Speedtech Xcellerator exhaust - initial review
#31
03-08-2010, 07:32 AM
Mike it would be great if we can get a bunch of us together to see who has the best sounding exhaust. Of course this will be subjective to each person's ears. But a good referance point for each of us.
Perhaps at this coming weekend get together we can compare?? My car has the Miltek and it is pretty drone free.
Perhaps at this coming weekend get together we can compare?? My car has the Miltek and it is pretty drone free.
#32
03-08-2010, 06:31 PM
Danyol, I read that post from Kevin. I don't like to disagree with Kevin, because normally when I do, he hunts me down and proves me wrong!! 
I think doing a little dynomatt would be good to place under the rear panels. That might be the total solution to the minimal drone found in this and other systems.
Every single car I've ridden in has had at least as much drone as this car, and actually all of them except Larry's (Landjet) has had more than this system.
Mike
I think doing a little dynomatt would be good to place under the rear panels. That might be the total solution to the minimal drone found in this and other systems.
Every single car I've ridden in has had at least as much drone as this car, and actually all of them except Larry's (Landjet) has had more than this system.
Mike
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!
#33
03-08-2010, 06:43 PM
you can't get rid of drone. No one can, but you can reduce it. Crossflow systems help, but there is still drone. H-pipe like mine helped but there is still drone. I think the goal is to reduce it to a manageable level. I have reduced the drone in my car to a comfortable level and am happy with that.
the biggest hindrance to us is the limited space we have for exhaust. it is hard to design an exhaust for our cars due to limited spacing. It can be done with other cars, but the distances for exhaust gases are so short that we don't have much to work with.
This speedtech looks really good and probably sounds very good. most crossflow exhausts do.
the biggest hindrance to us is the limited space we have for exhaust. it is hard to design an exhaust for our cars due to limited spacing. It can be done with other cars, but the distances for exhaust gases are so short that we don't have much to work with.
This speedtech looks really good and probably sounds very good. most crossflow exhausts do.
#34
03-08-2010, 07:53 PM
Mike it would be great if we can get a bunch of us together to see who has the best sounding exhaust. Of course this will be subjective to each person's ears. But a good referance point for each of us.
Perhaps at this coming weekend get together we can compare?? My car has the Miltek and it is pretty drone free.
Perhaps at this coming weekend get together we can compare?? My car has the Miltek and it is pretty drone free.
I want to hear Mike's new exhaust!
#35
03-08-2010, 07:57 PM
Registered User
Join Date: Nov 2009
Location: Bentonville, AR
Age: 54
Posts: 1,184
Rep Power: 87 
What kind do you have?
#36
03-08-2010, 10:17 PM
#37
03-09-2010, 12:53 AM
Seat of pants it sounds like you've gained some power?
I don't doubt his assertion crossflow => some loss of power over a conventional set-up. He is a "power merchant" by trade, fighting for every bhp, I can see how he'd have an issue with this. I personally would trade a little power for better sound.
BLKMGK; I don't think a sound level meter is enough, you need to know sound pressure at the different frequencies. You need some kind of spectrum analyzer. You could hook up your SPL meter to a laptop, there are a few programs out there meant for speaker analysis.
[quote756184]Danyol, I read that post from Kevin. I don't like to disagree with Kevin, because normally when I do, he hunts me down and proves me wrong!!
I think doing a little dynomatt would be good to place under the rear panels. That might be the total solution to the minimal drone found in this and other systems.
Every single car I've ridden in has had at least as much drone as this car, and actually all of them except Larry's (Landjet) has had more than this system.
Mike[/quote]
I don't doubt his assertion crossflow => some loss of power over a conventional set-up. He is a "power merchant" by trade, fighting for every bhp, I can see how he'd have an issue with this. I personally would trade a little power for better sound.
BLKMGK; I don't think a sound level meter is enough, you need to know sound pressure at the different frequencies. You need some kind of spectrum analyzer. You could hook up your SPL meter to a laptop, there are a few programs out there meant for speaker analysis.
[quote756184]Danyol, I read that post from Kevin. I don't like to disagree with Kevin, because normally when I do, he hunts me down and proves me wrong!!
I think doing a little dynomatt would be good to place under the rear panels. That might be the total solution to the minimal drone found in this and other systems.
