Speedtech Xcellerator exhaust - initial review
#16
03-07-2010 | 10:46 AM
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Hi Mike,
Thanks for the review - I agree about the straps and will look for a source, as it would make the installation a lot simpler. As for the drone, with the quiet version, I feel it is nearly completely eliminated and about as little as you can get and still have a free flowing performance exhaust. I am sensitive to drone, too and I can live the 2.5 quiet and totally enjoy it. Any more and it would cross the threshold for me.
Also, just so you know, the exhaust is 100% made in the USA, it's not an import. We actually design, test and manufacture the system ourselves.
Mark is right, the same exhaust will sound different with different sized turbos, OEM K16's being the quietest.
Thanks for the review - I agree about the straps and will look for a source, as it would make the installation a lot simpler. As for the drone, with the quiet version, I feel it is nearly completely eliminated and about as little as you can get and still have a free flowing performance exhaust. I am sensitive to drone, too and I can live the 2.5 quiet and totally enjoy it. Any more and it would cross the threshold for me.
Also, just so you know, the exhaust is 100% made in the USA, it's not an import. We actually design, test and manufacture the system ourselves.
Mark is right, the same exhaust will sound different with different sized turbos, OEM K16's being the quietest.
#17
03-07-2010 | 12:18 PM
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I also am a meniacal exhaust mental case.
I had on my car;
stock exhaust with tranporter supplied rip in it
PSI loud (bad drone)
PSI quiet (still bad drone)
Europipe Stage2 quiet (minimal, but some drone)
DGI (some drone, early version)
Switzer Performance (my personal favorite, with some drone)
DGI back on to sell the car
The best $Value$ was the DGI (Speedtech)
I had on my car;
stock exhaust with tranporter supplied rip in it
PSI loud (bad drone)
PSI quiet (still bad drone)
Europipe Stage2 quiet (minimal, but some drone)
DGI (some drone, early version)
Switzer Performance (my personal favorite, with some drone)
DGI back on to sell the car
The best $Value$ was the DGI (Speedtech)
#18
03-07-2010 | 01:36 PM
Well I'm back from another 1.5 hours drive out and back to visit family, and now with the UMW 93 Octane performance tune back on the car, it is actually quieter, and runs much smoother, pulling harder, and I'm pretty happy.
No Richard, No Ferrari for me. I'll live with what I have, now.
John, Thanks for the info on where the system is made. That's a bigger plus, and at the price point you're selling it for, that's a great value. I'm dead serious when comparing the sound of this system to the EP stage 2 quiet that I've heard on others!
Mike
No Richard, No Ferrari for me. I'll live with what I have, now.
John, Thanks for the info on where the system is made. That's a bigger plus, and at the price point you're selling it for, that's a great value. I'm dead serious when comparing the sound of this system to the EP stage 2 quiet that I've heard on others!
Mike
#19
03-07-2010 | 06:52 PM
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i'm very happy with my 70mm but if it i had been able to source new straps and much longer bolts my installation would have taken 1/4 of the time, this should be an option when purchasing
removing the old one was a ***** and if i had been able to cut the old straps it would have been a lot easier
drove it for the first time through a tunnel today and i will never forget it, what an amazing sound
removing the old one was a ***** and if i had been able to cut the old straps it would have been a lot easier
drove it for the first time through a tunnel today and i will never forget it, what an amazing sound
#20
03-07-2010 | 07:21 PM
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i'm very happy with my 70mm but if it i had been able to source new straps and much longer bolts my installation would have taken 1/4 of the time, this should be an option when purchasing
removing the old one was a ***** and if i had been able to cut the old straps it would have been a lot easier
drove it for the first time through a tunnel today and i will never forget it, what an amazing sound
removing the old one was a ***** and if i had been able to cut the old straps it would have been a lot easier
drove it for the first time through a tunnel today and i will never forget it, what an amazing sound
Agreed, the straps are the time consuming part.
