F3RR3T
1/2 ton status
biggest tire size with 6.2 or 6.5 diesel. dana 70 rear dana 60 front
will it take 44's
i really wanna stay diesel
will it take 44's
i really wanna stay diesel
CK5
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tire size with 6.2 or 6.5
- Thread starter F3RR3T
- Start date
Jishory
1/2 ton status
sure either of those can turn 44's, 6.2s not so good but a 6.5 would work nice, anyways with those axles you can get some steep gearing if you wanted
F3RR3T
1/2 ton status
next question suspension wise im going to run 6 inch lift springs front and rear. won on an ebay auction. and a 2 inch bl.
this is a mud truck and trail truck flex is important still what are yall opinions on johny joints or do i any other options to gain some flex.
the terrain that we ride is a dried of river full of big rocks about three feet and cypress logs and stumps
this is a mud truck and trail truck flex is important still what are yall opinions on johny joints or do i any other options to gain some flex.
the terrain that we ride is a dried of river full of big rocks about three feet and cypress logs and stumps
The engine doesn't matter too much as long as you gear it right...
...which is the one thing you haven't mentioned.
What's your gearing going to be?
...which is the one thing you haven't mentioned.
What's your gearing going to be?
F3RR3T
1/2 ton status
lol im redo the gearing when i get to the final stage but i need to be able to cruise at least 60 interstate
ok i dont have the closest idea about gearing im a noob at gearing
gearing makes me emo
i need a hug now
ok i dont have the closest idea about gearing im a noob at gearing
gearing makes me emo
i need a hug now
pauly383
Daddy383
Gearing should be an earlier stage . Tall tires and too high of a gear would suck . A diesel would turn larger tires better than a 305 with and 35's and highway gears , but I gotta feeling 44's and highway gears would be just as doggy to start rolling .
K5dreamer
1/2 ton status
im no expert when it comes to the truck field, im learning myself as i go, but my guess with the diesels and 44in tires, youre gonna want at LEAST a 4.10 ratio for any pep. for comparison, im running the 6.2L non turbo diesel, with the TH400 three speed, 3.08 gears, and 33in tires. its no slug, but i certainly wouldnt try to race anyone. for accelerating up to highway speeds it does pretty much what i would expect for such a big truck. and for the mild offroading ive done, dropping it into four low has gotten me over anything in my way without problem so long as ive had enough traction.
the main things ive done to help the diesel run are the common maintanence items, air filter, fuel filter, glow plugs, diesel fuel system treatment, oil change and filter, and it runs like a new engine, quieter, smoother, and with alot more pep. making the engine run better will also play a large part in how happy you are with its performance with the bigger tires.
before taking any of this to heart, wait and see if im corrected by any more experienced people, like i said, im pretty new to the trucks, although ive been into performance cars and engines since i was around 8.
the main things ive done to help the diesel run are the common maintanence items, air filter, fuel filter, glow plugs, diesel fuel system treatment, oil change and filter, and it runs like a new engine, quieter, smoother, and with alot more pep. making the engine run better will also play a large part in how happy you are with its performance with the bigger tires.
before taking any of this to heart, wait and see if im corrected by any more experienced people, like i said, im pretty new to the trucks, although ive been into performance cars and engines since i was around 8.
Since we're talking a GM diesel I'd go with at least a 4.56 gearing.
My CUCV pickup has 36" tires, a TH400, and 4.56 gears and lemme tell you, it'll easily do 70 but you don't really want to do it for long times. It seems happier around 60mph. 38's are in the back of my mind but I'm afraid if I go much lower I'll loose some of the driveability for around town stuff.
Since you want to run a MUCH taller and heavier tire I'd suggest at the very minimum 4.56's and if you really want the right ratio go for something in the 4.88 range. If you intend on putting an OD tranny in it then just shoot for 5.13's and have low range and take off. OD will keep the revs down at speed.
My CUCV pickup has 36" tires, a TH400, and 4.56 gears and lemme tell you, it'll easily do 70 but you don't really want to do it for long times. It seems happier around 60mph. 38's are in the back of my mind but I'm afraid if I go much lower I'll loose some of the driveability for around town stuff.
Since you want to run a MUCH taller and heavier tire I'd suggest at the very minimum 4.56's and if you really want the right ratio go for something in the 4.88 range. If you intend on putting an OD tranny in it then just shoot for 5.13's and have low range and take off. OD will keep the revs down at speed.
that's what you need to know right there.AJMBLAZER said:
with an sm465 or th400 and 4.56 gear ratio and 44" tires your rpms at 60: 2207rpm
i run a 6.2/sm465/4.10 gear ratio and 35" tires, at 60mph: 2495rpm. this gets me roughly 20mpg on the highway. with the manual tranny, you'll likely get similar mileage with the set-up listed above. i'd expect about 18 if you ran the th400 - it's known to be a power-hog.
that said, i'd expect it to be pretty slow with 4.56 and tires that tall.
