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Discussion Starter · #1 ·
My Cobra pick up 2psi of boost with my bassani cats remove. Do you think that they might be clog a bit. The car feels strong, but sometimes when the exaust is louder you get a feeling of more power just because of the louder sound.
Some people said that our cars will not gain much HP beacuse after market cats flow very well. Any thoughts? By the way the boost goes all the way to 19psi now, before was 17psi.
 

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The Ubiquitous Jimmy V.
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Seems odd to me..I thought when you remove a restriction in the exhaust you loose boost pressure.
 

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I have always seen people say they lost boost when they went to offroad exhaust, now if you had clogged cats and were robbing the motor of power then I say yes its probable.
 

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The Ubiquitous Jimmy V.
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trey193 said:
I have always seen people say they lost boost when they went to offroad exhaust, now if you had clogged cats and were robbing the motor of power then I say yes its probable.
Good point..There had to be something else going on there..
 

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That is very strange are you sure? You should have loss boost especially if the cats were clogged.
 

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Discussion Starter · #6 ·
trey193 said:
I have always seen people say they lost boost when they went to offroad exhaust, now if you had clogged cats and were robbing the motor of power then I say yes its probable.
I believe my bassani cats are clog; My motor was getting really hot with them. Also I could never get to 19psi boost with the 2-3/4 pulley, only up to 17psi at the gauge now at 19psi. I will put the cats back on a retest to see if was a fluke.
 

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Guys what is the H.P gain REALLY with a Bassani catted x-pipe? Just wondering, because it should be arriving by the weekend.
 

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Yea, that doesn't make any sense. The manifold pressure should have dropped.
 

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Discussion Starter · #10 ·
IWRBB said:
Yea, that doesn't make any sense. The manifold pressure should have dropped.
So does this means that we can make more Hp with a restrictive exaust because more boost than with one that has 0 back pressure like headers, no cats and high flow mufflers. I dont know; but Ill put back those cats back and read the boost gauge again and see what happens.
 

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Ok, time to help you out here..

Boost does NOT equal power. It has nothing to do with it.

Airflow is where the power is. Not manifold pressure. That's why a KB at 10 PSI kills a Eaton at 10 PSI. Way more airflow.

Boost is the pressure in your manifold above 1 atmosphere. That's it. Nothing more. It's just mainfold pressure.

You could put a 1/2" exhaust on your car, the boost would go way up. With a pos. displacement blower, you'd still make about the same HP, witness the massive KB thread. Roots blower don't care a whole lot if the outlet side is 10 PSI or 100 PSI. It'll move pretty much the same amount of air either way.

And in your case, you should see a drop in boost, but about the same HP, since the airflow through the blower is still the same. It has to be, it's determined by pulleys, not the exhaust system.

Boost is bad. All boost indicates is your engine/exhaust is too restrictive to flow the amount of air that the s/c is displacing without pressure on the intake side to push it through.

If your engine could breathe better, you'd make less boost, but approximatley the same power, with a roots blower.

Now n/a, centrifugals, or turbos are not the same. The airflow is not fixed like roots style blower.
 

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Rick @ Amazon tells me if I put cats on my car with my combo I will make more power, I am ready to put the stock H-pipe back on and see how the car feels!
 
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