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#1 |
Registered User
Join Date: Jan 2010
Location: Ceresco,Ne
Posts: 58
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Whos got the best gas mileage combo
Going to put together an engine for my 72 blazer with a 350 th350 3.73 gears 33.12.50 15 tires and am only getting 14 mpg now want to increase it.What are you guys getting with your blazers and whats in them for a combination.
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#2 |
I'm a poor spectator
Join Date: Aug 2006
Location: San Antonio, Tx
Posts: 2,287
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Re: Whos got the best gas mileage combo
You're doing pretty good right now, I got about the same with mine with a 350, sm465, cheapo 32's and 3.07's. If you wanted to get a little better mileage you could do all sorts of things (overdrive tranny, smaller tires with 3.07's, diesel swap, fuel injection...)
You see where i'm going, but the main thing is this, how much is it gonna cost you to get just a little better fuel economy??? Sure you'll save money at the pump but if it costs 3 grand then is it really worth it? I think your best bet if you really want better mileage is to look into an overdrive tranny (700r4 would be your best bet) and a throttle bottle injection system. This would get better mileage and not cost a ton but it won't really be that cheap. If you're pretty mechanically inclined you will save quite a bit of money doing this yourself. Oh and I would think this cam would be an all around decent cam if mileage is your main concern.
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2006 Jeep Unlimited IMPACT ORANGE 1993 Chevy 2500 4x4 ExCab LWB 454/NV4500 Tow rig ![]() 1977 Ford F100 2x4 LWB 1st truck I owned, still have it!!! ![]() 1979 Ford F150 4x4 SWB Built Ford Tough!!! ![]() 1971 Chevy Blazer 350 / SM465 / NP205 UNDER CONSTRUCTION Soon to have a LQ4 6.0!!! Last edited by Jtrux; 01-18-2010 at 08:56 PM. |
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#3 |
Registered User
![]() Join Date: May 2007
Location: Rapid City South Dakota
Posts: 2,359
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Re: Whos got the best gas mileage combo
If I can get 14mpg I'll be doing cartwheels across the gas station lot!
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Turp Mcspray New life for an old 2wd, farm blazer http://67-72chevytrucks.com/vboard/s...d.php?t=505987 My Blazer build http://67-72chevytrucks.com/vboard/s...d.php?t=342299 |
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#4 |
Registered User
![]() Join Date: Nov 2009
Location: Sioux City, IA
Posts: 158
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Re: Whos got the best gas mileage combo
14 isn't anything to complain about- 40 years of technology doesn't have the new full size SUVs doing much better
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Dustin '97 Dodge Ram (daily driver) '71 Blazer (supposed to be a toy... insists on being a project) '85 Monte Carlo SS (project) |
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#5 |
Registered User
Join Date: Feb 2003
Location: Santa Ana, CA
Posts: 2,191
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Re: Whos got the best gas mileage combo
I just finished installing my junk yard find Gear Vendors overdrive unit in my 72Blazer with 350/350TH/NP205 combo with 4.10 gears and 35x12.50x16.5 tires. Took it out on the highway for a test run and what a difference! 2500 at 70-75 mph. I need to take my GPS with me next time so I can get a more accurate speed (my speedo is not calibrated). I will let you know what my gas mileage is once I've determined it. BTW, the overdrive is 22%.
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#6 |
Registered User
Join Date: Jan 2010
Location: westcliffe colorado
Posts: 65
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Re: Whos got the best gas mileage combo
right now i got a 2 barrel carburetor on a 350, im baout to add a gas misting trick to increase mileage as well, if it works ill tell you guys how to do it.
I have 3.73 gears in the axle, so im curious to what i get with the 2 barrel, then i might slap a 4 barrel on as well for comparison. and im going to be putting in very small steel mesh inbetween the carb plates when the gas enters the screen it starts to mist. |
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#7 |
Registered User
Join Date: Oct 2003
Location: Central Vermont
Posts: 8,538
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Re: Whos got the best gas mileage combo
First thing to remember is that your pushing a huge brick down the road, the frontal offering may as well be flat like a sheet of plywood.
