S54 Header Design talk

[m3racer]

Sure, here they are. I did the PipeMax a while ago, but can try and answer any questions if you have any. And here is a diagram of the SuperSprint measurements. You can see that the second steps in the primaries are really not equal length, and the secondaries are not either.

The Burns design was a while ago too, but from what I remember they had found through testing that straight 6 engines liked short secondaries on the dyno.

[digger]

Sure, here they are. I did the PipeMax a while ago, but can try and answer any questions if you have any. And here is a diagram of the SuperSprint measurements. You can see that the second steps in the primaries are really not equal length, and the secondaries are not either.

The Burns design was a while ago too, but from what I remember they had found through testing that straight 6 engines liked short secondaries on the dyno.

Thanks for the SS data.

Just for reference. A Tri-Y is a 6-3-1 not 6-2-1. Also in pipemax to do a 6-2 you need to setup as a V6 and not tri-y

as for secondaries being short, that's fine if you arent after a wide power band. Below 4000/4500 rpm short secondaries are a torque killer due to reversion

[digger]

i have done some more sims with the simple engine model after adding a collector and will do a proper update over the weekend but it does explain some

[digger]

This is supersprint V1 as per above dimensions with different collector harmonic ~1800, 900, 450

You see that that 4th harmonic 450mm loses a bunch of low end torque for little benefit. this is why the merge whether H, X or Y should not be too close to the engine for a street engine as it's a poor compromise. I also suspect with vanos (or bigger cams) the loss would be higher and the slight midrange a little higher too though kind of exacerbating the differences

[digger]

This compares the SSV1 with its variable primaries to the same pipe sizes but made equal length (lengths are equal to the shortest of the primaries and the longest)

[3staxontheradio]

I have been slammed with work and will be able to get back into this in a few weeks but also davidinnyc loaned me a CSL header bank so I'm going to get that measured and scanned as an extra reference point:

[3staxontheradio]

Had time to run off a scan last night after work:

[3staxontheradio]

I was really curious about how expensive 3d printed headers would be. I made a super fast sketch of one of the banks of the CSL header, made it without flanges (I figure flanges could be traditionally cut to save money), set it to 1.5mm wall thickness and uploaded it on craftcloud. If its made as a single piece its kinda pricey. $1200 for one bank or $2400 for a set. This is because its over the size of almost everyone's DMLS machines so only one company could quote it. Check out pricing when split into two pieces:


Longer runners, possibly slightly thicker wall thickness, etc is going to involve more material but this is way cheaper than I thought it would be. I think for people willing to weld them in peices and mix with traditionally fabbed flanges, vbands, etc. the cost may end up around $1000.

[Bry5on]

Printing 316L is super reasonably priced. This is even a bit cheaper than I thought though. Guess a fully printed header is a better idea than before. After factoring in labor and the CNC bend costs, no way you could beat 3D printing's price for low volume. Wild.

[Obioban]

I wonder how much cost going double walled would add

[3staxontheradio]

I wonder how much cost going double walled would add

I had expected the cost to double because material usage is doubled but its about 50% more. I think a 3mm wall is overkill and also not an efficient way to add strength to the part. I'm sure some combination of webbing, gusseting/supports, and non uniform wall thickness would be a lot more cost effective.

[Bry5on]

I wonder how much cost going double walled would add

The problem becomes support material removal for complex geometry like this. You’d end up with a lot left in between the walls, which could get heavy fast. A weld on set of shells with some locating bosses would probably function better but at greater cost.

[siamkazi]

So for us non-engineering mortals, what's the consensus so far on the analysis done?

[maupineda]

So for us non-engineering mortals, what's the consensus so far on the analysis done?

Euro headers 🤓

[3staxontheradio]

Euro headers 🤓

Absolutely not. The euro headers are miles off. I can measure them out but they are waay too short and clearly living on a smaller harmonic than is ideal. It's not even close.

So far Kromer Kraft are the only off the shelf headers that seem to plausibly tuned well but NLA. I don't think supersprint can even really claim their V1 headers are well tuned when the runner lengths are literally all over the place. Not really a thing to tune runner lengths and then just use a 5" spread of different lengths. Which of the many lengths is considered the tuned one?

My takeaway so far is that S54 off the shelf headers have mostly been skipped over for off the shelf products. I'm sure people like achilles motorsport have been making much better custom headers but building headers from Jbends is probably too expensive for an off the shelf product compared to CNC bending used for other products. 3d scanning makes packaging precision way easier than it was 20 years ago. OEMs, even for the euro cars have a bunch of competing constraints that we don't have and CNC bending tube comes with a bunch of limitations for bend placement.

I'm pretty confident we can do better and also produce equal length secondaries at the same time so the car sounds better.