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Discussion Starter #1
Are the guys modifying their 6.7's? I'm sure there are people on here that do it! Let's see what ya got!
 

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Discussion Starter #3
Besides EFI-Live, you can do a ton to them! Turbo, injectors, billet rods, cam, head work, main studs, head studs, modified or twin CP3's, 47/48RE swaps or built 68RFE's, intercooler upgrades, water meth, nitrous, etc.

H&S just ran a 9.80 @ 14x in their 6.7 with triples, 4 link, 4R100 and their MCC software. That's not far behind Pro Street 5.9's in RCSB trim.
 

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Cost to reach that is just so much more than the 5.9 though. I want that same power I was getting out of my 5.9, but to do that reliably in this truck is giong to cost alot more than I can swing. I wish it was as easy as it used to be.
 

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Discussion Starter #5
I'm not sure man, I've spent the same amount to hit what a 5.9 would. The only difference I see is going over 800hp. 6.7's needs billet rods. 5.9 needs a bottom end build about 1000. And that's all due to the longer stroke of the 6.7.
 

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On my 5.9, I threw on a cheap programmer, intake, and exhaust, and went 13.9 on 37's. My truck now has an H&S on hot with a dpf delete and 35's, and I bet I would be lucky to see 14.5. The 3rd gen 6.7's have more options for tuning, so you are at an advantage there. I am referring to the 4th gens here.

Are there any 12 second 4th gens yet?
 

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Discussion Starter #7
I know one, on Cummins Forum. Also know a guy with 37's on his 4th gen and running high 13's with turbo, stock sticks and CP3.
 

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I know one, on Cummins Forum. Also know a guy with 37's on his 4th gen and running high 13's with turbo, stock sticks and CP3.
That's what I'm saying. My 07 5.9 with just a bullydog, intake, 5" exhaust, and stock turbo went 13.9 on the 37's. The tuning options available for the 5.9 made it easy to build a fast truck. The 4th gens have been out for 2 years now, and there is only 1 truck on a forum with thousands of cummins guys that has broke into the 12's. With a 5.9, it was as easy as a tune, 64mm turbo, and some 90hp nozzles and you were well into the 12's. Also, built transmissions could be made to handle over 600hp for about $3k whereas now it is going to cost no less than $7k or you end up having to take the route that you took and put a different tranny in there.

Stock for stock, there is no comparison that the 6.7 wins, but the aftermarket just hasnt caught up yet.
 

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Discussion Starter #9
Just wait for EFI-Live buddy =)

It made a world of difference on my truck. The two things 6.7's have going for them is 1) they can spool MUCH larger singles than a 5.9 could dream of and 2) the pistons and head handle head much better, so the issue of melted pistons aren't as prevalent as on the 04.5-07's.
 

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Besides EFI-Live, you can do a ton to them! Turbo, injectors, billet rods, cam, head work, main studs, head studs, modified or twin CP3's, 47/48RE swaps or built 68RFE's, intercooler upgrades, water meth, nitrous, etc.

H&S just ran a 9.80 @ 14x in their 6.7 with triples, 4 link, 4R100 and their MCC software. That's not far behind Pro Street 5.9's in RCSB trim.
The MCC software will be out soon for the 6.4 ;)
 

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Discussion Starter #11
The only problem I have with MCC is that it doesn't allow data-logging like EFI-Live. Data logging is what makes EFI what it is. Without it, I don't see how having access to all the tables does much.
 

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Just wait for EFI-Live buddy =)

It made a world of difference on my truck. The two things 6.7's have going for them is 1) they can spool MUCH larger singles than a 5.9 could dream of and 2) the pistons and head handle head much better, so the issue of melted pistons aren't as prevalent as on the 04.5-07's.
Sorry to burst bubbles but EFILive is moving to SCI 03-05 trucks instead of working on the 4th gen Cummins. I think they realized the demand for the SCI crowd over the 4th gen.

I will argue the point of melting pistons on the 325 trucks. The most common and what I call "known" effect of melted pistons is due to joe blow slapping a programmer on his truck with a sh1t ton of fuel being poured into the cylinder with advanced timing and a stock turbo. I've talked to many who mechanic on Cummins and deal with these trucks and melted pistons. It's a dime a dozen of stock turbo'd trucks with lots of fuel and advanced timing.

Out of the box the 6.7 is a better bang for the buck truck as aftermarket goes. But the aftermarket support for the 5.9 is never ending it seems. I wouldn't turn down a 6.7 but I still prefer my 5.9
 

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Discussion Starter #13
I don't know. I've seen over 1600 degrees probably several hundred times, between drag racing, dyno and tuning. Haven't melted a piston yet. And I know quite a few 6.7's in that same ballpark.

Where I have seen them melt (can think of several off the top of my head) is with a stock turbo and tons of fuel. But data logging my runs at the track, going through the traps I'm about 1800 degrees pre-turbo.
 

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I don't know. I've seen over 1600 degrees probably several hundred times, between drag racing, dyno and tuning. Haven't melted a piston yet. And I know quite a few 6.7's in that same ballpark.

Where I have seen them melt (can think of several off the top of my head) is with a stock turbo and tons of fuel. But data logging my runs at the track, going through the traps I'm about 1800 degrees pre-turbo.
My point exactly!

1600-1800 is alright for short amounts of time. But when morons are running 37'' tires on stock gearing with an inadequate amount of air to the fuel and air mixture, it's a great recipe for melted pistons.

The first Cummins in our family was a 96 3/4 ton 2wd my dad bought from our neighbor. It was bone stock! We put a mild fuel plate in it (#10 or so), messed with the pump a bit, added a boost elbow, adjusted transmission bands and added EGT and trans temp gauges. I used to love watching those gauges swing! When that converter locked up there would go that EGT gauge on the climb, but at the same time that trans temp would back off some. Unlock the converter and watch the EGT come down some while the trans creeped up... I think between watching those gauges all the time and the hunger to learn about diesel, I was scared straight to always want a lean/clean running truck with minimal smoke.

Soap box over, we can now return to regular scheduled 6.7 talk.
 

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Discussion Starter #15
I hear ya! I honestly don't know how someone could melt a piston . . . but not everybody uses common sense when modifying these things. Either leave them stock and never worry about it, or modify with some intelligence. And most importantly - ASK questions! This and other sites are good to learn about these trucks.
 

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Here is our new to us 2007.5 6.7 project truck which we bought just a couple of months ago.Its a Laramie/Sport 2500 auto with all the options except a Moon Roof.Truck has a 6" SuperLift on it and rides on 22" Novacanes with 37" Toyo Open Country M/T's.

Mods done to it already before we bought it were full delete with H&S parts,H&S XRT/Pro and a MBRP exhaust.A trip is coming soon to have the trans updated to handle what we want to do and we will go from there afterwards.Truck will get the set of twins off my 2005 truck and the twin CP3's this winter as we make changes to the other ride for next year.

 

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Discussion Starter #17
Very nice!
 
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