More Boost w/o Exhaust?

[got-psshh]

What up, i got a 4g63t cyclone and i just put it in and got it done.. But I was wondering b/c when i test drove it, it was lagging really bad, until it blew the downpipe off of when its clamped to the rest of exhaust, then i just heard the turbo spool up really fast to about 11 lb and pulled like hell. So i figured i exhaust was blocked up, so i gutted everything and it put back.. it was a little better, but not as good as it was when the exhaust was off.. I was wondering if you get more power without your exhaust on. There is also a loud noise when my exhaust is hooked up..just doesnt sound free flowing... When its off, it is loud of course, but sounds like it flows well and stuff. Any suggestions? help me out.
email me at [email protected] or reply on here thanks

 

[SBstar]

Yes supposedly you can feel more power without your exhaust hooked up. Turbo's make great mufflers or so I've heard. It will be loud and illegel on the street but many people unhook their downpipes when running on the track. doesn't make for more boost psi but does make a difference slightly in power.

 

[sleestack]

What happened is you decreased the backpressure after the turbo, effectivley increasing delta P across the turbine wheel. This transmits more power to the turbine shaft sooner.

The less backpressure the better, that is why everyone needs a minimum of a 3" exhuast.

 

[psychlow]

What happened is you decreased the backpressure after the turbo, effectivley increasing delta P across the turbine wheel. This transmits more power to the turbine shaft sooner.

If I may translate -

What you had accomplished with the exhaust off is increasing the pressure differential between the exhaust before the turbine wheel and the exhaust after the turbine wheel.

A turbocharger operates based on this pressure differential. If the pressure was the same on both sides, the air would stand still. In order for air to move, it has to have more pressure on the sending end (before the wheel) than on the receiving end (after the wheel). The more you increase the pressure on the sending end (without increasing the pressure on the receivng end), the faster the air wants to move. The same happens when you lessen the pressure on the receiving end (without lessening the pressure on the sending end.)

When you have a higher pressure differential, the engine can put a lot of the engergy (that it used to use to just press against the backpressure) into your turbocharger. This means faster spoolup, and more power.

 

[oldman]

What you had accomplished with the exhaust off is increasing the pressure differential between the exhaust before the turbine wheel and the exhaust after the turbine wheel.

A turbocharger operates based on this pressure differential. If the pressure was the same on both sides, the air would stand still. In order for air to move, it has to have more pressure on the sending end (before the wheel) than on the receiving end (after the wheel). The more you increase the pressure on the sending end (without increasing the pressure on the receivng end), the faster the air wants to move. The same happens when you lessen the pressure on the receiving end (without lessening the pressure on the sending end.)

When you have a higher pressure differential, the engine can put a lot of the engergy (that it used to use to just press against the backpressure) into your turbocharger. This means faster spoolup, and more power.

Allow me to translate.

No exhaust = faster spool

 

[psychlow]

Allow me to translate.

No exhaust = faster spool

OK, fine, DON'T explain why.

 

[got-psshh]

hey thanks that solved my problem with that, but what explains the really loud noise with the exhaust hooked up about 5-7k rpms.. without the exhaust it flowed nice it just seems reallyh loud and rough when the exhaust is on.. thanks