Are the stock mufflers all that restrictive?
04-22-02, 07:19 PM
#16
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For what its worth...
How nice would it be if someone designed a full cat back exhaust that actually added to the appearance and performance of the car without making it sound like a mustang?
On my car I took out the center resonator (mini muffler) with custom straight piping. I noticed a small but noticable increase in power. With that the noise level increased slightly as well.
Next I will include a silener and replace the two resonators leading to the mufflers. Then I will replace the stock mufflers with blitz or RMM mufflers. I suppose high converters will also be included but will go on last.
It is a gradual process as I am upgrading to a single turbo on my MKIV TT.
My best reccomendation for you Max is the Torque converter! It really gets rid of that slugglish start that is so commen with the SC's.
On my car I took out the center resonator (mini muffler) with custom straight piping. I noticed a small but noticable increase in power. With that the noise level increased slightly as well.
Next I will include a silener and replace the two resonators leading to the mufflers. Then I will replace the stock mufflers with blitz or RMM mufflers. I suppose high converters will also be included but will go on last.
It is a gradual process as I am upgrading to a single turbo on my MKIV TT.
My best reccomendation for you Max is the Torque converter! It really gets rid of that slugglish start that is so commen with the SC's.
04-22-02, 07:45 PM
#18
were my posts helpful, or did I just end up confusing you. I feel like I had a hard eloquently stating & explaining myself.... Geezeee! I must be a guy! Or an imbicile...
Or are they the same?
Or are they the same?
04-22-02, 09:56 PM
#19
Lexus Fanatic
Why are you guys so fearful of loud exhaust? I think it sounds sweet like music. I only WISH I could make my SC sound like a blown Cobra 351. It's an artful juxtaposition 
. Anyway, is there any way to make an SC sound mean yet refined? I don't want Hemicuda meaness, but I also don't want Elipse GSX+Greddy droning fart sounds. I'm thinking that removing hte midmufflers and putting in Borla or Magnaflow rear mufflers will do the job, but I have no idea?
. Anyway, is there any way to make an SC sound mean yet refined? I don't want Hemicuda meaness, but I also don't want Elipse GSX+Greddy droning fart sounds. I'm thinking that removing hte midmufflers and putting in Borla or Magnaflow rear mufflers will do the job, but I have no idea?
04-22-02, 11:45 PM
#20
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I was looking at a schematic of the Japanese spec exhaust system and the US spec exhaust system.
US system has three cats, two straight through resonators and two straight through mufflers and sounds like a V8.
The Japanese exhaust system has two cats, a straight through resonator (US has another Cat), two reflection type mufflers, and then another two reflection type mufflers and sounds like a real quiet family 6 cylinder car.
In Australia replacing the Japanese exhaust with a full exhaust and high flow cats gives 10kW at the wheels.
In the old days reducing the backpressure resulted in a loss of torque because the mixtures leaned out (more air going through, same petrol). Nowadays the ECU will always adjust the fuel mixtures and loss of torque does not happen on a Soarer (ECU may have to relearn). I have seen engine dynos where every time backpressure was introduced to the motor, torque was lost, less backpressure, more torque. The key is tuning the engine with the reduced backpressure. Reducing the backpressure and losing torque is a myth handed down from the old days - it doesn't apply any more to modern cars. It still applies to cars with carbies an no tuning. At the ALSC dyno day no Soarer with exhaust modifications lost any torque down low and they all gained up top with exhaust mods.
Modifying the US spec exhaust is not so straight forward as the Japanese spec exhaust - it is not as restrictive. After 10 years and 100 000 miles perhaps it is time to inspect the cats. That middle centre cat could certainly be upgraded to a three inch diameter high flow cat. In Australia such a cat cost $220. The rest of the exhaust looks as if it would yield only minimal gains. The front cats cannot be upgraded, only replaced with the genuine items(expensive) as they are a funny shape and size and aftermarket cats that are short enough to fit aren't as fat and don't flow as well.
You could replace the whole lot with a custom 2.5 inch dual system, replace the centre cat, and some nice 2.5 inch resonators and mufflers but the gains may not be anywhere near the 10kW at the wheels we get over here.
For the US spec exhaust I would try the centre cat first.
Then perhaps a complete 2.5 inch system with same number of mufflers to keep it quiet.
But I don't reckon there is a lot of horsepower hiding there.
Best to go for the sound you like, not horsepower gains.
Then decide if you like polished mufflers or the Original look.
Maybe the modified exhaust cams will help too - we shall see.
US system has three cats, two straight through resonators and two straight through mufflers and sounds like a V8.
The Japanese exhaust system has two cats, a straight through resonator (US has another Cat), two reflection type mufflers, and then another two reflection type mufflers and sounds like a real quiet family 6 cylinder car.
In Australia replacing the Japanese exhaust with a full exhaust and high flow cats gives 10kW at the wheels.
In the old days reducing the backpressure resulted in a loss of torque because the mixtures leaned out (more air going through, same petrol). Nowadays the ECU will always adjust the fuel mixtures and loss of torque does not happen on a Soarer (ECU may have to relearn). I have seen engine dynos where every time backpressure was introduced to the motor, torque was lost, less backpressure, more torque. The key is tuning the engine with the reduced backpressure. Reducing the backpressure and losing torque is a myth handed down from the old days - it doesn't apply any more to modern cars. It still applies to cars with carbies an no tuning. At the ALSC dyno day no Soarer with exhaust modifications lost any torque down low and they all gained up top with exhaust mods.