Every single car I've ridden in has had at least as much drone as this car, and actually all of them except Larry's (Landjet) has had more than this system.
Mike[/quote]
#38
03-09-2010, 06:13 AM
Registered User
Join Date: Nov 2009
Location: Bentonville, AR
Age: 54
Posts: 1,184
Rep Power: 87
#39
03-09-2010, 04:24 PM
My system picked up power based on the "detuned" file going form stock OEM exhaust to this system. It also stahled and didnt' rev as freely. I reprogrammed the computer with the UMW 93 Octane performance file and everything changed dramatically... For the better. Car revs freer, sounds better, runs better...
With all of the changes, the rebuild of the transmission, the upgraded shifter, the new exhaust system, and returning to the performance file, this car is truly a joy to drive. I've driven it EVERY DAY since installing the system on Friday. I LOVE this exhaust now that I'm used to it. The sound at redline in 3rd is simply AMAZING with the windows down, and with the taller gearing in 3rd, the speed is well over 100MPH...
I have a couple of other things cooking, thanks to another member I'm working with on some items, and I can tell you guys, I think I'm in the middle of building the perfect beast, again!! On the "power" side of the house the only thing I'll do is buy some of Marski's intercoolers for the system. Otherwise, I'm going to have Kevin lower the boost to 1.0 BAR, as I don't want to overstress the motor at the track with 4-6 30 minute sessions lapping at the track.
Mike
With all of the changes, the rebuild of the transmission, the upgraded shifter, the new exhaust system, and returning to the performance file, this car is truly a joy to drive. I've driven it EVERY DAY since installing the system on Friday. I LOVE this exhaust now that I'm used to it. The sound at redline in 3rd is simply AMAZING with the windows down, and with the taller gearing in 3rd, the speed is well over 100MPH...
I have a couple of other things cooking, thanks to another member I'm working with on some items, and I can tell you guys, I think I'm in the middle of building the perfect beast, again!! On the "power" side of the house the only thing I'll do is buy some of Marski's intercoolers for the system. Otherwise, I'm going to have Kevin lower the boost to 1.0 BAR, as I don't want to overstress the motor at the track with 4-6 30 minute sessions lapping at the track.
Mike
#40
03-09-2010, 05:27 PM
you can't get rid of drone. No one can, but you can reduce it. Crossflow systems help, but there is still drone. H-pipe like mine helped but there is still drone. I think the goal is to reduce it to a manageable level. I have reduced the drone in my car to a comfortable level and am happy with that.
the biggest hindrance to us is the limited space we have for exhaust. it is hard to design an exhaust for our cars due to limited spacing. It can be done with other cars, but the distances for exhaust gases are so short that we don't have much to work with.
This speedtech looks really good and probably sounds very good. most crossflow exhausts do.
the biggest hindrance to us is the limited space we have for exhaust. it is hard to design an exhaust for our cars due to limited spacing. It can be done with other cars, but the distances for exhaust gases are so short that we don't have much to work with.
This speedtech looks really good and probably sounds very good. most crossflow exhausts do.
#41
03-09-2010, 06:18 PM
I wondered that myself Mr. C4! I don't hear the NA guys complaining so I'm puzzled as well. I look forward to an opportunity to listen to other's exhaust if the rain holds off. Swapped my wheels, just need center caps 
#42
03-09-2010, 06:21 PM
I've driven it EVERY DAY since installing the system on Friday. I LOVE this exhaust now that I'm used to it. The sound at redline in 3rd is simply AMAZING with the windows down, and with the taller gearing in 3rd, the speed is well over 100MPH...
__________________
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
#43
06-02-2011, 07:33 AM
John,
I'm considering purchasing your 3" X-Cellerator exhaust. I'm curious as to whether the kit includes mounting straps yet. Thanks.
I'm considering purchasing your 3" X-Cellerator exhaust. I'm curious as to whether the kit includes mounting straps yet. Thanks.
#44
06-02-2011, 08:56 AM
Hi,
Yes, it comes with stainless steel straps and hardware making installation a lot easier than re-using the OEM bands. It goes on very quickly without removing the bumper cover...
John
Yes, it comes with stainless steel straps and hardware making installation a lot easier than re-using the OEM bands. It goes on very quickly without removing the bumper cover...
John
__________________
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
