Considering DD'ing 350k mile LB7?

[fl0w3n]

If you are set on replacing the turbo or it is bad, I say get the 63.5 turbo and limit the torque/hp in the tune until you have a clutch that can handle it. Then you can turn it up

I wouldn’t say I’m set on replacing it, I guess I’m just assuming it’s bad right now.

Thanks everyone for the info in the thread, this has been great learning.

The 63.5/64 being able to hurt my stock motor puts it into perspective. I guess I was thinking they were a little milder than they are. When it comes to $1,100-$1,200 for a stock reman, the $5-900 for the 63.5/64 or even the one from Yellow Chevy becomes attractive.

I’m sure lots of people say this, and then wind up going to complete opposite way, but I’m not looking to go much over 425/450hp with this truck. If I wanted to build a hot rod, I’d probably do an automatic and an LBZ.

 

[fl0w3n]

If you are set on replacing the turbo or it is bad, I say get the 63.5 turbo and limit the torque/hp in the tune until you have a clutch that can handle it. Then you can turn it up

If the turbo is bad, does the 63.5 actually fix it? It doesn’t come with any bearing or anything.

X2. Not that much of a difference in price. Or if the turbo is good the wheel and cover would be a good option while it’s all apart if you have the money. Lift pump first tho. Might can save by going a single Kennedy with a custom filter setup.

I was looking at pricing a custom filter setup and I think by the time it’s done with dual filters and all the fittings it would be $300 which basically matches the airdog price

Or, I do believe this wouldn't be a bad option and helps another forum member get some parts out of his garage. Pretty sure he's open to reasonable offers.

https://www.duramaxdiesels.com/forum/showthread.php?p=1135651#post1135651

That option seems good because it comes with bearings

 

[DAVe3283]

My brother had a truck with +60% VCO injectors and a Silver Bullet 66mm turbo on a stock bottom end. It was a RIOT to drive. Had the stock CP3, which kept power down, but it would come on so hard it ended up spinning the balancer on the crank.

You can blow up a stock bottom end on stock injectors & turbo if your tune is insane, and you can keep a stock bottom end alive with a 72mm turbo (my truck had a 72mm on stock bottom end for a while). It is ALL in the tuning. Too much torque, especially at low RPM, and you'll pretzel your rods or worse.

If you're looking for 425-450 HP, a stock turbo will easily support that. If yours works, why waste the money on a rebuild or replacement? If your stock turbo dies, it is really tempting to put on a Stealth 64 or similar turbo and just have a bit more power. But the "bit more power" argument is a slippery slope. And either way, you are better off spending the money on a lift pump now, then save up for a turbo if it ever does fail (or you get "the itch")

 

[fl0w3n]

My brother had a truck with +60% VCO injectors and a Silver Bullet 66mm turbo on a stock bottom end. It was a RIOT to drive. Had the stock CP3, which kept power down, but it would come on so hard it ended up spinning the balancer on the crank.

You can blow up a stock bottom end on stock injectors & turbo if your tune is insane, and you can keep a stock bottom end alive with a 72mm turbo (my truck had a 72mm on stock bottom end for a while). It is ALL in the tuning. Too much torque, especially at low RPM, and you'll pretzel your rods or worse.

If you're looking for 425-450 HP, a stock turbo will easily support that. If yours works, why waste the money on a rebuild or replacement? If your stock turbo dies, it is really tempting to put on a Stealth 64 or similar turbo and just have a bit more power. But the "bit more power" argument is a slippery slope. And either way, you are better off spending the money on a lift pump now, then save up for a turbo if it ever does fail (or you get "the itch")

With an Allison there’s lockup and an tcm/tq management that will kind of protect the motor (at the sacrifice of itself), but with my manual, do I just need to be wary of getting on it too hard in low rpm scenarios? Essentially my right foot becomes the tcm and tq management?

Should I only be worried about shaft play on the stock turbo? Once I get down there and have access to it, just wiggle the shaft and if it doesn’t move then I’m good to go?

Also, was your tune setup for an LBZ FPR and CP3?

 

[zakkb787]

FPR is the only difference and it just allows you to run a few more thousand rail psi. Jesse is running 800+ hp on a stock bottom end and zf6, but he has a lot of power and not much torque. It’s all in the tuning. Any truck with the wrong tune can pretzel a rod.

Also, I can’t see why you’d have more than $150 in a filter setup. The heads are $25-30. The filters aren’t as expensive as stock either if you get CAT filters.

But 450 hp will be a blast. And stock turbo can easily support that and fairly safely.

 

[DAVe3283]

With an Allison there’s lockup and an tcm/tq management that will kind of protect the motor (at the sacrifice of itself), but with my manual, do I just need to be wary of getting on it too hard in low rpm scenarios? Essentially my right foot becomes the tcm and tq management?

