GDE fuel economy

LibertyCRD · **Posted:** Thu Apr 22, 2010 7:46 am

I could point you to the right direction and write volumes on why the information you posted is wrong...but this was meant to be a thread about GDE and fuel economy...so I won't sidetrack my own thread.

Rixram · **Posted:** Thu Apr 22, 2010 8:04 am

geordi wrote:

You will be replacing your turbo (before the air filter) with oil that heavy. Too heavy to lube the turbo properly, especially when cold. The lack of cold oil lubrication is what killed my turbo, followed rapidly by the engine b/c I didn't know what had happened when it died. Also, making your pistons slog through that stuff will NOT "help your compression" but what it WILL do is destroy your existing MPG to the tune of losing another 2-3mpg at a minimum.

Short story: GET THAT OIL OUT OF THERE ASAP. It cost me $8000 to learn that lesson. You just got a bargain for it: the cost of an oil change.

As for the rest...

Where do you figure that 38psi is "too much" for the tires? Do you have 35-psi sidewall max Goodyear passenger CAR tires? I'm running 215/85/16 BFG tires, sidewall max is 80psi, I generally run them around 60. You need more air or better tires... Probably both, and then you will see some better economy from that. Tall and narrow is the way to go.

Lose that stock muffler PRONTO. It is a 60-lb sandbag under your CRD, and a Flowmaster from Advance Auto will give you MUCH better performance, the same quiet, at only about 15 lbs.

Well, it looks like I'll be doing an oil change tonight, then. Is there an oil safe to use to decrease blow-by?

Rixram · **Posted:** Thu Apr 22, 2010 10:13 am

stoutdog wrote:

CATCRD wrote:

So you re-routed crank case fumes to go through your air filter? It's going to get wet, oily and messy in there. Check it soon.

x2. You're going to ruin your air filter in no time... And I wouldn't run 20w-50; not when the service manual specifically states 0w-40 or 5w-40. That is far too significant a change for me...

Yes, I'll change the oil tonight. I'd still like to decrease the blow-by. What oil do you all recommend that would decrease that?

As for the air filter, I made a mod on the inside of the air-box to catch the oil coming on the "In", and have it collect into a "bilge diaper" (marine cloth designed to absorb oil) which I firmly secured to the bottom of the air-box to collect the errant oil.

Anyone know what the K&N air filter part number is for the CRD?

geordi · **Posted:** Thu Apr 22, 2010 10:23 am

The oil I use (Mobil 1) is great, but I think I know why you are having issues with "blow by" getting into the CCV - It isn't so much that the oil is getting past the cylinders, it is that you have too much oil.

The dipsticks on our CRDs (both of them I'm afraid) aren't that accurate. Many people have had to completely drain the oil, measure out the (IIRC!) 6.5 quarts that an oil change is supposed to take, and mark the correct level with a scratch on the dipstick. The factory level of "full" is wrong. If you have too much oil in the engine, it will slowly return itself to a proper level by ejecting that excess through the CCV. Right into your intake. An EHM mod will fix the oil entering your intake, but not the underlying cause - too much oil.

I would not use the K&N filter either - Too much gets through those.

Again, I use my blown engine as the example. The oil passages on this engine are TINY. The tolerances are equally small... Do you want to risk it with air that isn't as clean as possible?

I've compared both the FRAM and the Purolator air filters, both have lots of pleats and deep channels to filter the air. I went with the Fram b/c it is made in Canada instead of China, so I have a reasonable belief that the Fram will filter more effectively below the level of what I can see. The CRD has been running fine with that. For oil, be sure that you are looking at the API seal on the back to KNOW that it is rated for our engines. We take a CI-4 or higher rating (i.e. CJ is a higher rating than CI-4) and 0w-40 or 5w-40 full synthetic. Mobil 1 Turbo Diesel Truck is a properly rated choice for us, and available at most auto parts stores.

stoutdog · **Posted:** Thu Apr 22, 2010 12:42 pm

x2 to what Geordi said; except, I would recommend getting an Amsoil reusable air filter. They cost about $30, but are rated for 100k miles of use and successfully filter out the particles that make it through other filters (i.e. K&N).

