6.2L & 6.5L Performance Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines Related to Performance and Longevity

6.2 Performance

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  #11  
Old 09-28-2011, 07:02 PM
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There are alot of ways to gain performance, mileage and drivability. The two best upgrades? Turbo ( I run a banks, and it is fantastic) and a GearVendors overdrive. You can get quite the economy with these two additions. As far as turning up the Injector pump, it's alot of work for little gain. It also tends to make the engine run hotter. An electric lift pump can also make the truck much easier to live with; easier starts, less bleeding problems.
 
  #12  
Old 09-29-2011, 08:01 AM
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I have the electric pump. Installed that when I did the original conversion and have enjoyed the benefits immensely. Would love to have a turbo but have not found one for a van. Then again I stopped looking years ago due to frustration.
 
  #13  
Old 11-09-2011, 08:05 AM
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do you need a special electric lift pump or does it need to put out the right psi ? could it be for the tank? or inline let me know
 
  #14  
Old 11-10-2011, 12:58 AM
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No you don't need a special lift pump. The one on the engine will work but I decided to take it off and block off the hole with a plate and use an inline pump from the parts store. This does two things. One it keeps from having a problem with the engine oil getting diluted if the diaphragm on the pump gets a hole and Two it makes fuel filter changes very easy since all you have to do is turn on the key to fill the filter after a change. Keeps from possibly burning out a starter by cranking too long to get the mechanical pump to fill it.

If you are converting a vehicle that had fuel injection in it then you will have to take the tank out and remove the high pressure pump in there and replace it with a section of hose and the stock sock filter that goes on the bottom of it. Not a big deal at all and you can use the wire that went to the original pump to run your in line replacement.
 
  #15  
Old 12-07-2011, 09:04 PM
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I got an 84 6.2 with a banks sidewinder turbo set up, stock it had maybe 2" dual exhaust but I opened it up to a 3" straight pipe and I can feel a little bit more power
 
  #16  
Old 03-25-2012, 11:10 PM
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Yeah, the turbo is the way to go. Keep boost under 10 lbs anf egt under 1100.
 
  #17  
Old 12-17-2012, 06:10 PM
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I call BS
I have a 1992 6.2 n/a I custom built a 4" exhaust 7" tip turned up the fuel pump and added a 6.5 turbo intake to delete the erg and converted to amsoil synthetics
it added tons of power and great fuel mileage
 

Last edited by mtl5240; 12-17-2012 at 06:12 PM.
  #18  
Old 12-22-2012, 01:19 PM
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You can get improvements to the 6.2, but will not match a turboed 6.5 that has been similarly tweaked especially if the GM turbo has been scrapped for a better turbo like the ATT. A great build is a 6.2 bottom end with a 6.5 turbo upper end, cost is lowered mpg from a 6.2 n/a to a 17-20 mpg avg depending on final drive ratio a little more with 3:42 and a little less with 4:10s
 
  #19  
Old 01-01-2013, 07:38 PM
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Hmmm..
Where to start.
OK. First off that is incorrect that the 6.2 lower ends are weaker. In fact the 660 blocks were thought to be the strongest next to a Navistar 506(aka Optimizer/P400).
a 6.5 Turbo setup does not "Bolt on". It can be "made" to fit without alot of effort.
The main issue depends on what body style your truck is. If it's a GMT400(88+ not including 1 ton or K5) yeah it will pretty much bolt right on.
If it's in an older square body...there will be issues . Main one being whether or not you have A/C. Also depends on what year 6.2 and the angle of the injs .
Let's assume worst case scenario and it's an old Square Body, has A/C and has the long style injs.
First issue is the turbo will hit the a/c box.
You either have to ditch the a/c or I have heard people use a modified a/c box from an s10.
Now the long injs hit the ex manifold turbo side so you need shorties and it's still damn tight. You will use many many 4 letter words trying to get the exhaust manifolds on as they nearly touch the frame. Exhaust gets tricky too. Too much to type ight now but most run the main exhaust on the outside of the frame. That is what I did. Drivers side manifold hits the oil lines so either move the oil lines or use the 6.2 manifold and fab a crossover(what I did).
I would strongly recommend Doing the headgaskets. it's easy to do with all the manifolds off. the crap *** printo seal HG's that GM used on 6.2 don't seal worth a crap and the fire rings suck. use 6.5 HG's with ARP studs and you can run 14 lbs of boost easy. You can turn up your existing IP . If you want even more fuel, I swapped my IP to a 4911 of a 6.5 and turned it up. It rolls some coal but damn that truck will run and I see little difference between a DS4 6.5. The DS4 puts out a bit more fuel and the timing curves are controlled better but the sacrifice is reliability. The DB2 is way more reliable. My truck weighs around 7,000 lbs and it runs like a raped ape. Even towing and I have long said the GMT400s run hot because the grilles are poorly designed and too much rap stacked in front. I have owned many 6.5 GMT400 trucks and everyone of them could run hot and high egts. I CANNOT get my 6.2 over 1,000 and that is pushing it hard and even towing it never has gone over 200 although I am running a HO 6.5 cooling system.
Anyway my elbows and hands hurt(damn tendonitis)so chew on that for a bit and ask away.
 
