CHip tuning a 98 300D - PeachParts Mercedes-Benz Forum

roane3 · #1 06-27-2007, 08:57 AM

Please give me some insight on chip tuning a 98 300 d. I would like some real world feedback on power and fuel economy.

The chip I am considering is a www.speedtuningusa.com chip.

Thanks,

roane3

#2 06-27-2007, 11:39 AM

Check out THIS and THIS.

TMAllison · #3 06-27-2007, 12:14 PM

UBERWGN and MDISAV both have that chip.

aklim · #4 06-27-2007, 01:27 PM

So does AKLIM.

Doing 85 cruising, I get about 33 mpg and the power is much better.

dukegrad98 · #5 06-27-2007, 10:21 PM

Wow... Aklim's post makes me think I need to reconsider. I opted not to chip after getting mixed advice in a similar thread a while back. I can't even get 33mpg at 70mph right now, nevermind 80+! For me, some added power would be nice, but added efficiency is much more valuable -- I bought this to cruise and put miles on, not race. Sounds like I could pick up both...? Hmmm.

More things to ponder, lose sleep over, and save up budget for I guess...

Cheers, John

aklim · #6 06-27-2007, 10:24 PM

We are talking of a day in Mid may with the cruise control on. I'm quite sure I could get more if I was doing say 65 or less because of the wind resistance. Fuel used is measured pretty accurately. I wait till it clicks off and pump in about 3 more gals. That and some rocking is about all the tank will take before it spills out.

79300sdtd · #7 06-27-2007, 10:49 PM

Quote:

Originally Posted by aklim

I wait till it clicks off and pump in about 3 more gals. That and some rocking is about all the tank will take before it spills out.

that is the fill method i use too

dukegrad98 · #8 06-27-2007, 11:44 PM

Wow, by the time the auto-shutoff feature on the diesel pump clicks off, I very nearly have fuel spewing out of the filler neck. Odd that yours will take another 3 gallons from that point! And mine is definitely full -- it pegs the gauge at auto cutoff and the needle doesn't budge until I've driven about 50 miles.

I'm burning B99, so I expect slightly lower mileage than D2, but I haven't cracked 30mpg yet, even at 70mph with cruise on. Lots of AC running this time of year down here, but still...

Cheers, John

TMAllison · #9 06-28-2007, 01:53 AM

Mines like yours John...I get 2-3 more clicks after it auto shuts off and maybe 1/4-1/2 gal more into the tank. AKLIM has his fill neck reamed out and was using the semi truck pump the last i read so gets lots of air mixed in because of the excessive flow rate; therefore it will take more in after it settles and bubbles escape.

I doubt you would get "better" mileage with a chip; afterall, they are not designed to be miserly......

nhdoc · #10 06-28-2007, 05:58 AM

The '99 had an EPA highway estimate of 36 MPG while the '98 was 34 so there was a difference between the cars - I heard some where it had something to do with the camshafts.

AKLIM has a '99. Mine is a '98, unchipped, and I have been getting low 30's on the highway with it at speeds in the 75-80 range with A/C on. I don't see how chipping it could improve fuel economy any...but without an A/B test on the same car it is impossible to say one way or another.

I have no complaints about the power of my '98 unchipped...I'm a fairly agressive driver but don't need a car that can go 0-60 in 8 seconds, 9.5-10 is fine. I'd considered doing it, but I am a big believer in "if it ain't broke, don't fix it" and there's enough broke on these cars of mine sometimes to keep me busy enough

aklim · #11 06-28-2007, 07:00 AM

Quote:

Originally Posted by dukegrad98

And mine is definitely full -- it pegs the gauge at auto cutoff and the needle doesn't budge until I've driven about 50 miles.

I'm burning B99, so I expect slightly lower mileage than D2, but I haven't cracked 30mpg yet, even at 70mph with cruise on. Lots of AC running this time of year down here, but still...

Cheers, John

Same here.

When I ran bio, I lost mileage. See what you get after running a couple tanks of D2

aklim · #12 06-28-2007, 07:04 AM

Quote:

Originally Posted by TMAllison

AKLIM has his fill neck reamed out and was using the semi truck pump the last i read so gets lots of air mixed in because of the excessive flow rate; therefore it will take more in after it settles and bubbles escape.

I doubt you would get "better" mileage with a chip; afterall, they are not designed to be miserly......

I had it reamed out so I can use the semi truck pumps. However, it doesn't seem to make a difference in this sense. I can squeeze 3 more gals into in whether I use the small hose or the large one. This was also true before I had it hogged out.

You don't if you can't keep your foot out of it. It seems a little better if you are doing straight cruising with the cruise control set for the most part. Now if you floor it, you get black smoke which tells me that you are having unburnt fuel.

On a side note, Oliver from speedtuning told me that you can lengthen the rod of the wastegate so you can get more boost when you need it.