Thank you guys, MOONDOGGIE: i'm just trying to figure this new to me 1986 6.2 suburban and try to figure the MPG
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Thank you guys, MOONDOGGIE: i'm just trying to figure this new to me 1986 6.2 suburban and try to figure the MPG
Hey Panchosteam, you are in my neck of the woods. That does not sound like to good a mileage for the Suburban. Our 82 has the same gears and 700R4 automatic. Does yours have the TH400 or 700R4? Around town we get around 18 mpg and on trips a little over 20 mpg. We do not go much over 65 mph with it. 75 mph and TH400 would both hurt the mpg, but should still do a little better than 11/12 mpg.
Thank you CRAIG M, i found some leaks on this truck so i'm going to have to work them out and go from there,could i do better with 245/85/16 ? or will it be worse? about the trans. i was trying to find out which one i have but i could'nt see the info on it, to greasy , i think i saw something like turbo... i do not remember i will have to check again, any way i'll be checking for mor leaks tomorrow after work
i also found a bad motor mount on the passenger side so after i change it maybe i can see ifthe lift pump leaks. I liked the way my 1984 sierra pick up used to ride with the 6.5 td engine on it so that's why i went ahead and got this other diesel,one thing for sure is that it doesn't ride like my pick up, this suburban been a 4x4 is not comfortable as i expected it to be when i get better mileage on the diesel i'll be happy!
Hey guys
Im new at this I have my 99 chev sub 6.5 about 3yrs and have had the pmd changed twice. when I first got the truck it did about 20mpg at 60 since the pump was changed cant do any better than 17mpg at 55 - 60 what could change the milage?
Thanks the new guy
Good Day!
I'd bet timing. You might want to get it hooked up to a Tech II or such & find out what the TDC offset is presently. I don't know what TDC offset will produce the best mpg. In fact, I'm not sure anyone does. The good news is that More Power has already purchased his next project truck, which is a 6.5 & will be set up to find out such things. :D
Blessings!
You know, I have spent a few minutes digesting the postings to this mileage issue. I got my engineering degree in electronics/electrical but the facts still remain that increased pumping loses of a turbo will decrease efficency provided adequite air/fuel ratios are maintained. This being said, the additional back pressure of a turbo can produce loses in efficiency in the mid-range area of a diesel engine. If we all agree that the "optimum" range is 1700 to 2100 RPM for the 6.2 then we realize that a trubo will probably not add but take away from efficiency. I.E. lose mileage. At higer RPM's this will not be true and at lower RPM's, there will be no effective restriction. The key here is to have a turbo that will spool up with boost of 1+ PSI after the 2000 RPM and produce about 6-8 PSI at about 2800 RPM. Makes pulling a hill with a load efficient but does not add to the pumping loses at 1800 RPM crusing. All said, the 6.2 is a well balance engine. With a Banks it is even better. Flying a GMC (Brick in the wind) truck is not the most efficient but is an albeit usefull and confortable means of transportation. And anyone that is getting about 20mpg pushing this brick down the road is not doing badly.
If you want gains in mileage, reduce the air friction, rolling friction and increase gearing to the 2.88-3.08 final drive ratios. Back off the boost at mid range, and save the power circuit for pulling at full throttle only.
This is all fascinating, especially to a kindergarten-level diesel enthusiast like me. On my last trip Atlanta to Gulfport for weekend ANG duty, I got an average of just under 19MPG calculated over three fuel stops (not knowing availability of #2 on the Gulf coast). That's in my '88 6.2 Banks 4wd with a non-functioning TCC. Kept it at 65 or below as much as possible. The trip took a little longer, but my wallet wasn't as light afterwards.
I really appreciate this forum; it's a great way to learn about these neat old beasts.
Buzz
Just put ol blue away for the winter, last two tanks average 19 mpg @65 mph back and forth to work 65 mile rt.
won't complain with this mileage, think it would hit 20 w/out the town portion.
Now if I can find my STA-BIL I'll be set.
Merle
Hi,Just my experiance,1989,6.2, chevy 4 by 4,2500,running boards,3.73,262000 miles,
temp.20, At 55 tail gate open 22mpg
temp.70 at 55 tail gate open 24mpg best ever
at 65+ 19.3 tail gate closed.
short trips,farming,haul,pull trailer,my normal 16.3mpg
Merry Christmas
Butch
Well, a logistical challenge has been overcome, and the 6.5L El Camino project will begin soon.
As soon as I acquire a couple decent images (of someone elses Camino) to use as a lead-in for the introduction, I'll post a new article that outlines the project, and hits the highlights for maximizing fuel economy.
For now, you can visit the following link to see what a 1972 Chevrolet El Camino looks like.