That being said, when fuel mileage jumped up in the early 80's it was due mainly to over-drive transmission's, not the introduction of fuel injection alone. Then comes fuel injection, a better fuel management system will help in many more ways than just increased mileage. Now...consider gearing, where do you do the most driving and where is your engine running 'happy'. (what rpm) Okay, then there's tires...bigger means more turning mass & weight. It's a long list and a rather complicated formula to figure out but IMO, the first step to better fuel mileage is getting an overdrive & slowing down those RPM's without sacrificing torque. Last edited by vtblazer; 01-22-2010 at 07:24 PM. |
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#8 |
Registered User
Join Date: Jan 2010
Location: westcliffe colorado
Posts: 65
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Re: Whos got the best gas mileage combo
I am guessing im going to need to get a new transmission that has a overdrive gear to even get too that point correct?
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#9 |
Registered User
![]() Join Date: Jun 2007
Location: Madison, AL
Posts: 140
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Let's hear from the EFI crowd
I would love to hear mileage estimates from some of you running GenIII/IV engine/tranny combos. I was guessing with the right gear ratio, you could possibly get 18-20 mpg, but no one has chimed in yet.
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#10 |
2WD Jimmy
![]() Join Date: Mar 2005
Location: Davis County, Utah
Posts: 2,564
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Re: Whos got the best gas mileage combo
See #5 above. The GV gives you six forward speeds and is unbreakable. ITs WORTH the $$$ save your money if you need to.
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#11 | |
Workin to live...
Join Date: Jun 2003
Location: Texas Hill Country
Posts: 261
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Re: Whos got the best gas mileage combo
Quote:
![]() 14 is great! I get 9/11, city/hwy, with my 350/350/np205/33x12.50 combo. I'd also be interested in the gear vendor unit. Will it fit behind the np205 on my Jimmy?
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Jason |
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#12 |
Registered User
![]() Join Date: Nov 2009
Location: Sioux City, IA
Posts: 158
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Re: Whos got the best gas mileage combo
For every 1 out there claiming 20 mpg there are 3 complaining that they can't get 15. Not saying that you aren't getting 20, just that it is rare. Even at 20 that's only 6 mpg better than man-a-fre & your sub has fuel injection, overdrive, etc... still nothing to brag about.
__________________
Dustin '97 Dodge Ram (daily driver) '71 Blazer (supposed to be a toy... insists on being a project) '85 Monte Carlo SS (project) |
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#13 |
Registered User
Join Date: Jan 2010
Location: westcliffe colorado
Posts: 65
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Re: Whos got the best gas mileage combo
Has anyone atempted steam injection? I have been considering doing this for some time, theres a few things you have to do. i could understand cold water injection it would cool the gas down before being burned but steam seems to be the opposite direction. so just some ideas i have gathered in the past.
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#14 |
Registered User
Join Date: Jan 2010
Location: Campbell Hill IL
Posts: 17
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Re: Whos got the best gas mileage combo
14!? lol i get 12 and i have a 350 3 spd wit a 4 barrel
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#16 |
Registered User
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 2,396
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Re: Whos got the best gas mileage combo
Considering your combo, 14 isn't bad.
I'm running a 355/350 turbo with 3.07's and 33 inch tall tires. With a 750 holley on top and a mild crane cam to boot. I'm getting 13 mpg in stop and go driving, and it has to work pretty hard. I haven't hit the highway yet with the changes I've made, but considering the pickup in mileage from city to highway it made in the past, it should be in the 15-16 mpg range on the highway. With this combo I can cruise at 70 mph at only 2400 rpms, so it's pretty comfy. I'm not complaining. Considering most all of the new SUV's are lucky to tickle 14 mpg with overdrives and fuel injection I'd say we are all doing pretty darn good. My 79 1 ton pickup with a 454/400 turbo and 3.73 gears, weighs 5,300 lbs. and has 30 inch tall tires gets 14 mpg highway. I can pull a 10,000 lbs. enclosed trailer and still get 11 mpg. It spins 2,800 rpms at 65 mph. Pretty damn good for what it is. Considering my father has a 3/4 ton 2003 pickup with a fuel injected 6.0 and 4L80E overdrive and he only gets 13 mpg empty ![]() |
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#17 | |
Registered User
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 2,396
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Re: Let's hear from the EFI crowd
Quote:
![]() I've got our 4th gen camaros getting 30 mpg highway, and 22-23 around town. Stock it was more like 26/19. I posted what I'm getting in our blazer with the current combo above, that matches what new SUV's get, and I'm doing it with 40 year old technoligy. With the 6.0 swap along with an overdrive I'm looking to better that. With a few tuning sessions it should be no sweat. |
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#18 |
Registered User
Join Date: Feb 2007
Location: Orange Ca.
