TheSamba.com :: View topic - W. B. X-awst!

Sun Jan 06, 2008 2:20 pm

tencentlife wrote: But you're saying with gas shielding I can weld the SS bungs to mild steel tubing?

I will confirm that this is true.

Sun Jan 06, 2008 2:59 pm

Thanks, Andrew and Chris. That's very very good to know.

Quote: Get out the peanut oil!

I already remembered TK's idea, I'm tempted to do just that. Was that supposed to work on raw metal, or was it more to protect a painted surface?

Sun Jan 06, 2008 3:16 pm

I'm pretty sure it is for a raw metal surface. My cast iron cookware has never been painted, but occasional oiling keeps them rust free. And I would guess the protection improves with multiple coats.

I think Terry recommended a cotton glove soaked with the oil, applied to the exhaust prior to heating it up.

You may have to come up with a creative deterrence to prevent your dogs (and the native local fauna) from sampling your work.

Sun Jan 06, 2008 5:57 pm

I just ordered a box of stuff from Summit today, including this 1500F silicone paint. It'll get here before next wekend so I'll have time to paint with that and give it a try. The idea of a stir-fry-loving coyote gnawing on my pipes gives me pause.

Also got the Aux Box for my LM1, which completes the setup for the Not-Yet-Poor-Man's dyno! We'll need it to do the datalogging and analysis for another FI enhancement project that's in the pipeline (attn. loogy). The Aux Box has an accelerometer, so I can do controlled road-tests out here in the boonies and see if hardware and tuning changes actually improve power or not.

Sun Jan 06, 2008 9:05 pm

tencentlife wrote: We'll need it to do the datalogging and analysis for another FI enhancement project that's in the pipeline (attn. loogy).

DING, DING, DING!!!

Wed Jan 16, 2008 8:35 pm

My Borla Pro XS all-SS muffler and more sleeve clamps got here this week, so today I got a chance to fit them up.

On this prototype, the collector has a short straight bit 3" long between the first and second curve of the collector. In final versions, there will be a split there and I'll include an extra sleeve clamp so you can swing the collector end up and down a bit, to allow the use of offset-inlet oval mufflers or to allow the muffler to be tucked up under the tail further, especially with a round muffler. It will also make installing #2 runner easier. That'll be the cheap version, for more money I can offer a V-band clamp there and also supply them for your muffler inlet as well. I anticipate the V-bands will seal better than the sleeves, but they're very expensive so it will be an option.

What your buddies will see:

Lookit that El Cheapo FLAPS chromed tip! Sah-MOKIN!!

I made a support of 1" steel angle, box welded at the corners for strength. It bolts to the aluminum engine carrier ear. A 3/4" steel band encircles the tailpipe. Very rigid. This is just for muffler-only situations. I'll have to figure out something more adaptable for use with the full emissions package:

A few finishing touches, paint, and it can go on the car! First I want to datalog what the engine does with the present exhaust, then see what changes and whether it pulls harder with the tuned one. If I like it, in a couple of weeks I could get it on the dyno.

Wed Jan 16, 2008 10:18 pm

out-f#%@ing-standing

Thu Jan 17, 2008 8:51 am

That looks really cool, 10c. Can't wait to hear it sing.

Thu Jan 17, 2008 10:18 am

I have an engineering sense that this system needs a few flex joints or more braces similar to the way the original has. Anything hanging in the air like that is going to stress the welds at the flanges. No greater pita than an exhaust system that keeps cracking.

On a related note, 20 years of use tells me that those "turbo" style mufflers last a few months before the baffles inside get loose. Then you get wonderful vibrations at a particular range of rpms. It goes away, but always rattles at one rev range. You are warned.

Dead meat....

