Gas mileage survey and discussion - Page 5 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #61 (permalink)  
Old 09-06-2007, 12:02 AM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
454...note that my diesel is a 99...a 2nd generation and a 5 spd. not a 3rd gen. 6.7. These get considerably better mpg. I do have records for the last 10k+ of every drop used and every mile operated. Matter of fact I have several spreadsheets covering all costs of operating.

Many guys with similar trucks get even better when driven sensibly.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #62 (permalink)  
Old 09-06-2007, 08:01 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 24 Times in 24 Posts
That is what I was thinking. That is why I listed the test truck specs. I guess there is no perfect upgrade. More power and tech from the newer engine but worst mpg. I think I would prefer the better mpg.
Reply With Quote Quick reply to this message
  #63 (permalink)  
Old 09-06-2007, 09:09 AM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
I've added a Smarty. This is a good mpg improver and 50 hp power adder. On the mpg setting it really helps around town. Highway I find the SW 3 works better. It's a great downloader. SW3 works great towing. probably 2 mpg improvement. All based on proper driving of course.

Next are the RV injectors worth about another 50 hp and 1-2 mpg.

With this combination many guys with 3.54 gears get 23-24 unloaded even driving 65-70. I've heard even better but I'd have to see it first. My truck weighs 7800 with the junk in it and I'm considered a lightweight.

The power adders are so addictive that many get worse mpg because they can't keep the right foot out of it. haha

Nothing like smoking all 4 rear tires while pulling a trailer. haha.

My main interest is mpg around town so I plan my changes carefully to help this and drive pretty conservatively. Actually the 4.10 gear is better in town as I can easily keep the motor at 2000 rpm which is the real sweet spot.

The 3rd gen Dodge has extra injection events for each firing of the cylinder. This is to help quiet the motor and make the burn smoother. But it uses more fuel in the process so worse mpg.
Reply With Quote Quick reply to this message
  #64 (permalink)  
Old 09-11-2007, 11:32 AM
ChevelleSS_LS6's Avatar
Jeep XJ and a Javelin
 
Last wiki edit: Compression test
Last journal entry: August 9, part III
Last photo:
Join Date: Dec 2001
Location: Grand Rapids, Michigan
Age: 29
Posts: 1,610
Wiki Edits: 7

Thanks: 3
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by strummin67
19-20. That's about what I get with my stock 6 banger Nova wagon-with all 6 cylinders firing.
same with my 1996 Jeep, 4.0HO with enlarged airbox hole and a 2.5" exhaust.
Reply With Quote Quick reply to this message
  #65 (permalink)  
Old 10-24-2007, 04:15 PM
Berliner Bel Air's Avatar
Beyond the Sea
 
Last photo:
Join Date: Feb 2004
Location: Berlin, Germany
Age: 52
Posts: 171
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
This thread is just up my alley I love tuning my ol' 55 Chev and 55 Roadmaster for mileage. That's been the case since I was a kid in Canada and could hardly afford the gas for my 69 Olds Cutlass (which was a 350ci, Turbo 350 trany, highway gears and Q-jet). That car got 19 mpg on the highway at a steady 70-80mph. Gas was always quite a lot more expensive in Canada than in the USA.

When I bought my Bel Air back in '98 it only got 10mpg with a worn 283. Its been a long, slow process but I just achieved 21 mpg on a long Autobahn drive in Sept. a new all-time best at 55-60 mpg. Then I retuned the idle and acheived 22 mpg last week . I'm not finished yet, my ultimate goal is 24-25 mpg.

Here's what it has: 283, 9.1 CR, Performer intake, Comp Cam 240H, Vortec 305 cylinder heads, 1 5/8 headers, 2004R, 3.73:1, Q-jet from '84 with the APT function (very cool way to tune cruise!), HEI, warm air filter housing with hot air ducting to headers and cool air duct to area behind grill - this was a big mileage and driveability improver - dual exhaust, 40 psi on the tires, car weighs 3800 lbs. When I installed the new engine 3 years ago I considered a roller cam, but it would not have been economic to do so. Same with fuel injection (plus I don't like electronic stuff). The overdrive got me nothing mileage-wise. It did get faster and more comfortable though.

This combo still has potential for improvement. I think the headers hurt mileage. A little more back pressure would keep the intake charge from leaking out into the exhaust in the valve overlap phase (any thoughts on this?). I'm going to switch to a higher temp thermostat, remove the mechanical fan (I have an electric one already installed), recurve the distributor more, install a vacuum guage and an MSD variable timing device (to discover where timing should ideally be at any given speed, when used with vacuum guage). An MSD 6 ignition with high end coil and plugs will allow an even leaner burn at cruise. I just bought a wide band o2 LM-1 to tune the power and cruise circuits optimally. Probably will switch to synthetic motor oil, diff and tranny already are.

