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| | | Re: Dumb question about improving gas mileage | Joined: Aug 2005 Posts: 21,211 Likes: 25 Supreme Master | Supreme Master Joined: Aug 2005 Posts: 21,211 Likes: 25 | Wow Reed..why don't you come out here and dial my 85 in?
Nate Breece | | | Re: Dumb question about improving gas mileage | Joined: Aug 2001 Posts: 12,107 Likes: 37 Maniac | Maniac Joined: Aug 2001 Posts: 12,107 Likes: 37 |
Windows- they're what make a van worth owning! | | | Re: Dumb question about improving gas mileage | Joined: Oct 2007 Posts: 1,317 old hand | old hand Joined: Oct 2007 Posts: 1,317 | My mileage has worsened since developing exhaust leaks from every possible point that can leak before the cat, I assume it's affecting the O2 sensor readings. 9MPG city, 13-14 highway with a 3.9 but I'm not fixing any of them since I'm working on a 318, but if you have exhaust leaks try fixing them.
In search of the illusive prairie lobster "If you dont stand behind our troops feel free to stand in front of them" | | | Re: Dumb question about improving gas mileage | Joined: Aug 2001 Posts: 12,107 Likes: 37 Maniac | Maniac Joined: Aug 2001 Posts: 12,107 Likes: 37 | Verve- Actually, I say fix the leaks AND replace the cats- most likely they are clogged and/or have failed internally causing excessive backpressure. Universal fit high-flow catalytic converters are reasonably priced these days. If you can afford it, go with 2 1/4 inch line all the way back and get some free flowing mufflers too.
I have heard the late 80s/early 90s Mopar TBI systems are terrible as well. You might actually do better mileage-wise with a carb.
Windows- they're what make a van worth owning! | | | Re: Dumb question about improving gas mileage | Joined: Apr 2009 Posts: 29 newbie | OP newbie Joined: Apr 2009 Posts: 29 | Reed, I don't have a 318 or 360, but a 400 big block, any changes to your advice? Thanks.
- Pete vanlivin.com
| | | Re: Dumb question about improving gas mileage | Joined: Aug 2001 Posts: 12,107 Likes: 37 Maniac | Maniac Joined: Aug 2001 Posts: 12,107 Likes: 37 | Wow, that makes it worse. Okay, what that really changes is my tranny recommendation. No automatic four speed with overdrive was ever offered for the big bloxk, so you are stuck with your stock 727. But you can still tweak it like i said- remove the accumulator spring, back out the line pressure screw.
I still recommend a Offy Dual-Port or Edelbrock SP2P intake, but for a carb I would say get a thermoquad or get an Edelbrock performer, 500 CFM with the electric choke. I would recommend the dual port over the SP2P however. You might still be able to get away with using the Holley 4360 carb, but it flows 450 CFM and is a spread bore carc. That might be too little air flow for a 400, but if you are building for low RPM torque it might do just fine.
Windows- they're what make a van worth owning! | | | Re: Dumb question about improving gas mileage | Joined: Aug 2001 Posts: 12,107 Likes: 37 Maniac | Maniac Joined: Aug 2001 Posts: 12,107 Likes: 37 | Also, swapping to an "RV" cam or a cam designed for low RPM torque and HP would help.
Windows- they're what make a van worth owning! | | | Re: Dumb question about improving gas mileage | Joined: Oct 2006 Posts: 78 journeyman | journeyman Joined: Oct 2006 Posts: 78 | now this question is for super beast. Just like putting a taller tire on the rear wouldn't that increase your gas mileage tremendously by itself? I mean then you would always be running downhill! | | | Re: Dumb question about improving gas mileage | Joined: Oct 2007 Posts: 1,317 old hand | old hand Joined: Oct 2007 Posts: 1,317 | Is the a518 not an over drive version of the 727?
In search of the illusive prairie lobster "If you dont stand behind our troops feel free to stand in front of them" | | |
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