Cam vs. Boost?

[kevins]

Since installing the VS cam i seem to have dropped down to 5lbs of boost. I could have sworn it was at 6 or 7 before. Stock pulley. Does the cam have any effect on boost levels?

[Fivefingerdeathpunch]

more flow = less boost

[TheOtherNick]

Yeah a cam will drop the boost pressure, I really hope some one is helping you tune.

[SnowFlake]

Less boost is actually better.

[gtpsleeper]

Less boost is actually better.

to a certain extent...

Just think of boost as a girl... you dont wanna have sex with the 200lb girl, but you dont want an anorexic girl either right?

its all about finding something in the middle that works best for you

[04boostedindyss]

the motor is breathing more efficiently with the cam hence the boost loss which is completely normal...now tune and pulley drop

[kevins]

Yeah im getting it dyno tuned, just have to finish the rewire for the fuel pump. Just wanted to make sure im good before i take it to tuner. I got the mps system so i can try diff pulleys while tuning.

[04boostedindyss]

Good deal, what are your other mods btw

[redlinepontiac]

to a certain extent...

Just think of boost as a girl... you dont wanna have sex with the 200lb girl, but you dont want an anorexic girl either right?

its all about finding something in the middle that works best for you

Greatest thing ive heard all night haha

[PurpleGuy]

To a certain extent? What do you mean? The less boost the more effecienctly it's flowing.
In the case of this cam it allowed more flow, thus less boost. You already know that.
Im confused why you think boost needs to be in the middle. The lower your boost the better the system if flowing.(Usually. You could have a vac leak but that's diff)
Boost doesn't mean a whole lot. It tells you how good(or bad) your system flows.

[SnowFlake]

To a certain extent? What do you mean? The less boost the more effecienctly it's flowing.
In the case of this cam it allowed more flow, thus less boost. You already know that.
Im confused why you think boost needs to be in the middle. The lower your boost the better the system if flowing.(Usually. You could have a vac leak but that's diff)
Boost doesn't mean a whole lot. It tells you how good(or bad) your system flows.

It's a balance, dude. If your logic was on, we'd all run M45s at 4psi.

[99prixgt]

these cars are best at around 12psi

[SnowFlake]

these cars are best at around 12psi

This is also an arbitrary number.
Stock cars have horrible knock at only 8psi.

[Juanmiguel]

I get 7 pounds with vs cam and 3.25 pulley

[gtpsleeper]

To a certain extent? What do you mean? The less boost the more effecienctly it's flowing.
In the case of this cam it allowed more flow, thus less boost. You already know that.
Im confused why you think boost needs to be in the middle. The lower your boost the better the system if flowing.(Usually. You could have a vac leak but that's diff)
Boost doesn't mean a whole lot. It tells you how good(or bad) your system flows.

if thats the case then i guess I should run my E85 on a stock pulley...

thats like saying 6-8 psi of boost on a 3.8 pulley is the same as 6-8 psi of boost on a 3.0 pulley... its just wrong

[PurpleGuy]

I kind of understand how my logic is flawed.
I do understand that 6-8 PSI on a 3.8" and a 3.0" is diff though. A 3.0" running the same "boost" as a 3.8" is gonna make more power..at least theoretically it should.

[gtpsleeper]

I kind of understand how my logic is flawed.
I do understand that 6-8 PSI on a 3.8" and a 3.0" is diff though. A 3.0" running the same "boost" as a 3.8" is gonna make more power..at least theoretically it should.

exactly... the 6-8 psi on a stock pulley is pushing a certain amount of boost through... where as the the 3.0 will push MORE air through at ( in theory ) colder temperatures to give you the same amount of pressure but with twice as much air...

its hard to explain but its all basically thermodynamics...

[PurpleGuy]

But given a certain pulley size. We'll say a 3.0". If your making 8 PSI vs 5 PSI the 5 PSI may be less "boost" BUT it should be a colder boost and create more power, once again, int theory. Correct? Or am I wrong?

[matt5112]

I was once told by a guy who does plenty of tuning on these cars that there are boost levels you'd want to see.

IIRC:

10-12 psi for low comp.

same for high comp with intercooling.

7-9 for high comp, no intercool.

[gtpsleeper]

But given a certain pulley size. We'll say a 3.0". If your making 8 PSI vs 5 PSI the 5 PSI may be less "boost" BUT it should be a colder boost and create more power, once again, int theory. Correct? Or am I wrong?

wrong...

if you keep a constant pulley size and add flow mods to drop from 8 - 5 psi your air temp is going to be cooler yes but your still having the same amount of air being pushed in regardless of its temperature... your still basically getting the same amount of air into the combustion chamber as before though...

that being said, remember that this isn ALL about psi... the other half is spark. Remember, spark ( especially at WOT ) is limited for safety of our engines...

the thinking here is that you wanna have the most air in the combustion chamber with the highest degree of spark for optimal power...

Think of it like this (im explaining this as easy i can sorry) if your running 20-22 degrees of timing on a 3.1 knock free, you will make MORE power on a 3.0 knock free with the same timing due to added air into the combustion chamber...

make since?