How sound change at V10 if exhaust is 10 into 1 vs 10 into 2?
F1 always had 10 into 2? what are advantages of that in power and aero aspect?
here they put 10 into 1 and then into 2 pipes, sound higher, better. Is this always case?
Do lenght of pipes must be equal or their curvature,number of bend must be same as well?
Especially with naturally aspirated engines, tuned, equal-length headers have the greatest advantage. Tuned, meaning the primary tubing is the diameter and length that produces the most power. The collector has an ideal location and the extension after the collector also has an important function. The x pipe these gents installed will help with scavenging, with the added effect of changing the timbre of the exhaust sound.
In any race car, packaging can and often does have a significant effect on the primary lengths, the position of the collector, as well as the extension after. The ideal is equal length primaries from each bank, into a collector, through a collector extension, then mixed with the other bank's exhaust pulses. The number of smooth bends doesn't matter, nor does the shape of the tubing as long as the cross sectional area remains the same.
I disagree with several statements here regarding length vs bends and most just sound like canned magazine or ChatGPT responses. I base mine on personal experience working with and conversations with a header fabricator who has been involved in championship winning NASCAR, World of Outlaws, NHRA, and IMSA campaigns, as well as some NASCAR contacts and knowing what their headers spec like.
First, equal lengths only matter if every cylinder has the same induction length and has the same power potential. We know this isn’t always the case due to things like manifold assymetry. The other factor is mass flow isn’t always the same… there is charge robbing / intake interference happening in the intake plenum (yes even for NA F1 cars, it’s all documented by Honda) and its effect varies depending, there is flow assymetry in the airbox from the shape, and bends will determine a primaries ultimate ability to move mass.
To quote Dr Randolph of ECR and formerly Hendricks, best power is often when blow down time losses are balanced with pumping losses, from an exhaust / exhaust timing standpoint.
The reality is, even on WOT only, max power, tight power band applications only, you will always make more power varying primary length up to 4” if it means improving packaging and being able to use larger bend radii… A F1 car spends a bunch of time at part throttle with much wider power bands, so even more so as doing this spreads the power band out some. Again, Honda has documented all of this with their Third Generation development, but F1 isn’t unique in application or needs.
You have to remember, with a tighter bend radii, you have more flow losses, so you have to use a bigger diameter tube. A bigger diameter tube is 1) harder to package thus sending you on a bend radii doom loop 2) it will preserve the top end but at the expense of the mid range, bottom end, and part throttle. It reduces exhaust velocity and makes the engine more reversion sensitive. Focusing on the total package and larger bend radii, at the expense of being perfect on the lengths, will make a header that works better in the real world.
For example; we had a header built that was the same exact length, same collector, but focus on packaging and nice big bend radii. Doing so allowed us to be able to use tubing off the head that matched the port flange area, which was much smaller than before. The header stepped up over its length. Even with the same length, it made 10-12% more power everywhere and much better in the transients. This exercise was all about managing flow losses which opens up your ability to use diameters the engine actually wants and makes sense for the use.
The other factor to consider here is aero. F1 designers are always willing to give up some power if it means better packaging for aero and drag reduction / downforce creation. Same for NASCAR… their designs that make the best dyno power don’t always end up on the cars, as other designs package in a way that helps under car flow and increases downforce… and that’s always faster on a race track.
The reality is the V10s did 2x 5-1 because 1) packaging 2) the engines revved high enough and the tune lengths short enough, that merging into a single tailpipe doesn’t make sense.
On road race V8s, with peak power under 9,000rpm, it’s usually better to have 2x 4-2-1 > feeding into a single tailpipe. Usually power upstairs stays the same but mid range and low end is better. The x-pipe is partly a similiar effect but existed because NASCAR had a rule on what the pipe exit should look like and their flat “boom tubes” require it to be so.
