How much better mileage, CA to Fed conversion, '85 300D?
 

I would like to hear from anyone who has removed the trap cat from his/her 1985 300D. What improvement in fuel economy did you see? Not theoretical numbers or EPA numbers or "hoped for" numbers but actual before and after miles per gallon numbers.

My "test pipe" installation is still so new that I don't have any numbers to share with the prospective buyers of my car. All I have are two years of data with the trap cat: around town on B100 biodiesel, about 21 MPG. On the road, mostly D2 with some biodiesel, 24 MPG with a high of 26 once when I tried driving 65 mph (dangerous, nearly got squashed by the trucks :eek:).

With the trap cat now replaced by a test pipe, running B20 because B100 has gotten so expensive, I would expect to see 23-24 around town and 27-28 on the road. Lacking any experience with a Federalized '85, I ask you to share your data.

Jeremy

Well, all I can offer is what my wagon gets as a 1985 Federal. All it's ever been.
And today I filled up and I might be on to something with my wagon. Here's the short long version.
Bought the wagon in '05 and I can swear I got a couple of tanks at 28mpg. But for the last 3 years it has been 22 after 22 after 22 with the occasional 19 or 20! :eek: :mad: Never over 23 I don't think.
Well, today I filled up and was just a few hundredths from 27mpg! What did I do different? Well, I just swapped the tires and wheels with the Squash! The wagon immediately quit pulling to the right {hard too} and the Squash immediately started to. I had rotated the tires before front to back on each side but it made no difference.
I swapped the tires because one was literally flying apart. Had a huge knot in it and several 4-6" splits in the sidewall. :eek: Got really lucky on that.
But I will have to monitor the fuel consumption for awhile to verify, but this was immediate and I haven't been close to it since the first 2 tanks.
What did I do after the first 2 tanks? I put those stinkin' tires and wheels on the wagon from my '77 parts car. {steelies and hubbies}
So, that is the short long version of a Federal's fuel mileage. Hoping for 27-28 with the AC on in mixed highway/city driving, but been at around 22 prior to this.
Your results may vary......;)