air silencer removed?

[jguerrero]

just got a k&n air filter yesterday, debating wether to remove the air silencer or mot. I been getting mixed reviews. Any one have any extra info, it would be appreciated. thankyou

[jguerrero]

finally have a pic that will post, had to include it:haha:

[DaveSVT03]

I removed it on my car and it seems to make a difference. Not sure if the same will be true once the weather warms up though.

[norcal_cobra]

The only problem with removing the air silencer is that the air you are now exposing your filter to is warm engine compartment air being blown directly on it from the fan.

norcal_cobra

[Brad12]

The K&N filter gains you almost nothing in HP,both mine and my friends dynos showed this.The cold air kit is what really made a diff.However if you know anyone who wants a K&N filter with about 100 miles on it let me know,it was a waste of 50 bucks

[postban]

http://www.svtperformance.com/forums/showthread.php?threadid=18232&highlight=worthwhile

(from September 3rd 2002)

Just a few measurements folks. Seems we need some hard facts about just what is going on under the hood.

I just took a little afterdark drive, about 45 minutes worth. Ambient temperature is 81 degrees here in Wyandotte at approx 9PM. My logic was to eliminate sunshine as a heat inducing element and just get temp readings from engine output alone. Also did not have much choice cause I got stuck working OT for 3 hrs anyway. It just plain had to be afterdark.

I am using a DIGI-SENSE DUAL J-T-E-K THERMOCOUPLE THERMOMETER Model 91100-40 last calibrated on 8-16-02 to ISO sumthin-or-other-wasn't-paying-attention-doesn't-really-matter.


The AIRBOX is inplace and my intention is to measure temperatures inside it first. I attached the alligator clip equipped sensor directly to the top of my K&N (simply clips to a fold in the filter element) and fed the wire along the hood and back into the passenger window and to the thermometer.
I turned the thermometer on and recorded a temperature of;
Cold Engine before starting---------83.4 F
After 5 mins cruising at 35 mph-----78.7 F (yes, less than ambient)
After 10 mins cruising at 35 mph----80.2 F

At 10 minutes the car was at full warm with the temp needle indicating halfway between C----H

I pulled into a parking lot to see what idling would do to the temp being recorded at the K&N.
1 min -------- from 80.2 to 101.2
2 min -------- 122.2 (FAN ON)
3 min -------- 117.1 (FAN ON)
4 min -------- 120.9 (FAN CYCLING)
5 min -------- 126.9 (FAN CYCLING)
6 min -------- 124.6 (FAN CYCLING)
7 min -------- 135.6 (FAN CYCLING)
8 min -------- 137.0 (FAN CYCLING)
9 min -------- 132.8 (FAN ON)
10 min ------- 135.0 (FAN ON)

I pulled out of the parking lot and within 2 blocks the temp was down to 80.6 and at 1 mile from the parking lot temp was down to 78.1
Apparently my airbox is not completely sealed against seepage of engine bay air. I have intentionally left it easily removable. I would only need add a few more pieces of foam tape to the fender wall to seal that gap and similar treatment to the front edge of the side plate.

After this short drive I pulled into another parking lot and unclipped the sensor from the K&N. I then Clipped the sensor to a plastic ziptie I had placed just to the left of the airbox, totally exposed to engine bay air.

Initial reading outside the airbox was 148.0 F

After 1 minute at idle the temp was 171.1 F
I then left the parking lot and went for a short 3 minute drive and the reading fell to 146.9 F. It stayed there plus/minus 1 degree for all of another 10 minute drive at 40 mph. When I pulled into start the next test the temp was immediatley 166 F

Brief summary so far; With AIRBOX average 80 F with car moving from 25mph-and-up to 137 F max after long idle with hot engine. Better sealing would improve/lower max temp.

Outside AIRBOX average 146.9 F with car moving from 25mph-and-up to 171.1 at brief idle.

Without the airbox or any attempt at getting cooler air to the filter element you will nearly double the temp of your intake air. I don't want to guess what adding hot midday sun will do to the equation.
Any one know the Laws of Gasses well enough to calculate what 1 degree F cooler/denser air will do for horsepower? How about 67 degree cooler air!!!!!

AIRBOX (CAI) gave me 67F difference while moving and 34.1 F difference at hot idle. This is not just a few marginal degrees here guys, there is serious power in them numbers.

