This weeks exhaust design (long)
10-06-2002, 08:28 PM
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This weeks exhaust design (long)
This project is one in a long line of exhaust designs, will essentially remove the inboard portion of a OEM exhaust (blue), providing flow from a single CAT bank (red), out through a set of twin stainless exhausts. This should provide max outflow without any bends or restrictions, and with the cat and turbo, provide the minimal back-pressure needed(Although I can never get a number on the needed back-pressure if any for max performance with a turbo). Red arrow is flow. Should also lighten by some 30lbs. Some things noted form past trials, removing all of the resonators does little to increase resonance, but does increase flow and give a nice tone. Noise cancelling from both sides of the engine exhaust as well as the cats and turbos provide enough reduction in sound that removing a fair amount of internals does not cause a dramatic increase in sound, ala Ruf. Increase in outflow pipe diameter over 10 cm (4") (tips or direct pipe) does little for performance . My engineer explained that its because your trying to move a larger column of cooler dense air instead of hotter less dense air. Any feedback would be great, project should be done in a couple of weeks, with dyno results.
10-06-2002, 10:31 PM
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Will remove the second bank of cats completely, then reduce first bank to 200 cell cats. I'M assuming somewhat loud but no resonant drone.
Seats are awesome, acid test of holding power will be at Virginia International next week. Found a way to put in seat heat, so will be keeping significant other happy this winter.
How is your new cat-less pipe?
Seats are awesome, acid test of holding power will be at Virginia International next week. Found a way to put in seat heat, so will be keeping significant other happy this winter.
How is your new cat-less pipe?
10-07-2002, 01:22 AM
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I used a set of elements from R.A.M.E.<a href="http://www.rameinc.com/seat_heaters.htm" target="_blank">R.A.M.E.</a>.
about $30.00 for pair of two elements. You can use the stock control, which is the plug next to the seat belt plug in the harness, and tap the hot wires off of the seat harness. Or more simply use the cigarette lighter attachment that comes with it.
about $30.00 for pair of two elements. You can use the stock control, which is the plug next to the seat belt plug in the harness, and tap the hot wires off of the seat harness. Or more simply use the cigarette lighter attachment that comes with it.
10-07-2002, 07:06 PM
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Hi Cobra,
I am just now finishing my "stock" exhaust mod I started 6 weeks ago. I think I was more aggressive in removing internal metal than your first muffler. I considered a straight through exhaust like you are doing, but adding some kind of valve (ala 996 sport exhaust) to direct the gases through the muffler for an adjustable sound. Please keep us posted on your results!
BTW, have you discovered any tricks to reinstalling the muffler bands?
mcneil141
I am just now finishing my "stock" exhaust mod I started 6 weeks ago. I think I was more aggressive in removing internal metal than your first muffler. I considered a straight through exhaust like you are doing, but adding some kind of valve (ala 996 sport exhaust) to direct the gases through the muffler for an adjustable sound. Please keep us posted on your results!
BTW, have you discovered any tricks to reinstalling the muffler bands?
mcneil141
10-07-2002, 07:19 PM
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Cobra,
I have held off doing the muffler for two reasons.
1. The shop really wanted me to put on 100 cell cats. They felt it would have resonance if I removed them.
2. Cost. After investing $500.00 into a good used muffler, plus having to pay $3,500.00 for labor and the 100 cell cats, I came to the conclusion that if I wanted to ever sell it, I would take a bath. It would be better to purchase a Ruf muffler. It is guaranteed to work and you can always resell it. The other financial factor is EVO started selling modified stock mufflers with 100 cell cats for about $1,800 parts and labor(exchange). I am planning on making a decision this week.
I have held off doing the muffler for two reasons.
1. The shop really wanted me to put on 100 cell cats. They felt it would have resonance if I removed them.
2. Cost. After investing $500.00 into a good used muffler, plus having to pay $3,500.00 for labor and the 100 cell cats, I came to the conclusion that if I wanted to ever sell it, I would take a bath. It would be better to purchase a Ruf muffler. It is guaranteed to work and you can always resell it. The other financial factor is EVO started selling modified stock mufflers with 100 cell cats for about $1,800 parts and labor(exchange). I am planning on making a decision this week.
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10-07-2002, 08:03 PM
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mcneil
I have a "gutted version that is not that loud and has a really nice WOT sound with no resonance... very suprising . Removed the bulkheads and insulation and opened up the resonators. RE: the bands..I just make sure to remove the allen all the way and then slide them into position and tighten. The one upper right turbo/exhaust nut is the one that kills me.
996TTR
Probably a sound decision, I think Fabspeed sells the 100 cell cats for around $750, they can be easily welded to a stock setup, modifications internally should really not cost more then $900-$1000, its not rocket science, and the stock exhaust is very forgiving.
