308 V12 conversion begins

I had planned on sticking with 4 round tips similar to stock outside but they would be just pipes not resonators to get the ID I need without needing a massive (stupid looking) OD.

I saw this oval transition and oval tubing in the burns catalog though and now I’m thinking polished up and angle cut they might make kind of a cool looking exhaust tips. I‘m thinking the QV exhaust cover has oval cut-outs so oval tips sticking though them might look nice. I’ll need to think about this a little.
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Hey Mike,
Have you looked at the oval tubing from SpinTech? I believe all their tubing and mufflers and such are stainless and oval for really low ground clearance, don't know if it would help you at all.

Laters,

Brian

 

I got a call from the girl at Burns this afternoon....

Last night when I was ordering I noticed they had 2 part numbers for most of the bends I wanted, one being about 15% cheaper....and I thoght to myself "well I'm cheap so the cheaper number seems perfect!" and since I couldn't figureout what the heck the difference was I ordered the cheap stuff.

Back to Burns girl calling. They din't have enought of one of the parts in the -B part number and she wanted to know if I would be willing to take "A" parts instead. This got me thinking ....A, B ....could that means seconds? SO i asked and yes in fact -B parts are seconds, it means they have small ripples, it happens a lot on 18g appearently. It wasn't packed yet so I changed the order to A parts as I didn't think ripples were such a good idea....the good new is that bumped the order over $1000 geting me the tier 3 price so I got the A parts for very close to what I would have paid for the B stuff. Good deal....still not good enough to give me the nerve to tell Lana what I bought, but good.

 

You're gonna get in trouuuble,......... you're gonna get in trouuuuuble......., neener neener neeeeeener.

 

I sure am....you see what I do for you guys?

I got started on the flange tonight. I'm making 4 the same so I tacked the pieces together so I can do them all at once, then they will fall apart when I maching the ends. Cutting SS is slooooow, it looks like I'll be on this a couple nights.
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Is it not cheaper to have them Laser cut ?? Here in SA the laser guy's are very competitive . Those flanges would be less than $10 maybe even $5 each

 

Doh!, now you tell me....Do you mean $5-$10 per cyl or for the 3 cyl flange?

I have the material, so at this point machining the flanges is free. I should have them done tomorrow.

all the tubing I ordered from bother places was in stock and shipping yesterday. Its 7 days from CA so actual header building starts mid-next week.

 

I'll take a look. Burns has oval tubing and bends too, but I don't need that...I was just liking the transitions as a possible tip option.

 

Wow, finally my withdrawals are ending.

Glad to see you are back to making good progress Mark. Looking excellent.

Tom...

 

I don’t remember what I was thinking about mufflers when last I thought about it…but at the moment I’m thinking a pair of borla 40575 mufflers. They are 3” in/out, 16in long oval case multi-core XR-1 racing mufflers….and at $250 a piece they are 2-3 time the price of most of the other options, so right in line with the budget over-runs in the rest of the exhaust project.
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For future reference.....Water jet cutting is pretty cheap too and it doesn't heat up the metal.

 

In SA waterjet is just way more expensive ( less machines so I think pricing is not as competitive ) , but if you want to cut very think material it's the way to go .

 

I guess a single magnaflow 12469 for $110 is also a decent option. It’s not as pretty as the borlas, but no one ever sees it either. It would save me $400 and 10+ lbs I’ll bet.
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A little time on google and it appears there are good reasons the borla costs more.

The borla has more sound damping material and compartments in it to help reduce noise by about 5-6 bd more than the magnaflow (3 bd is twice the sound) as well as producing a depper sound.

The borla also has 2 tubes smaller tubes instead one 1 big tube. This give more surface area to impove sound damping but it also gets rid of the drone you can get with large pipes mufflers (think fart can -clearly not what I'm after).

Way back on a muffler thread I was talking about maybe splitting the 3" pipe into two 2.25 pipes and sending it into 2 dual inlet/outlet mufflers....or maybe 4 short mufflers wleded together to make 2 longer ones as that would be quiter. 2 borlas basically does exactly this so price wise I should be comparing to 4 magnflows....which would cost the smes $500 as the 2 borlas.

Borlas it is I guess.

 

I got a like more done on the flanges tonight. Hopefully 1 more night and they'll be done.... I ugess it depends on how fancy I make the exterior profile.
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I had a little time this mornign waiting for the truck to come get red car, so I finished up the inside of the flanges.

Also, I reminded Lana that she said when the red car goes, blue car part are allowed....so it won't be a total surprise when the UPS man comes next week.
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Your a brave man. I know when my wife comes out to the garage she looks around and says "where did that come from". My reply "oh I made it out of the extra parts I had". Try that one.

John

 

Are you welding the header tube onto the flanges ? I have normally ovalled the tube and pushed it through , so those hole need to be the wall thickness bigger ? then you weld from the inside , I'm sure you are going to do such . Also give you a little angle movement , so the pipe end does not have to be exact .

 

That is of course the best and easiest way to do it,thank you for pointing it out.

 

Yes, I use some different Borlas on my big CI SB Corvette.

They idle very quietly, they cruise very quietly, only at WOT do they start to announce your presence.

They also flow better than all but one or two other mufflers, and both of those are considerably (~9 db) louder at cruise.

Doug

 

Yes, make a cardboard or paper (pencil rubbing) template off the head and a water jet place can cut 3/8" four tube flanges for around $40 each, more or less, based on my experience.

Doug

 

I still have to clean them up a little, but they are pretty much done now.
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Surely a lightening hole (or 2) needs to be drilled in between ports on those flanges ... .

Pete

 

They look very cool, and agree a lightening hole would be a nice touch. I love this thread! Amazing workmanship!

 

Neat job and as you say it was for free , bar the material