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#1 |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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Answers about my 17 mpg in my Burb.
I have had a few people PM me about how I am getting 17 mpg in my burb. I posted the following to a question on my Gas tank for sale post. I thought I would post it here so it would be easier to find:
L-48 350, HEI, Plugs gapped at 60, Timing set by ear, 1406 Edelbrock carb leaned 2 steps on the chart in the book, 5w30 motor oil, turbo 400 Trans, 3.08 rear end, Accel 2 stage oil charged air cleaner. 55 lbs of air in the tires that don't have an agressive profile. Things that I am going to try next: 0w30 ynthetic motor oil, syntetic gear lube. Fumigating the fuel with propane. Vortec Heads. Huck has basically the same set up as me, but has a 5 speed stick and is getting 20 mpg. Here is a link to jku72 post. He is getting over 18 mpg: http://67-72chevytrucks.com/vboard/s...threadid=53670 __________________
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Just sitting here contemplating contemplation. Last edited by 68 Suburban; 05-28-2003 at 09:49 AM. |
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#2 |
Registered User
Join Date: May 2003
Location: Shreveport LA
Posts: 3,170
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link didn't work
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#3 |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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The link should work now.
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Just sitting here contemplating contemplation. |
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#4 |
Registered User
Join Date: Jan 2002
Location: cornville, maine
Posts: 659
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If you swap a Quadrajet in instead of the Edelbrock 1406, you will likely see better results. The Quadrajet, if it can be made to operate correctly, has small primaries, which give superior mileage than the rather large primaries on the edelbrock. The Edelbrock has a maximum of 600 CFM, the Q-jet, with secondaries, is 750, for better max power flow as well.
What exhaust are you running?
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jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers |
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#5 |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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I down sized the primary jets on my 1406. My exhaust is ram horns with regular dual and a cross over. Please dont tell me headers
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Just sitting here contemplating contemplation. |
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#6 |
Registered User
Join Date: Jan 2002
Location: cornville, maine
Posts: 659
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I think that the crossover helps a good deal. Did your headers leak? That is a common problem, which I think I solved in an unapproved, unscientific way.(on my longhorn) I just took the header bolts, and with a single sharp blow, hammered the threads, so that they were peened on one side. They haven't loosened in 2 years of operation. My burb has a junk puny single exhaust, and am thinking of a new system. I am thinking of trying small tube headers, crossover, and 2" twice pipes.
I mentioned the edelbrock thing because no matter how you jet it down, you can never achieve the venturi velocity with a higher primary CFM carb like the edelbrock. The drawback to the Qjet is that it can be a big Pain in the butt if it isnt right, whereas the edelbrock is way easier to work with. Do you think a cold air induction is worth the hassle? Any idea of the effects of using a little extra of the methanol based drygas? I'd like to see if it affects things in a positive way. I run my burb on the highway as well, and am keen to boost the mileage to the max. I even contemplate 2.76 gears, since I have a low first gear that I never use. What Torque converter are you using? A really tight one should help a little as well.
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jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers Last edited by jku72; 05-28-2003 at 09:45 AM. |
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#7 |
Senior Member
Join Date: Jul 2001
Location: Muskegon,MI,USA
Posts: 6,026
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68 Suburban,
That is great mileage for a Burb. I can see that you are doing fundamental things to get the mileage up there and I am glad to see it working out. My son is hoping that is Burb will get 16 mpg, (72 with 350/350 and 4x4. Jim |
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#8 |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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I hate headers because they do losen up, but more so, because of the under hood heat that is generated. Screws up staters, wires, my hands....lol. I really dont think the benifits are there for a daily driver. Im not driving a high performance sports car here :p
I think cooler air can help, I don't know how much though. And yes I like the edelbrock for its simplicity. I can adjusted or change things in under 3 minutes. It is nice to be able to make these adjustments when I need to tow something.
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Just sitting here contemplating contemplation. |
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#9 | |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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Quote:
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Just sitting here contemplating contemplation. |
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#10 |
97' Tahoe 2dr/2wd
Join Date: Jul 2002
Location: Huffman,TX
Posts: 1,168
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what type of gears do you have in the rear end for this gas mileage?
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#11 | |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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Quote:
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Just sitting here contemplating contemplation. |
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#12 | |
Life is Good !
Join Date: Mar 2002
Location: Hollister, Ca.