Also, I felt (just my hand) the side of the intercooler resevoir, it was nearly ambient temp, nowhere near the temp of the engine. It was bubbling away and showing no signs of getting hot. I had not been into the blower throughout his test.

I also took time to measure another temperature, hood vent air temp. I clipped the sensor right to the middle of my right hood vent grill. Initial idle temperature was 136 F. After 2 minutes driving a 30 mph temp was 85. At a stoplight for 30 seconds temp shot up to 103F, rolled another two blocks temp down to 85F. Then another stoplight 45 seconds, temp went to 146.5F. This pattern was consistent, while driving the air coming out of the hood vents was 85 within 1 F up or down. At each light or intentional idle it would rocket up to over 150F. I stopped at a gas station, engine off for 2 minutes and hood vent air temp was 167.8F. That is a lot of heat escaping from the engine bay.

This demonstrates precisely what an SVT engineer told me personally. Opening the hood vents helps with "heat degas" (removal of heat)

No flame is meant here, just evaluate these measurements and S.W.A.G. away gentlemen and ladies.

FREE CAI plans at AIRBOX link in my sig

[trmn8er]

Good job! Nothing like a little raw data to help paint the picture. Why did Ford put the silencer in the fenderwell? Probably because they did some simple testing like you did!

[DaveSVT03]

MM and FF reported gains of ~ 18hp by removing the rubber snorkel and with a K&N with no other changes.

Not saying there isn't a good reason to leave the snorkel in. I will probably put mine back in when the weather gets hot. But I noticed a difference in my car by using the K&N and removing the snorkel.

[ObieFox]

Leave the silencer on..... Watch for the CAI shootout results coming in a future 5.0 magazine. The K&N results with silencer are surprising!!!

Take care,

Kevin

[dwtalso]

Take the silencer off. It helps and it really doesn't hurt.

I performed a series of experiments similar to postban's except that I used my Autotap to monitor the intake air temperature (IAT)sensor and MAF flow rate data. I dunno, but postban's temperatures seem a little high to me, but I'm at 5300 ft altitude and the air density difference may be part of it.

In my experiments the ambient air temperature was 75 degrees F, the barometric pressure was 24.4 inHG (gage), and I did this in full sunlight on a bright day, about midday. I ran both a complete air box with K&N and an open, 9" K&N element attached directly to the MAF. I idled the car for 15 minutes between runs and got a high IAT reading of 137 degrees F with the open element and 110 degrees with the stock air box. The coolant temperature reached as high as 210 degrees F in both cases.

I made several quarter mile runs while logging IAT data and MAF flow rate. The largest temperature difference I measured was 27 degrees F, between the stock air box and open element and that was at a dead stop. The air temperature dropped with vehicle speed similarly between the two setups with the open element actually dropping in temperature a little faster at higher speeds. The difference at 105 mph, about where I end my quarter mile, was 20 degrees F, the open element being higher.

Now, the interesting thing is the MAF flow rate. At low engine and vehicle speed there was clearly some indication that the stock air box was flowing slightly more air. However, above 30 mph, at any engine speed, with the open element, the MAF measured more air being ingested by motor. Roughly 3% more air, on average.

So, yes, the stock air box with snorkle keeps the intake air charge temperature lower. Yet, the engine ingests more air with the open element. More air means more fuel burned, and that means more power, even if the air is hotter.

Thus, my conclusion is that the stock air box is so restrictive, relative to an open element, that any benefit from the snorkle pulling cooler air from the fender is negated.

But the story still isn't quite complete. I would like to repeat these experiments while monitoring AFR as well. Since the MAF is metering more air with an open element, the only remaining factor that could impact final power is the AFR and timing that the PCM dictates. I don't know what the PCM does with the hotter intake air at WOT. Its strategy may be to richen the mixture, or pull timing, to buffer the heat in the chamber and some power might be lost. I haven't heard of this happening, and I don't see that on dyno graphs that I have, but it is a possibility.

[jguerrero]

first of all I want to thank everyone for their posts. However I did some tests yesterrday.