  #20  
Old 01-01-2013, 09:09 PM
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Originally Posted by acesneights1
Hmmm..
Where to start.
OK. First off that is incorrect that the 6.2 lower ends are weaker. In fact the 660 blocks were thought to be the strongest next to a Navistar 506(aka Optimizer/P400).
a 6.5 Turbo setup does not "Bolt on". It can be "made" to fit without alot of effort.
The main issue depends on what body style your truck is. If it's a GMT400(88+ not including 1 ton or K5) yeah it will pretty much bolt right on.
If it's in an older square body...there will be issues . Main one being whether or not you have A/C. Also depends on what year 6.2 and the angle of the injs .
Let's assume worst case scenario and it's an old Square Body, has A/C and has the long style injs.
First issue is the turbo will hit the a/c box.
You either have to ditch the a/c or I have heard people use a modified a/c box from an s10.
Now the long injs hit the ex manifold turbo side so you need shorties and it's still damn tight. You will use many many 4 letter words trying to get the exhaust manifolds on as they nearly touch the frame. Exhaust gets tricky too. Too much to type ight now but most run the main exhaust on the outside of the frame. That is what I did. Drivers side manifold hits the oil lines so either move the oil lines or use the 6.2 manifold and fab a crossover(what I did).
I would strongly recommend Doing the headgaskets. it's easy to do with all the manifolds off. the crap *** printo seal HG's that GM used on 6.2 don't seal worth a crap and the fire rings suck. use 6.5 HG's with ARP studs and you can run 14 lbs of boost easy. You can turn up your existing IP . If you want even more fuel, I swapped my IP to a 4911 of a 6.5 and turned it up. It rolls some coal but damn that truck will run and I see little difference between a DS4 6.5. The DS4 puts out a bit more fuel and the timing curves are controlled better but the sacrifice is reliability. The DB2 is way more reliable. My truck weighs around 7,000 lbs and it runs like a raped ape. Even towing and I have long said the GMT400s run hot because the grilles are poorly designed and too much rap stacked in front. I have owned many 6.5 GMT400 trucks and everyone of them could run hot and high egts. I CANNOT get my 6.2 over 1,000 and that is pushing it hard and even towing it never has gone over 200 although I am running a HO 6.5 cooling system.
Anyway my elbows and hands hurt(damn tendonitis)so chew on that for a bit and ask away.

I am sorry I really hate to **** people off but to say all 6.5/6.2s are week in the bottom end just because you read it or because you can’t build one right! SORRY!
I am one of those people who bleave that the factory did a little better job on mine and that there is no task too hard to handle! I have nothing to ask you or any one easel but not just to say you Esperance makes all 6.5/6.2s bad well that just stupidity not fact
FACT MY STOCK 6.2 before mods with (highway gear) had no problems hauling my z71 with 5.7 at 70 mph with no problems unlike (I CANNOT get my 6.2 over 1,000 and that is pushing it hard ! ) chew on what your own a pos ! Lol great sell it so someone who knows a little bit more about their truck!
The 6.2 and 6.5 from 1992 are all the same the bore is it the problem is they kept the crank too throws boost and too much fuel at it and yea it’s a time bomb! Even under full tow mine will only puff a little I have had it on a dino for 3 weeks straight to know what I know now!
Yep I broke it too but only mudding a turbo and a 6.5 ip turned 3/4 a turn! So yea they are WEAK compared to a Cummins!

SO I SAY GO BACK TO SCHOOL! COME BACK WHEN YOU HAVE NEW INFO!
Its a chevy not dodge (mild power) not ***** to the wall power house !
 


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