: Ram Air! (Maybe)



Ekindler0584
11-07-07, 09:39 PM
I had a thought while reading the Northstar air consumption thread a page or two back.. and decided to do some math.

(Please correct my calculations if needed)

...A 4.6 liter engine at 6200 RPM (assuming the intake valves are open through the full down stroke, taking in the maximum amount of air possible) uses 237.67 Liters of air per second. Assuming air entering a "tube" at 65 MPH with no restrictions or back pressure, the tube would have to be 10.21 Centimeters in diameter (thats 4.02 inches) to achieve a 0 psi Plenum pressure.

So, couldn't you potentialy design some sort of air "scoop" placed in the front lower grill, to force air into a duct, and achieve this effect. And while I am at it, why not a 5 or 6 inch diameter aluminum duct for good measure. Even if you couldn't achieve 0 psi, i think it might still free up some HP on the freeway. Just thinking out loud, don't mind me!

Highline Cady
11-07-07, 11:30 PM
You know I've been looking at the same thing. I've installed a few Vararam's on a C5 and most recently on a C6, I've never made it down to the track to see if it cut off .3-.4 seconds in the 1/4, like they advertise, but besides the noise they both felt a little quicker.

So I was looking at modifying my Volant on my DHS to achieve the same affect. The problems that I have noticed is that the hole behind the headlight is way to small and that there isn't any room anyway to run a hose. The only other option I could see is drilling a big 4 inch hole through the bottom of the Volant and through the sheet metal below. Which while looking at it, would work and then running some sort of scoop to through the front fascia.

All that being said, I really don't want to drill that big of a hole. So for me at least, this idea is dead. But good luck to you if you figure out something better or even try this, if you do post pics, I'd be curious to see any ideas on this topic.

dkozloski
11-07-07, 11:52 PM
Contrary to popular opinion you want the air inlet to be small and the plenum behind it to be large. The high velocity of the entering air is converted to a higher pressue air as it slows down in the plenum. You want just the opposite of having a big funnel on the front of the car leading to the engine. The air intake I designed for my Cessna 180 floatplane fuel injected engine conversion provides about 1.5 inches of additional manifold pressure at cruise speeds.

ejguillot
11-07-07, 11:55 PM
I too have looked at this... and have done something to that effect. (I'll take pics saturday, when i'm under the car.)

Went to Lowe's, bought a 8' length of 4" metal flex dryer duct for $10. I removed the intake part that sits beneath the main airbox that the PCM sits in (Mine's a 2000 STS, so this would be applicable to the 98-04 SLS and STS). Then I ran the flex pipe from the trapezoidal opening in the main airbox (molding the flex pipe opening for as tight a seal as possible, the 4" diameter was a nearly perfect fit), routed the flex pipe behind and around the fog light, and ended with the pipe opening facing directly forward, tucked in to fit in the left side of the lower grille opening. Note: with the splash shield reinstalled, the pipe will be somewhat restricted, as the available space isn't much (without trimming away metal, which I don't want to do)

Results: A small difference felt at interstate speed, the engine note is more distinct under acceleration (a good thing!), and I have to pull the filter out once a month to shake out the embedded grit.

Worth doing? For $10 and 90 minutes of my time (most of it spent figuring out the pipe routing), yes!

Highline Cady
11-08-07, 04:35 AM
Sounds cool. I know that the deville and the seville airbox designs are different but would love to see the pics anyway. Keep us updated.

msta293412
11-08-07, 08:34 AM
What kind of filter are you all using?....Paper or mesh?...

Ranger
11-08-07, 11:19 AM
Is the PCM still in the intake air flow?

Ekindler0584
11-08-07, 12:45 PM
I am thinking about having aluminum tube made to go all the way from the grill to the TB... It would consist of a 2 piece design, with a bolted flange joining the two pieces, beneath where the air box currently sits. What dkozloski said makes sense though. I think a 4 inch pipe with a large "intake scoop" in the front bumper would be the best design. Keep in mind, I have a guy that can do all this metal work for around $200-$300, he put together an under-the-car "scoop" and sealed “airbox” that my father designed for his corvette, and it cost him $150.

The lower portion would be the easiest part, by only having it mate with the existing air box, everything else would remain stock. However, removing the airbox would present two problems, even though I would prefer to redo everything. Filtering the incoming air, and cooling the PCM would be the main problems.

As far as filtering goes, i think a two stage filter would be best. A K&N on the main intake in the front bumper, to remove large debris and block moisture, and (maybe) a paper filter in the stock location to get the smaller particles. So maybe a custom aluminum box to take the place of the existing air box? Would heat sinking the PCM to this aluminum box provide enough cooling? Or should the PCM be inside the box? And also, how would this “airbox” affect air flow (i.e. pressure and air speed)?

Having never designed a “ram air” system, I am looking for any feedback someone more knowledgable could provide… (Cough, dkozloski, cough)

Maybe I should just get a cheap centrifugal supercharger…..

Ekindler0584
11-08-07, 01:36 PM
My real issue though is that (and I mentioned this on a previous thread) my car is already running lean just from gutting the air box, and taking out the "U tube" underneath. So new injecters and an adjustable regulator mught also be a must.

I thought that the computer would adjust, but it seems it can only adjust so much.

ejguillot
11-08-07, 04:15 PM
To answer the questions... The PCM still sits in the airflow, and the filter is the factory OEM piece. Pics coming Saturday!

