendyPhoto · November 26, 2003

No need to use premium, it's a myth. More expensive gas doesnt run any better for you, unless you have an old engine that pings and knocks ALOT.

gunslinger45 · November 26, 2003

I would definitely second the notion that there is no need to be running higher octain fuel in the 8.1L unless you hear evidence of piston knock (separate from all of this CSK crap). The 8.1's compression ratio is like 9.1:1 which is very easy to avoiding knocking from. If the comp ratio was up around 9.6:1, like the Dodge Hemi, then you may have to start moving up to midgrade, and obviously high grade as your comp ratio increases past that. The only way the hemi gets away from not mandating high octain fuel (and to pass emissions) is to use two plugs in each cyclinder. Seems a little like gaming, but enough people seem to like it. All cars that come with a compression ratio higher than 10.0:1 would definitily have to be using high octain fuel to avoid knocking. So that includes all turbo and supercharged vehicles.

Thanks guys, interesting posts

gunslinger45

422 SS · November 26, 2003

I need to clarify what I meant by premium fuel.I was referring to those that use aftermarket programmers on their gas trucks.It isnt necessary with the stock tune.

tbyrne · November 27, 2003

d**n, some of you guys can type! Good posts

I think the Duramax guys have an advantage over the 8.1 owners. They get better gas mileage than my two 8.1s combined plus they can add 100+ horsepower in about 10 minutes (programming upgrade). They pay more up front but they get more in the end. If I was going to buy a truck that was going to tow alot and not see much "regular driving" I would go with a Duramax. I use mine as daily drivers and tow once in awhile so I went with the 8.1.

As for mods, there is quite a bit avaialble - inductions, headers, catbacks, MAFs, computer programming and superchargers to name a few. Comp Cams has 3 different cams available -

46-408-9

Comp Cam -Great torque, good for towing & RV’s. Works with O.E. exhaust and intake - 206/212 .510/.510 112

46-413-9

Comp Cam - Good midrange performance, great for daily driver, headers recommended - 212/218 .510/.510 112

46-422-9

Comp Cam - Best in performance applications, after-market intake and exhaust recommended - 218/224 .510/.510 112

I run their mild cam in my Silverado but might go with a more aggressive grind soon. Either that or bolt on one of the new Paxton superchargers to see how it performs. I run an Intercooled Whipple with other mods in the Suburban. That made 407hp/558ft-lb torque (about 520/715 at the flywheel).

I also have a set of stock 8.1 heads here for a core if anyone would like to have a set ported.

Tom