The 55 Roadmaster ist a huge beast. It has a 350 Chevy, 350 trany, Performer intake and Edelbrock carb. It got 13 mpg when I bought it in March this year. After changing the vacuum can, adjusting the timing, leaning out the carb it gets 19 mpg! Once I put on a Q-jet it will get 21 mpg. When I compare the two cars I imagine the Buick is very close to optimal, but the Chevy should be able to get significantly better mileage, being a smaller, lighter car with a smaller engine.

With gas at $5 already 3 years ago I started posting and reading and learning a lot right here. Now gas is $7.50 here in Germany and I'm glad I've been working towards better mileage all this time. As the prices keep going up more and more of us (especially you Americans) will start building and tuning their cars with a more balanced mix of performance and mileage in mind.

I would like to see a category for mileage freaks here, any takers?
Reply With Quote Quick reply to this message
  #66 (permalink)  
Old 10-24-2007, 04:46 PM
mopar34's Avatar
Registered User
 
Last photo:
Join Date: Oct 2007
Location: Stewartstown, PA
Age: 68
Posts: 27
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
My 34 Plymouth has a 350/350hp sbc with a TH400 and a 2.73 rear (vette) and gets about 12 in town and 15 hwy. Another source of my low mpg is I am currently running an Edelbrock Torker I single plane intake (3500 - 5500) and a 600 CFM carb. I need to replace it with a Performer dual plane intake and upgrade to a 700R4 which should boost my hiway mpg to about 20.

My 57 Olds has the original 371 big block with the J2 (3 deuces), and hydramatic 4 speed tranny. This beauty is currently getting 7.3 mpg around town and about 10 on the hiway . A fresh tune up on tune up will probably boost mpg to 9 and 12 respectively. Other than that a fresh 455 (or a new 502) with a 700R4 is my only other hope. Hope is the key word here, because I don't see the 371 J2 going anywhere anytime soon.
Reply With Quote Quick reply to this message
  #67 (permalink)  
Old 10-24-2007, 07:47 PM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
Berlin...That's a remarkable improvement in mpg. You've done about everything right. Even to the tires. Congrats on a god job. Question...how come your 55 BelAir is so heavy?? I never had a BelAir sedan that weighed over 3400. The wagons and Nomad might go 3500. Even my 57 2dr 210 only weighed 3325. Heater only.no a/c 4spd.

I love the 55-60 mph. When I can do this I get 23+ with my big 1 ton dually diesel. I just got 18 even pulling 11k on and open trailer. Funny thing it was a buddy's 3/4 ton suburban with a diesel and I got better towing him than he gets cruising under his own power.

You might try using a vacuum gage and try for max vacuum as much as possible. You ought to be able to squeeze a bit more tuning with the 02. You should be able to see what happens when the od kicks in. Might surprise you.
Reply With Quote Quick reply to this message
  #68 (permalink)  
Old 10-25-2007, 08:08 AM
Registered User
 
Join Date: Sep 2007
Location: Grand Rapids, MI
Posts: 88
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Berliner Bel Air
Here's what it has: 283, 9.1 CR, Performer intake, Comp Cam 240H, Vortec 305 cylinder heads, 1 5/8 headers, 2004R, 3.73:1, Q-jet from '84 with the APT function (very cool way to tune cruise!), HEI, warm air filter housing with hot air ducting to headers and cool air duct to area behind grill - this was a big mileage and driveability improver - dual exhaust, 40 psi on the tires, car weighs 3800 lbs. When I installed the new engine 3 years ago I considered a roller cam, but it would not have been economic to do so. Same with fuel injection (plus I don't like electronic stuff). The overdrive got me nothing mileage-wise. It did get faster and more comfortable though.
So which was your big mileage improver, the hot and cold air ducts or the dual exhaust?
Reply With Quote Quick reply to this message
  #69 (permalink)  
Old 10-25-2007, 09:01 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 24 Times in 24 Posts
I've heard cold air induction can hurt mpg. Hot air helps vaporize the fuel which allows for a leaner and more even distribution. Don't know for sure because I have never done a "before and after" test with my cold air system.

Headers should help mpg but air/fuel ratio needs to be adjusted to compensate for the headers.

I recently switched over to a Q-jet and picked up 25% better mpg over a holley 750 (3310, vacuum secondary). Q-jets are much more tricky to tune and takes a little time to figure them out. Performance and MPG can both be good with a Q-jet but tuning is critical.

50 to 55 degrees of timing during light loads will help mpg. An overdrive may have reduced overall timing because the rpms are lowered. An efi system with ignition timing control would be best. A lock up converter will also help a lot.
Reply With Quote Quick reply to this message
  #70 (permalink)  
Old 10-25-2007, 09:17 AM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
454.. I think what you are meaning is to use vacuum advance. The od itself won't reduce the vacuum. If the OD is on at too low of rpm you will have to step on the throttle more to maintain speed, IE request more power from the motor thus reducing the vacuum as the load increases. You can clearly see this with a vacuum gage connected to direct manifold vacuum.
Reply With Quote Quick reply to this message
  #71 (permalink)  
Old 10-25-2007, 10:44 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 24 Times in 24 Posts
Yes, the OD will make more load on the engine and could reduce the amount of vacuum advance. But also, since the rpms are lower, the total mechanical advance may not be all in. So if you are driving at 2000 rpm at 60 then the total mechanical advance most likely isn't all in. Most old school sbc's need 50 to 55 degrees of timing while driving down the highway. Could account for no MPG improvements with the OD.

