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Discussion Starter · #142 · (Edited)
Nice progress man! How much is the runner length difference between each of them @HusseinHolland?
So, I didn't measure them before cutting to check if they were equal, however with the modified runners, 2&3 are 30" and 1&4 are 28". What is you opinion on the variance? When I make the 2-1 runners, I will likely have one runner shorter than the other by a couple inches. The existing 2-1 runners were about 5' - is there any benefit in trying to extend that length if possible?

Because of the angle of the rear valance, I may need to drop them down & forward something like this (which will make them closer to 8-10'):

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Discussion Starter · #143 · (Edited)
After futzing with the previous ideas, I determined dropping the runners would end up too low - below the rear valance & close to the bottom of the crossmember.

So, it's gonna be more like this:
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Lower pipe will need a short 'pie cut' from a mandrel bend - that runner will end up about 3" longer than the upper runner

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Discussion Starter · #145 · (Edited)
Is that the possibility to compensate a part of the 50 mm difference of 2-3 and 1-4?
I'm not sure how I can get those equal length - I don't have enough space to run the legs out further & put bends to add length. I read on a forum that for 4cyl 2-1 runners should be as short as possible , is that accurate in your experience?

Or did you mean to compensate for the main runner difference?
 

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Discussion Starter · #146 ·
Header is mostly assembled at this point. Next I need to rework the entire exhaust around it. I would like to keep a cat in the system, so I will probably have to do a whole extra loop to the right side & back again

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I have to accept whatever penalty in flow the uneven lengths will cause - just no way to route it otherwise.

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Runner for 2-3 into the 2-1 collector is 3"(!) longer than the other.

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uneven lengths will create a different engine sound. It is a common OEM concept for “sporty” i4 engines to make one of the primaries longer or shorter than the others to create higher harmonics for a more sporty sound. You might get some Subaru/VW Boxer engine sound traits from this.
 

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Header is mostly assembled at this point. Next I need to rework the entire exhaust around it. I would like to keep a cat in the system, so I will probably have to do a whole extra loop to the right side & back again

View attachment 106172

I have to accept whatever penalty in flow the uneven lengths will cause - just no way to route it otherwise.

View attachment 106173

View attachment 106174

View attachment 106175

View attachment 106176

Runner for 2-3 into the 2-1 collector is 3"(!) longer than the other.

View attachment 106177
This looks like it’s going to sound pretty cool 😎
 

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uneven lengths will create a different engine sound. It is a common OEM concept for “sporty” i4 engines to make one of the primaries longer or shorter than the others to create higher harmonics for a more sporty sound. You might get some Subaru/VW Boxer engine sound traits from this.
A little rumble never hurt 😅
 

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Discussion Starter · #150 ·
uneven lengths will create a different engine sound. It is a common OEM concept for “sporty” i4 engines to make one of the primaries longer or shorter than the others to create higher harmonics for a more sporty sound. You might get some Subaru/VW Boxer engine sound traits from this.
This looks like it’s going to sound pretty cool 😎
Thanks for the input - I am looking forward to hearing how it sounds across the rpm range, for sure! Even if it is compromised somewhat, it has to been far, far better than my old shorty header for performance.

What I'm wondering now is whether I should try to make the rest of the 2.5" exhaust as long as possible -
I am thinking of putting a U bend after the collector, then the cat, then running pipe under the 4-2 collector, over to the right side. From there the pipe would loop up & over the collector, into the muffler (set closer to the right side), and exit on the left, going down & out that side instead of on the right. That would give me a substantial increase in overall pipe length. I could also just build it similar to existing, but then I have to eliminate the cat. I'd rather not do that if possible.

This is what it looked like prior

 

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Discussion Starter · #152 ·
More fiddling around today

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This mandrel bend will be cut to feed into the muffler on top

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What will make this possible is this: Tightest mandrel bend "U" available. 7.5" outer radii will be perfect to feed the header collector into the cat.
Circle Auto part Automotive wheel system Composite material Rim


smaller OD Poly mount has more clearance off the header

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clearance off the crossmember

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So... I made some cuts & reshaped the crossmember & upper crossbar. Will be welded later

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upper clearance after

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Discussion Starter · #153 ·
lower

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Pretty sure I'm good now. All will be cleaned up & painted after welding

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The header has to be pivoted thus to remove/install. So, the body support has to be a removable section no matter what

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Discussion Starter · #155 ·
Nice solution to get the header you wanted in there 👍 back to the dyno soon ?
Next year - I don't drive the car in the winter - tires are way to soft for below 50f. It's gonna be at least 2 weeks or more before I get the exhaust welded (waiting for mandrel bends and muffler), and weld the chassis. After that, I also have to figure out a revised cross brace, and fabricate/weld/paint all that, so at least a month or more all told before it's even ready to drive.
 

