New exhaust

[Patrick]

Planning an update to the exhaust, starting early in the morning or coming back late is a bit of an issue. Dispite the sound passing SVA (just, like 99.X something db) it’s a tad disruptive. On long trips at 50mph you get quite a bit of resonance.

This setup using Varex X-Force back boxes gives the best of both. Open it up and it's a straight through perforated style muffler same as the magnaflow boxes on there now and when closed the sound is reduced to stock or lower levels.

Adjustment is via a keyfob, you can set open/close and anywhere in between.

Pipes by Jetex same as the current exhaust - great quality and lots of choice.

V band clamps from eBay, will have to see how the quality lasts on the clamps.





















Some jetex parts:



If any of you are classic car fans, we installed a very similar system on Richards 67 Mustang with a 289 small block V8 (Original marked in Video had two tiny bullet mufflers and it literally made your ears ring after 10mins of driving, was also a two pipe system. New varex setup also added an x pipe)

https://youtu.be/WaUs6yx8vtc

Lots more on this car here: http://www.mustang67.co.uk/

Now I just need to find time to build the new one! Doing a bit of planning in Autodesk Fusion 360 - which is aviable for free if you're a hobbist, well worth a look if you're into playing with CAD.

This shows some jetex parts to bridge the height difference between the exhaust run and back box height (and moves from the 2" pipe size to the 2.5" input size on the back box), lengths will change once I actually start holding bits up to the car:



Updated design:

[stevejgreen]

Re: New exhaust

Could to with that on my bike when going through sleepy spanish villages. Earplugs work for me on long runs.

[Patrick]

Re: New exhaust

I've started to use ear plugs on longer trips. I perfer not leaving early or returning to home late at night which can limit trips plan at times.

I don't plan to use the extra resonators that I have on there now. The two magnaflow boxes alone were oh so very loud when I built the first exhaust so I added two smaller jetex straight through mufflers half way. Will be interesting if the varex boxes silence more than the magnaflows when they're open and much quiter it is closed.

[Patrick]

Re: New exhaust

Progress on building the new exhaust. The welds a’it purdy but they’re solid and not tea bag considering I’ve never used a TIG before and have learned how to use it with YouTube tutorials…

Step 1: Remove the old exhaust:



Step 2: Test fit some pipes, ordered the wrong bend, so either need to modify or get another one



Step 3: CAD (Card board aided design) to get the angles for the 2″ to 2.5″ transition. The height difference is 80mm, the input and output are parallel.



Step 4: Transition parts tacked together with v-bands clamps at one end. The v-band connects the backbox to the rest of the pipes, will allow for some angle adjustment later if needed.



Step 5: Back gas feed, v band clamp in place to reduce chance of warping when welding that part.



Step 6: The two height / size transitions welded up (don’t look too closely). Back gas worked well, clean weld through no sugaring / oxidisation on the backs.



Step 7: Cut down the inputs on the back boxes, they input at a slight angle so needed cutting flush for the v-band to be welded on.



Step 8: V-bands welded on – these were both back gassed



Step 9: Cut out hangers for from stainless tock and cut holes in each.



Step 10: Hangers bent 90º – welded these on, bit of a tough one to get the amps right, melted away a bit much of the original metal but I think I made it longer than it needs to be to compensate.



Step 11: Finishing up welding the first piece – this goes from the exsiting output all the way to the back box



Step 12: Pipe in place, it will be clamped were the colour changes from stainless, to stainless covered in dirt



Step 13: Back box in place on the hanger (into the existing E36 style exhaust hanger).



Step 14: May need to move the head shield a bit as the back boxes are closer to the centre of the car due to the offset inlet.



The bullet mufflers are now no longer part of the exhaust system, in theory the closed setting should be quieter than before and open should be the same or louder!

Part 2 coming soon!

[David]

Re: New exhaust

Good work and well documented.

[listerjp2]

Re: New exhaust

Wow sure as hell knocks my one into touch, impressed.

Adrian

[greyV8pete]

Re: New exhaust

Most impressed with the workmanship. Have sent you a PM. Peter.

[Patrick]

Re: New exhaust

Thanks guys

I recommend these youtube channels if you want to get hints and tips on welding, the eastwood channel has some really good beginner videos where they teach the camera operator to weld:

Eastwood - 40 min beginner sessions: https://www.youtube.com/channel/UCMb...Kx-zKDchXjeNfQ
Welding tips and tricks: https://www.youtube.com/channel/UCqq...j4-UApS_m_6mPw
The Fabrication Series: https://www.youtube.com/channel/UCcx...rjTVSSUkzZ2Jlg

Need to finish up the other side and weld the tips on too, might have some time later this week. Then it's a case of wiring up the remote fob control unit.

[angusgrooby]

Re: New exhaust

Excellent fabrication going on there well done, I am interested in what make and model welder you are using maybe even a photo of it. Cheers Angus

[Patrick]

Re: New exhaust

Excellent fabrication going on there well done, I am interested in what make and model welder you are using maybe even a photo of it. Cheers Angus

Thanks It's an Eastwood TIG 200 Digital AC/DC - www.frost.co.uk sell them (I also considered the r-tech digital before buying). A bit OTT for a home gamer but it has a lot of options and will run up to 200amps, not been past 150amps yet. Most of the stainless pipe I've had it set to 80 amps with control on the pedal so probably lower for quite a bit of it. I'm not fast enough yet to use higher amps.

Note: it comes with a regulator that has US pipe thread so I bought a replacement with BSP. I also had to bit a UK 15 amp plug to it as it came with a USA 240v plug.

I also ended up getting a Y split and two flow read outs for the back gassing. I want to try some aluminium welding at some point which it will also do:



I got supplies from https://www.weldequip.com/ and https://www.thewelderswarehouse.com/ gas is hobby weld from local welding shop, there's a deposit on the bottle, gas refills are about £55.

The welding table is really nice, UK made from these guys: https://www.ebay.co.uk/itm/800x580x6...e/153218823171

The torch holder was very cheap and well worth getting, it's just resting on top in this picture.

[Patrick]

Re: New exhaust

Small update today, prepared the backbox output to fit the tips in the right place :

Step 14: Cut down the output pipes, otherwise the tips would stick out too far.



Step 15: Tip test fit, could move these back further by cutting the tip input down a little which would make the hole bigger.



Step 16: Test fit on car, it’s just push fit to at this point



Opened up the cover that’s over the mechanisum which actuates the volume flap



View from the top, position seems quite good here



View of the inside of the back box, the perforated metal is the bypass output



The other side, the hole show is the bypass, the perforated tube up to the flap works much like the straight though magnaflow back boxes I took off when it is open.

[Alan c]

Re: New exhaust

Great job. Watch air flow over car pulling in exhaust fumes when roof down. I had similar system fitted and get a smell of exhaust during around town - ok on runs. You would think air flow would take it away obviously eddy's create a problem

[Alan c]

Re: New exhaust

My previous system had a bend in tail pipe to direct it to the side

[Patrick]

Re: New exhaust

Thanks Alan good tip, the old exhaust did get some fumes in the cabin. I'm planning on sealing up the rear tub better to see if that improves things, if not making changes is not too hard - could use some bends in and/or use different tip style. Could go full TVR and exit out the side at the back, not sure how that would look on the Sportster though!

[angusgrooby]

Re: New exhaust

Hi Patrick looking good, thank you for the detailed info on the welder you are using and the links all very interesting I just need to convince the wife now and a good project to justify buying a tig welder now. ????????????