I disagree with several statements here regarding length vs bends and most just sound like canned magazine or ChatGPT responses.....
https://www.classicbikeshop.co.uk/exhau ... pipes.html
shows clearly the conventional exhaust pipe and the 'swept-back' type used on the Velocette Venom Thruxton
the swept-back has a tight bend c.130 degrees to allow a more direct pipe route to get the correct tuned length
(UK racing regs require the system to nearly (3" ?) reach the rear wheel spindle)
the swept-back design emerged c.1950 on over-the-counter-racers Norton & AJS with the megaphone exhaust ...
spread to road machines made for endurance races BSA Gold Star & Velocette Thruxton & Triumph Thruxton Bonneville
won maybe 50000 races
and became a popular aftermarket fashion for the road
a musically-inclined friend played my Gold Star system like a bugle ...
producing 2 and sometimes 3 notes (corresponding to different multiples of half wavelengths ?) ....
presumably the 'swept-back' was about getting resonance at the primary frequency eg 7000 rpm .....
presumably eg 15000 rpm machines worked a higher frequency (or their very long megaphones in effect shortened the system)
Last edited by Tommy Cookers on 02 Oct 2024, 13:49, edited 1 time in total.
If memory serves, I recall rumours of the mp4/16 testing a 2x5into1 into 1. But it was more of a convention 2x5 with Siamesed outlets in the center of the diffuser. At the time the discussion related to an attempt to form a single unified flow and it coincided with the ilmor being a particularly high pitch scream and also the disappearance of the exhaust chimneys on the topside! When you look at the MP4/16 you can see the layout, but there’s not enough room to unify the pipes prior to the start of the exit. It’s more likely they were close for external reasons, rather than internal!
If memory serves, I recall rumours of the mp4/16 testing a 2x5into1 into 1. But it was more of a convention 2x5 with Siamesed outlets in the center of the diffuser. At the time the discussion related to an attempt to form a single unified flow and it coincided with the ilmor being a particularly high pitch scream and also the disappearance of the exhaust chimneys on the topside! When you look at the MP4/16 you can see the layout, but there’s not enough room to unify the pipes prior to the start of the exit. It’s more likely they were close for external reasons, rather than internal!
If memory serves, I recall rumours of the mp4/16 testing a 2x5into1 into 1. But it was more of a convention 2x5 with Siamesed outlets in the center of the diffuser. At the time the discussion related to an attempt to form a single unified flow and it coincided with the ilmor being a particularly high pitch scream and also the disappearance of the exhaust chimneys on the topside! When you look at the MP4/16 you can see the layout, but there’s not enough room to unify the pipes prior to the start of the exit. It’s more likely they were close for external reasons, rather than internal!
What a great sound/timber these Illmor v10's have! Dawn Treader on Twitter did a rebuild on one of these a couple years back with a ton of images. Was cool to finally see the variable baffle in the 5-1 collector. Curious if the baffle drives the pitch a little in addition to the exhaust layouts.
for racing ....
length equality of 'headers' is much more important than curvatures
4 cylinders have had 4 - 1 or 4 - 2 - 1 or 4 - 4
even with 5 or 10 cylinders there has been some unusual designs
F1 always had at V10 10 into 2, never 10 into 1, is this for performance or regulation?
The 2000 and 2001 McLaren F1 cars, sort of had 10 into one merged pipes and they sounded incredible!
I don't know if I'm misunderstanding you...but the McLaren of the years 2000 and 2001 had two V-shaped cylinder banks with 5 cylinders each, i.e. a V10 at a 90 degree angle. Each cylinder bank ended in a tailpipe. So there were 2 tailpipes that ended in the diffuser.
F1 always had at V10 10 into 2, never 10 into 1, is this for performance or regulation?
The 2000 and 2001 McLaren F1 cars, sort of had 10 into one merged pipes and they sounded incredible!
I don't know if I'm misunderstanding you...but the McLaren of the years 2000 and 2001 had two V-shaped cylinder banks with 5 cylinders each, i.e. a V10 at a 90 degree angle. Each cylinder bank ended in a tailpipe. So there were 2 tailpipes that ended in the diffuser.