I have had my cobra now for about 5 months and up until yesterday it was completely stock. I installed the K&N airfilter into the stock casing and removed the silencer. Wow, let me tell you, I know what the stock form of my car feels like, but this simple mod made a difference. I felt a little more go, and it sounds a hell of a lot better. Now, I beleive that what wouldn't work is if you attach the filter right to the MAF and let it pull air from the engine conpartment, to much heat. But by putting the K&N into the stock casing,(fits with a little force to out in into the casing) it is still pulling air from the fender. If everyone can remember what SVT said ' it(cobra) is breathing through a straw', if that isn't a hint, i dont know what is. The reason why SVT had to out that silencer is to cut down on noise caused by the blower to meet government restrictions. By removing the silencer, you can see that the thing does its job. The blower sounds ten times better without the silencer, and restricts the hell out of the air coming in. The boost guage goes a little further, im skeptical however if this is the case, but anyway THERE IS A DIFFERNCE. After I install my magnaflow catback and x-pipe next week, I think that the intake setup will pay dividends by allowing more air for the exhaust to put out. Remember the rule, the more air in, the more air that goes out.(or something like that). It's one of the first rules in modding.
Also, just to help eliminate any hot air that may sneak around to the small exposed section of the airbox, I want to try the hood blanket mod that everyone is talking about. If any one has any pics, or a link, please send it my way.

Hope this helps, sorry it is long

[Mongoose]

Remembering my drag racing days in the late 60's and early 70's.......Open headers, No filter on carb. Restriction was a bad thing, and in my opinion it still is. I don't know who drummed up the idea that a motor needs backpressure. I say NOT.:bash:

[TBSVTOA]

Originally posted by Mongoose
Remembering my drag racing days in the late 60's and early 70's.......Open headers, No filter on carb. Restriction was a bad thing, and in my opinion it still is. I don't know who drummed up the idea that a motor needs backpressure. I say NOT.:bash:


Dont forget to take the from right headlight for more air at the strip.

[03SNAKERUSH]

One word..INTERCOOLER...all 03 Cobras have them.....ditch that silencer and drive!

[rachrse]

I took the silencer off and it did make a differance, put a straw in your mouth and try to breath, the silencer is like having a straw in your air box. Rachrse

[Jhendrix]

I tried to e-mail you...Do you know who won the shootout. I do know the silencer "on" produced more horsepower than silencer "off". I heard it was an air velocity thing? Am looking for the best CAI wthout a lot of hassle in maintenance. The stock housing HAS TO GO as I keep loosing bits of knuckles trying to pull up and seperate the thing. Darn near had a stroke trying put the silencer back on. I thought about cutting about 6 inches of silencer nose off so that it would go on easier..but if that shape has a purpose perhaps I shouldn't do that..:)

[ObieFox]

Jhendrix,
I was at the 5.0 CAI shootout. My '03 was one of the stock test cars. I'm not going to argue with all these "experts", but I know what I saw on the Dyno. I can't give details about who won or lost, but here are 2 posts from Dr. Jamie Meyer who is writing the article for 5.0....

Take care,
Kevin


RESULTS: 5.0 Mag CAI Shootout
Disclaimer: I can not publish dyno results on the internet. I hope everyone respects the fact that 5.0 Mustang & Super Fords magazine owns the rights to the data that were collected yesterday. Without the involvement of 5.0 Mustang & Super Fords magazine, I could not have carried out this study. This complete story will be published in approximately 2 months. Please, watch for it and read 5.0 Mustang & Super Fords magazine. Thanks.

Thank You: There are many important people that I need to thank.

Paul’s Automotive Engineering in Cincinnati, OH (Please, call these folks if you need work or dyno tuning on your cars. Paul Faessler, Tom Honsaker, and Big Mike Wilson ran this project for me.

Car owners: Gary Richardson, Kevin O’Brien, Shane and Lisa Reffett, and Tim Probst were awesome. We put over 40 pulls on their cars.

Crew: Ian Mullane helped with the wrenches.

Cold Air Kit manufacturers: These folks were brave enough to let us find out how there stuff stacked up.

Here are the conditions that were tested:
1. Stock – air filter, box, "silencer", etc.
2. K&N stock filter replacement
3. K&N CAI
4. Amazon Racing CAI
5. Paul’s High Performance CAI
6. Johnny Lightning Performance CAI
7. Unlimited Performance Racing (UPR) CAI
8. Densecharger CAI (6-inch K&N filter)
9. Densecharger CAI (9-inch K&N filter)
10. JDM Performance CAI: I didn’t get this in time for Saturday. I will hopefully get some pulls in this week on the JDM setup.