No, it's all in the tune. The tune can be set as soft or aggressive as desired. I usually keep torque below 2000 RPM close to stock, and I usually soften up throttle response below 1/3 throttle a bit too. I find it is smoother to drive on rough roads and off-road. Above half throttle is where things get fun.

Should I only be worried about shaft play on the stock turbo? Once I get down there and have access to it, just wiggle the shaft and if it doesn’t move then I’m good to go?

Some play along the axis of the shaft is OK, but too much play up/down or left/right indicates bearing wear. If the turbo has been sitting for a while, the oil drains out, so some play is normal, since the OEM turbo is journal bearing.

Also, was your tune setup for an LBZ FPR and CP3?

The one I posted isn't, but it is easy to change that table. If you want to try the one I wrote for my brother's SAC45's, that already is setup for the LBZ FPR.

 

[Chevy1925]

FPR is the only difference and it just allows you to run a few more thousand rail psi. Jesse is running 800+ hp on a stock bottom end and zf6, but he has a lot of power and not much torque. It’s all in the tuning. Any truck with the wrong tune can pretzel a rod.

Also, I can’t see why you’d have more than $150 in a filter setup. The heads are $25-30. The filters aren’t as expensive as stock either if you get CAT filters.

But 450 hp will be a blast. And stock turbo can easily support that and fairly safely.

A lb7/lly fpr will run 26k desires rail just as a lbz one will. No reason to change unless you have a weak fpr or are striving for well beyond 26k but at that point, you won’t be running a stock fpr

 

[zakkb787]

A lb7/lly fpr will run 26k desires rail just as a lbz one will. No reason to change unless you have a weak fpr or are striving for well beyond 26k but at that point, you won’t be running a stock fpr

Didn’t know this James. So what’s the point of everyone putting a lbz cp3 in?

 

[torqued2dmax]

Didn’t know this James. So what’s the point of everyone putting a lbz cp3 in?

2x

 

[DAVe3283]

The LBZ FPR uses a square slot in the plunger, while the LB7/LLY regulator uses a triangle slot. The square slot has more area, so the newer regulator will flow a bit more fuel. Not a huge amount, but the costs are similar, so why not use the newer one if you're replacing it anyway.

As for the CP3 itself, I think people use it because the LBZ CP3 is a bit cheaper, though I'm not sure why.

 

[Chevy1925]

Everyone “thinks” it flows more to gain more rail pressure on a weak cp3. It was something done way back in the days before guys realized, 1. A lb7/lly could hit the same pressures. 2. Adding /modding a fpr for more flow was a band aid for a weak cp3 and if modded too much could cause erratic rail issues.

THe mouth of the lbz fpr does have a little larger end to it at full open but I’ve yet to see it actually add 3k rail that bumping up a stock fpr didn’t do. It’s like adding “bag of parts” to your cp3 that was an II gimmick years ago.

It’s old tech that’s been outdated imho. If you have weak rail pressure, it’s time to look at cp3, injectors, and then if you want more rail to gain a few extra ponies (assuming you have the air to use the extra fuel), you can bump up rail. Then you have no rail surge issues like some lbz fpr swaps give and still the same amount of added fuel. Real simple to do in the tune

 

[Chevy1925]

The LBZ FPR uses a square slot in the plunger, while the LB7/LLY regulator uses a triangle slot. The square slot has more area, so the newer regulator will flow a bit more fuel. Not a huge amount, but the costs are similar, so why not use the newer one if you're replacing it anyway.

As for the CP3 itself, I think people use it because the LBZ CP3 is a bit cheaper, though I'm not sure why.

From what I’ve seen, there is no gain and it’s more tuning to deal with. Specially with the “picky” customer

 

[DAVe3283]

From what I’ve seen, there is no gain and it’s more tuning to deal with. Specially with the “picky” customer

I've never had too much trouble tuning a LBZ FPR in a stock CP3, but my 12mm CP3 with LBZ reg did give me some trouble. Still can't get it to follow rail as close as I like on a snap decel (end of a 1/4 run for example). It will hang high for a few frames, then undershoot and come back to desired after 300ms or so. Any tweaks I make to the so-called PID tables (it's not a real PID control on the LB7) seem to cause more trouble than they're worth on the whole. None of this was bad enough to throw a code, but I'm probably my own "picky" customer LOL

The reason I end up with LBZ FPRs in everything is because like the LBZ CP3, they seem to be cheaper, and I'm cheap. Fix it with software!

 

[fl0w3n]

From what I’ve seen, there is no gain and it’s more tuning to deal with. Specially with the “picky” customer

I plan to just replace my CP3 either way, the LDS Super Sport is $100 more than an LB7 unit. I have a pretty much brand new LB7 FPR in my current one.
Should I save the $100 and go with the LB7 unit instead?

