How much boost?

[Ducati18]

How much boost can you run on a stock motor?

 

[2000Yukon]

I probably wouldn't go over 12 psi but other people may have a better suggestion.

 

[BlackDenali]

On a 5.3.........I'd ask JK

 

[JKmotorsports]

I've seen some people run 12psi w/o any probs. But I've also seen people run 8-10 psi and throw rods, blow head gaskets, etc. A lot of it will depend on the tuning to make sure you aren't detonating or running too lean. If the pcm tuning is spot on, you should be able to run 10-12 psi w/o any probs. A lot of it will depend on the mileage and condition of the engine and proper pcm tuning. Even on a new stock 5.3 LSx and a dead on perfect pcm tune, I personally wouldn't run anymore than 12-13 psi just to be safe.

 

[JennaBear]

I am currently running right around 11psi.

 

[JKmotorsports]

I am currently running right around 11psi.

Are you running the 2.9" or did you pulley down again?

 

[rigo_jones]

Its not about how many psi. Picture a very small turbo, it will flow a certain CFM of air. For simplicity lets just say 10. Now a bigger turbo can flow up to say 20. It might take the smaller turbo 10psi to flow the 10cfm of air. While on the bigger turbo at 10psi it might be flowing more air and making more power. Thus depending on what turbo size you have, determines what power you theoritcally CAN "flow".

So dont confuse PSI and HP. HP kills motors not pressure from the turbo or blower also tune has a lot to do with this. avoid detonation..

 

[Ducati18]

I've seen some people run 12psi w/o any probs. But I've also seen people run 8-10 psi and throw rods, blow head gaskets, etc. A lot of it will depend on the tuning to make sure you aren't detonating or running too lean. If the pcm tuning is spot on, you should be able to run 10-12 psi w/o any probs. A lot of it will depend on the mileage and condition of the engine and proper pcm tuning. Even on a new stock 5.3 LSx and a dead on perfect pcm tune, I personally wouldn't run anymore than 12-13 psi just to be safe.

I am getting it tuned next month. So i figured that I would change my pulley before getting my tune. Do you know the pulley size that i would need to get to acheive that kind of boost?

 

[JKmotorsports]

Its not about how many psi. Picture a very small turbo, it will flow a certain CFM of air. For simplicity lets just say 10. Now a bigger turbo can flow up to say 20. It might take the smaller turbo 10psi to flow the 10cfm of air. While on the bigger turbo at 10psi it might be flowing more air and making more power. Thus depending on what turbo size you have, determines what power you theoritcally CAN "flow".

So dont confuse PSI and HP. HP kills motors not pressure from the turbo or blower also tune has a lot to do with this. avoid detonation..

hp is the end result of the total equation. The more cylinder pressure that is created, the more power that can be made. Proportionatly adding more air and fuel (i.e. forced induction) will create a more powerful explosion, driving the pistons down with more force, making more hp. With a more powerful explosion and higher cylinder pressures, you're adding more stress to the rotating assembly, especially the pistons and rods. So it's not the end result (hp) that kills the motor, it's what goes into the equation (pressure) to make the higher hp numbers that killls the motor.

I am getting it tuned next month. So i figured that I would change my pulley before getting my tune. Do you know the pulley size that i would need to get to acheive that kind of boost?

The type of supercharger, cam profile, exhaust setup, cr, engine size, etc. will all play a part in how much boost the motor will actually see. The same supercharger on one motor might make 10 lbs of boost, while on a motor with more valve overlap in the cam grind and more free flowing exhaust will make less boost, but you still get more power from the engine breathing better from the cam and exhaust mods. It's better to make more power with a better breathing engine and less boost than more boost and more restrictive engine. Make sense?
On a stock 5.3 with a maggie, I'd say a 3.0" pulley should get you roughly around 10psi.

 

[JennaBear]

Are you running the 2.9" or did you pulley down again?

Still running the 2.9" just been opening it up a bit more. I know I have belt slip, so once I pin the crank I should see 12-13psi

As for the 3.0" pulley on a 5.3L, you should expect to see ~11-12psi. The killer will be belt slip