Thu Jan 17, 2008 10:32 am

Nice Job, I really like the layout of the tubes, that alone is the toughest part and there are usually only a few good solutions that are practicle in a give space. My observation is the collector is much larger than most T1 headers , is this purposeful? I do know it can affect low end torque.
My experience with mufflers is straight throughs are loud unless used with a turbo. Borla makes an S tube muffler from stainless for $100 That looks the same with an offset outlet. This muffler still flows well and knocks the noise down a bit. Also you would be suprised how much a 90* bent tail pipe reduces sound. Put one up to the tailpipe once you get it running and see.
Any plans for a dyno test when done? I'm curious how this turns out

Thu Jan 17, 2008 10:48 am

r39o wrote: I have an engineering sense that this system needs a few flex joints or more braces similar to the way the original has. Anything hanging in the air like that is going to stress the welds at the flanges. No greater pita than an exhaust system that keeps cracking.

On a related note, 20 years of use tells me that those "turbo" style mufflers last a few months before the baffles inside get loose. Then you get wonderful vibrations at a particular range of rpms. It goes away, but always rattles at one rev range. You are warned.

Dead meat....

Keep in mind that he is using a Borla muffler: all stainless steel construction and it comes with Borla's well known 1 million mile warranty. I know it looks like a turbo muffler, but it is actually one of the highest quality mufflers you can buy.

Also, the need for flex joints is only on exhaust systems where engine rock causes stresses. Since Vanagon systems are completely supported by the engine, they rock and roll with the engine. Stress cracks shouldn't be a problem. Expansion bellows are commonly used where differences of expansion (dissimilar materials, varying manifold thicknesses) are present. With uniform gauge material this shouldn't be an issue.

David

Thu Jan 17, 2008 11:50 am

Right, this isn't a baffled muffler. It's an all-stainless "glass-pack", and yes, Joe VW, I anticipate it being LOUD. But we'll see.

I do plan on adding a bend to the tailpipe to get the tip out from under the body, which will cut interior noise substantially even if it doesn't do much for bystanders. I have to be careful as any straight-thru muffler becomes a portion of my second-wave tuned length and I don't want to go much over. Baffled mufflers or catalysts will terminate the tuned length at a fourth-wave length which is the end of the collector. In installations using one or both, the tailpipe could do anything you want and it will have zero effect on tuning so long as flow is adequate.

This Borla is only one of several mufflers I plan on testing with this system. I want to be able to supply or recommend units that will work well with the system, and I won't know if I don't test them. I have in mind some other baffled "turbo" and hi-flow mufflers, all top-shelf items. If you read my text in the last post, I will include a feature that will offer flexibility in use of many styles of mufflers with and without catalysts.

This Borla is not one of their racing mufflers, and it tested one of the quietest but least restrictive in a matchup test of many performance muffs. But, the testing, like nearly every thing you can find about muffs and custom exhaust on the internet, was done on a large V-8 platform. It seems no one with fewer than 8 cylinders ever does anything with exhaust, or if they do they don't write about it. Anyway, you never know how any muffler will sound until it's actually mounted to the system in question. Period. So we'll see. It does have very high quality construction and a million-mile warranty for very low cost. But I really just got it for the cool sticker.

As far as bracing, there isnt anything "hanging in the air like that " at all; the tailpipe is rigidly supported, and mounted to the motor itself so it will all move as a unit. I'm wary of oversupporting things, as in my experience too many mounting points actually creates additional stress as the overall system can't thermally "breathe". The brace pictured is just a quick solution for my use. I'm dreaming up an all-in-one sort of bracing system I can ship with the headers to allow use with cats and muffs or muffs alone, and it may include an additional support point for the collector terminus if I decide that that would be advantageous.

JoeVW, the collector size is determined by a ratio of the total combined runner area. There are numerous formulae and calculators online and everyone has a different approach. I combed thru everything I could find and used the methodologies that were best supported by fact and made the most sense to figure the final dimensions and ratios. I honestly don't know how it will work out. This may be just the first of several prototypes I'll need to go thru to get the results I want. I hope not, but it's fun to build anyway. Once more, "we shall see".

Thu Jan 17, 2008 11:58 am

:P ..............pause to wipe drool off keyboard. I have nothing constructive to add except "I want one!"

BTW-I had a SS Borla muff. on my old MKIII Jetta, they sound grrrrrrrrrrrreat!