with a 700r4, 4.56 and 44" tires at 60: 1463 rpm, but you'll likely have trouble keeping it in OD with rpms that low. the 700 has the advantage of having a 3.06 first gear to help get those tires moving quicker tho, versus the 2.48 first gear of the th400.
all that up there is pretty easy stuff to come by, but if you want to do it right, here it is:
6.2/nv4500/np205/doubler?/4.88s. the tranny is very similar to the sm465 only it has an overdrive. the first useful gear on the road is 3.44 (it has a granny low) and that will get you up and going pretty quick. the overdrive will keep your rpm's to 1768 at 65 on the highway, which should give something greater than 20mpg - i'd suspect about 22 or 23. your crawl ratio is about 60:1, which is pretty damn good for the tire/gear combination and no doubler. go doubler and you'll be in the 120 range!
OR
go to 5.13 with the above drivetrain and your rpms at 65 are 1859, so 20+mpg are expected with tons of get up and go. crawl ratio: 63.
don't mess up your gearing. this should be one of the highest things on your list to do right. a mismatched tire/gear ratio set up makes for one gigantic, expensive metal piece of crap that some would refer to as a truck.
86Cucvbeater
1/2 ton status
what tranny? i would go with an sm465. what gear ratio? i would go as low as you can.F3RR3T said:
right now i have a th400(sucks a lot of power) and 4.56 gears. in 2wd on the street its slow. in 4 low it does the job but i have been in some sticky mud past the tires and wasn't able to spin them anymore. that really sucked but most things i try my truck gets it done. still, i would like to change some things. im trying to decide whether to put in a 350 running on propane or do a doubler detup. either way it would make the truck more enjoyable to drive.
the big thing is my truck is locked front and rear so it goes up most anything but it just isn't as fun as scooting around in 2wd sometimes. it's whatever is more important to you. just conquering the trail or having a blast doing it.
screw the mpg and od crap. i doubt he will be driving on the street much with 44s.
K5dreamer
1/2 ton status
youve got 4.56 gears and think its slow? guess ive just got low expectations for the big trucks.
K5dreamer said:
Remember he's talking about a 4.56 gear and 44" tires.
GM geared these trucks high in the '80's in the hopes of getting slightly better fleet mpg in order to make the EPA happy. So ideal gearing for a 31" or so stock tire is about 3.73. 4.10 is a good towing gear for that size tire or a good around town gear for one of these on 33's. 4.56's = 35's, 4.88's = 38-40's, 5.13's = 42-44's, etc
These are all standard gears/tires equations for fullsize trucks with V8 engines. If you have no OD in your trans, a BEEG diesel like a Cummins or Navistar, or just a really torquey engine you can probably pull a lower gear for your chosen tire size.
In short your truck was geared too high from the factory. The military didn't care because convoy speed is 35mph, beyond that they didn't expect it to see much. The diesel could chug it up to 35-50mph pretty easily on the stock tires.
K5dreamer
1/2 ton status
ahhh didnt realize he was also running 44's 
although im not at all dissapointed with my trucks performance, in all honesty, id probly get better around town mileage with a set of 3.73 or 4.10 gears. ive got the camaro to go fast, ive never expected the truck to do that for me. i yeild to yalls experience here, all my gear selection experience has regarded my third gen camaro, but then again, its got 25 in tires
although im not at all dissapointed with my trucks performance, in all honesty, id probly get better around town mileage with a set of 3.73 or 4.10 gears. ive got the camaro to go fast, ive never expected the truck to do that for me. i yeild to yalls experience here, all my gear selection experience has regarded my third gen camaro, but then again, its got 25 in tires
I run 40's with the 4.56's and the 6.2. The last tranny I had was the SM 465. I have never run into a situation where I couldn't get the tires spinning when it was muddy. Around town it was fine, on the freeway it was loud. 2600 rpm doesn't seem so bad when you read it in print, but in reality it's hard to listen to for longer trips.
With 44's I'd go with 5.13's...lets be honest, you're not likely to be making long freeway trips with 44's. Even if you did, it'd be turning about 2500 rpm at 65 mph which is tolerable.
The 6.2 can tolerate slightly taller gearing than a small block, but in my opinion it should still be geared as if it was a small block. This will get you the performance you want.
Overdrive is great to have, if you normally run tires under 38" tall. I don't think there is anything larger than that, that will run down the freeway decently. My 40's were OK when new, but now that they're worn they suck on the highway. i don't see any point of having OD with 44's.
Rene
With 44's I'd go with 5.13's...lets be honest, you're not likely to be making long freeway trips with 44's. Even if you did, it'd be turning about 2500 rpm at 65 mph which is tolerable.
The 6.2 can tolerate slightly taller gearing than a small block, but in my opinion it should still be geared as if it was a small block. This will get you the performance you want.
Overdrive is great to have, if you normally run tires under 38" tall. I don't think there is anything larger than that, that will run down the freeway decently. My 40's were OK when new, but now that they're worn they suck on the highway. i don't see any point of having OD with 44's.