Posts: 1,992
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Quote:
68 Suburban, you could always have the headers coated. Just an idea. I am trying to get my wifes 71 C-10 350/350 to get better fuel milage also. I would like to get 18MPG. Good job. Landon
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'72 Chevy C10 4x4 shortbed "Project" '71 Chevy C10 2wd longbed "partsrunner" '91 Chevy Burb 4x4 "kidrunner" '14 Honda Accord Sport "commuter" |
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#13 |
14.1 @ 96MPH
Join Date: Jul 2001
Location: Mesa, AZ
Posts: 2,811
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0w30 in Phoenix would scare me...but then again, it is Mobil1.
You need overdrive, man. ![]()
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#14 | |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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Quote:
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Just sitting here contemplating contemplation. |
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#15 |
Member since 2000
Join Date: Dec 2000
Location: Mountain View Ca / Mexico
Posts: 7,879
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have you thought about a MSD?
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#16 | |
14.1 @ 96MPH
Join Date: Jul 2001
Location: Mesa, AZ
Posts: 2,811
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Quote:
![]() I think the bottom end is pretty good aside from liking 20w50 to keep the pressure normal. I used to have to dump in a quart every hundred or two miles; turns out the heads must've been sucking it through the valveguides or something, because since the Vortecs, it's down to a quart every 1000 or so.
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#17 |
Registered User
Join Date: Apr 2000
Location: Frisco, Tx, USA
Posts: 606
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I always thought that an O2 sensor in the exhaust stream (and the resultant data you can aquire) would be the way to tune for mileage, that way you can get even closer to the optimal mix for your style of driving.
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http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades. |
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#18 |
Senior Member
Join Date: Aug 2002
Location: Valley Center KS
Posts: 3,525
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That's it, I'm going to rejet my edlebrock. I've been thinking of jetting down (was thinking just one step though) since christmas. I just haven't gotten around to it. I'm getting like 11 mpg on the highway.
Good thing my truck isn't my daily driver. I'll post my results when I get them. I too have thought of the O2 sensor to tune, both for performance and economey. It wouldn't be that hard. Hmmmm ![]() |
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#19 |
Registered User
Join Date: Jan 2002
Location: cornville, maine
Posts: 659
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A vaccuum guage works nearly as well.
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jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers |
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#20 |
Registered User
Join Date: Mar 2003
Location: Northern Illinois
Posts: 2,181
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Holley has an O2 sensor that they sell as an add-on kit to their TBI systems.
The interface is very simple -- it acts as a variable resistor. Should be a piece of cake to hook it up to a small voltmeter. Brian |
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#21 |
Account Suspended
Join Date: Sep 2000
Posts: 4,002
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You could probably double that number if you porpoise :p
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#22 |
Binder Rep
Join Date: Jan 2001
Location: Salcha, AK
Posts: 1,506
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Oil?
You guys ever check the owner's manual chart for oil?
For hot climates, like the desert in the summer, it calls for 20W-50, and this was for the brand new engines when these trucks were new. In fact, it says you can use straight 30W motor oil in some temps (small range). The one that gives you the best temp range is 10W-40 (covers all 10W-30 ranges because of the 10W when cold and also covers more upper temp ranges than 10W-30). With synthetics a 0W-40 or 5W-50 or so would seem to be a good combo. A thinner oil might slightly help your economy, but these engines weren't designed for it and it can hurt engine life. I'm wanting to try amsoil in the scout once I get my dual drain plug pan in, and then in the '70 later. (amsoil gives you a longer drain interval, you just check the oil and I've heard of upwards of 100,000 miles with just changing the filter and putting that extra quart back in). I've seen reports that amsoil can reduce oil consumption too, don't see how but I'm curious about that. |
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#23 | |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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Re: Oil?
Quote:
Show me one car or truck today that calls for 20w50, or even 10w40 for that matter? You seem to be a big believer in amsoil, why not read about their 0w30? http://www.amsoil.com/products/tso.html
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Just sitting here contemplating contemplation. Last edited by 68 Suburban; 05-28-2003 at 08:02 PM. |
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#24 | |
Binder Rep
Join Date: Jan 2001
Location: Salcha, AK
Posts: 1,506
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Re: Re: Oil?
Quote:
The call for the lower weight oil to get higher fuel economy numbers, that is all. Show me one car or truck today that will last for as long as our trucks will. IIRC my dad's 91 Z71 w/ 350 still calls for 10W-40 in higher temps. |
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#25 |
Registered User
Join Date: Oct 2000
Location: From Chicago, Live in Phoenix, AZ
Posts: 6,802
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Your not serious? Todays trucks and cars engines will last a lot longer than any car and truck engine from the 60's if the all conditions are the same.
You mean to tell me that you would rather run dino 10w40 rather than synthetic 5w30? If you think that 10w40 is giving you better protection, go for it. By the way the new Corvette calls for Synthetic 5w30.
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