I was pondering which intake system to use to help my 12V breathe a little easier. I hear great things about the ScottyII, but I just can't bring myself to cut a 4.5" hole in my cowl. The wife and kids would freak everytime they rode in it. So my question is this: If I don't cut a hole in the cowl, how does the ScottyII compare to say an aFe Megacannon or the new K&N performance?

 

still about 50 degreese cooler then the cannon. And quieter.

 

Whiff,<br><br>I would suggest either the AFE megacannon or the Scotty 2.<br>The way it sounds, the Scotty 2 is the one for you.<br>It will let your truck breathe easier and lower your EGT's.<br><br>If you are going for just absolute air flow, I suggest the AFE megacannon filter.<br><br>--Justin

 

The thing about the Scotty is that it has an airbox, pulls in outside air. Megga cannon has a shield, lets in some hot under-hood air.<br><br>I would go for the Scotty. You could cut the hole later if you wanted to. I believe it also comes with a blockoff plate in case you decide you don't like the hole.

 

[quote author=PourinDiesel link=board=7;threadid=16168;start=0#151840 date=1056212369]<br>If you are going for just absolute air flow, I suggest the AFE megacannon filter.<br>[/quote]<br><br>If you're talking about airflow on a dyno, the Cannon may flow more air, although we haven't had any testing done on the Scotty II. The Scotty I flowed a little over 1000 cfm on a static bench (aFe's test results before I was partnered with Scotty, so I'm unsure of the test parameters).<br><br>On a truck thats moving down the road, given that the Scotty reduces EGTs by up to 250F more than a Cannon, the Scotty flows more. It has to, as the differential between outside air temps and underhood temps can not account for that much extra EGT reduction.<br><br>Rod

 

[quote author=Push Rod link=board=7;threadid=16168;start=0#152051 date=1056298378]<br>[quote author=PourinDiesel link=board=7;threadid=16168;start=0#151840 date=1056212369]<br>If you are going for just absolute air flow, I suggest the AFE megacannon filter.<br>[/quote]<br><br>If you're talking about airflow on a dyno, the Cannon may flow more air, although we haven't had any testing done on the Scotty II. The Scotty I flowed a little over 1000 cfm on a static bench (aFe's test results before I was partnered with Scotty, so I'm unsure of the test parameters).<br><br>On a truck thats moving down the road, given that the Scotty reduces EGTs by up to 250F more than a Cannon, the Scotty flows more. It has to, as the differential between outside air temps and underhood temps can not account for that much extra EGT reduction.<br><br>Rod<br>[/quote]<br><br>I'm still trying to figure out how the Scotty reduces EGTs up to 250* more than the Mega Cannon. From the specs it looks as though the Cannon flows more air than the Scotty (from the AFE specs it certainly has a larger filter area, and Joe's dyno tests have shown it increases hp over no filter at all). Suppose they both flow the same amount. Is this to say that there is a 250* temperature difference between underhood air and outside air? I understand the concept of cooler air in/cooler air out in a one to one ratio. Does that ratio change when using the Scotty?<br><br>Can somebody explain the physics of this to me? Facts and not hype please.<br><br>Thanks

 

When Air is compressed it is heated exponentially hotter as boost gets linearly hotter by a factor of &quot;k&quot; - the ratio of specific heats (Cp/Cv). In simply calculations, you can use an isentropic relation to calculate the exit temperature based on a known intake and exit pressure (the delta P). The equation is as follows:<br><br>T = T_in*(P_out/P_in)^((k-1)/k)<br><br>for air at ambient temps k=1.4<br><br>Using this equation for 45 psi and inputting two different air temps: 80 degrees F for outside air and 120 degrees F for underhood air yields the following:<br><br>Intake Temp: 80* Exit Temp: 340*<br>Intake Temp: 120* Exit Temp: 400*<br><br>As you can see, lowering the intake air temp at the filter has very beneficial results. Those temps assume a 100% efficient compressor, so you would have to factor in the actual inefficieny to get a real world temp number.<br><br>John<br><br>

 

So that means there is a 178* difference between aoutside air and underhood air to reduce EGTs 250* at 45 psi boost?

 

[quote author=Bart Timothy link=board=7;threadid=16168;start=0#156172 date=1057253303]<br>I'm still trying to figure out how the Scotty reduces EGTs up to 250* more than the Mega Cannon. From the specs it looks as though the Cannon flows more air than the Scotty (from the AFE specs it certainly has a larger filter area, and Joe's dyno tests have shown it increases hp over no filter at all). <br>[/quote]<br><br>The Scotty works better than open element filters for three main reasons:<br><br>1) Outside air temp differential. We've seen up to 60F differential between outside air temps and underhood temps.<br><br>2) An enclosed housing which actually shapes and guides airflow over the filter. Less turbulence = more airflow<br><br>3) Ram air. Filter surface area is only an indicator of flow when used on static benches or on dynos. Once installed on a vehicle, overall system design takes over. Ram air works. It was used throughout the 60s and 70s on muscle cars with great results, and it works in this case as well.<br><br>In a way, I wish Joe had never done his dyno test. All his test showed is what air system works on a dyno. He'll even tell you that himself. Once a vehicle is moving down a road, all airflow dynamics are changed. Even static bench tests are pretty much useless as the water restriction that the filters may be tested at will only tell you the maximum flow of the filter AT THAT PRESSURE. You decrease or increase the restriction, the maximum flow of a filter changes.<br><br>And if this isn't enough to convince you, talk to the few guys on here who have swapped from MegaCannons to Scottys. To a man, they've seen better EGT reductions.<br><br>Rod

