Info: How much has tuning improved in the last 10 years?

[MAXX IT OUT]

Just out of curiosity, it seems more and more stock bottem end duramaxs have been making more power than previous thought was wise or safe. Are people just getting lucky, or people are starting to use a better combo of parts to make the power, or has tuning just evolved so we aren't stressing the engines as much? I remember when the answer to how much power can I make was 550-600hp otherwise you will split a piston or bend a rod. What would everyone rate the power potential for the LB7, LLY, LBZ, LMM, LML, and LP5. Is there anymore envelope to push?

 

[PureHybrid]

Well, tuning has definitely improved since a few (or maybe just one? ) have started monitoring real time cylinder pressure. I'd still say 550hp is a "sane" number, many have surpassed that but it hasn't proven to be reliable over time. Which at that power level (600+) anything can happen

 

[2004LB7]

I'll have to agree. It used to be common to add more timing in an attempt to get more power. As we monitored cylinder pressure it was discovered that it hurt power if it went too far. Timing in that last few years or so has actually gone down for many tunes without any loss of power but with less stress on the bottom end

Also, larger injectors have helped with keeping the duration down too

 

[THEFERMANATOR]

As a couple of people started monitoring cylinder pressure, I think a better understanding of what was causing the failures was discovered. And instead of just shoving more fuel in with stock injectors it's now understood you need to address pulsewidth to narrow the injection window, and get a bigger turbo to move more air instead of just trying to max your boost and push more pressure(more pressure does not always equal more actual flow). So I would say tuning has evolved, but so has the understanding that the whole package needs modified, not just tuning.

 

[TheBac]

^^ Yep. Ferm always seems to get right to the point.

But stock turbo/stock injector setups should still be limited to the same old 550 number. Not many people doing that anymore, though.

 

[MAXX IT OUT]

What would stock fuel system will a descent pump max out at?

 

[ZeroGravity58]

What would stock fuel system will a descent pump max out at?

Stock pump and injectors? Probably 550-600 but for longevity I think you would be better with a stock pump with a bigger injector to keep pulsewidth down.

 

[Vmyrhaug]

What will be a good injector size to max out bottom end? Sac45? Or larger?

 

[zakkb787]

What will be a good injector size to max out bottom end? Sac45? Or larger?

You can max out the bottom end on stock fuel easily.

 

[THEFERMANATOR]

You can max out the bottom end on stock fuel easily.

Yes, but narrowing the injection window will allow you to run more power through a stock bottom end. This has been proven several times over.

 

[Josh154]

I’ve been running my lml at 600 on stock turbo/injectors and trans for a year now. Made at least 30 1/4 mile passes and several 12 sec passes.

Also ran my lmm with modded vgt at 3200uS for 2 years stock sticks/cp3. Then switched out to 369sxe 10mil cp3 and stock sticks at 3200us for 6 months before I sold it. Lmm was beat on for a few years at 600 and still held together.

 

[ZeroGravity58]

I’ve been running my lml at 600 on stock turbo/injectors and trans for a year now. Made at least 30 1/4 mile passes and several 12 sec passes.

Also ran my lmm with modded vgt at 3200uS for 2 years stock sticks/cp3. Then switched out to 369sxe 10mil cp3 and stock sticks at 3200us for 6 months before I sold it. Lmm was beat on for a few years at 600 and still held together.

We have all done it but it is not the most efficient way. Chasing the piston with fuel just creates excessive EGTs. In my experiences if you would take your setup now and put a set of 60 overs in it I bet you would gain 2-3 tenths in the 1/4.

 

[Josh154]

Oh forsure I’m not disagreeing one bit. Since I ran the 12.9 I haven’t been back and I don’t beat on it. Rarely does it see wot. It was more of a wanting to hit a 12 on all stock lml besides cp3 essentially. As we all know the next step is a speedy one. Essentially to do it right is trans, turbo and sticks.

