Not all headers are created equal!!!

I have an old video

 

My crude understanding:

The whole point of the equal length headers is to take advantage of the exhaust pulses from one cylinder going into the collector and creating a slight vacuum on another cylinder to improve exhaust scavenging for that cylinder. The lengths need to be equal in order for the timing of one pulse to line up with the exhaust stroke on another cylinder. The whole process is disrupted by the air rails as they allow communication between cylinders at a separate location.

That's probably at least half wrong/misunderstood, but it has been proven on a dyno with a 575 (which Trev knows way more on than me).

 

Interesting. Do you recall the magnitude of the change that the dyno picked up?

I agree with the rest of what you said. The air rails and braided hose are empty space up to a control valve on each side. It makes sense that it would be reducing the energy in the exhaust gas pulse and reducing the scavenging effect.

 

I don't have the numbers I'm afraid, but I remember Trev telling me it was significant. @360trev can you comment?

 

Great explanation on the importance of having equal length headers on performance and exhaust note. Which is why unequal length headers like Top Speed and Top Gear will make your Ferrari sound like a lumpy American V8 on idle.

 

Is there more than one company called Topgear? I have topgear euro headers and all pipes are the same length at just over 23.5”.

 

So my mechanic tells me they offer to reweld the OEM headers properly ( they have been doing this for years ).
I myself still have the OEM ones on my 2007, but has anyone else heard of this option when the headers go kaput?

Sent from my Pixel 8 Pro using Tapatalk

 

I think it’s easy to mix up “top speed” with “top gear”. Personally, I don’t like the sound of either of their headers for the 430, but that’s just personal preference.

I had considered Top Gear UK’s headers at one point for the price (to combine with a Kline exhaust), but this video and it’s comments made me run (I’m still unsure if the person commenting had top gear or top speed headers)…

 

The lengths also need to be calculated/precise because the scavenging effect depends on the exhaust valve of the target cylinder being open.

 

Absolutely, my Ferrari dealer does it all the time too. I was going to do the same myself when one of mine cracked. Getting the heatshields off and back on again is the difficult part. I got mine off and found the crack but a set of challenge headers fell in my lap. So they are still waiting for the weld repair.

 

Wait so your Ferrari main dealer actually repairs cracked headers/manifolds? Or did I misunderstand you?


Sent from my iPhone using FerrariChat.com mobile app

 

Correct, they send them out to have them welded. The service manager who told me that has now branched out as an indy. He used to fit Hill Engineering ball joints too. The dealership now only does Ferrari ball joints. So maybe now they don't do weld repairs. Are 430 manifolds still available new from Ferrari?

 

The scavenge effect works on such narrow rpm/cylinder filling range it has neglible effect on any street application.
The whole "equal length" thing is a bit of a myth. If someone wants to test this, run the engine with equal length manifold on a dyno, then cut off the collector. Chances are you will not see a measurable change in results, as long as the headers are correctly built.
Total length and shape are more relevant than them all being exactly equal.