An idea to lower Exh. Manifold pressure

[DriFt3r]

Will it work? Internal Waste Gate only.

weld in a metal hose 3/16 inch dia, or 1/4 inch dia from the exh. manifold to the down pipe. These wire hoses will have about a 2/16 or less inner diameter.

I was thinking that this might lower the exhaust manifold pressure for guys who are running a small turbo with high boost or when they are boosting in higher rpms.

What do you guys think?

[spitz7985]

that would be like having a very small wastegate open all the time. it would probly lengthen spool up time and decrease maximum boosting ability. i'm not sure by how much.

also, no hose i know of can hole 700+ degree exhaust gas. those stainless steel hoses have silicone in them that can melt.

[C-Kwik]

It will cause slower spool up and won't add any benefit to the top end if the wastegate can handle the necessary airflow. Even then, if wastegate flow were the problem, you'ld get overboost.

While I understand where you are coming from as far as trying to keep backpressure to the motor low, a turbo requires a certain amount of airflow. It will use that airflow regardless of how the air is diverted from the turbine once the max set boost is reached. So having a diversion tube of some sort would only cause the wastegate to divert less air. But the turbine will still see the same air and the manifold will run at the same pressure. Of course this is assuming the hole is not so large as to cause the turbo not to be able to reach max boost at all...

[MikeMurphy]

I like your thinking drifter. I think we are in the same boat.

My solution is going to be a nice equal length manifold with a well matched turbine. Likely a straight T4 setup.

[MikeMurphy]

Manifold design is VERY important to this...

[DriFt3r]

Thanks,

the reason I'm thinking this is because I am useing a t3 with both compressor and exhaust side being .48 A/R. Since the KA is 2.4 liters and the dyno showed me that my power is droping after 5.5 k. I just wanted to flatline my power band instead of having it dropped off.

[C-Kwik]

Well the drop off is the result of the necessity of the T3 to spin at a high speed, it's poor compressor efficiency at high RPM's and it's restrictive turbine(all three being relative to a larger turbo). These three things add to the backpressure, but is necessary to drive the turbo at the speed and boost you are running.