6.2 IDI vs. 6.9 IDI

[JPalmer81]

Just like the title says, I want to pick all your brains and have a good discussion on these 2 iconic IDI motors that started it all. I am not partial to either one, but I want to know what you think.

-Pro's and Con's of both motors
-Which is more reliable
-Which has more potential for power
-Which is cheaper to upgrade
-Which would you rather have
-Which is better in NA form
-Which is better for turbo setup
-MPG's?

 

[Black dawg]

Just like the title says, I want to pick all your brains and have a good discussion on these 2 iconic IDI motors that started it all. I am not partial to either one, but I want to know what you think.

-Pro's and Con's of both motors
-Which is more reliable
-Which has more potential for power
-Which is cheaper to upgrade
-Which would you rather have
-Which is better in NA form
-Which is better for turbo setup
-MPG's?

The 6.2 will spank the 6.9 for mpg. as far as reliability being used hard the 6.9 has the upper hand.

If I wanted to have an NA motor, I would have a 6.2 because of the mpg.
as far as upgrades, they cost about the same. Just find a used turbo kit, turn up the fuel, and it is upgraded.

also the 6.9, doesnt have the tendency to run hot like the 6.2

 

[tanman_2006]

6.2 has more hp potential and more available upgrades and after market. 6.2 also gets better mpg. New 6.5's cast by navistar can be bought still and are on par with a 6.9 in block stability.

6.9 has a little better torque and a stouter block out of the box.

 

[Black dawg]

6.2 has more hp potential and more available upgrades and after market. 6.2 also gets better mpg. New 6.5's cast by navistar can be bought still and are on par with a 6.9 in block stability.

6.9 has a little better torque and a stouter block out of the box.

what gives the 6.2 more hp potential?

 

[tanman_2006]

Mostly the way its built, its got less rotating mass and can spin higher rpm with ease

 

[Black dawg]

forgot about the extra rpm.

 

[JPalmer81]

What about potential torque for hauling a good size load down the freeway?

 

[towcat]

What about potential torque for hauling a good size load down the freeway?

i own and build both makes. my rule of thumb for which truck to use is simple.
if I am hauling ass and commuting.....6.2/6.5 GM.
if I am hauling heavy or going where you are a participant in the food chain.....6.9/7.3 IH
my '92 F350 is build to haul 10k/lb trailers without breaking a sweat.
442Bob's '83 C2500 is built to haul ass. It will leave my '92 standing still at the lights the moment the throttle is dumped.
if I want to haul 15k/lb gross spread between two axles, I break out my '89 F450 and not be a serious hurry getting there and back.
each truck has an intended purpose. there isn't a rule that you can't use a truck outside it's purpose but it won't work to it's best potential.

 

[JPalmer81]

i own and build both makes. my rule of thumb for which truck to use is simple.
if I am hauling ass and commuting.....6.2/6.5 GM.
if I am hauling heavy or going where you are a participant in the food chain.....6.9/7.3 IH
my '92 F350 is build to haul 10k/lb trailers without breaking a sweat.
442Bob's '83 C2500 is built to haul ass. It will leave my '92 standing still at the lights the moment the throttle is dumped.
if I want to haul 15k/lb gross spread between two axles, I break out my '89 F450 and not be a serious hurry getting there and back.
each truck has an intended purpose. there isn't a rule that you can't use a truck outside it's purpose but it won't work to it's best potential.

If you had to pick just one truck, which one would it be?

What kinda driving around empty mileage can you get out of a NA 6.9 with an OD?

 

[tanman_2006]

My 93 6.5 will pull the axles off of any trailer you put behind it, Honestly I think it pulls better than my dmax but doesnt stand a chance without a load.

One thing you have to realize about a 6.2L is the torque curve is higher in the RPM and the motor doesnt like lower RPM lugging. With an A Team Turbo I can run 3000 rpm all day and not break a sweat grossing ~30K. I'm guessing the NA motor will do good around 2200-2500 towing, that might be no OD running 50-55 but it will work, most NA 6.9's cant hold much over that anyways.

 

[JPalmer81]

My 93 6.5 will pull the axles off of any trailer you put behind it, Honestly I think it pulls better than my dmax but doesnt stand a chance without a load.

One thing you have to realize about a 6.2L is the torque curve is higher in the RPM and the motor doesnt like lower RPM lugging. With an A Team Turbo I can run 3000 rpm all day and not break a sweat grossing ~30K. I'm guessing the NA motor will do good around 2200-2500 towing, that might be no OD running 50-55 but it will work, most NA 6.9's cant hold much over that anyways.

Yeah, the 6.2 hits its max TQ around 2000-2200 RPM and the 6.9 is like 1400 RPM or something crazy low like that. In the Army in AK, all of our HMMWV's still have the NA 6.2's, well most of them i should say. And we pull crazy loads with them and they don't seem like they break a sweat at all, however with the gearing we are only going 45 MPH, but you can build your truck to run at a certain RPM.

 

[tanman_2006]

I want 4.56's and a ranger OD on my 93, I could pull all day at ~60mph with NV4500 in 4th and ranger in OD and run ~2700 then kick into 5th when the load is off and back down to ~2200 at 65. My RPM's might not be exactly on but they gotta be close, with 4.10s and my 235/85's i run ~2200 @ 65 now.

With the aftermarket non gated A Team Turbo the 6.5 can make its torque from 2000 to 2700peak and hold it through 3000 before it trails off and HP keeps picking up, fueling is short above 3,000 on a stock pump, a built pump would help alot.

 

[JPalmer81]

I want 4.56's and a ranger OD on my 93, I could pull all day at ~60mph with NV4500 in 4th and ranger in OD and run ~2700 then kick into 5th when the load is off and back down to ~2200 at 65. My RPM's might not be exactly on but they gotta be close, with 4.10s and my 235/85's i run ~2200 @ 65 now.

With the aftermarket non gated A Team Turbo the 6.5 can make its torque from 2000 to 2700peak and hold it through 3000 before it trails off and HP keeps picking up, fueling is short above 3,000 on a stock pump, a built pump would help alot.

If you put a Ranger in front of an NV4500 with 4.56 gears and 235's your 65 MPH cruise speed RPM would be 1995, that would be nice for MPG's that is for sure.

 

[tanman_2006]

Thats kinda what I was thinking. I had all the math done on that a while back but didnt wanna dig it out.

The trucks main purpose isnt MPG its to be a tow pig and test out turbo's for that application, after i find the turbo i am happiest with I will test the DB4 for towing. I am gonna assume i will lose the engine sooner or later and have a built engine to run for another variable.

 

[JPalmer81]

Thats kinda what I was thinking. I had all the math done on that a while back but didnt wanna dig it out.

The trucks main purpose isnt MPG its to be a tow pig and test out turbo's for that application, after i find the turbo i am happiest with I will test the DB4 for towing. I am gonna assume i will lose the engine sooner or later and have a built engine to run for another variable.

Speaking of having another motor on stand-by, who sells new blocks for 6.2/6.5? Can civilians order from Navistar?