John, would be good to have new straps and longer bolts
#21
03-07-2010 | 07:31 PM
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Ok a question for those who know. I have done the TJW mod. ( I think that's the name? ) that gave the stock muffler a lot better sound at idle but the droan got louder between 1,700 and 2,400 RPMs. In fact it is as loud as I want to have from any muffler. The good thing is it goes completely quite after 2,400 RPMs. So I try to keep it above that.
I'm now thinking of taking the stock muffler off and drilling out the cats and opening it up. For those that have done this what was the sound and or droan like? Also, did you drill out all of the cat or just the center part?
I'm now thinking of taking the stock muffler off and drilling out the cats and opening it up. For those that have done this what was the sound and or droan like? Also, did you drill out all of the cat or just the center part?
#22
03-07-2010 | 07:50 PM
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Ok a question for those who know. I have done the TJW mod. ( I think that's the name? ) that gave the stock muffler a lot better sound at idle but the droan got louder between 1,700 and 2,400 RPMs. In fact it is as loud as I want to have from any muffler. The good thing is it goes completely quite after 2,400 RPMs. So I try to keep it above that.
I'm now thinking of taking the stock muffler off and drilling out the cats and opening it up. For those that have done this what was the sound and or droan like? Also, did you drill out all of the cat or just the center part?
I'm now thinking of taking the stock muffler off and drilling out the cats and opening it up. For those that have done this what was the sound and or droan like? Also, did you drill out all of the cat or just the center part?
Someone I know did this and it sounded pretty good. I don't know if they drilled out the cat or not, however. But if you drill out the cat, I think you need to drill it all out, since partial drill out will just cause it to break off into your exhaust since it's structure has been compromised.
#23
03-07-2010 | 08:04 PM
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Thanks.
#24
03-07-2010 | 08:13 PM
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Someone I know did this and it sounded pretty good. I don't know if they drilled out the cat or not, however. But if you drill out the cat, I think you need to drill it all out, since partial drill out will just cause it to break off into your exhaust since it's structure has been compromised.
#25
03-07-2010 | 08:25 PM
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John, would be good to have new straps and longer bolts 
I know what you mean because I went through the same process as you...
We are working on it and have designed a strap to be included with our exhausts. For future customers, the installation will be easier.
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991.2 GT3 RS Weissach Racing Yellow
991.2 Turbo S GT Silver
991.2 GT3 Chalk (Manual)
2022 Cayenne White
former 1972 911T white, 1984 911 3.2 Targa black, 993 cab white, 993TT arena red, 993TT silver, 996TT speed yellow, 991.1 GT3 white
www.speedtechexhausts.com
info@speedtechexhausts.com
Testimonials facebook SpeedTech Exhaust Videos
#26
03-07-2010 | 08:30 PM
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some cats have metal cross braces holding the fill in place, but most I see today don't. The cross braces could hold a partial fill, but the effectiveness of the cat is gone at that point. The new, non braced cats would fall apart I would think fairly quickly. A couple of high rpm WOT blasts should do it.
Someone on another thread also indicated that there are two cats in the factory exhaust on each side. Don't know how they managed to get two in, when there only seems barely enough room for one. But that is what they saw when they cut it open.
#27
03-07-2010 | 09:04 PM
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Straps would be a good idea John, I'm pretty sure I no longer have straps on my existing exhaust. I've not been under there in awhile but I think that's the case. Mine is droning pretty good so I'll have to see how Mike's sounds ASAP and make a decision.
#28
03-07-2010 | 09:05 PM
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Yes I think there's some "drone", but for my personal taste its a good compromise for being louder. I've gotten used to the on throttle, high RPM cam sound, I find it quite intoxicating, difficult to give up. I've tried different tips but I think the single big one is a good choice; personally i'd like a twin to sound like the single big one. John's been great to work with and he produces a good product.
