Big cams equal less boost?

[pyro719]

I just had My galant vr4 tuned yesterday and My tuner informed me that my 280 cams are preventing my big 16g turbo from making more than 23 psi. Im pretty new to the dsm game but thought this was kind of odd. My previous car a 1989 Mirage 4g61t was able to hold 38 psi on a big 16 but the cams were stock. Any input on this guys?

 

[91stocker]

Yes it means less boost generally. More airflow but at lower pressure.

 

[3kgt2nv]

from your profile i see your running a stock block and im guessing stock heads with a huge cam. your car most likely is not supporting the 280 cams for them to preform properly. a smaller or stock cam would be better untill the motor is able to provide enough flow to need such a large cam.

did you upgrade the valve springs and retainers to prevent valve float at high rpm to take advantage of the cams even?

 

[Colt4G63 also]

Boost pressure is a measure of restriction, and 38 PSI is too high to run a 16g turbo.

 

[pyro719]

from your profile i see your running a stock block and im guessing stock heads with a huge cam. your car most likely is not supporting the 280 cams for them to preform properly. a smaller or stock cam would be better untill the motor is able to provide enough flow to need such a large cam.

did you upgrade the valve springs and retainers to prevent valve float at high rpm to take advantage of the cams even?

Has the proper vale springs installed. I did not build this car but I do know some of the history. The motor is fully forged with a ported and polished head.

 

[3kgt2nv]

i would update your profile so people will be able to help knowing your current setup

 

[1SloEvo]

Colt4G63 said it perfect. Boost is a measure of restriction. Your motor "should" be running more efficiently with the bigger cams and ported head, therefore the amount of boost (or restriction of airflow) is lower because the air is getting through the motor with less restriction and more efficient...thus creating much more power with less stress and better efficiency!

 

[pyro719]

Makes alot of sense. So I guess the next step to more power is a bigger turbo. What turbo would get me to 500 awhp?

 

[c2ypt1c]

What turbo would get me to 500 awhp?

DSM Dyno Challenge - Highest Horsepower

Check out what other dsm'ers are running in the 500hp range.

 

[donniekak]

from your profile i see your running a stock block and im guessing stock heads with a huge cam. your car most likely is not supporting the 280 cams for them to preform properly. a smaller or stock cam would be better untill the motor is able to provide enough flow to need such a large cam.

did you upgrade the valve springs and retainers to prevent valve float at high rpm to take advantage of the cams even?

The block, pistons, and rods have nothing to do with airflow, as long as displacement is the same. Head, cams, and turbo are the main actors on airflow.

To the op, you are probably blowing the wastegate open, or have another issue. On a cammed 2.0 you should still hold over 25 psi, with a 16g.

 

[canada4g63]

Boost pressure is a measure of restriction, and 38 PSI is too high to run a 16g turbo.

Not on a evo3 16g, if you have every supporting mod know to man kinda to go with it.

 

[3kgt2nv]

The block, pistons, and rods have nothing to do with airflow, as long as displacement is the same. Head, cams, and turbo are the main actors on airflow.

i was thinking higher compression pistons in the build