Are you saying tuning will open the LB7 CP3 up past 3k rpm?

 

[Chevy1925]

I plan to just replace my CP3 either way, the LDS Super Sport is $100 more than an LB7 unit. I have a pretty much brand new LB7 FPR in my current one.

Should I save the $100 and go with the LB7 unit instead?



Are you saying tuning will open the LB7 CP3 up past 3k rpm?

No, gotta read closer. I’m saying the 3k rail pressure that most guys are trying to gain (max the stock rail pressure sensor sees) can be had with tuning. Nothing tuning wise will change the rpm fuel flow limit a stock cp3 has.

 

[Chevy1925]

I've never had too much trouble tuning a LBZ FPR in a stock CP3, but my 12mm CP3 with LBZ reg did give me some trouble. Still can't get it to follow rail as close as I like on a snap decel (end of a 1/4 run for example). It will hang high for a few frames, then undershoot and come back to desired after 300ms or so. Any tweaks I make to the so-called PID tables (it's not a real PID control on the LB7) seem to cause more trouble than they're worth on the whole. None of this was bad enough to throw a code, but I'm probably my own "picky" customer LOL

The reason I end up with LBZ FPRs in everything is because like the LBZ CP3, they seem to be cheaper, and I'm cheap. Fix it with software!

It seems to be a case by case basis. Some damn near never need a tweak, others are a god damn nightmare. Really doesn’t make sense to me. That’s varied from stock cp3’s, bigger singles, two stockers (both with lbz fpr) or mixing cp3’s. Mixing larger cp3’s has been the toughest to get things calmed down. Specially with a ppe cp3 controller. Fingers controller is much easier to control different sized cp3’s imho. It’s mainly in the areas you mentioned as well as altitude changes and temp control that is hardest to dial in. Basically a daily driver.

 

[fl0w3n]

No, gotta read closer. I’m saying the 3k rail pressure that most guys are trying to gain (max the stock rail pressure sensor sees) can be had with tuning. Nothing tuning wise will change the rpm fuel flow limit a stock cp3 has.

Oh okay, I get it now. That’s what I thought at first but didn’t understand.

I’m not tuning stuff myself like a lot of you guys, so my understanding is just at an armchair general level. I just wanted to make sure you weren’t recommending something else. I’m trying to keep the costs low, but also do it right.

 

[Bdsankey]

It seems to be a case by case basis. Some damn near never need a tweak, others are a god damn nightmare. Really doesn’t make sense to me. That’s varied from stock cp3’s, bigger singles, two stockers (both with lbz fpr) or mixing cp3’s. Mixing larger cp3’s has been the toughest to get things calmed down. Specially with a ppe cp3 controller. Fingers controller is much easier to control different sized cp3’s imho. It’s mainly in the areas you mentioned as well as altitude changes and temp control that is hardest to dial in. Basically a daily driver.

Surprisingly my truck (14mm street in the valley with a stock LBZ on the belt) hasn't given my tuner any issues with a PPE controller.

 

[fl0w3n]

FPR is the only difference and it just allows you to run a few more thousand rail psi. Jesse is running 800+ hp on a stock bottom end and zf6, but he has a lot of power and not much torque. It’s all in the tuning. Any truck with the wrong tune can pretzel a rod.

Also, I can’t see why you’d have more than $150 in a filter setup. The heads are $25-30. The filters aren’t as expensive as stock either if you get CAT filters.

But 450 hp will be a blast. And stock turbo can easily support that and fairly safely.

Do you have links to the filter heads you’re talking about? Do they need adapters or does the CAT filter fit right on the head?

 

[zakkb787]

Do you have links to the filter heads you’re talking about? Do they need adapters or does the CAT filter fit right on the head?

Google Napa 4770 or WIX 24770. It’s a pretty standard thread. Should be able to find them easily, after all that’s what the filter heads are designed for. Kennedy pumps run low psi high volume so standard fuel hose and clamps on a barbed fitting should work just fine. I had considered putting both heads after the pump to make things simpler but the inlet/outlet design messes with that. My plan is to put one head behind the pump with a higher micron filter/water separator to make sure the pump is getting clean fuel, then put a 2 micron CAT or 1 micron Baldwin filter in front of of it so that it pushes the fuel thru and all the way directly to the cp3. I do plan to use a sump on my truck as it will never see hard off roading. I would highly recommend getting the full Kennedy kit with pickup. Easy install, less restriction, peace of mind, and at your mileage and age there’s no telling how your factory pickup is looking inside there.

Air dog will simplify this by leaps and bounds, but I’m partial to the Kennedy design. I see many more airdog/fass pumps failing than Kennedy. Part of this could be because of how many there are out there in comparison, but the Kennedy design in theory shouldn’t ever wear out. No moving parts.