Custom 850 exhaust vids

Personally, I think it sounds Awefull,there are so many better offerings out there.

Has Any one heard Shiggsys Csi on Magnafows? or Hallworths v12 ?

The first clip sounds like there is a backpressure issue.... all the bangs are not good.

Supersprint too has a kit in the making for all e31's.
sent them a mail yesterday requesting info on completion and prices.
this includes headers, kats, straight pipe center section and new rear boxes.

Zitat von stevep840

Has Any one heard Shiggsys Csi on Magnafows?

I have.

Actually I have had them quietened down since you last heard them. (If you turned up at the meetings you'd know that though! )

Cheeky bugger

Re: Custom 850 exhaust vids

Zitat von Seb

I know a couple of the V12 guys have been asking about exhausts and it just so happens that the boys at Torqueflow have made a system for an 850 - no idea what the spec is, but here's a couple of clips:

http://www.youtube.com/watch?v=t7MYa56HXL4

http://www.youtube.com/watch?v=6unhdg1QoBM

Looked and listened to both clips and some others from Torqueflow on the site and all sound terrible, like some kind of tractor with misfiring. There's more to exhaust systems than just stainless-steel tubing and cans and it seems from listening to these clips that Torqueflow don't have what it takes.
A good exhaust system will treat resonant air patterns to help discharge the cylinders and improve torque in certain rev ranges. Like Noggie pointed out, the banging is not good and the exhaust is not working as it should.

I have G-Power exhaust, I think it sounds fantastic, very low rumble, no backfire, just a smooth classy sound, Next project "CAT" removal, I think that will make it louder for sure, but I have read reports of 25+ HP gains...

DMP

DMprentice.
25hp might be true, but how old was that car??
an old clogged up cat will steal alot of hp. and by removing it, it will give you a gain, but so would probably just replacing them do too.

--------

Exhaust is a science... not just straight tubes and a muffler.
each cylinder sends a pulse down the pipe, the clue is to make them come out in a good order, one pulse helpes the other along, much like slipstreaming in racing.
upset that balance and you get backpressure problems, banging noises, missfire and in worst car power loss.
The engine is designed to have a certain backpressure to work properly.
mess up the exhaust and you can mess up the whole engine characteristics, loss of torque at certain revs, missfire at others.....

my thoughts are that the exhaust system in these clips still needs some fine tuning....

Zitat von Noggie

........Exhaust is a science... not just straight tubes and a muffler....
....loss of torque at certain revs, missfire at others..... .

Agreed. That's why, from the sound of that video in the other post, "Torqueflow" is a misnoma.

There are some aftermarket" stainless steel"systems out there that do not live up to expectations,& as always it's down to Quality or the lack of it, a Mate had a rusted stainless steel back box replaced after 3 yrs [even a cheap mild steel box would last longer] Equally if in doubt try running a magnet over your newly acquired S/S system if it sticks ask yourself how you have managed to get shafted ie it aint S/S

Zitat von Seb

While I agree that there's a science to exhaust manufacture, back when I was into Japanese performance cars, the aftermarket exhausts where pretty much a straight piece of pipe with a straight through back box on the end. There was, quite literally, nothing more to it. If you de-catted your car then you had a single diameter piece of tubing from your downpipe all the way to your exhaust tip, and all of it was the same length as your standard system.

When you have a turbo charged enginge the exhaust is less critical.
after the exhaust gass leave the turbo it really don't have much influence anymore, unless it gets to tight and prevent the turbo from working right. So a straight pipe for a Turbo engine sounds right.
However the piece infront of the Turbo, the equal lenght headers plays a crucial role in how the engine performs. and again the pulses need tocome at the right spacing to optimize the turbo spinning.

Now, I'm no expert on this matter, but I do know a little.

Try taking the exhaus off an 850 and go for a drive.... If you ignore the noice I think you would find that the engine does not perform as well as normal.

Zitat von stevep840

There are some aftermarket" stainless steel"systems out there that do not live up to expectations,& as always it's down to Quality or the lack of it, a Mate had a rusted stainless steel back box replaced after 3 yrs [even a cheap mild steel box would last longer] Equally if in doubt try running a magnet over your newly acquired S/S system if it sticks ask yourself how you have managed to get shafted ie it aint S/S

There are many different types of "Stainless-Steel" and with most types, when welded, the stainless properties are lost.

The best variety for corrosion and heat resistance is 316L.