Link
Jim
Jim, I am plannin' on giving you a run for your money in the Olds! At least on mileage :D
The Max fuel economy project has begun! While this will be a max mpg project using a mechanically injected non-turbo (to begin with) 6.5L diesel, much of what will be discussed can be directly applied to all 6.2/6.5 diesel equipped vehicles (including some aspects of a Duramax equipped truck as well). We may even be using some 6.2 specific components…
Things like engine rpm, vehicle weight & drag, and driving strategies for max fuel economy will apply to just about any light diesel. Our vehicle choice will allow us to explore what effect weight and drag have on fuel efficiency.
I think you'll be surprised at what components are available for all 6.2/6.5 diesels (EFI and MFI) that were designed to improve fuel economy, and we'll be discussing them in future Project MPG updates. Some components you may already know about, but there are a few you probably don't… At least not yet!
Jim
MP,
What ever happened to the 6.5 powered s-10 blazer you talked about in Florida? Ive always wanted to do something like that because Iam sure it could get 30+ MPG
It was one of those phone calls - like many I receive - from a member who told me what he had done. I asked that he send some images and discussion to let more people know about his project. That's where it is... We'll wait & see...
I'd like to see it here, cuz it adds to what we're doing with fuel economy.
Jim
My early 82 ( delivered in Nov81 ) 3/4 2w
4 sp std tran w OD, ( weighed 5500 lbs )
24 MPG, always, drove truck to 230K miles
( 1 rebuilt pump ) sold it and it ran more miles,
I would note that the fuel back than was
heavy,yellowish, and not as much foam...
Ah, Progress... ( house oil ran good also.)
6.2L/6.5L Fuel Economy
Cylinder Heads & Ricardo Comet
Part II
The 6.2L diesel engine was introduced during a time when the world energy market sent fuel prices skyrocketing. While it may surprise you, gas & diesel pump prices during the early 1980's were actually higher than they are now - when adjusted for inflation. GM's 6.2L diesel was designed and developed for tight fuel supplies and high pump prices, and we may need to revisit the 6.2/6.5 to help provide a solution to the high fuel costs we're seeing now. The early light-duty 6.2L diesel powered trucks would consistently deliver 22-24 mpg when driven conservatively, while the later light-duty 6.5L turbodiesels produced 5 or more miles per gallon less. Why is that? The answer to that question is what we're investigating this time.
I have a '92 GMC Vandura 3500 work van I go as fast as 75 mph Max(Rarely) never tow with it, have 2 3500 6.5 TD 93 & 97 It currently runs a wore out 350 in. Gas Engine I want to convert to diesel for equal or a little bit more torque but better gas effieiency what would work best for suck a heavy, large, non airodynamic brick.
Also on another subject the housing for my Differential is damaged where the driveshaft comes in and there is extra play it bangs sometimes. I plan on just replacing the whole rear end with a newer lower milage one What readend would give me the best Fuel Economy, power is unimportant because I drive the van REALLY Slow
More Power,
The 6.2/6.5 article is great! Please keep the articles coming.
I have just stumbled across this forum. I am trying to get away from the uncomfortable and noisy ride that is a small 4 cylinder econo-car, but I want to keep the high fuel economy (or close to it). I can't wait to read more on the El Camino project. :)
I owned a 1982 K1500 SWB 6.2 with a manual 4 speed with OD and 3.42 gears. This truck broke 30 mpg on several ocassions driving at 58-60 mph and doing my very best to be smooth on the pedal. I would build a little speed down hill at let it fall off some on the next hill. This sounds to good to be true now but I always fill up to where I can touch the fuel in the neck of the filler. Having since owned 2 other 6.5 turbos a 1994 K3500 LWB 5 speed manual 4.10 18.5 mpg and 1995 2500 Suburban 4 speed auto 3.73's 18-20 mpg I would say 6.2 NA without a doubt. I would really like to have my old truck back now with fuel prices what they are.
6.5 Turbo Diesel
Here is my plan. Let me know what ya'll think.
1973-1974 Chevrolet short stepside
Tonneau cover.
Front air dam.
Rear roll pan.
Lowered around 4/5.
Ton sway bars.
Poly bushings.
Aligned real good.
T-56 6 speed.
Synthetic lube in the rear end.
Small mirrors.
Custom built headers for the turbos(plural:D).
GM-8 turbos. may go with one GM-8 and a little turbo off of a daytona or caravan.(which should deliver the best economy).
3 inch downpipes.
3 inch or 3.5 inch NASCAR boom tubes with x pipe daul exit right under the steps no mufflers for as long as I can get away with it.
Daul front mount intercoolers.