I've got to say I'm sensitive to the sound too, knowing you have some "sound" experience in the previous life, let's get technical on some things I've noticed.
- I think there's a fundamental resonance in the structure of the vehicle around 90 - 100 Hz (wavelength around 150"; interesting, isn't that the length of a 911?). In my opinion this is the one excited around 2 - 2.5k RPM. This is the area everyone appears to describe as "drone"
- The factory exhaust appears really well suppressing the band of resonance but ends up sounding wussy in the process. Interestingly in standard vehicles I hear the "drone" as well (particularly under load) although well suppressed.
- Depending on my mood I'm a lot more sensitive to it than others. The "drone" with any exhaust is stronger with the windows up than down.
- with some exhausts this band of resonance can be extended into the upper 2k ranges.
- The cold engine/exhaust is louder.
Mike, you have a UMW tune; Kevin mentioned in an earlier post timing retard with "crossflow" type exhausts, what do you think?
How do we eliminate drone altogether? If anyone can try a flexible rubber mount, it may help; I'd be worried about setting fire to something. The geek way of doing this is to feed an inverted sound-wave through the stereo system. Taking orders, who'd be interested...just kidding; MOD please don't ban me!
I've got to say I'm sensitive to the sound too, knowing you have some "sound" experience in the previous life, let's get technical on some things I've noticed.
- I think there's a fundamental resonance in the structure of the vehicle around 90 - 100 Hz (wavelength around 150"; interesting, isn't that the length of a 911?
). In my opinion this is the one excited around 2 - 2.5k RPM. This is the area everyone appears to describe as "drone" - The factory exhaust appears really well suppressing the band of resonance but ends up sounding wussy in the process. Interestingly in standard vehicles I hear the "drone" as well (particularly under load) although well suppressed.
- Depending on my mood I'm a lot more sensitive to it than others. The "drone" with any exhaust is stronger with the windows up than down.
- with some exhausts this band of resonance can be extended into the upper 2k ranges.
- The cold engine/exhaust is louder.
Mike, you have a UMW tune; Kevin mentioned in an earlier post timing retard with "crossflow" type exhausts, what do you think?
How do we eliminate drone altogether? If anyone can try a flexible rubber mount, it may help; I'd be worried about setting fire to something. The geek way of doing this is to feed an inverted sound-wave through the stereo system. Taking orders, who'd be interested...just kidding; MOD please don't ban me!
So after about 2.5 hours round trip in the car I'm torn. The exhaust SOUNDS amazing when you crack into it with the windows down and the roof open as Danyol mentions. There is a drone under load between 55-65mph, but it isn't horrible. I "think" I can live with it. Overall it wasn't bad on the interstate at 75-78MPH and it passed the 65mph on the bluetooth standalone speaker test. This system also exhibited no "buzzing" in the interior, so the drone is very minimal in most RPM ranges.
This IS the quiet version... I admit I'm picky when it comes to interior noise (mentioned earlier) and I had to crank the iPod up well above 10 on the volume (I'm used to 5-6) to compete with cabin noise, but only sometimes...
Duanne996TT, I had that same exhaust and John claims that I got an early version that had issues with tonal change under hot track extended driving conditions. That system got so bad for me I was getting headaches driving the car. It's not the "LOUDness" of the system, but the drone was horrid. It was so bad that we simply wouldn't drive the car when I was taking my wife anywhere with me.
BKF4lyfe, I got the large single round tips and they look very nice. I'll put the car back on the lift and give the bolts another tightening, now that the system has been heat cycled a time or two.
Overall this system is a good bargain, but again, it isn't going to be as quiet as stock inside the car. I don't know if the stock system has an equal when it comes to interior quiet comfort. I've even been in a couple of those vaulted "Europipe" equipped cars with the EP2 Quiet and they're about as loud as this system, but much heavier.
