FUEL MILEAGE TIPS AND TRICKS FOR ALL

luvrbus · November 04, 2014, 10:51:14 AM

Why the need for cetene booster in the fuel ?

Jon · November 04, 2014, 12:20:05 PM

Count me among the cynics. Detroit Diesel has some pretty smart people working for the company. Oil companies also have some smart people working for them. Jointly they determine what is best for an engine. When Detroit lists the specs for fluids it does not do that based on gut feel, but on testing and analysis.

Unless and until the list of specified fluids, either by product name, brand name, MIL spec or any other description is listed as recommended by Detroit Diesel, is expanded to include some of the stuff cited above I will stick with the list I have from Detroit Diesel for everything from fuel, to oil, to coolant.

Dave5Cs · November 04, 2014, 02:01:22 PM

Where is Van with the Popcorn when we need him?

digesterman · November 04, 2014, 02:09:33 PM

There is nothing wrong with using synthetic blends in many applications, look at the chemical makeup of synthetics vs. oil. My wife's Prius uses synthetic oil probably because of the tight tolerances found in the new engines, something DD's two strokes might not have to worry about.

With that said tho I myself would be following the manufactures recommendations. As Jon brought out they understand their products better than anyone else and along with millions upon millions of miles of on the road data haven't seen a need to change it. If they did then maybe a good time to look into it.

But if it works for you by all means go for it

chessie4905 · November 04, 2014, 04:52:22 PM

Has Detroit Diesel done any recent testing on current synthetics on a basically obsolete engine? Yes, I know it is still used in marine and military applications. I wonder. GM for years recommended straight 30w oil in their 5.7 and 6.2 and 6.5 diesels, even when 15w 40 was available and used with great success in the 60 series. They have always been pretty conservative on such things.How many of us will ever put 200,000 +miles on our engines? I'll still use 40w, but also because it is more economical compared to synthetics. 40 weight is getting pretty expensive anymore though. Pardon me while I refill my popcorn bowl.

RJ · November 04, 2014, 11:10:32 PM

Dan -

Since you're so pleased with the results of the multi-viscosity synthetic oil you're running in your 8V71, why don't you share with us the brand name & it's part number so those that are interested can pick up some for their own use?

FWIW & HTH. . .

luvrbus · November 05, 2014, 05:57:24 AM

Royal Purple 40W synthetic oil for years was the only DD approved synthetic I don't know about the rest of the brands

Seangie · November 05, 2014, 06:00:40 AM

Dan,

I'm excited to see someone who uses an alternative to straight 40 as its getting hard to find these days. 20-50 sounds promising. Let me know when you get to about 150k miles. If I can't find 40 straight anymore I'm up for the switch. Also - using synthetic in the tranny makes a huge difference just expensive to make the change.

PS- If you ever use that dirty three letter "O" word around here just be prepared for the onslaught. It guarantees 10 pages of replies to your post. They might as well just copy and paste everything from the last persons post who used the "O" word.

-Sean

Wandering the country in a 1984 Eagle 10S.
www.herdofturtles.org

itspaidfor · November 05, 2014, 11:48:18 AM

Actually you can switch to synthetic tranny fluid with out doing it twice right a way just switch it out after 10,000 miles and another filter you will be fine. As for the brand I use just google it I would sure not want to be accused of pushing an inferior synthetic oil brand on my busnut friends. AS for the knife throwing no problem. Have a great day guys I have to go out & pick up 8-v71 parts out of the road LOL! Dan

chessie4905 · November 06, 2014, 02:22:36 PM

Why does this sound like Amsoil?

Oonrahnjay · November 06, 2014, 05:15:49 PM

Quote from: chessie4905 on November 06, 2014, 02:22:36 PMWhy does this sound like Amsoil?

Can't be Amsoil - Amsoil be big, big magic, Bwana!!!

chessie4905 · November 06, 2014, 05:34:40 PM

Looks like a campaign poster with the top cut off.

Jim Eh. · November 06, 2014, 07:41:17 PM

Or an ad for a service station in the middle of Saskatchewan!

RoyJ · November 07, 2014, 10:49:56 AM

Are there any formal studies on the topic of multi-viscosity oil polymers needing to "relax"?

I'm curious what constitutes as a "relax", in terms of time frame. 1 ms? 5 ms? 1 second?

As we know, oil doesn't stay stationary inside bearings. Eventually they'll flow out into the open crankcase / oil pan where there's plenty of time to relax.

Also, what are the shear viscosity of a 20w50 synthetic vs 40wt conventional, at operating temperature? If they are comparable, then can we not conclude they should perform the same, regardless of polymer relaxation concerns?

It just boggles my mind that the modern synthetic can work in a 650 hp ISX or C15, yet can't protect a 318 hp 8V71. The journal bearing stresses on the modern turbo diesel is got to be much higher than the old Detroit. Perhaps modern high performance synthetics simply weren't around when GM did testing and certification for the 2 strokes?

Having said all that, I do run 40wt, simply because I can get them for $40 a 5 gal pail. But I sure like to try and explorer the benefits mentioned by Dan. Even if my engine life is reduced, my bus will probably rot before it needs a rebuilt!

itspaidfor · November 07, 2014, 11:41:01 AM

Roy thanks for the reply the only thing I will add is starting on a cold day & going down the road is totally different than it was before. Lots more power does'nt lope when cold starting no smoke I can stand at the back of the coach & my eyes don't water LOL! You are correct the oil I use has a higher shear number than delo 100 40 wt. The hardest thing on the old green detroits is starting cold causing fuel dilution (white smoke). Also fuel pump lubrication keeping those injectors free & spraying correctly......Dan