De-snorkeled my Box 5 minutes max

[mptoledo]

Originally Posted by JFP in PA

Sorry, but I still don’t buy it for multiple reasons. Interestingly, he ran his tests on a hub design dyno that is well known for always giving considerably higher readings (10-12% are not uncommon) than conventional roller units in side by side runs. I know the manufacturer claims this is because it’s unique design which “eliminates the “roller effect”, but at the end of the day, the rollers are in much wider use. In any case, while I am not going to challenge the veracity of his test; I can tell you that two different cars that I watched being tested showed a slight, but measurable drop in HP and Torque when tested on the rollers. When combined with consistent comments that multiple cars saw lower gas mileage with it out, but recovered the mileage when it was reinstalled; I think you are “tilting at windmills” here……………

Again, I am still in the wait and see camp. I check my MPG after every fill up. I do like the sound with it off. Even using an inferior dyno, it should give a consistent before and after reading even if they are both high. Enough of that. As I said in the OP, HP and torque gains(if any)are negligible and aren't the reason I did this.

I am glad you brought up the MPG issue, as to me that is way more important than any small gains or losses in hp or torque. I will definitely keep an eye on them over time and report my findings, as unscientific as they may be. I still think most people rev up and wind out through the gears more to hear the noise, which makes sense why they would see lower mpg.

[JFP in PA]

OK, I went and looked up one of the guys that ran the test I watched on the rollers and he sent me the following data on multiple runs, with and without the baffle;

***18 Jul Stock no mods ***
RF-001 258.31 bhp 220.54 ft/lb
RF-002 258.21 bhp 221.92
RF-003 258.44 bhp 221.03

********* 18 Jul De-Snorked runs *****
RF-004 256.95 bhp 217.82 ft/lb
RF-005 256.17 bhp 218.46
RF-006 255.95 bhp 218.91
RF-007 256.19 bhp 220.00

Doesn’t look very promising on the performance side, but it was noisier……

I have no idea about the source of the MPG change, so you could be correct in that it results from "too much right foot"..........

[Boxtaboy]

I agree with JFP, in that I think desnorking does make you lose a little power. I was desnorked for a year, and always noticed that at highway speeds over 60+mph, it always felt like I had less power with the snork out. My personal layman's theory is that the snork was designed with the curved, trumpeted opening (which sits closer to the grille opening) to better facilitate airflow into the airbox, giving it a smoother and less turbulent flow into the airbox. With the snork out, there is a void in that area that includes all these waffled edges at the rear section which cannot help airflow into the airbox. Couple that with the fact that the remaining opening after pulling out the snork leaves a straight edge whereas the snork used to have a curved opening, and the flow must be worse than before, IMO.

That being said, ultimately, after putting the snork back in, and feeling like the power had come back at speed, I still really disliked having the snork back in place because there is a remarkable difference in the way the car sounds with the snork back in.... it was just too quiet for my liking, and I soon was back at pulling that snork out. This time, however, after pulling out the snork, I took a dremel to the remaining straight edged opening at the rear section, and sanded it into a curved opening to simulate the curved opening of the snork (and then vacumed out the sanded out bits prior to putting it back together). You can't see it too well in the crappy picture I took at the time, but I now have a curved opening into the airbox. Not sure if it helps or not, but I do love the sound of the car desnorked, and if it means a 2hp loss as JFP shows, so be it...at least I can hear the sweet growl of the intake while I'm going slower, and getting less mileage.

Desnorked and dremeled remaining opening:

[JFP in PA]

The baffle’s function is misunderstood; it is there so that the car meets the ridiculously stringent Swiss noise laws, the same reason for the overly complex Sports Exhausts design, with its valves and speed controls as a factory installation. The Swiss have very tight requirements on how much noise a car can make and certain speeds and under certain conditions; the so-called “snorkel” is there to comply with that requirement. It’s rather peculiar design speaks to meeting the sound level without disturbing the flow of the rest of the intake system, which obviously works. When it is removed, the sound level rises, but the intake system is no longer “optimized”, so performance suffers slightly.

