8l90

[vet57air]

Originally Posted by dhutton

I was thinking the same thing. The ZL1 uses 2.85 gears with a 27” tall tire so it’s similar to 3.73 gears with 31” tall tires if I did the math right. Got me wondering what the Connect and Cruise tune assumes.

Don

The install docs for the LT4 8L90 specify 3:08 to 4:11 gear and 26" to 30" tall tire. Yes I went with a 31" tire but assumed the transmission only sees the driveshaft rotation as an end result? Funny my speed to the Dakota speedo was within 5 mph first time out.

[dhutton]

Originally Posted by vet57air

The install docs for the LT4 8L90 specify 3:08 to 4:11 gear and 26" to 30" tall tire. Yes I went with a 31" tire but assumed the transmission only sees the driveshaft rotation as an end result? Funny my speed to the Dakota speedo was within 5 mph first time out.

Ya I think the rear gear ratio sort of cancels out the tall tires.

Don

[130fe]

Do you have HP Tuners? You can change it that way in the gear/tire wizard in the tune. You are using the Gen V connect and cruise pcm correct?

[vet57air]

Originally Posted by 130fe

Do you have HP Tuners? You can change it that way in the gear/tire wizard in the tune. You are using the Gen V connect and cruise pcm correct?

I am using the GM connect and cruise pcm. Is HP tuner the way to go? Are there others? What other stuff will it do?

[protour]

Originally Posted by vet57air

I am using the GM connect and cruise pcm. Is HP tuner the way to go? Are there others? What other stuff will it do?

HP Tuners is your only option with stock ecu. Where in BC are you again?

[vet57air]

Originally Posted by protour

HP Tuners is your only option with stock ecu. Where in BC are you again?

On the island, Port Alberni

[protour]

Originally Posted by vet57air

On the island, Port Alberni

Im not super familiar that far west, You could try calling the guys at Gen III Speed in Kelowna and see if they can help you out or recommend a shop closer your way.

[shelteredV]

Get with a really good tuner and they can make that trans work awesome with HPT. Just make sure they have experience with tranny tuning.