The plus side of John's system is you really do put the car on a diet with this system. All of the clamps, and pipes go together with ease, and the finish of the components is top notch. Yea the system is probably made in south east asia, but I don't honestly care. I can't save the world, might as well save my wallet.
I'm over on renntrack, as well as rennlist and renntech, for those who care.
Mike
This IS the quiet version... I admit I'm picky when it comes to interior noise (mentioned earlier) and I had to crank the iPod up well above 10 on the volume (I'm used to 5-6) to compete with cabin noise, but only sometimes...
Duanne996TT, I had that same exhaust and John claims that I got an early version that had issues with tonal change under hot track extended driving conditions. That system got so bad for me I was getting headaches driving the car. It's not the "LOUDness" of the system, but the drone was horrid. It was so bad that we simply wouldn't drive the car when I was taking my wife anywhere with me.
BKF4lyfe, I got the large single round tips and they look very nice. I'll put the car back on the lift and give the bolts another tightening, now that the system has been heat cycled a time or two.
Overall this system is a good bargain, but again, it isn't going to be as quiet as stock inside the car. I don't know if the stock system has an equal when it comes to interior quiet comfort. I've even been in a couple of those vaulted "Europipe" equipped cars with the EP2 Quiet and they're about as loud as this system, but much heavier.
The plus side of John's system is you really do put the car on a diet with this system. All of the clamps, and pipes go together with ease, and the finish of the components is top notch. Yea the system is probably made in south east asia, but I don't honestly care. I can't save the world, might as well save my wallet.
I'm over on renntrack, as well as rennlist and renntech, for those who care.
Mike
Last edited by Danyol; 03-07-2010 at 09:17 PM.
#29
03-07-2010 | 11:34 PM
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Mine is droning pretty good so I'll have to see how Mike's sounds ASAP and make a decision.
Although there is a little drone with our 2.5 cross-flow, it is very slight and in a fairly small window. With windows down in the summer, it's barely even noticeable. With windows up, a little more noticeable, but still very mild, IMO. I think you will be really surprised. As Danyol mentioned "its a good compromise for being louder. I've gotten used to the on throttle, high RPM cam sound, I find it quite intoxicating, difficult to give up". I agree 100% with this statement and our cross-flow sound really is intoxicating, in a way that typical standard exhausts can not duplicate. Try to hear it in person, I think you will like it.
__________________
991.2 GT3 RS Weissach Racing Yellow
991.2 Turbo S GT Silver
991.2 GT3 Chalk (Manual)
2022 Cayenne White
former 1972 911T white, 1984 911 3.2 Targa black, 993 cab white, 993TT arena red, 993TT silver, 996TT speed yellow, 991.1 GT3 white
www.speedtechexhausts.com
info@speedtechexhausts.com
Testimonials facebook SpeedTech Exhaust Videos
991.2 GT3 RS Weissach Racing Yellow
991.2 Turbo S GT Silver
991.2 GT3 Chalk (Manual)
2022 Cayenne White
former 1972 911T white, 1984 911 3.2 Targa black, 993 cab white, 993TT arena red, 993TT silver, 996TT speed yellow, 991.1 GT3 white
www.speedtechexhausts.com
info@speedtechexhausts.com
Testimonials facebook SpeedTech Exhaust Videos
Last edited by John@SpeedTech; 03-08-2010 at 01:07 AM.
#30
03-08-2010 | 05:57 AM
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some cats have metal cross braces holding the fill in place, but most I see today don't. The cross braces could hold a partial fill, but the effectiveness of the cat is gone at that point. The new, non braced cats would fall apart I would think fairly quickly. A couple of high rpm WOT blasts should do it. Someone on another thread also indicated that there are two cats in the factory exhaust on each side. Don't know how they managed to get two in, when there only seems barely enough room for one. But that is what they saw when they cut it open.
Someone on another thread also indicated that there are two cats in the factory exhaust on each side. Don't know how they managed to get two in, when there only seems barely enough room for one. But that is what they saw when they cut it open.