Thu Jan 17, 2008 1:45 pm

I'm surprised some of the famed NM aliens haven't abducted Tencentlife yet, in order to reengineer all of their spacecraft. Flying saucers are all powered by Wasserboxers, I'm told- and while crafted to extremely high tolerances, they were not perfected. It must be something in that really slick red mud down there or something. I bet he could get an extra 30 HP out of a stump. Way to go man.

Thu Jan 24, 2008 5:01 pm

OK, kiddies, here it is installed, finally:

I got a fancier tip with my last parts order. More awesome-looking than that cheap FLAPS one. All the new shiny stuff really highlights the mud, too!:

I can do some experimenting with the final tailpipe length, and with adding a bend to bring the tip out from under the body to cut down the interior noise. But for now, I'm going to enjoy the drone.

The view under the transom. Still have the same road clearance:

I'm doing datalogging to compare the pulling power before and after. I'll post my conclusions once I have time to compare the data. Already I can see some upper-rpm improvement on my standard road test pull.

The sound? Niiice! Sounds like a little road-race rocketship. The Borla has a nice, smooth, throaty hum.

I took a video clip with my digital camera, but it doesn't do it any justice. The tiny mic doesn't record the low tones well at all, so I'm not going to bother with posting it.

Thu Jan 24, 2008 5:28 pm

Very nice 10c. At first, in one of the photos I thought maybe the left side was hanging too low but then I saw the final pic and it looks just right. Can't wait to see your road test results. That exhaust looks MEAN!!!

Thu Jan 24, 2008 6:53 pm

I like the way it fits. It uses every bit of extra space to the left of the engine, but the pipes look well routed and I like the fact nothing hangs down. Is it a lot louder inside the van?

Congrats on a first rate fabrication job.

David

Thu Jan 24, 2008 9:00 pm

I'm really diggin the fatness and tuck. Awesome work man!

Thu Jan 24, 2008 9:29 pm

Yeah well feast thine eyes on that nice clean aluminum paint. You can see how muddy the rest of my rig is this time of year. One or two more trips to town and the pipes will look as cruddy as the rest of it. Then we'll see if that silicone heat coating can shed the dirt.

I like the big collector too, Paul. Phat is where it at.

It is quite a bit louder than the old setup with its NAPA muffler, but really not as loud as I thought it might be. The tone is sweet, it definitely sounds more balanced and smooth like a nicely-tuned four-banger should, but the interior drone on a long trip could get to be a bit much. I was running it with only the engine lid laid on top, not even sealed down, since my instrumentation wires had to exit the bay opening, and there wasn't the foam bed that's usually there. With it all sealed up, I expect the inside noise to be a lot quieter. If I fool with the tailpipe and angle it so it exits outside the bodywork I also expect some more volume reduction. An offset-outlet muffler would have been a better choice for doing that. But I do like the way this one looks, for what that's worth.

I'm still running the unusual rocker combo of 1.1 intakes and 1.25 exhaust, which gave a better idle and big low-end torque with the old exhaust, but tomorrow I'll swap the rockers for all 1.25's. I expect to see the best power output in the high-revs then. That was the whole point of building this thing; to wake up this engine in the top end.

But my first datalogs already show much higher g-pulls in the low gears. I'm not getting good WOT enrichment, though. I talked to reiney about that and we decided it was due to noise from the inductive ignition pickup being too close to the unshielded o2 feedback wire from the LM1. There's a lot of noise on the some of the other data channels as well. I'll move the pickup to another cylinder further away and get some shielded cable for the o2 signal and hopefully that will clean things up. Can't get max power if it's running lean!

Sat Jan 26, 2008 4:44 pm

Added a shielded coax for the o2 signal extension and moved the nductive spark pickup to the other side of the engine. Changed the rockers back to all 1.25's. Haven't had any time to drive to my test road and datalog some pulls, but I ran a brief sample recording close to home and the noise is cleaned right up. Looked like it was back to a normal WOT enrichment as well, but I think the AFM will need some more tweaking now that it breathes better.