 

[Chevy1925]

First realization was that torque bends rods. So detorquing tunes started or upping rpm. Then the idea of larger injectors to shorten pulse width and save pistons came up, use to be "a dumb idea" to put 60% overs or 100% overs on a stock engine with a single stock pump because you couldnt use all the fuel they would give but those that knew how large pulse width was sky rocketing pressure and temps in the cyl didnt listen to those guys.

So no guys are not bending rods but making more power and as time went on, pistons are cracking less and less (this doesnt account for guys who went a long time on stock injector high pulse width). Then fingers started the cyl pressure sensor idea. mark got one and started publicising it on here showing how there is a point of deminished return with pulse width, peak power and cyl pressures even if you played with timing. on something with a large amount of fuel (250% overs and more), 200uS less from an even larger injector could make more power with less cylinder pressure. Thats going from say 1500uS to 1300uS.

When you start pushing the 2000uS, you are at the point of diminished return. i see alot of guys keeping 1500-1600 max for big HP trucks and even try to push for less if possible. it makes a difference.

Anyhow, you combine all this with a large single turbo or make sure you rev a twin setup up and stock engines live much higher in the HP range. you throw some better breathing heads on it, a cam and valve train thats good for 4500rpm+ and they can take more.

the L5P short block has been up to 850hp or 900hp and 1600ft lbs. that is far beyond what any other previous generations have done. Its just a matter of how long will the pistons last at that level. the l5p can also spin a s472 box stock charger up to 15psi at 1600rpm like its a stock lb7 charger. it has a very good head/cam flow.

 

[slowlml]

That last sentence makes me want a single s475 on a l5p as a daily lol James and ferm hit the nail on the head. Its a combination of knowledge built of trial n error that has been able to work together very nicely these days.

 

[Bdsankey]

First realization was that torque bends rods. So detorquing tunes started or upping rpm. Then the idea of larger injectors to shorten pulse width and save pistons came up, use to be "a dumb idea" to put 60% overs or 100% overs on a stock engine with a single stock pump because you couldnt use all the fuel they would give but those that knew how large pulse width was sky rocketing pressure and temps in the cyl didnt listen to those guys.

So no guys are not bending rods but making more power and as time went on, pistons are cracking less and less (this doesnt account for guys who went a long time on stock injector high pulse width). Then fingers started the cyl pressure sensor idea. mark got one and started publicising it on here showing how there is a point of deminished return with pulse width, peak power and cyl pressures even if you played with timing. on something with a large amount of fuel (250% overs and more), 200uS less from an even larger injector could make more power with less cylinder pressure. Thats going from say 1500uS to 1300uS.

When you start pushing the 2000uS, you are at the point of diminished return. i see alot of guys keeping 1500-1600 max for big HP trucks and even try to push for less if possible. it makes a difference.

Anyhow, you combine all this with a large single turbo or make sure you rev a twin setup up and stock engines live much higher in the HP range. you throw some better breathing heads on it, a cam and valve train thats good for 4500rpm+ and they can take more.

the L5P short block has been up to 850hp or 900hp and 1600ft lbs. that is far beyond what any other previous generations have done. Its just a matter of how long will the pistons last at that level. the l5p can also spin a s472 box stock charger up to 15psi at 1600rpm like its a stock lb7 charger. it has a very good head/cam flow.

This is literally why I am jumping up injector size, you've hit the nail on the head yet again James!

 

[Chevy1925]

That last sentence makes me want a single s475 on a l5p as a daily lol James and ferm hit the nail on the head. Its a combination of knowledge built of trial n error that has been able to work together very nicely these days.

thats why i wanted L5P heads if they would have bolted on, probably would have got a cam too to compare to my stocker. its absolutely nuts!

 

[ikeG]

Oh forsure I’m not disagreeing one bit. Since I ran the 12.9 I haven’t been back and I don’t beat on it. Rarely does it see wot. It was more of a wanting to hit a 12 on all stock lml besides cp3 essentially. As we all know the next step is a speedy one. Essentially to do it right is trans, turbo and sticks.

I would steer clear of sticks. I recommend good quality injectors instead.

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[Robby Avery]

subd

 

[1TRIKHD]

Subd for reading later.

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