Hydraulic Jack · **Posted:** Fri Apr 23, 2010 6:23 pm

My first time I'm able to do a mileage check.......It was done manually and city only driving.....22.6 mpg! That's about a 3mpg increase........HJ

LibertyCRD · **Posted:** Fri Apr 23, 2010 6:45 pm

Tonight I am beginning an experiment. I removed my stock muffler and tailpipe at the flange. This is essentially a straight pipe now for all intents and purposes. Going to see if it makes any difference in mileage and if I can find that magical 3 MPG gain that others are seeing.

geordi · **Posted:** Fri Apr 23, 2010 8:32 pm

How is the noise difference? I didn't like it b/c the sound echos off the road and the underside of the truck. I went with a 2.5 inch straight pipe from turbo back, Flowmaster muffler, and then kept the stock tailpipe behind the muffler b/c that really isn't causing any restrictions...

I think you will like the ability to coast now. The stock muffler really causes too much backpressure.

stoutdog · **Posted:** Fri Apr 23, 2010 8:44 pm

geordi wrote:

How is the noise difference? I didn't like it b/c the sound echos off the road and the underside of the truck. I went with a 2.5 inch straight pipe from turbo back, Flowmaster muffler, and then kept the stock tailpipe behind the muffler b/c that really isn't causing any restrictions...

I think you will like the ability to coast now. The stock muffler really causes too much backpressure.

x2. And be sure to use that extended coasting ability. I'm fairly certain that removing the muffler itself does very little to increase fuel economy, as you are only losing a few lbs and a little restriction. It's the ability to coast looooong distances to red lights that, when utilized to its fullest extent, enables you to get those higher mpgs.

LibertyCRD · **Posted:** Fri Apr 23, 2010 9:57 pm

^
That's my face during the first drive with the muffler and tailpipe removed.

I've done a ton of things to a ton of different vehicles in my life....and I have never noticed such a seat-of-the-pants feel like what I noticed tonight. With the muffler gone, this thing seems to have endless torque. It just rushes on and pulls and pulls and pulls. :shock:

When I straight-piped my other CRD I did not see this kind of improvement.

With the Euro TC, GDE HOT tune, no engine fan, and no muffler/tailpipe...this thing is finally starting to wake up! :shock:

My EVIC climbed 1.5 MPG during my 20 mile test trip...and that was with me playing on the accelerator some.

There is no drone. You can tell there is extra noise above 65 MPH. Below 65 it's not very noticeable. With the radio on, can't even tell the muffler is gone. I still am not crazy about the ricey sound outside the Jeep...but this is, afterall, an experiment just to see what would happen.

dieseldoesit · **Posted:** Sat Apr 24, 2010 1:34 am

I don't know man. Isn't this like the opposite of everyone else? Didn't most people not notice much of an improvement with the muffler, but noticed a big difference with the hot tune?

Was something screwed up with your exhaust? Banana in the tailpipe maybe? lol

Just seems odd is all. Good on you for finding your hidden MPG and HP though.

racertracer · **Posted:** Sat Apr 24, 2010 5:15 am

The best thing I have ever done to this CRD was to replace the restrictive big azz muffler with a 2 1/2"one so the engine can breathe, the difference was significant.

The engine quieted down, no more noise from the engine compartment, it responded quicker and the miles per gallon went up.

Rixram · **Posted:** Sat Apr 24, 2010 9:11 am

Hey, I fixed my oil issue. NAPA had the Mobil-1 0w-40 I needed. Next up: glass packs.

Hey, I really like that Fuelly tag a lot of you have. Surprised that not everyone here is doing i. Must be a "Cool Kids" thing...
:lol:

GDE fuel economy

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