Possibly a cowl hood to let air out of the engine compartment better.
Free flowing air intake to the turbos.
Ported intake or maybe make custom Ram Logs similar to this(which should deliver the best economy).http://banksdiesel.com/Dmax-Gallery-...nal_sketch.jpg
May go with rear disc brakes.
May do a partial bellypan.
Daul electric fans.
Polish up the exhaust ports a little.
40ish psi in the tires
No A/C (I hate ac in a vehicle..gives me headaches:rolleyes:)
And a slick shiney black paint job:cool:.
Here is the 73-74 grille after I redid it
http://www.hotrodders.com/forum/atta...chmentid=24798
and what I started with http://www.hotrodders.com/forum/atta...chmentid=24799
Heres the step by step process
http://www.hotrodders.com/forum/repa...le-125972.html
I am hoping for 30mpg plus while crusing with a light foot. Do you think it is possible? Any thoughts or suggestions?
Thanks
Shane
I Have Been Getting 19 City- That's Between 35-40 Mph. And About 21 0r 22 At About 50 -55 Mph. Hows That Sound For A 4x4. Puts Gassers To Shame. Yay 6.2
i thought i was going crazy, but indeed i am not. for the last 3 tanks i have been getting 25 mpg. i run the winter bottle of power source and have put 30'' mickey thompson baja claw radials on, with a th400 and 3.73's:D:D
i put them on to replace the 245 65r16 tires i had on it. i put the larger tires on to in tern slightly reduce the ring and pinion gear. what i mean is that with a bigger tire it is spinning the gears slower so the engine is reving lower, therefore giving a slight increase in mileage. form doing this i picked up a extra 2 or 3 mpg. i also drive it very easy and have a fresh IP rebuilt a good flowing 4'' exhaust, the intake mod i posted and the winter POWER SERVICE WHITE BOTTLE.
88 crewcab 3/4 ton 6.2 diesel(newer heavy casting) turbo charged(some rotomaster I found on swap meet),ported heads( everything made in the backyard except 6.5 exhaust manifold) coupled to nv4500 5 speed through 3.42 gears.
28 to 32 mpg @65 ish 21 to 22 @85mph.
Hate to say it but my duramax doesn't even come close.
Just punched the block to 6.5, had piston top cracking with 6.2 pistons.
6.5 pistons have more meat in the top area(mahle pistons).
Not sure what this will do for mileage but hope it will be just as good.
so far im getting 34 mpg in my jeep, 6.2 n/a, 2600 lbs, 33" tires, th400, 3.31 gears
It was very interesting following this thread. I have a 1982 Suburban with the original 6.2 diesel and Scenario #2 is what this rig is set up for. Last year, I took a road trip around the US and added 15k miles on the odometer. Since fuel was much more expensive than it is now, I kept my speed 60 mph (1600 rpm) since I was not in a hurry and this is where I could pull in the best mileage. I consistently got 28 mpg and got at high as 32 mpg on several tanks.
Here's my setup:
2 wheel drive
3.08 gears
700R4 transmission from 1989 truck
30”x9.50 tires
Ported and polished heads – 1983 heads
Intake manifold runners matched to heads and casting smoothed out
Exhaust Headers
Dual 2-1/2” exhaust with H-pipe
Timing gear
Injection pump turned up ¼ turn
I also tow a 26 ft. Airstream which weights around 6000 lbs. I tow in 3rd gear and 2nd gear on the hills. I can manually lock the torque converter to keep the temperatures down on long grades. I get 16 mpg with this setup.
Some things that I could do improve economy:
Super Tune engine using glow plugs.
http://www.ford-trucks.com/forums/59...he-engine.html
Hydrogen Generator
http://pesn.com/2007/01/08/9500445_B...rolyzer_Plans/
Aerodynamic mods such as front air dam and rear fender skirts
My dad had an '82 caprice with a 5.7 diesel, 350c tranny with a lockup torque converter, and 3.08:1 rear axle ratio ...it got 35mpg running 65-70 on I-40 going from Jackson Tn to Cookeville Tn and back. A few months later, the 5.7 stripped the head bolt threads out of the block ( blowing the head gasket ) and the car got parked. If I hadn't moved to Oklahoma, I was going to replace the 5.7 with a 6.2
Hmm, I may join in on trying to get some more economy out of a 6.2L.
I picked up another 1982 Short Bed truck, but I want to just drive this one with the 6.2L engine with the hope of better economy.
My other 1982 SWB truck got 25 at 70mph pretty easily when it was a 6.2, pretty stock engine and truck. My 86 LWB got 24 at 65, and 22 at 70, so I liked the 25 the lighter truck got.