We ran each of these conditions on both a stock 2003 Cobra and a Cobra that was modified (pulley, chip, exhaust) in duplicate under the exact same conditions. We started at 8:00am and finished last night at 11:00pm. I hope that explains the delay in posting! LOL

This has to be a cryptic post for the reasons stated above. And, of course, we all know that we are racing dynos here with the weather conditions, tune, and dyno driver affecting the results from your area and advertised hp gains. Okay? On the stock cars there was one clear leader. On the modified cars, things seem to even out quite a bit. You will read some surprising results (as much as a 25 rwhp gain) on the stock cars, and the best performing kit on the modified cars is one that has taken a lot of heat on this board. But, again, the kits are all very even with modified cars.

SPECIAL NOTE: On a tip, we tested the value of removing the "silencer". We found that this is a big mistake on these cars. YOU ARE LOSING POWER WHEN YOU REMOVE THE "SILENCER". We saw as much as a 5 rwhp loss with the "silencer" out on a stock car. This was popularized with MM&FF’s original drag test on the 2003 Cobra. However, they removed both the silencer and the filter. The FILTER is the restriction not the "silencer". In fact, the K&N stock replacement filter with the "silencer" in the stock location is a very good choice for making power. Again, this may not hold up in drag testing, but when racing dynos you want to leave the "silencer" in the car.

That is about all of the information that I am willing to divulge at this time. This hasn’t been done to tease anyone, but to inform you of the information that will become available to you. Again, thanks to all that were involved.

Thanks to svtperformance.com,
Jamie



AND ANOTHER.....


The 2003 CAI Shootout didn't get pushed because there is a problem with the 2003 owners. This is the magazine business - at best, the things you read in the "latest" issue of ANY magazine are three months old. Most features are shot 6-18 months in advance. It's not the attitude of the writer/editor/publisher, it's the nature of the media.

I will end this "can't wait to decide over a $100-$300 part" debate by saying that the Densecharger is a wonderful choice for a completely stock car. When modified with a pulley/exhaust/chip, it is joined by the K&N kit, UPR, PHP, Amazon, JDM, and Johnny Lightning kit. They are all so close on a modified car that I feel it would not be statistically significant if tested with a large n.

There, that is the answer you have all been waiting for …

Thanks,
Jamie

[Jhendrix]

I knew you "had information" when you mentioned the stock tube. Needless to say, I'll be buying the magazine for the results. Thanks again :)

[dwtalso]

Okay, so the answer would seem to be, if you keep the paper element, leave the snorkle. If you get a K&N, pull the snorkle or not, it doesn't really matter. Otherwise, replace the entire air box.

Sounds like pretty much what most people have been saying :).

[Jhendrix]

Get K&N and keep snorkle/silencer...Good luck replacing filter and getting the darn silencer back in there. It cost me quite a few nicks on my hands and raised my blood pressure!

Stock filter is the problem.

I might add, until I decide, I put K&N filter in AND my silencer in...sorta.. Today, I cut about 4" off the end in a somewhat diagonal cut so about 1 &1/2 inches go into to fender. It was much easier to install and provided a larger air opening from the fender.

I have no idea if this did anything other than "look" stock. I did also install Magnaflow cat back system. It has more power than I know what to do with on city streets as this is a daily driver.

Am awaiting results of CAI shoot out :)

[ObieFox]

What Jamie said in his post is that with a K&N filter in the stock airbox we lost 5+ RWHP when we removed the silencer. Plain and simple. Our testing was pretty comprehensive. We backed up all our dyno pulls with duplicate runs just to be sure.

Let's be real, 5HP is no big deal. If I had the stock airbox, I would remove the silencer just to make the blower whine louder.

My 2 cents

Kevin

[dwtalso]

Originally posted by ObieFox
What Jamie said in his post is that with a K&N filter in the stock airbox we lost 5+ RWHP when we removed the silencer. Plain and simple. Our testing was pretty comprehensive. We backed up all our dyno pulls with duplicate runs just to be sure.

Oh, well in that case, I'll probably disagree :). I did a similar test on one of my first dyno sessions, stock air box, K&N, with and without snorkle, and gained about 4 rwhp with the snorkle removed.


Let's be real, 5HP is no big deal. If I had the stock airbox, I would remove the silencer just to make the blower whine louder.


Exactly, it's not so simple an answer as yes or no with the data we have :). Especially since I'll bet both our results are close to the error limit of the test equipment.

I'll stick with it doesn't matter :).

[Mongoose]

Decisions, decisions......makin it tough for me to decide which CAI to go with. I believe I will wait till 5.0 Mustang & Super Fords magazine releases the figures:wtf: