LLY - Cracked piston

[Bdsankey]

i played with a few different ones but yes, 100%'s. i think i finally settled on 1000uS for summer. it was like 480-500hp (felt neutered compared to before ) as i was tired of starring at the coolant temp. i could just put my foot to the floor and go. There was a fine line in enough fuel to light the 483 and not like Shane says. the 900uS i used at one point coming back from a trip would hardly get the 483 to do anything, 475 should work off that but not much lower. i never tried it but ive heard going under 800uS can be hard to tune part throttle.

That's was one of my concerns with my 480 and why I went 70%, but my HP goal also is less than 800 (would be nice but towing/drivability>power)

 

[S Phinney]

i played with a few different ones but yes, 100%'s. i think i finally settled on 1000uS for summer. it was like 480-500hp (felt neutered compared to before ) as i was tired of starring at the coolant temp. i could just put my foot to the floor and go. There was a fine line in enough fuel to light the 483 and not like Shane says. the 900uS i used at one point coming back from a trip would hardly get the 483 to do anything, 475 should work off that but not much lower. i never tried it but ive heard going under 800uS can be hard to tune part throttle.

About the lowest I have ran was 1000uS tried 950 and just didn’t like it. Also we were using a 66/480 on this truck. It really comes down to preference and what makes you satisfied.


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[NevadaLLY]

I think the main goal is to be able to tow out here with some decent power and a reliable build. Nevada regularly sees 90's-100 in the summer and we are at 4500ft so cooling has always been an issue - its one of the main reasons I went with compound over big single. I'm trying to balance power for the build as towing at 450-500, reliably, with room to spare is my goal. Lowering cylinder pressures with lower pulse is a plus, lower CR with the new pistons will also help, which ideally will improve the engine efficiency and lower temps somewhat. I'll also be running the waterless coolant (i'll update if it's any good once I run in the summer). Unloaded on the hot tune, it would be fun to see what she's got but that's less than 10% of the use of the truck.

 

[Dozerboy]

I agree with 100s. Thats what I have with Mark’s 65mm stg2 turbo. While I don’t have twins in my initial tuning I believe my pulse width was 900us and it drove fine. It felt like a stock power level. If I can teach myself to tune 100s to run clean any real tuner should be able to do it.

 

[NevadaLLY]

This has been quiet for a little - finally heard back from the machine shop - .020 over for sure. So decision time! - My real question now is can I tune 100 overs with stock CP3 and lift pump which will perform well with my compound setup. Seeing a few posts above where compounds struggled on 100's and I don't really want to have that issue as my tuner isn't close by. Additionally I understand I probably cant fuel a huge pulse width that the 100's can support, but keeping the hp sub 800 for this build, what's the consensus on 60's vs 100's (or something in between for that matter)?

 

[rcr1978]

My buddies LB7 I put 100's in when his stock injectors started hazing it has a stock CP3 and LBZ regulator it was maxd out 1450-1500ish pulse and would hold 165ish mpa but it was a stock turbo/motor truck. It ran good to for a only having the single stock pump but it was in good shape. Definately better than the 2900@170mpa max effort stock injector tune it had before. I know yours is a LLY but the 100 over LLY injectors are a little smaller than the LB7's but not much. My truck with 100's and twins does pretty decent in the 1500ish range not as good as 1800-2000 pulse but still decent. My tow tune is 1200ish unless I get excited for passing , 800-850 felt close to stock. On my first set of twins were stock/475 turbos 1500pulse felt pretty strong, with the new set it doesn't quite feel as strong around that pulse width but I think I'm used to it also, it takes 1800 plus to get that smile back.

I vote for the 100's and get a bigger CP3 later

 

[NevadaLLY]

Pulled the trigger on 100 overs from LDS and a bunch of other goodies. Will be doing the pinned oil pump, wagler rods, mahle performance cast pistons .020 over no pockets, heads are being done, and balanced rotating assy. That’s about it for the big stuff. Holding off on the AF CAM. I like the lower pulse on the tow tune to keep everything happy but also drive the stock/475 setup. This is largely a tow rig so if I have to go dual fuel later, I will.