I had a friend that connected a choke cable to the vacuum advance. This allowed him to adjust the advance to achieve max efficiency while driving down the highway. He would drive at 60 mph on a flat road then hold his foot in that position then adjust the timing with the choke cable to get a several more MPH's at the same throttle input. Could be fun to play with something like that.
Reply With Quote Quick reply to this message
  #72 (permalink)  
Old 10-25-2007, 01:44 PM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
You are right about that on all points. A much quicker mech advance is probably in order. My old 265 and 283's all ran about 38 t0 40 deg mech all in by 2400 max. I don't remember the vac but I think they were about 12 deg.

For BelAir... If you are not aware of it there are adjustable vac advance unit for the after market. My MSD has one.

I think it is really cool to tune for max economy. It would be nice to see 350 hp and 25 mpg in a "55 shoebox". You see it in the 'vettes all the time but then again they have probably only 1/4 of the aerodynamic drag at 60 mph and probably less than 10% at 75 mph of a 55 BelAir.

We complain about the high cost of gas and diesel fuel but in reality it is more fun to suck up a couple gallons of fuel and leave 5000 miles of burned rubber on the highway. Worry about the cost later. Heck. it's only $6 for gas and $25 for tire wear. Pretty cheap intertaiment here. haha
Reply With Quote Quick reply to this message
  #73 (permalink)  
Old 10-25-2007, 02:35 PM
seriousracer's Avatar
be a man dodge tree bark!
 
Last photo:
Join Date: Feb 2007
Location: south bend in
Posts: 167
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by 454C10
Yes, the OD will make more load on the engine and could reduce the amount of vacuum advance. But also, since the rpms are lower, the total mechanical advance may not be all in. So if you are driving at 2000 rpm at 60 then the total mechanical advance most likely isn't all in. Most old school sbc's need 50 to 55 degrees of timing while driving down the highway. Could account for no MPG improvements with the OD.

I had a friend that connected a choke cable to the vacuum advance. This allowed him to adjust the advance to achieve max efficiency while driving down the highway. He would drive at 60 mph on a flat road then hold his foot in that position then adjust the timing with the choke cable to get a several more MPH's at the same throttle input. Could be fun to play with something like that.
he could have don that better with the msd timing knob... that how i did it..52 degrees total going down the road.

full roller 408 with a 4speed NO clutch fan in a 1980 3/4 ton truck 17 to 18 depending on the speed i drive...anything ove 70mph i do pay for it..
Reply With Quote Quick reply to this message
  #74 (permalink)  
Old 10-25-2007, 02:43 PM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 24 Times in 24 Posts
Yes, msd knob is better. The cable was used before msd. Maybe 20 years ago now. Man times go by fast.
Reply With Quote Quick reply to this message
  #75 (permalink)  
Old 10-25-2007, 05:31 PM
Berliner Bel Air's Avatar
Beyond the Sea
 
Last photo:
Join Date: Feb 2004
Location: Berlin, Germany
Age: 52
Posts: 171
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
My Bel Air is really overweight: about 80 lbs. roll of tarpaper under the carpets and seats to make it real quiet (maybe I should take it out again...), a conti kit (maybe 50 lbs.), a big heavy welded in trailer hitch (60lbs?), AC, Stereo, cruise, fire extinguisher, alarm, steering wheel locking bar, tool box, fenderskirts, all available trim and accessory bumpers, all-in-all about 400 lbs. of extra fat.

I've ordered that MSD knob and a vacuum guage already. I'll use it just like described, get on a flat open road and adjust the cruise timing to get the max. vacuum at a steady speed. It won't be at 50 degrees, for sure less. Recently on a hunch I reduced the max. advance from 52 deg. to 45 and picked up nearly 2 mpg. That's what got me looking for a way of determing the absolute best timing for my combo.

My car always had a dual exhaust, the warm air intake I just recently installed (see pic). This is an old hat thing, it was used from the mid 60's till about the end of the carb days. The version I use came off a 77 Chev pickup, it has a hose that I've run up behind the grill for some (slightly) pressurized cold air. This gets mixed with some hot air from the header area via a air duct hose. Result is that the carb gets a supply of air at a constant temp. of about 100F. This allows a very precise, lean mixture without encountering drivability problems, or having to run too rich. It doesn't stumble when cold, and is quite lean at low throttle. Mileage picked up by about 2 mpg as a result of the leaner tuning, which is only now do-able.

My Chev has a lock-up with the OD. The Buick has neither (which makes it all the more surprising how good on gas it is...)

Edit: I have Vortec 305 heads on the Chev, thats probably why I need LESS vacuum advance.
Attached Thumbnails
Click image for larger version

Name:	motorraum.jpg
Views:	104
Size:	34.2 KB
ID:	25082  
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 01:27 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.