There is only so much you can do inside of one of these, unless a nitrous tank or rocket booster can be mounted internally
If interested my guy charges about $1000 + to do it, takes him a 1/2 day, now that he's done 5 of them for me.(I'M not selling here, just trying to be helpful) The biggest slow down is removing the second cat and re-welding the canister back on.
The exhaust pictured above has little restriction, essentially in, makes a turn then out, mixing with the other side via a 31/2 in' connector
I have a "gutted version that is not that loud and has a really nice WOT sound with no resonance... very suprising . Removed the bulkheads and insulation and opened up the resonators. RE: the bands..I just make sure to remove the allen all the way and then slide them into position and tighten. The one upper right turbo/exhaust nut is the one that kills me.
996TTR
Probably a sound decision, I think Fabspeed sells the 100 cell cats for around $750, they can be easily welded to a stock setup, modifications internally should really not cost more then $900-$1000, its not rocket science, and the stock exhaust is very forgiving.
There is only so much you can do inside of one of these, unless a nitrous tank or rocket booster can be mounted internally
If interested my guy charges about $1000 + to do it, takes him a 1/2 day, now that he's done 5 of them for me.(I'M not selling here, just trying to be helpful) The biggest slow down is removing the second cat and re-welding the canister back on.
The exhaust pictured above has little restriction, essentially in, makes a turn then out, mixing with the other side via a 31/2 in' connector
10-07-2002, 08:32 PM
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Cobra,
That is why I am considering the EVO stock modified unit. It comes with 100 cell cats and they are running a special($1,650.00). I only really care about the horsepower and stealth sound is a plus. You know how tough my wife is.
That is why I am considering the EVO stock modified unit. It comes with 100 cell cats and they are running a special($1,650.00). I only really care about the horsepower and stealth sound is a plus. You know how tough my wife is.
10-08-2002, 08:47 PM
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Thanks for the tips, cobra. I just got back from the welder, and will install the muffler tonight. I'll keep everyone posted on how it goes.
BTW, you guys will kill me, but my total investment on this muffler is $110. I bought the muffler off ebay for $49 and the welding shop (OK...he's my buddy) charged $60
Cutting it open and removing the cat was a real PIA. I put in at least 6 hours (I'm obviously not a mechanic)
mcneil141
BTW, you guys will kill me, but my total investment on this muffler is $110. I bought the muffler off ebay for $49 and the welding shop (OK...he's my buddy) charged $60
Cutting it open and removing the cat was a real PIA. I put in at least 6 hours (I'm obviously not a mechanic)mcneil141
10-08-2002, 09:10 PM
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$1650 sounds hard to beat especially with the 100 cell CATS, definitely the way to go.
Seems like more and more tuners and dealers are in the muffler modification business.
BTW one just went unsold on Ebay for $349.00.
I really think the Ruf exhaust is the most costly because they are using new exhausts from Boysen, these things can't be cheap to buy new.
McNeil did you remove the whole cat? or just the second bank?. Did you remove all of the internal baffels?.
I have one last trial then I'M on to something new to obsess about
Seems like more and more tuners and dealers are in the muffler modification business.
BTW one just went unsold on Ebay for $349.00.
I really think the Ruf exhaust is the most costly because they are using new exhausts from Boysen, these things can't be cheap to buy new.
McNeil did you remove the whole cat? or just the second bank?. Did you remove all of the internal baffels?.
I have one last trial then I'M on to something new to obsess about
10-09-2002, 01:24 AM
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[quote]Originally posted by cobra06:
<strong>
McNeil did you remove the whole cat? or just the second bank?. Did you remove all of the internal baffels?.
</strong><hr></blockquote>
I followed your lead and only removed the second (larger) cat. I left the baffle walls intact, but removed all of the resonators, and enlarged the remaining holes. I also shortened the exhaust pipe and removed all of the packing material.
I just finished installing the muffler and test drove it. I has a pleasant sound and no apparent resonance, but I must admit that I hoped it to be somewhat louder. It doesn't seem to be any louder at idle. On the plus side, this mod added at least 100 hp
mcneil141
<strong>
McNeil did you remove the whole cat? or just the second bank?. Did you remove all of the internal baffels?.
</strong><hr></blockquote>
I followed your lead and only removed the second (larger) cat. I left the baffle walls intact, but removed all of the resonators, and enlarged the remaining holes. I also shortened the exhaust pipe and removed all of the packing material.
I just finished installing the muffler and test drove it. I has a pleasant sound and no apparent resonance, but I must admit that I hoped it to be somewhat louder. It doesn't seem to be any louder at idle. On the plus side, this mod added at least 100 hp
mcneil141
10-09-2002, 08:27 AM
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Well rest assured, you reduced back pressure by a bunch. The only way to get it louder is block off the exchange between the other side. The communication has a noise-cancelling effect. putting a pair of $3.oo stainless tail pipes would louden it up as well.
I'll bet you picked up at least 35 H.P.
I'll bet you picked up at least 35 H.P.