Look here for some interesting Information:

http://www.quicksilverexhausts.com/technology.asp

There's a lot of information on the net, but basically, 304 is the regular 18/8 stainless that's used for making kitchen sinks, saucepans etc. It's the most common grade. However, it is not particularly corrosion resistant in severe environments at high temperatures:

"...Grade 316 is the standard molybdenum-bearing grade, second in importance to 304 amongst the austenitic stainless steels. The molybdenum gives 316 better overall corrosion resistant properties than Grade 304, particularly higher resistance to pitting and crevice corrosion in chloride environments...."

(There is also a low-carbon, L-version and a high-strength, H-version of 304)

Corrosion Resistance of Stainless Steel 304

Stainless steel 304 has excellent corrosion resistance in a wide variety of environments and when in contact with different corrosive media. Pitting and crevice corrosion can occur in environments containing chlorides. Stress corrosion cracking can occur at temperatures over 60°C.

Heat Resistance of Stainless Steel 304

Stainless steel 304 has good resistance to oxidation in intermittent service up to 870°C and in continuous service to 925°C. However, continuous use at 425-860°C is not recommended if corrosion resistance in water is required. In this instance 304L is recommended due to its resistance to carbide precipitation.

Where high strength is required at temperatures above 500°C and up to 800°C, grade 304H is recommended. This material will retain aqueous corrosion resistance.

Fabrication of Stainless Steel 304

Fabrication of all stainless steels should be done only with tools dedicated to stainless steel materials. Tooling and work surfaces must be thoroughly cleaned before use. These precautions are necessary to avoid cross contamination of stainless steel by easily corroded metals that may discolour the surface of the fabricated product.

Welding of Stainless Steel 304

Fusion welding performance for Stainless steel 304 is excellent both with and without fillers. Recommended filler rods and electrodes for stainless steel 304 is grade 308 stainless steel. For 304L the recommended filler is 308L. Heavy welded sections may require post-weld annealing. This step is not required for 304L. Grade 321 may be used if post-weld heat treatment is not possible.

304 info:
http://www.azom.com/details.asp?ArticleID=2867

316 info:
http://www.azom.com/Details.asp?ArticleID=863

Stainless steel grades (from Wiki):

* 100 Series—austenitic chromium-nickel-manganese alloys
o Type 101—austenitic that is hardenable through cold working for furniture
o Type 102—austenitic general purpose stainless steel working for furniture
* 200 Series—austenitic chromium-nickel-manganese alloys
o Type 201—austenitic that is hardenable through cold working
o Type 202—austenitic general purpose stainless steel
* 300 Series—austenitic chromium-nickel alloys
o Type 301—highly ductile, for formed products. Also hardens rapidly during mechanical working. Good weldability. Better wear resistance and fatigue strength than 304.
o Type 302—same corrosion resistance as 304, with slightly higher strength due to additional carbon.
o Type 303—free machining version of 304 via addition of sulfur and phosphorus. Also referred to as "A1" in accordance with ISO 3506.[5]
o Type 304—the most common grade; the classic 18/8 stainless steel. Also referred to as "A2" in accordance with ISO 3506.[5]
o Type 304L—the 304 grade but specially modified for welding.
o Type 308—used as the filler metal when welding 304
o Type 309—better temperature resistance than 304, also sometimes used as filler metal when welding dissimilar steels, along with inconel.
o Type 316—the second most common grade (after 304); for food and surgical stainless steel uses; alloy addition of molybdenum prevents specific forms of corrosion. 316 steel is used in the manufacture and handling of food and pharmaceutical products where it is often required in order to minimize metallic contamination. It is also known as marine grade stainless steel due to its increased resistance to chloride corrosion compared to type 304. SS316 is often used for building nuclear reprocessing plants. Most watches that are made of stainless steel are made of Type 316L; Rolex is an exception in that they use Type 904L. Also referred to as "A4" in accordance with ISO 3506.[5] 316Ti (which includes titanium for heat resistance) is used in flexible chimney liners, and is able to withstand temperatures up to 2000 degrees Fahrenheit, the hottest possible temperature of a chimney fire.
o Type 321—similar to 304 but lower risk of weld decay due to addition of titanium. See also 347 with addition of niobium for desensitization during welding.
* 400 Series—ferritic and martensitic chromium alloys
o Type 405—a ferritic especially made for welding applications
o Type 408—heat-resistant; poor corrosion resistance; 11% chromium, 8% nickel.
o Type 409—cheapest type; used for automobile exhausts; ferritic (iron/chromium only).
o Type 410—martensitic (high-strength iron/chromium). Wear-resistant, but less corrosion-resistant.
o Type 416—easy to machine due to additional sulfur
o Type 420—Cutlery Grade martensitic; similar to the Brearley's original rustless steel. Excellent polishability.
o Type 430—decorative, e.g., for automotive trim; ferritic. Good formability, but with reduced temperature and corrosion resistance.
o Type 440—a higher grade of cutlery steel, with more carbon in it, which allows for much better edge retention when the steel is heat-treated properly. It can be hardened to around Rockwell 58 hardness, making it one of the hardest stainless steels. Due to its toughness and relatively low cost, most display-only and replica swords or knives are made of 440 stainless. Also known as razor blade steel. Available in four grades: 440A, 440B, 440C, and the uncommon 440F (free machinable). 440A, having the least amount of carbon in it, is the most stain-resistant; 440C, having the most, is the strongest and is usually considered a more desirable choice in knifemaking than 440A except for diving or other salt-water applications.
o Type 446—For elevated temperature service
* 500 Series—heat-resisting chromium alloys

