Got my Yukon tuned today

[swathdiver]

They supposedly turned off all of the tq management but it still feels the same when you dead stop and punch it. It hesitates for like 20-40ft than takes off. I thought a tune woukd fix this but I guess not.

Turbo lag...

 

[JDopirak]

Turbo lag...

Ya know the guys at CSP tried to convince me to do a turbo. I said I'd only consider a supercharger, I just prefer them.

 

[swathdiver]

Ya know the guys at CSP tried to convince me to do a turbo. I said I'd only consider a supercharger, I just prefer them.

Either is a lot of fun. I spent many years racing turbocharged Buicks but am enjoying these naturally aspirated LS engines. They do respond very well to forced induction though! But that doesn't solve your problem, neither did my joke.

So could it be the converter flashes to its stall speed and then the motor has to overcome the mass until the motor spins up to maximum torque and horsepower bands? I would say mine does the same thing in that instance.

 

[JDopirak]

Either is a lot of fun. I spent many years racing turbocharged Buicks but am enjoying these naturally aspirated LS engines. They do respond very well to forced induction though! But that doesn't solve your problem, neither did my joke.

So could it be the converter flashes to its stall speed and then the motor has to overcome the mass until the motor spins up to maximum torque and horsepower bands? I would say mine does the same thing in that instance.

Well I dont have alot of technical knowledge past fixing and replacing stuff but I can tell you it has no tq according to the graph till about 3500-4k. And the stock stall doesnt allow me to get anywhere near that range. I was able to start on some gravel and get it to do a burn out and in the rain but clean dry road it wont spin.

 

[swathdiver]

Well I dont have alot of technical knowledge past fixing and replacing stuff but I can tell you it has no tq according to the graph till about 3500-4k. And the stock stall doesnt allow me to get anywhere near that range. I was able to start on some gravel and get it to do a burn out and in the rain but clean dry road it wont spin.

View attachment 227271

So you have shorty headers feeding into what? Still have factory y-pipe and cats? Does it go into a whole new exhaust or just the Magnaflow muffler?

 

[esoteric_ast]

Well I dont have alot of technical knowledge past fixing and replacing stuff but I can tell you it has no tq according to the graph till about 3500-4k. And the stock stall doesnt allow me to get anywhere near that range. I was able to start on some gravel and get it to do a burn out and in the rain but clean dry road it wont spin.

View attachment 227271

2600-3000 stall will help.

 

[JDopirak]

So you have shorty headers feeding into what? Still have factory y-pipe and cats? Does it go into a whole new exhaust or just the Magnaflow muffler?

Shortys, Factory y pipe, magnaflow muffler and slp resonator delete to finish it off. I was going to do a whole custom catback system but factory piping is in perfect condition and it's already 2.75" so I didnt see any point in getting rid of it, Thats plenty big enough piping for the kinda power I want to eventually put down."350-375"

 

[swathdiver]

Shortys, Factory y pipe, magnaflow muffler and slp resonator delete to finish it off. I was going to do a whole custom catback system but factory piping is in perfect condition and it's already 2.75" so I didnt see any point in getting rid of it, Thats plenty big enough piping for the kinda power I want to eventually put down."350-375"

You're spot on, too big, 3" piping, on a 5.3 is too big in my experience. I was thinking that if the pipes were larger, you may have lost the scavenging effect which may contribute to the sluggishness off the line. So that's out. 3.08 or 3.42 gears? I'm thinking the tune needs further work, do you have an AutoCal to do data logs to give to your tuner or can you easily work with him in person?

 

[JDopirak]

You're spot on, too big, 3" piping, on a 5.3 is too big in my experience. I was thinking that if the pipes were larger, you may have lost the scavenging effect which may contribute to the sluggishness off the line. So that's out. 3.08 or 3.42 gears? I'm thinking the tune needs further work, do you have an AutoCal to do data logs to give to your tuner or can you easily work with him in person?

3.42 gears
91 octane

And no autocal, I just called and said I wanted to get it tuned. They asked what I was doing to the truck and than I showed up and they tossed it on the dyno and tuned it. They said it was all messed up from the new parts. They said it was pulling alot of timing prior.

 

[swathdiver]

3.42 gears
91 octane

And no autocal, I just called and said I wanted to get it tuned. They asked what I was doing to the truck and than I showed up and they tossed it on the dyno and tuned it. They said it was all messed up from the new parts. They said it was pulling alot of timing prior.

This not my area of expertise, but did they tune it only at WOT or for idle and cruise and such as well? The computers also learn and performance should increase over time, a tank or gas at most I would think. See if it smooths out after a few hundred miles.