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Discussion Starter · #156 ·
Just had time to weld the notched areas yesterday & get some paint on it today

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had to do some finagling with the torque mount - I noticed the rubber mount was skewed, so I made some adjustments to the mount bracket. Also needed a 1/4" shim to get the same height as the rubber one.

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Discussion Starter · #157 · (Edited)
not much done this week - finished the rewiring for the solenoids & sensors to move them as far from the header as possible

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Started making the removable upper support - it will be at least two parts, using "C" section 1.5x.5" .125" thick mild steel
lower vertical piece is anchored using the trunk lid mount points

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and one additional anchor in the trunk wall

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Upper plate tucks in on the right, then is fed back 5" into the left side notch on right is to clear the trunk support bracket. Original top plate will bolt in place, to provide the lip for trunk seal & cosmetic appearance
Wood Musical instrument Gas Folk instrument Bumper


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3 anchors on each side
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I'm planning on boxing the "C" section to make it more rigid
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The horizontal and vertical sections will also be tied together in the middle area
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Inner trunk access cover will be something along these lines, the header only protrudes 3/4 - 1" into the trunk cavity
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fitted the 4-2-1 collector & check placement of mandrel bend & cat - should work out well. V-bands on both sides to allow disassembly & height adjustment of cat/cross pipe while I figure out muffler placement, etc.
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Man I wanted to thank you for being dedicated to your build and this build thread. Of late I have been drawing inspiration from your thread to push my harder to finish my own build. I tend to work limited hours on my build (2-3 hrs) at a time. My heart and chronic pain have been throwing a fit of late and my energy levels are down. It is hard to tell what is going on some days, I just know it feels good to get things done. I take enough heart medicine for four people with hypertension 1 and this started at 33. I am now 44 and well versed in dealing with and living with jacked up disabilities. I am due for another reconstructive ankle fusion surgery to strengthen one of the ankle fusions. I am over due for a triple tendon surgery on the other fused ankle/foot. At some point from both achilles having tendinitis, something will have to be done. If I attempt to function like a normal full time worker on my feet, the edema is so bad from achilles tendinitis my doctor sidelines me after 7 days of working.

Honestly, I prefer to live slowly instead of force myself to continue to have surgeries. After 4 major ones directly on both ankles, I am trying to stay away from them. I like the part where I get to lay around and sleep on pain meds watch movies etc. It is the rehab that sucks. It sucks because my body is opiate tolerant and getting relief after surgery is hard and treating chronic pain is impossible after the fact without taking copious amounts of pain medicine, that is no life raising children like I do. Medicine can be a vicious cycle if needed for chronic treatment. These days I am teaching my father how to live with Afib and heart disease who was recently diagnosed with Afib. I was diagnosed with Afib, hypertension 2, and a pulse disorder 11 years ago and have been dealing with it. Weird how life works.


Today I am getting geared up to pull the head of the engine and work on the valve train then new head gasket. I swear I am in slow motion and I am finally OK with that, moving in slow motion that is. I can't find my damn camshaft locking pins, I am on the last three boxes to look in and went to check PM's.

Thank you for sharing your build.
 

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I also thank you sharing your project progress here, also the issues and obstacles, which is often more interesting to me then perfect built progress stories. The last is out of what I am here for, I am here for to learn about engine design and solutions of adaption for different chassis. Your example is a perfect example how far an chassis force you to tweak the ideal regarding alternation of load parts, just to have an K-series implemented into that drive-able 4-wheel box. It is great to see your idea finds it's way to realisation, you solve the challenges by your DIY capability to get your torque curve improved. That is what engine design makes challenging, the requirements by race rules, chassis clearances and requirements for driveability. Getting out the best of each of this challenges is a tough job. I really appreciate your shared experience, obstacles and successes.
 

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I like how that circle fitting worked out for you there. Your welds get better and better as you go along this header.

Do you have mig or flux w/ 75/25? I use 309 fluxcore wire w/ 75/25 on carbon steel welding, stainless welding, does not matter. It always works like butter. It is $50 for a 2lb spool. works great for tacking, stitching chassis, hardly has weld balls. Some people do not believe until they try it out. A 2lb roll can stitch weld an entire Honda engine bay and some more.
 
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