It would be interesting to see if gains could be made by totally redesigning the runner system to operate without the baffle, but that would require a lot of flow bench time at a minimum……………..

[Boxtaboy]

Originally Posted by JFP in PA

The baffle’s function is misunderstood; it is there so that the car meets the ridiculously stringent Swiss noise laws, the same reason for the overly complex Sports Exhausts design, with its valves and speed controls as a factory installation. The Swiss have very tight requirements on how much noise a car can make and certain speeds and under certain conditions; the so-called “snorkel” is there to comply with that requirement. It’s rather peculiar design speaks to meeting the sound level without disturbing the flow of the rest of the intake system, which obviously works. When it is removed, the sound level rises, but the intake system is no longer “optimized”, so performance suffers slightly.

It would be interesting to see if gains could be made by totally redesigning the runner system to operate without the baffle, but that would require a lot of flow bench time at a minimum……………..

I've heard that theory about the snork being placed there to meet the stringent sound limitations in certain countries, but I then wonder why that type of snork tube is inserted in many different types of cars, even domestic ones.... you find them in the older air cooled 911s, in Mazda pickups, all sorts of cars....they all have snorks leading to their intakes. Therefore, I would think that there was a reason for them being there (maybe one function is to further quell sound), but there has to be another benefit to them, no? In fact, I would bet that you could get the Boxster up to higher speeds without even realizing the louder noise of the desnork because the extra growl from the desnork doesn't even come on until after 4k+ rpms really. This is why I don't think the snork is there solely for the purpose of noise abatement.

[JFP in PA]

Originally Posted by Boxtaboy

I've heard that theory about the snork being placed there to meet the stringent sound limitations in certain countries, but I then wonder why that type of snork tube is inserted in many different types of cars, even domestic ones.... you find them in the older air cooled 911s, in Mazda pickups, all sorts of cars....they all have snorks leading to their intakes. Therefore, I would think that there was a reason for them being there (maybe one function is to further quell sound), but there has to be another benefit to them, no? In fact, I would bet that you could get the Boxster up to higher speeds without even realizing the louder noise of the desnork because the extra growl from the desnork doesn't even come on until after 4k+ rpms really. This is why I don't think the snork is there solely for the purpose of noise abatement.

Actually, it is for noise abatement, and different OEM’s handle the issue in various ways. We currently have a Nissan product in the shop that has two factory options: A really slick cold air system and a large diameter, low restriction stainless steel exhausts system. Because the car came from the factory with these, there are two small decals on the radiator support noting that “the car is not legal for export to certain European countries”, because both the intake and exhaust fail to meet “TUV noise standards”. The non option version of the same car has a plastic box in the intake system with a similar baffle to the one on the Boxster inside of it, if you disconnect the box; you get a pronounced intake “roar”, much like the cold air system has. Interestingly, the optional cold air system, which while simple, is beautifully designed, adds 8-10 HP at the wheels, and the exhaust another 10-12 over the standard stuff, so the addition of these does make a significant difference.

The Swiss must drive the OEM’s nuts with this stuff………..

[Boxtaboy]

Originally Posted by JFP in PA

Actually, it is for noise abatement, and different OEM’s handle the issue in various ways. We currently have a Nissan product in the shop that has two factory options: A really slick cold air system and a large diameter, low restriction stainless steel exhausts system. Because the car came from the factory with these, there are two small decals on the radiator support noting that “the car is not legal for export to certain European countries”, because both the intake and exhaust fail to meet “TUV noise standards”. The non option version of the same car has a plastic box in the intake system with a similar baffle to the one on the Boxster inside of it, if you disconnect the box; you get a pronounced intake “roar”, much like the cold air system has. Interestingly, the optional cold air system, which while simple, is beautifully designed, adds 8-10 HP at the wheels, and the exhaust another 10-12 over the standard stuff, so the addition of these does make a significant difference.

The Swiss must drive the OEM’s nuts with this stuff………..

Cool, then all I have to figure out is a way to block out the waffle voids in my intake area, design a bigger curved scoop, and I'll have put that 2hp back into my car!