L8P or L8T in 2018 PPV Tahoe

[MadMax_MFP]

Getting close to installing the crate L8P in place of the AFM/DOD dying 5.3L. I noticed on this forum several L8T swaps but no L8P swaps. Any reason I should be aware of? I am not looking for a tow truck replacement engine so I am not worried about the larger cam pushing the power higher up the rpm range. More gear in rear end, billet convertor and I am rarely below 2000 rpm's anyway.

 

[CMoore711]

Never even heard of the GM L8P motor until this post. It appears to be an L8T 6.6 non-AFM motor with an LT-2 based cam, forged crank, and upgraded valvetrain to accommodate the cam. GM performance crate motor putting out 535 HP/543 TQ what's not to like?

On the surface it seems like the swap process would be the same as swapping in an L8T. My guess as to why you haven't seen this one on the forum is because it's a GM Performance crate engine. I believe the few members who have swapped in the L8T end up purchasing lightly used low mileage engines to swap in and are not purchasing brand new crate motors to swap in.

Keep us updated on your swap and the process so others can confirm if the swap is in fact the same as dropping in the L8T.

 

[Too_L8T]

I looked into it. but figured a crate L8T for 4500 was the better value than what the cost of the L8P was, and i’m using it as a daily and toting campers.

 

[MadMax_MFP]

I looked into it. but figured a crate L8T for 4500 was the better value than what the cost of the L8P was, and i’m using it as a daily and toting campers.

This is the correct answer for towing and definitely will save some cash.

 

[MadMax_MFP]

I am not towing as this is more of a play time project. The L8P order is presently sitting at approximately 2 weeks. I am trying to find a good quality convertor to use that has an order lead time of less than 6 weeks. More updates to come as the parts become available.

 

[CMoore711]

I’m guessing since you have a 5.3L Tahoe you have a 6l80 6 speed transmission?

Are you sticking that 6.6 L8P and all its 543 TQ in front of a stock 6l80e?

How many miles on your 6l80?
How many times have you changed the fluid/filter in it?

 

[MadMax_MFP]

I’m guessing since you have a 5.3L Tahoe you have a 6l80 6 speed transmission?

Are you sticking that 6.6 L8P and all its 543 TQ in front of a stock 6l80e?

How many miles on your 6l80?
How many times have you changed the fluid/filter in it?

Yes, 5.3L with 6L80e. For this build and reference information to anyone else who reads this the trans will be completely overhauled. I was planning on using a Circle D convertor but they never respond to me so I will spend my money somewhere else. I am also upgrading the driveshaft and rear differential to handle the power.
I already replaced the suspension, installed a 3-4 drop, Brembo 6 piston front brakes, installed 21+ ppv wheels and upgraded the sway bars front and rear.

 

[CMoore711]

@MadMax_MFP Sounds like an awesome fun build for a fun street SUV!

Not sure if you’ve already rebuilt the 6l80e or sourced a torque converter, but for not much more money you could swap in a low mileage 10l80.

2015-2020 GM SUV - Powertrain Swap Solutions

www.powertrainswapsolutions.com

You'll be spinning lower RPMS which should equal lower operating temps, the 10l80 will handle the torque from the L8P better, and you’ll always be in the right gear.

So far looking at the numbers and trading a few emails with PSS to do this on the GMT900 if you purchase a lightly used 10l80e transmission (<10K miles) with a torque converter plus the PSS kit…

You’re looking at about an additional $1,500+/- more than a built 6l80e plus aftermarket billet torque converter.

For me once you’re in for $6-7K what’s another $1,500; But I’m not everyone.

Might be worth considering since I’m sure you’re planing on keeping and driving this rig for a while.

 

[MadMax_MFP]

@MadMax_MFP Sounds like an awesome fun build for a fun street SUV!

Not sure if you’ve already rebuilt the 6l80e or sourced a torque converter, but for not much more money you could swap in a low mileage 10l80.

2015-2020 GM SUV - Powertrain Swap Solutions

www.powertrainswapsolutions.com

You'll be spinning lower RPMS which should equal lower operating temps, the 10l80 will handle the torque from the L8P better, and you’ll always be in the right gear.

So far looking at the numbers and trading a few emails with PSS to do this on the GMT900 if you purchase a lightly used 10l80e transmission (<10K miles) with a torque converter plus the PSS kit…

You’re looking at about an additional $1,500+/- more than a built 6l80e plus aftermarket billet torque converter.

For me once you’re in for $6-7K what’s another $1,500; But I’m not everyone.

Might be worth considering since I’m sure you’re planing on keeping and driving this rig for a while.

You really grabbed my attention here as I am keeping her for awhile. I like the thought of the 10sp as it will be a better combo. After some brief searching , I am looking into ECM compatibilities with the 2018 ppv as I have not changed my cluster (not going to do that), I have not changed my display center or radio and the BCM is good with the present settings. Trans tuning will be needed and I have not found anyone that has used PSS conversion and tuned the trans, they just did plug and play.

 

[CMoore711]

@MadMax_MFP The 10 speed conversion kit from PSS includes an unlocked TCM with a stock GM OEM 10l80 tune on it.

Now I didn’t get far enough with PSS to detail what model TCM if that would even be shared or if it really matters? Clearly they’ve figured out what TCM and harness modifications offer a successful conversion. Additionally, I don’t know enough about tuning transmissions to know if the TCM tune of a 10l80e behind a 6.2 is different than if it’s behind a 6.6. That being said, the TCM is loaded with a stock GM 10l80 transmission tune that works will run and operate just fine. Further custom tuning is not required but would optimize your specific application and with the PSS conversion kit is possible because the included TCM is already unlocked.

Given the process required to unlock a stock GM TCM I have to believe that is a decent portion of the cost of the PSS conversion kit.

 

[MadMax_MFP]

The L8P engine has arrived, time to finalize the list before teardown begins. @NickTransmissions I am looking at installing the 10 speed trans but also want to build the 6 sp for another project. I will be in Vegas next week so I would like to talk about getting you the unit to work on, thanks!

 

[NickTransmissions]

The L8P engine has arrived, time to finalize the list before teardown begins. @NickTransmissions I am looking at installing the 10 speed trans but also want to build the 6 sp for another project. I will be in Vegas next week so I would like to talk about getting you the unit to work on, thanks!

Sent you a DM w/my contact info - thanks, @MadMax_MFP!