Improving turbo performance with equal length headers?

[116HDi]

I heard a lot of contradicting claims concerning equal length headers used in turbo engines.

Some say the equally spaced exhaust pulses will get the turbo to spool up faster and improve efficiency, others say the heat loss over the longer headers will lead to less exhaust energy to reach the turbine wheel.

Couldn't the second problem be solved by insulating the headers and reducing the heat loss?

What are your thoughts on this? Or does anyone have experience with such a modification? Looking forward reading your comments!

If it is of interest: The engine I plan to add this mod to is a 2014 DV6 (1.6HDi) with 115PS

[cRiPpLe_rOoStEr]

Originally Posted by 116HDi

I heard a lot of contradicting claims concerning equal length headers used in turbo engines.

Some say the equally spaced exhaust pulses will get the turbo to spool up faster and improve efficiency, others say the heat loss over the longer headers will lead to less exhaust energy to reach the turbine wheel.

Not only heat losses. Exhaust pressure may also decrease inside longer headers and turbo-lag becomes more noticeable.

[oil pan 4]

The problem with equal length headers on a turbo diesel is more heat loss. Best bet is to probably wrap what you have.

[freebeard]

There must be some good reason why the turbos aren't cast right into the heads.

[samwichse]

Still not that common to have the exhaust manifold cast into the head... although some cars are starting to do this. The first car I had with the is the first gen Honda insight.

But practically, your casting is getting kind of silly if you have the head, exhaust manifold, AND the turbo in there... Makes sense to me to the have the turbo unit separate, even if it's basically just bolted to the side of a cast-in manifold.

[freebeard]

I phrased that carefully.

Turbo, head and displacement are all related. No bolting on a bigger unit. OTOH, additive manufacturing means you can make impossibly complex shapes. Rocket motors and Porsche's oil cooled pistons for examples.

[R.W.Dale]

In my experience with turbo air cooled VW and turbo ls builds is that until you get to the extremes of what horsepower a platform is capable of making that the turbo and engine just doesn't give a crap what shape the hot side is in within reason.

Imo after the turbo is where you can see some gains on street able setups. More open is better. There's no such thing as post turbo exhaust scavenging

[freebeard]

3D print a integrated free valve head/turbo and you can sell two to every customer.

Accommodate varied displacements with adding or removing vanes similar to Porsche cooling fans.

[cRiPpLe_rOoStEr]

Originally Posted by samwichse

Makes sense to me to the have the turbo unit separate, even if it's basically just bolted to the side of a cast-in manifold.

Even if gassers became turbocharged by default, just like Diesels nowadays, it's worth to consider the cost of replacing a damaged turbo or upgrading it. There might also be some issues with thermal managementt of the engine. A cast-in turbocharger could maybe increase oil temperature through heat irradiation at the cylinder head for instance.

[freebeard]

I have no idea about the pluses and minuses. A plenum between the exhaust valve[s] and the spool might be necessary or gathering multiple exhaust pulses (OP's question) in a header; OR less heat energy is lost before the turbo.