Modifying the US spec exhaust is not so straight forward as the Japanese spec exhaust - it is not as restrictive. After 10 years and 100 000 miles perhaps it is time to inspect the cats. That middle centre cat could certainly be upgraded to a three inch diameter high flow cat. In Australia such a cat cost $220. The rest of the exhaust looks as if it would yield only minimal gains. The front cats cannot be upgraded, only replaced with the genuine items(expensive) as they are a funny shape and size and aftermarket cats that are short enough to fit aren't as fat and don't flow as well.
You could replace the whole lot with a custom 2.5 inch dual system, replace the centre cat, and some nice 2.5 inch resonators and mufflers but the gains may not be anywhere near the 10kW at the wheels we get over here.
For the US spec exhaust I would try the centre cat first.
Then perhaps a complete 2.5 inch system with same number of mufflers to keep it quiet.
But I don't reckon there is a lot of horsepower hiding there.
Best to go for the sound you like, not horsepower gains.
Then decide if you like polished mufflers or the Original look.
Maybe the modified exhaust cams will help too - we shall see.
04-23-02, 04:23 AM
#21
Mortgage Slave
Hi Pete,
Very interesting testing you've done with your Soarer!
Since you've done quite a bit of testing with the Soarer exhaust system, what type of system would you recommend for a Soarer TT?
Very interesting testing you've done with your Soarer!
Since you've done quite a bit of testing with the Soarer exhaust system, what type of system would you recommend for a Soarer TT?
04-24-02, 01:49 AM
#22
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For the Twin Turbo:
Stage 1
Unbolt the centre exhaust pipe, or "Y" pipe, put it around the back of the shed (it won't rust) - replace with 3 inch mild steel pipe going into twin 2.5 inch mild steel pipe - no resonators.
Stage 2
Unbolt the rear mufflers, put them around back of the shed with the center piece (they won't rust either). Replace with Lukey UltrFlow Stainless 2.5 inch double offset straight through mufflers ($179 from MotorMate) and 2.5 inch mild steel pipe.
Stage 3
Unbolt the pipe with the cat in it at the front of the exhaust - (put it around the shed with the other stuff), replace with 3 inch mild steel pipe and 3 inch high flow cat (Exhaust Technology sell them in SA - $220 - might have gone up in price - will ship).
Leave dump pipe alone.
If too loud install straight resonators in center section.
Stage 1
Unbolt the centre exhaust pipe, or "Y" pipe, put it around the back of the shed (it won't rust) - replace with 3 inch mild steel pipe going into twin 2.5 inch mild steel pipe - no resonators.
Stage 2
Unbolt the rear mufflers, put them around back of the shed with the center piece (they won't rust either). Replace with Lukey UltrFlow Stainless 2.5 inch double offset straight through mufflers ($179 from MotorMate) and 2.5 inch mild steel pipe.
Stage 3
Unbolt the pipe with the cat in it at the front of the exhaust - (put it around the shed with the other stuff), replace with 3 inch mild steel pipe and 3 inch high flow cat (Exhaust Technology sell them in SA - $220 - might have gone up in price - will ship).
Leave dump pipe alone.
If too loud install straight resonators in center section.
04-24-02, 08:43 AM
#23
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Re: For what its worth...
Originally posted by whosdady
How nice would it be if someone designed a full cat back exhaust that actually added to the appearance and performance of the car without making it sound like a mustang?
On my car I took out the center resonator (mini muffler) with custom straight piping. I noticed a small but noticable increase in power. With that the noise level increased slightly as well.
Next I will include a silener and replace the two resonators leading to the mufflers. Then I will replace the stock mufflers with blitz or RMM mufflers. I suppose high converters will also be included but will go on last.
It is a gradual process as I am upgrading to a single turbo on my MKIV TT.
My best reccomendation for you Max is the Torque converter! It really gets rid of that slugglish start that is so commen with the SC's.
How nice would it be if someone designed a full cat back exhaust that actually added to the appearance and performance of the car without making it sound like a mustang?
On my car I took out the center resonator (mini muffler) with custom straight piping. I noticed a small but noticable increase in power. With that the noise level increased slightly as well.
Next I will include a silener and replace the two resonators leading to the mufflers. Then I will replace the stock mufflers with blitz or RMM mufflers. I suppose high converters will also be included but will go on last.
It is a gradual process as I am upgrading to a single turbo on my MKIV TT.
My best reccomendation for you Max is the Torque converter! It really gets rid of that slugglish start that is so commen with the SC's.
007
04-24-02, 07:17 PM
#24
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That's my car but not my quote.
The two huge cats are scratched up going out the driveway and the stainless x-pipe has turned a gold colour. Retail price in Australia is $179 each for stainless mufflers, $220 for x-pipe, $200 each for big high flow cats and $300 for custom 2.5 inch pipe work (cost twice as much in Adelaide, this was Mt Barker price - small country town) and fitting from the headers and $70 each for stainless tips.
The cats are CarSound (USA) and the xpipe is Magnaflow? (USA) - I forget. The mufflers are Lukey (AUST).
The two huge cats are scratched up going out the driveway and the stainless x-pipe has turned a gold colour. Retail price in Australia is $179 each for stainless mufflers, $220 for x-pipe, $200 each for big high flow cats and $300 for custom 2.5 inch pipe work (cost twice as much in Adelaide, this was Mt Barker price - small country town) and fitting from the headers and $70 each for stainless tips.
The cats are CarSound (USA) and the xpipe is Magnaflow? (USA) - I forget. The mufflers are Lukey (AUST).
04-25-02, 07:41 AM
#25
Why do people use the X pipe? Wouldn't it be better is you had 2 full pipes parallel to each other? Less bends on the pipe = less resistance and since it would be virtually straight you would save on weight also no? I've got in touch with this guy who does exhausts and he told me he would custom a whole system 3" mandrel bent system but I want to weigh in my options power gain/cost/noise level etc. I don't want to go to this guy and sound all stupid. thanks
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