* 600 Series—martensitic precipitation hardening alloys
o 601 through 604: Martensitic low-alloy steels.
o 610 through 613: Martensitic secondary hardening steels.
o 614 through 619: Martensitic chromium steels.
o 630 through 635: Semiaustenitic and martensitic precipitation-hardening stainless steels.
+ Type 630 is most common PH stainless, better known as 17-4; 17% chromium, 4% nickel.
o 650 through 653: Austenitic steels strengthened by hot/cold work.
o 660 through 665: Austenitic superalloys; all grades except alloy 661 are strengthened by second-phase precipitation.

*
o Type 2205— 2205 is the most widely used duplex (ferritic/austenitic) stainless steel grade. It finds applications due to both excellent corrosion resistance and high strength.

Zitat von arnie

There are many different types of "Stainless-Steel" and with most types, when welded, the stainless properties are lost.

The best variety for corrosion and heat resistance is 316L.

We live and learn don't we - I have today for example learnt that not all SS is magnetic - never crossed my mind before, in my ignorance I assumed that being ferrous based it would be magnetic but that's not always the case

I haven't been able to listen to the Torqueflow youtube posts yet (youtube is firewall blocked here at work) but I'll try and listen to it tonight. The question of backpressure is important - as Noggie pointed out, if you don't have sufficient backpressure this will affect the way the engine breathes significantly. Straight-through systems allow the exhaust gases to escape more quickly (and consequently they are louder) but allowing the gasses to escape too quickly can cause problems. Pulse tuning in both induction and exhaust systems is a fine art. A brief example - my old 1968 Sunbeam Rapier had a Holbay tuned 1725 engine with twin Weber carbs. These carbs had a longer internal venturi fitted - this was the only application of Webers that used this longer venturi and many didn't know why. If you swapped the venturi for a more common shorter one (i.e. it didn't stick out the end of the "trumpet") the engine would still run - but terribly. The longer venturi was there to assist in pulse tuning (according to an engine tuning company I've discussed this issue with that tunes these engines regularly)- I'm not qualified to answer the question properly but I do believe that there's more to creating a proper sounding and importantly, proper functioning exhaust system than just bunging some striaght pipes and cans together.
BTW, for the Sunbeam I bought a SS system from London Stainless (which I think is also called Quicksilver) - the system was great and not too loud. I have no idea if it's magnetic or not, never thought to find out.

Cheers,
Jason

extract from http://www.quicksilverexhausts.com/technology.asp:

"..........Our ‘straight through’ silencers contain a perforated tube surrounded by a finely-woven metal sock. Made from semi-continuous (Type 434) stainless steel filaments this sock outperforms conventional glass and basalt alternatives at high temperature and is used to insulate and retain the acoustic stuffing. This is an essential component for most high temperature applications.

For sound absorption we still employ long strand Basalt filament that offers excellent acoustic performance up to 1500 Hz. It's thermal properties are comparable with continuous high temperature glass but more stable at temperatures over 600° C. This material requires rigid handling procedures in the factory.

So, for environmental reasons we are moving over to use Advantex and Acousta-Fil stuffing, these have similar temperature and acoustic properties as the Basalt .

Acoustafil

Advantex is manufactured by Owens Corning Corp. Says Heinz Otto, President, Composites Systems Business. "The glass fiber remains in place, even under the harshest conditions, meeting manufacturer’s extended warranty requirements. This has been proven at Toyota, Volvo, DaimlerChrysler and GM Opel”.

In our conventional chambered silencers we employ various techniques to fabricate all the internal components. Stricter emissions regulations are demanding ever-more complex silencer designs and here are a couple of cutaway drawings made for us by the late Bob Freeman. The first is a Ferrari F355 silencer showing seven internal chambers in one silencer and featuring internal tubes of different length & diameter to produce musical chords at different pressures. The second is another Ferrari, a 550, with a similar layout........."