 

Thanks for the replies.<br><br>If there's a difference of &quot;up to 60&quot;* between underhood and outside air temps, that comes out to an EGT reduction of up to 84* with a &quot;k&quot; value of 1.4. That's a long way off &quot;up to 250*&quot;, and my question still isn't answered. How does the Scotty reduce EGTs by up to 250* over a Mega Cannon, or a stock filter, for that matter? Does it cause the 'k&quot; value to increase? At this point I'm still not convinced that it out flows the the Mega Cannon, even considering the ram air effect and air box design.<br><br>Facts and not hype, please. If I belived EVERYONE here the question wouldn't have to be asked, and a year ago the BHAF would have been king.<br><br>Thanks<br><br>

 

I have run the 4 1/2&quot; hole and a hose with the stock filter and the BHAF with my own shield that sealed to the hood. and the ScottyII still droped crusing temps 70* and towing temps 150-200*.<br>Bruce

 

[quote author=Bart Timothy link=board=7;threadid=16168;start=0#156380 date=1057290903]
If there's a difference of &quot;up to 60&quot;* between underhood and outside air temps, that comes out to an EGT reduction of up to 84* with a &quot;k&quot; value of 1.4. That's a long way off &quot;up to 250*&quot;, and my question still isn't answered. How does the Scotty reduce EGTs by up to 250* over a Mega Cannon, or a stock filter, for that matter? Does it cause the 'k&quot; value to increase? At this point I'm still not convinced that it out flows the the Mega Cannon, even considering the ram air effect and air box design.

Facts and not hype, please. If I belived EVERYONE here the question wouldn't have to be asked, and a year ago the BHAF would have been king.
[/quote]

Well Bart, you just answered your own question. Indeed, drawing outside air cannot explain the radical difference between the Scotty and MegaCannon. Have we done any kind of flow number testing on a truck? No we haven't. There hasn't been any need to. We've had customer reports of up to 400F EGT reductions between the stocker airbox and the Scotty. The highest EGT reductions we've seen reported from shielded air elements has been 150F.

I believe the single biggest difference between the two units comes from the ram air effect and the housing design. I remember reading some old 60s and 70s muscle car magazines that quoted 6x greater airflow from cowl induction. Were these measurements accurate? I really haven't got a sniff. But there is a reason why virtually all performance automobiles in competition use a ram air or cowl induction air intake, including Nascar and NHRA.

I'm not really sure what you are getting at with this thread. The proof, as they say, is in pudding. The Scotty II simply reduces EGTs better than any other system. This is no longer hype or sales babble. This has been proven by close to 400 satisfied customers.

Rod

 

And my question has been thoroughly answered! Thanks for the thermodynamics lesson and the &quot;heated&quot; debate! (Pun intended!)<br>Sorry if my original question caused so much consternation among loyalists in different camps!

 

Bart: I know that assumptions are like openings of lower body parts ;-) everybody has one.<br><br>I assume that the you do not have to change k when you calculate that a: the air under the hood is at a lower pressure than outside and b: the air at the point where the scotty takes it is at a higher pressure than ambient. Since the wastegate of the turbo opens at a certain absolute pressure the wastegate will open at a lower compressor speed because due to the ram air effect this pressure is reached at the lower speed of the compressor. And therefore the backpressure in the exhaust per psi*cfm is reduced significantly. Also since the compressor of the turbo does not need to make this much delta P (we've already got some p) the heat produced by compressing should also be less. <br>Naturally this will only work when there is some significant airflow over the hood. <br><br>Just my 2c<br><br>AlpineRAM

 

I'm going to chalk this Scotty tempature reduction thing up mostly hype, for the time being. Human nature being as it is, most folks haven't got a clue. They're going to rationalize that $200 investment they just made. It's no different than other hypes - &quot;propane ruduces EGTs&quot; or a &quot;4 inch exhaust improves spoolup and EGTs on stock trucks&quot;, or &quot;more boost necessarily gives more power&quot;.<br><br>What I asked to see was hard, empirical facts and not unproven theory or customer reports and opinions, which by the way, isn't universally unanimous in these large EGT reductions. That's why I brought the subject up. So far, the only empitical data air intake systems I've seen has been Joe's dyno tests and manufacture's rated flow data. Those tests obviously don't take into account many real world factors, but they are at least done in a controlled enviroment. Nobody has reported any flow or dyno tests with the Scotty, let alone any done in some sort of a controlled enviroment, that I've seen.<br><br>Manufactures and dealers usually always make unrealistic claims for their products. For example, Volant claims a 25 hp increase over stock by using their system. Are we supposed to believe that?<br><br>When you're towing, a gentle 5 to 10 mph headwind, can easily increase EGTs by 250*. With a tail wind, the oppisite. Small, hardly noticable, enviroment factors like temperature, humidity and cross winds can, alone, make these differences in EGTs, so wild customer reports are not surprising at all. In my estimation, actual EGT reductions by the Scotty are probably under 100* over the stock system, in even modified trucks, until I see hard, independent evidence to the contrary.<br>