S54 Header Design talk

[jayjaya29]

Non-broken link:

https://5150autosport.com/products/p54-racing-header

[3staxontheradio]

That's similar to the layout I have been using but not the same basic dimensions for primaries and diameters.
I have been getting back into this and closer to printing a first design for testing. I'm also building an all new exhaust and planning to A/B dyno test with my megan racing headers.

Over the weekend I redid the scan for the chassis and header packaging, I found some errors in the last one I did between the above the engine bay and under the car alignment. I also expanded the scan into the complete underbody and a decent amount of the engine bay. The new scan is on my github as a 5 million triangle, 1m triangle, and 500k mesh. https://github.com/AlecMoody/AlecMoo...haustPackaging

This is also by far the largest scan I have put together. About 3600 photos and over 24 hours to process the final mesh which was 4.5 billion triangles.

[freebird]

Awesome!

[Bry5on]

Wow that is excellent. If only it were an e46

I've been stalled on my end, happy to share the files if they're helpful though

[3staxontheradio]

Wow that is excellent. If only it were an e46

I've been stalled on my end, happy to share the files if they're helpful though

I do have an E46 I plan to do the same thing with but its got an M54 so someone will need to figure out how to get the engine/exhaust ports into the correct location. I think I'm pretty much good with the design right now? I want to do some flow bench testing on my scrap head for a last sanity check on all the diameters involved.

[ApexPothole]

Given what Bry5on's scan data does to my machine, I am in fear and awe at whatever you are using to process that! Really impressive, and makes me want to get my car up on a lift for a scan. Expect N64-esque polygon counts though.

[3staxontheradio]

Given what Bry5on's scan data does to my machine, I am in fear and awe at whatever you are using to process that! Really impressive, and makes me want to get my car up on a lift for a scan. Expect N64-esque polygon counts though.

If only I had a lift. Lol. This is quickjacks laying on my stomach with the camera resting on the ground facing up, scoot and shoot, move about 4" and repeat.

[ApexPothole]

Thats crazy man. It totally blows my mind the quality you are able to get with your photogrammetry process. I need to dig back into your posts explaining the process.

[3staxontheradio]

Looking mostly at diameters lately and wanted to get everything I have measured out of my notebook into one place and share it.

The supersprint header diameters are actually pretty close to what I want to do but the primaries are a very different length and its lacking any kind of choke in the merge.

I tweaked my pipemax file and im getting horsepower and torque numbers that make a lot of sense and translate well to diameters that look like how existing headers would be designed.

My current plan is a tapered primary from 42mm OD (a hair over matching the port exit) up to 46mm at the merge. A 52mm choke/ venturi in the merge collector that tapers out to a 63.5mm OD collector diameter. Still looking a smaller than 63.5mm collector as well. I think something like a 60mm collector into a 63.5mm anti reversion chamber and then place that on some very short harmonic on the tuned collector length.
Primaries at 550mm length with merges inline for equal length collectors / good sound.

[siamkazi]

Looking mostly at diameters lately and wanted to get everything I have measured out of my notebook into one place and share it.

The supersprint header diameters are actually pretty close to what I want to do but the primaries are a very different length and its lacking any kind of choke in the merge.

I tweaked my pipemax file and im getting horsepower and torque numbers that make a lot of sense and translate well to diameters that look like how existing headers would be designed.

My current plan is a tapered primary from 42mm OD (a hair over matching the port exit) up to 46mm at the merge. A 52mm choke/ venturi in the merge collector that tapers out to a 63.5mm OD collector diameter. Still looking a smaller than 63.5mm collector as well. I think something like a 60mm collector into a 63.5mm anti reversion chamber and then place that on some very short harmonic on the tuned collector length.
Primaries at 550mm length with merges inline for equal length collectors / good sound.

MY MAN, did you make this 'infographic"? I NEED this as a poster, so frickin cool!

[3staxontheradio]

I think I have pipemax basically dialed perfectly for a relatively stock S54 now. If I switch up my output to give me a "Street/strip" header instead of a race header the outputs basically look like the euro manifolds on a 5th harmonic: Some of the pipemax documentation is really not great. No idea what exactly the intended output paramters for a street/strip vs a race header are. I'm already specifying what RPM I want target peak torque and what RPM I want target peak HP at regardless of which output I use.