Rene
F3RR3T
1/2 ton status
TRANSMISSION wise i dont know im researching it
i have to have an automatic cuz my right shoulder from an accident and the shifting agravates it
good news is i have a lead on a duramax and allison trans all the wiring and computer. for 4000
but thats not in the picture right now do to the upcoming child unless i sell a few toys and my dakota
i have to have an automatic cuz my right shoulder from an accident and the shifting agravates it
good news is i have a lead on a duramax and allison trans all the wiring and computer. for 4000
but thats not in the picture right now do to the upcoming child unless i sell a few toys and my dakota
K5dreamer
1/2 ton status
just keep in mind with the duramax allison swap youre gonna probly need to do some body work, or a body lift. the allison tranny is BIG, and IIRC wont fit in the smaller blazer tranny tunnel. i was interested in doing the same drivetrain in an older first gen blazer, and thats what i remember being told. although it would be a damn hot setup 
F3RR3T
1/2 ton status
iss either go with the duramax with means fab for the allison boxed frame new driveshaft yada yada.
or built a hp 6.5 turbo at about 450 hp 1100 torque is what i was told from local engine builder for 7000.
or do a stock 6.5 twin turbo with some block work and twin injection pumps for about 4500.
and to top of this situation
the gf has been having bad stomach pains and such so as soon as she gets home we are going to the hospital
or built a hp 6.5 turbo at about 450 hp 1100 torque is what i was told from local engine builder for 7000.
or do a stock 6.5 twin turbo with some block work and twin injection pumps for about 4500.
and to top of this situation
the gf has been having bad stomach pains and such so as soon as she gets home we are going to the hospital
K5dreamer
1/2 ton status
first off, sorry to hear about the gf, hope all is well with that.
second, im pretty floored by the power claims your builder is quoting for the 6.5L, im over here, looking at what is nessesary to get 250hp and 500ftlbs out of my 6.2 and its lookin pretty invovled. although if youre lookin at twin turbos and twin pump setups youre obviously going quite a bit farther than i had intended.
ive seen some after market companys building the 6.5 for marine applications making up to 700hp, but i hadnt seen any for the street, id be interested to know what mods your buiilder is suggesting for those power levels.
the duramax/allison swap would be alot more work, however IMHO, it would be a helluva lot cooler. and with all the mods youre doing to get power from the older engines, you would most likely be giving up the mileage advantage anyway, so the fact that the duramax dosnt get the same mileage isnt really an issue. and for higher power levels, the duramax would respond simply to a programer and a control box and is far more durable from an block archetecture standpoint. unless you were getting the newest 6.5L casting, the blocks for the 6.2 and 6.5 were known to cracks and whatnot. the duramax has shown itself, even in high power applications to be pretty much bullet proof.
second, im pretty floored by the power claims your builder is quoting for the 6.5L, im over here, looking at what is nessesary to get 250hp and 500ftlbs out of my 6.2 and its lookin pretty invovled. although if youre lookin at twin turbos and twin pump setups youre obviously going quite a bit farther than i had intended.
ive seen some after market companys building the 6.5 for marine applications making up to 700hp, but i hadnt seen any for the street, id be interested to know what mods your buiilder is suggesting for those power levels.
the duramax/allison swap would be alot more work, however IMHO, it would be a helluva lot cooler. and with all the mods youre doing to get power from the older engines, you would most likely be giving up the mileage advantage anyway, so the fact that the duramax dosnt get the same mileage isnt really an issue. and for higher power levels, the duramax would respond simply to a programer and a control box and is far more durable from an block archetecture standpoint. unless you were getting the newest 6.5L casting, the blocks for the 6.2 and 6.5 were known to cracks and whatnot. the duramax has shown itself, even in high power applications to be pretty much bullet proof.
F3RR3T
1/2 ton status
TRUE only reason im more prone to lean toward 6.2 6.5 is because of the mechanical operation i dislike eletronic engines.
i wish there was a way to make the duramax a pure mechanical for the most part idk i need more research time.
i found one guy that is building 6.5 twin turbo diesels that run on bio diesal but they use spark plugs
im lookin for a mpg and horsepower which dont exist except the one above at 400 hp 800 torque and 38 mpg
i wish there was a way to make the duramax a pure mechanical for the most part idk i need more research time.
i found one guy that is building 6.5 twin turbo diesels that run on bio diesal but they use spark plugs
im lookin for a mpg and horsepower which dont exist except the one above at 400 hp 800 torque and 38 mpg
K5dreamer
1/2 ton status
im sure there is a way to make the duramax mechanical, but it certainly wouldnt be easy, and youd wind up giving up one of the critical reasons the duramax makes such great power. the computer controls on the duramax respond extremely well to control boxes. a mechanical one would just run what you got, and you might be getting around 250hp and 500ftlbs if you were lucky. if you want all mechanical, just stick with the DD engines. (6.2 and 6.5 were detroit diesel engines) im also planning on running my truck on biodiesel at some point, although spark plugs werent part of my plan......