This new one is lowered almost 6", and I figure that would help the drag bit, plus I'm going to help the engine run a little better to increase it's efficientcy (exhaust, air, stuff). My hope is 29-30mpg at 65mph eventually, or around 27 at 70mph.
As soon as I get the specifics on the truck hammered out, testing will occur. Someone removed the TH700 and installed a TH350, since i have the engine and trans removed from the truck at the current I will be going back with a good TH700 I have, and then will identify what the gears are in the rear differential (hoping for 3.08), and I have a 2.73 to try as well.
J
Having a 3.08 rear differential is probably about at tall as you want to go with an overdrive transmission unless you are planning use very small diameter tires. My 82 Suburban has 3.08 gears and a TH700 and it is pretty gutless at 60 mph in overdrive. It has more performance at speeds over 65 mph but fuel economy decreases due to wind drag.
my old 90 gm diesel has a good set its slow but i can get up to 30 mpg on a good highway run it has a 99 6.5 n/a turbo 400 with 4.10 gears in the rear end i just set the cruise at 60 and let little basterd go :cool:
so i just came back to the 6.2 world.
my suburban had a 6.2 mated to a th400 & 4.11s. it hit 17-19 mpg on long freeway drives.
i just bought a blazer/jimmy w/ the 6.2 mated to a 700r4 (not sure gears). havent done a full calculation but im getting close to 23-25mpg. this thing is totaly freeway friendly minus getting up to speed to merge onto the freeway.
& im just curious has anyone over heated one of these 6.2s(w/ a working cooling system)? i could not make either of them hit 200 degrees unless up a steep grade w/ my foot pinned
Hey everyone new here, thought I'd post in this because it's basically what I'm gonna ask.
I have a 1988 Grand Wagoneer, currently with 3.31 gears (could change that)
lookin at a 2-4" lift with 32s
probably all onroad driving (never been offroading)
And I am not a heavy footed driver, though some power isn't the worst thing in the world :D
I was curious what everyone thought would be the best engine choice of the 4 for me?
Either a GM 6.2 or Cummins 3.9 4BT. Do you have overdrive? The 6.2 likes to cruise at 1800 rpms and Cummins is a bit lower like 1500-1700 rpms. The 4BT would likely yield better fuel economy. However, a 6.2 that is set up with fuel economy in mind can yield close to 30 mpg.
Here’s what I did to get 30 mpg (US) on my 82 Suburban.
1. I used 1982 heads with small pre-combustion chambers and large valves. These heads get the best gas mileage but suffered from cracking. Of course mine had cracks in between every valve seat so I installed liners between each valve seat.
2. Ported / polished the heads
3. Stan’s Headers – Made a big difference in power since stock power was 130 hp
4. Free flowing exhaust – Dual 2-1/2” with H-pipe and Thrush tube mufflers.
5. DSG Timing Gear
6. Ported / polished J code intake manifold
7. 700R4 automatic with overdrive
8. 3.08 rear end
9. Tall & skinny tires – 30x9.50 with 50 psi of pressure
And of course, the most important, an easy foot. To achieve 30 mpg, I have to keep it under 60 mph. Over that, it drops off rapidly with the square front end on the Suburban. For example at 75, it’ll drop down to about 23 mpg. The 75 mph gas mileage can be increased considerably with aero mods but I rarely drive that speed so I have not done any aero mods on my Suburban.
>> Unfortunately because of CA dmv I cannot do a Cummins swap.
I don’t believe the 88 Jeep Grand Wagoneer was ever offered with a diesel in the U.S. So technically, CA DMV won’t allow installing any diesel. However, if you push the right buttons, I believe you can get it through even with a Cummins. PM me if you’re serious about doing this swap and I’ll tell you how.
Nice setup, I will be taking all of those into consideration once I get mine going. Some users on the other diesel forum are making me feel like I can't get good mileage without doing a 4bt with the specs I'm looking at of 3-4" lift and 32s.
I'm thinking of a turbo, which kind would be better for an mpg application. I've heard that they can increase or decrease mpg, depending. I know that they can back up exhaust a bit, decreasing mpg. I have been talking to another user tho who added hummer exhaust manifolds and said they breathe way better
The lift and wide tires is counterproductive towards good fuel economy but low 20's with that set up should be achievable. With 32's, 3.08's would be too tall so 3.42's would probably be more appropriate. If the hummer exhaust manifolds fit in your Jeep, that might be the way to go. A good exhaust/headers will get you about 70-80% of the power of a Banks Turbo with a lot less complication. Add some head work and you can get very close to the power levels of having a turbo. Turbo's usually usually don't get as good fuel economy with solo driving. However, they seem to add efficiency under high work loads.