[3staxontheradio]

For anyone curious my final header design is intended for stock or mild cam engines with a wide powerband like the euro header. Diameters can easily be changed to support higher output engines. Anyone with specific knowledge is welcomed to pick this plan apart:

The euro header is a 320mm (5th harmonic) primary at a diameter that is basically a port match for the exhaust exit (41ish mm OD if using 1.5mm wall tube). This dumps into a formed merge which ends up in a 55mm collector. Merges on most of these headers are way out of line so total collector length is really mismatched which is why part of why our engines sound the way they do.

Primaries:
My plan is a 3rd harmonic primary, roughly 600mm long. Starting primary diameter will match the port/euro header at ~41.5mm and it will taper to about 46mm. My hope is the taper can do two things: 1) make up for wall losses from the very long primaries and 2)Hopefully work like steps to spread some of the energy from the scavenging waves out over a larger RPM. Primaries will terminate into actual merge collector with a choke at about 52mm.

Collector:
The merge will taper from 52mm to 60mm. At about 250mm from the merge the collector I'm going to transition from 60mm to 64.5 for 2.5" exhausts. I plan to make this transition with a small anti reversion trap. The jump in diameter should create an additional small scavenging wave at peak torque rpm (like primary steps do) and I can sneak a small AR trap in there to help limit reversion. The merges will be in line so the collectors should be very close to equal length which will sound good.

For the rest of the exhaust:
The third harmonic for the collector length is about 1000mm from the merge and that is the location just behind the transmission tail shaft which is where I will put an X pipe. I'm also planning to print an interchangeable Z pipe and assuming performance similar between the two I will pick whichever sounds better. For the rest of the exhaust I'm going to run dual 2.5" all the way back with a straight through set of center resonators and then out to a vibrant straight through dual 2.5 (universal 10538).


Overall picture of this is like a longer primary euro header with slightly bumped up diameters and a few features to hopefully hold onto velocity/torque across a wide power band. Since diameters are bigger I think it's possible it will lose some bottom end power on stock engines engines with cams not doing a lot a low rpm.

[digger]

are you going to be able to do bank 1 or 2 with the primary and merge in a single print?

IMO you would probably want to test the merge without a choke and without AR first

[3staxontheradio]

I want to try to do the merge as a slip fit so it can be swapped out without dealing with the cost of the whole header again. I'm unsure if tolerances will make that possible? I might be able to print the merge with the inner walls with extra material and then machine them to whatever it needs to be based on the actual final diameter of the primaries.

The AR and choke are things I have been thinking about (also collector diameter). It would be shame to oversize the collector and lose some bottom end on my stock engine or have other features get in the way of the basic concept. A 52mm choke is so conservative though, total stock collector is only 55mm. I think the manzo headers are a copy of the super Sprint V2 non-step headers. Looking at those super Sprint headers - they step the ID down for the slit fit joint into the section one of the exhaust so I think super Sprint is also using about a 60 mm collector. Has anyone posted dynos of the V2 super Sprint versus something more conventional like Euro headers or the Megan racing which are a decent looking clone?.



Also check out these achillies Motorsports headers. Long primaries and merges placed in line. I'm going to attempt to measure out the dimensions based on the photos.

https://www.achillesmotorsports.com/Achilles-Motorsports-Headers-Built-to-Customer-p/18-am-h.htm

[Bry5on]

Interesting that Achilles chose to keep the US header bank output positions and that allowed them to 'dip' the bank 2 pipes lower for packaging. That looks more flexible than the 3-finger-grip design I'd been playing with that matches the euro bank output locations. Sticking to 580-600mm seems like an awesome play and I like that you're converging on a less 'extreme' engine setup. Also agree with your collector multi-piece strategy.

For the taper - are you planning to start the taper at the ideal step point and end at the termination point of the primary then?

Anything I can do to help, just shout! Remind me what you're using for CAD software and if there's a collaborative option?