2004 GTO '57 Chevy Swap Tune Question

[mattwilcher44]

Hey Guys,
Looking for some guidance here. I'm new to this and giving it my best shot. Helping my uncle with his '57 Chevy with a 2004 GTO LS1/4L460, headers, and cold air. Tune 1 was done by the guy who modified the wiring harness, Tune 2 is my tune. Both tunes seem to "feel good "when you drive the car. This thing has a 3.70 Ford 9 inch. It runs and sounds like a beast but it won't perform a power brake. Before you make fun you need to know this car is my 75 yr old uncle's car. He restored it from the ground up and I helped wire and install the LS1. If he's 75 and he wants to power brake I dont ask questions I just try to help lol. He has a point though. When you attempt to power brake once you get around 1200 RPM and hit the throttle it falls just like a car would if traction control was on. I mean that is exactly what it feels like. I'm told it's brake torque but I cant see where that gets turned off for sure. Tune 1 you'll see the guy turned off abuse mode and all kinds of stuff. In my tune I was a little more conservative. The IAT is a fast acting and should be getting a real good source of cool air, yet it showed about 29-25' above ambient when cruising. Anyhow if anyone could take a peek and give me some pointers it might be worth a case of beer or something lol. I appreciate any advice. tune 1.hpltune 2 6-22-19.hpltune1.hpttune2.hpt

[cobaltssoverbooster]

Start with disabling engine abuse and transmission abuse modes. Settings are found under trq mgmt in the engine and transmission sections.

[5FDP]

Brake tq mngt is set to 1 in the system options but it's not likely to be the cause for everything.

Disabling the engine abuse is the easiest.

You do have a pretty good lean condition at idle too, fuel trims are up around +20%.

With the engine TM disabled you want to bring the enable torque for PE way down to like 50% too.

Verify fuel pressure too. When you did go wide open throttle your o2 sensor took a nose dive to nothing. That tells me it's super lean. You need 58psi of fuel pressure for this engine.