 

[KRODMAX/KS]

Sounds like a fun setup, but don't forget the SoCal 125# beehive springs, 3/8 push rods and 3388 cam while your there.

 

[NevadaLLY]

I don’t plan to push more than 50psi on the hot tune - tow will be around 35ish. Not sure the additional cost of the cam/pushrods/springs are worth it?

 

[NevadaLLY]

Just wanted to post a few photos of the tear down. As I said - everything is at the machine shop so looking forward to assembly time in a few weeks.

 

[Josh154]

Nice! I better sub to this thread lol. I’m sure I will be doing the same thing as well sometime soon. Had similar plans too, crower rods, race cast pistons. Thought about just keying stock cam & crank. I don’t ever plan to go past 1000hp with lml 100s being my stopping point.

 

[Dozerboy]

I don’t plan to push more than 50psi on the hot tune - tow will be around 35ish. Not sure the additional cost of the cam/pushrods/springs are worth it?

From what I’ve been told as long as you don’t go over 4000rpms with that much boost you should be fine. Just set the seat pressure as high as they can on the stock springs.

 

[Animals1234]

I like this thread. I’m doing a similar setup on my Lly. Hope to see more pictures

 

[NevadaLLY]

Don’t forget to save some money for oil cooling. That should be done sooner than later especially with twins. Looks like you have some already but a 2020 cooler would be nice.

Do you know if the 2020 oil cooler (or a banks 2020 version cooler) will work with the PPE race manifolds?

 

[Bdsankey]

Do you know if the 2020 oil cooler (or a banks 2020 version cooler) will work with the PPE race manifolds?

Banks doesn’t produce a 2020 oil cooler, they’re buying the GM one.

As for fitment, I don’t know about PPE but I can confirm it does work with ProFab castflow manifolds as I sent Rick my 2020 cooler to mock-up.

 

[NevadaLLY]

Banks doesn’t produce a 2020 oil cooler, they’re buying the GM one.

As for fitment, I don’t know about PPE but I can confirm it does work with ProFab castflow manifolds as I sent Rick my 2020 cooler to mock-up.

I think pro-fab and PPE are about the same - I only mentioned banks as they kit the whole thing to adapt to the older blocks.

 

[Bdsankey]

I think pro-fab and PPE are about the same - I only mentioned banks as they kit the whole thing to adapt to the older blocks.

They do, and they’re absolutely raping you for it. $549 is insane for a cooler that’s around $300-$350 at the dealer.


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[NevadaLLY]

They do, and they’re absolutely raping you for it. $549 is insane for a cooler that’s around $300-$350 at the dealer.


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What does the elbow run? Do you happen to have a p/n?

 

[Bdsankey]

What does the elbow run? Do you happen to have a p/n?

~$15. I don’t have the PNs. I know there in the oil cooling thread in one of the posts you had quoted sometime last year. JoshH posted the PNs.


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[NevadaLLY]

~$15. I don’t have the PNs. I know there in the oil cooling thread in one of the posts you had quoted sometime last year. JoshH posted the PNs.


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Found this on another forum - recent write up and had everything needed. Thanks for pointing it all out. Good to save a few bucks with just a bit more DIY research.

https://nc4x4.com/forum/thread/2020-duramax-l5p-oil-cooler-upgrade.199455/

I’ll be adding this to the build list.
Other updates: Also added the BD flex plate to the build. My pistons were mis-labeled .040” so the vendor offered to send me the .020” over they had ready which are ceramic coated. Apparently there is a huge piston shortage and he couldn’t tell me if/when we’d hear back on the lead time. I wasn’t planning on running those but we worked it out for just a small $$ more. Additionally, I’m fairly convinced to do a slightly better cam in order to get a keyed cam. If I take the stock out and key it, might as well buy an aftermarket, stage 1 that is already keyed. Any input from you all on stage 1 cams? I’m looking at SoCal and comp cams.