Posts: 11
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Re: Whos got the best gas mileage combo
14mpg must be nice... I thought i was doing good at around 10mpg... 3.73's/SM465/np205/33inch tires/355ci, 750carb/ tri-y headers. I wish i could pull 14+mpg
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#19 |
So Many Ideas, So Little Money
Join Date: Sep 2001
Location: Marshalltown, IA
Posts: 1,610
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Re: Whos got the best gas mileage combo
i get like 7MPG oh well its too much fun to let it sit!
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72 Blazer 3/4 ton running gear 4.10s NP205/TH350 350 4in lift half doors 71 C10 with 454 99 S-10 5.1L SBC 700R4 09 Malibu ![]() Marshalltown, Iowa |
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#20 |
Registered User
![]() Join Date: Sep 2008
Location: Charleston, SC
Posts: 159
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Re: Whos got the best gas mileage combo
LQ9 - 4L80 - 3.42 (I think)
The only time I checked was when I drove her from Charleston SC to Atlanta. Left at rush hour on a Friday so I sat in traffic in both Charleston and Columbia SC. Avg moving speed was between 75-90 mph...aggressive passing...a couple of runs to 100. Averaged 18.5mpg. I'd imagine a moving avg at highway speed would be pretty close to 20mpg. I dig it. |
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#21 | |
Registered User
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 2,396
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Re: Whos got the best gas mileage combo
Quote:
With my 3.07's and 33's it has to work pretty hard around town, and the part throttle shift points accur way too early, so most of the time it's pulling itself around in 3rd gear,,,and I'm still knocking down 13 mpg,,,in town. I'm certain some highway driving would pick it up 2-3 mpg. I tune it with the wideband. A few idle circuit tricks on the 750 holley, and some jet changes for a decent AFR got me where it's at. And it's not perfect yet. I still have some tinkering to do, but I'm waiting for warmer weather up here at 5,000 feet so the DA rises a bit. It will probably still be a bit rich when that happens. Last edited by Firebirdjones; 02-14-2010 at 01:46 PM. |
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#22 |
Registered User
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 2,396
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Re: Whos got the best gas mileage combo
![]() ![]() Last edited by Firebirdjones; 02-14-2010 at 10:10 AM. |
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#23 |
Registered User
Join Date: Nov 2008
Location: BROOKELAND,TX
Posts: 24
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14 is great i have a new chevy 6.2 six speed auto seeing 11.8 - 13 hwy and my Blazer and Jimmy probably around 10 mpg lucky you.
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#24 |
Registered User
Join Date: Apr 2008
Location: Talent, Oregon
Posts: 30
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Re: Whos got the best gas mileage combo
23 combined city/hwy... see signature... Big loud 4WD Blazer, I'm shooting for at least 25 with it when I have time to fiddle with tuning and such.
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1971 K5 Blazer, Cummins 4BT, ZF 5spd, Hydraulic Clutch, 3.42 Gears, 32X11.50, 4" Straight Piped 1999.5 MKIV Golf TDI, Red, 2Dr, 5spd, Arietta's, 14lb G60 Flywheel, VR6 Clutch. 2002 VFR800, Red, Polished Wheels, otherwise stock. |
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#25 |
Registered User
Join Date: Mar 2009
Location: Sutter CA
Posts: 26
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Re: Whos got the best gas mileage combo
Keep tire type/model in mind. My '07 chevy diesel went from 17 mpg to 15.4 changing from street tires to off road tires of same diameter. Gotta burn some fuel to make all that noise!
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