I have 5 PSI of back pressure post turbo, is that bad?

[cyrus]

I have 5 PSI of back pressure post turbo, is that bad? Yeah yeah I know it is, but how much power should I gain by bring that down to .05 PSI? Presently my 2JZ-GTE is making ~315 at the wheels.

[Pyro]

From what I have read, 3 to 4 psi of back pressure is considered a very low restriction exhaust system for a NA engine.

 

I don't think 0.5 psi is obtainable with a full exhaust system. Maybe 0.5 psi is obtainable if only run a very short and straight pipe from the turbo turbine is used as the exhaust.

 

5 psi is pretty good but I would think the lower the back pressure, the louder the exhaust.

[Z-Gad]

Forgive me on this one, but how do you measure back pressure?

Thanks in advance,

mike

[cyrus]

I drilled a .125" hole in the exhaust and put a brass line leading to a gauge.

 

 

UPdate I cut the muffler off and am now seeing a 1.5 max PSI.

 

3.5" dial pipe here I come.

 

PS who sells the pipe and elbows in huge sizes?

[Z-Gad]

Contact Hoover again. I understand he has a line on large diameter mandrel bent piping.

[dapiper]

During development of my L28 custom turbo with DynoJet and complete data acq, found 3" Flowmaster imposed 7.5 psi at 18 psi, 370 RWHP which dropped to 2.5 psi after cut off, which matched same with DynoMax straight thru oval can. HP jumped to 410 with no other changes, had 38 psig at turbine b4.