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Discussion Starter · #1 ·
Hello friends! First post, but I have been lurking this website for over a year now. I will try to keep this post as short as I can but we'll see! First, a little about the truck -

89 K2500 with a late 80s 6.2 J code that I swapped from a motorhome (I know right) in June of this year. Motor has an hx35 turbo gated at 10 psi (sometimes will get up to 11 or 12). Motor is otherwise stock internally. It is mated to an sm465. I have 31.3" tires and 4.11 gears. I have an EGT and obviously a boost gauge as extras.

The fuel pump is a db2, not a 4911 or anything fancy (I looked it up and it was not memorable...I can dig it up again if someone needs it). When I installed the turbo, I turned it 1/4 turn.

Now that you know what I am working with, I'll give you the scenario and question!

I had my first experience pulling a decent load (5500-6000 lbs) this weekend. On the flats, it does just fine, but you can tell there is a load behind you. Cruising EGTs around 550-600 at 55-60 mph. Before my home, there is a very steep hill with a grade of 7% that is about 2 miles long. While trying to pull this hill, I had the pedal to the floor and could not get above 50 mph. EGTS were in the 900s. At the last half mile, my EGTs got up to about 1050 and I began to lose speed (the last half mile has a turn on the grade). Once I realized that my EGTs were climbing and I was losing speed, I panicked and shifted down into 2nd (or 3rd depending on how you view the SM465) and finished the hill at 40mph, pretty embarrassed. Boost held steady at 10 PSI.

My question - Do I need more fuel? I feel that if I could have maintained a higher speed (and higher RPMs accordingly) I would have had lower EGTs rather than basically "lugging" in my highest gear. Or does my experience sound exactly like the limit of what the 6.2 can do? As an additional piece of info, I cannot get my EGTs over 850 with the truck empty, regardless of the hill. pedal to the floor etc. (although sometimes my boost will try and climb over 10 as my speed increases).

I just need some opinions and advice. Right now, I am tempted to get into the pump and try and go another 1/4 turn.

Post ended up being longer than I hoped. Thanks everyone and God bless.
 

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Welcome to DieselPlace
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Discussion Starter · #3 ·
Anybody at all have an opinion? I don't feel that there is a perfect answer. Your opinion is worth more then the truth 😁
 

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You are gonna have to try it, some of this is trial an error.
I have seen where some will run the screw all the way in and back off 1/8 turn but the EGTs quickly climb to 1300.

I don't think you are going to do much better going up that grade, more fuel equals more heat.
And no intercooler doesn't help.
 

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I think you're tapped. These motors do like to spin though! I use to go mildly loaded over a pass with mine regularly and if I saw 900+ out of the EGT's it was lugging. I'd drop it out of OD into 4th (NV4500) and it would clear up the exhaust a bit and drop the EGT's down. You could try another 1/8th of a turn, but it sounds like you're getting all the fuel you need since the turbo is up against the wastegate. Any more fuel and you're just going to get more smoke is my guess.
 
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Discussion Starter · #6 ·
I think what I will do is bump the fuel some.

I am also going to look at getting an intercooler.

Once my head gaskets go, I'm going to replace the heads with 6.5 heads and and see if the better flow and pre cups result in more power and lower EGTs. I suspect they will.

I will bump this thread after that point (we'll see how long this stock motor lasts) and go from there.
 

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I probably wouldnt waste time looking for 6.5 heads if your 6.2 heads are good. From my understanding the only thing that changed was the injector angle so they arent so close to the exhaust manifold. Precups too, but that's a different story. Intercooler would be sweet! Always wanted to do that to mine, but never did until a put a 12v in it shrugs
 
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