Submariner409
11-09-07, 10:47 AM
For the system to function as a "ram air" principle your vehicle speed would have to be pretty darn fast. Think about it.

What you have created is a true Cold Air Intake system, unlike the eyecandy underhood units, and for a lot less money, apparently.

As you have done, I did a year ago. No regrets and the panel filter does not seem to become "dirty" any quicker than with the U-tube intake behind the headlight.

ejguillot
11-09-07, 12:04 PM
I agree on all counts. No real difference is felt until I'm going faster than 80, and drawing air from the front bumper area is as cold as it's going to get. I did set it up so that the front of the pipe is facing the airflow directly.

Even a purpose engineered factory ram air system will only show minimal gains unless going at a high rate of speed. Example: the new Infiniti G35 sedan, where they claim a 3HP increase at 60MPH, or 1%.


For the system to function as a "ram air" principle your vehicle speed would have to be pretty darn fast. Think about it.

What you have created is a true Cold Air Intake system, unlike the eyecandy underhood units, and for a lot less money, apparently.

As you have done, I did a year ago. No regrets and the panel filter does not seem to become "dirty" any quicker than with the U-tube intake behind the headlight.

stngh8r
11-09-07, 05:10 PM
General rule of thumb:

10* cooler air = 1HP

Moving the intake inlet to receive cool air could potentially end up being a large benefit simply due to air temp. Also, insulating the intake tract has shown dyno proven results and large decreases in intake air temp. as measured before and after with the IAT.

Ram AIR? You would not likely create a positive manifold pressure simply due to the fact it would be very hard to push a positive pressure through a air filter. However, creating a system by where outside air is pushed into the air box is still greatly beneficial. It may not have a "charging" effect, but still makes it easier for the engine to pull the air through and/or less resistence due to the pressure being placed on the air filter.

CAI or Ram Air is going to yield and increase HP potential. The only concern I have is the mention of a lean condition? Would like to see some more info on this matter.

Ranger
11-09-07, 09:16 PM
Follow your intact duct to its source. It is already pulling cool ambient air. Moving it to the grill won't make it any cooler.

As far as ram air goes, I agree with Sub. I am pretty sure you'd have to be WELL over 100 MPH to achieve any effect.

ejguillot
11-10-07, 12:52 PM
As promised, pics. One change that I plan to make: repaint the part behind the grill a flat black, to make it really inconspicous.

I got the inspiration for this from the following articles:

http://autospeed.com/cms/A_107824/article.html
http://autospeed.com/cms/A_107825/article.html
http://autospeed.com/cms/A_107826/article.html
http://autospeed.com/cms/A_107827/article.html
http://autospeed.com/cms/A_107828/article.html

Read through the articles, they're a quite interesting read.

dwight.j.carter
11-12-07, 05:28 PM
I had a thought while reading the Northstar air consumption thread a page or two back.. and decided to do some math.

(Please correct my calculations if needed)

...A 4.6 liter engine at 6200 RPM (assuming the intake valves are open through the full down stroke, taking in the maximum amount of air possible) uses 237.67 Liters of air per second. Assuming air entering a "tube" at 65 MPH with no restrictions or back pressure, the tube would have to be 10.21 Centimeters in diameter (thats 4.02 inches) to achieve a 0 psi Plenum pressure.

So, couldn't you potentialy design some sort of air "scoop" placed in the front lower grill, to force air into a duct, and achieve this effect. And while I am at it, why not a 5 or 6 inch diameter aluminum duct for good measure. Even if you couldn't achieve 0 psi, i think it might still free up some HP on the freeway. Just thinking out loud, don't mind me!

I thought of this also. What about getting a hood off of a ws6 trans am and cutting out the ram air part and making it part of the seville or eldo hood. then route a hose to the throttle and you would have a true ram air setup.

zhida
09-05-08, 06:24 AM
danm good ideal i was gonna put a ws6 hood on my mountain bike hopefully will ad horsepower along with my alum foil bling and baseball card muffler...thanks man lol thank would look like crap...no offfense lol i know your just playing

zhida
09-05-08, 06:25 AM
good ideal though ej imma try that except im using 4 inch PVC pipe muahahaha

Submariner409
09-05-08, 07:59 AM
:wtf:.............as Judy Collins once sang: "Send in The Clowns...."

codewize
09-06-08, 12:09 PM
I don't know if this helps or not but i have some things to say

If there was a way to get ducting from the grille or lower grille in a DeVille I would have done it when I installed my Volant.

If the ducting you have installed were smooth and polished inside rather than flexitube it would be better

Yes, we did the math once and decided that a ram air effect from driving will only be effective on a N* over 100 MPH.

Yes 10* = 1HP. Fill the airbox with ice when you go to the track, then you can look like all the ricers cooling off their turbos. LOL.

The hood idea might work but I don't think you're going to gain anything, and that's going to require hours of fabrication.

Submariner409
09-06-08, 12:54 PM
Code is exactly correct: The speeds you have to travel to create any "RamAir" effect are so far above the upper end of the car's capability as to be ludicrous. It takes a LOT of tube mouth area and speed to get over the theoretical hump at 0" of manifold vacuum, and any modern car with a clean air filter will normally be able to get to less than 2" easily at WOT.

Don't forget that at 60 mph your manifold vacuum normally floats around 16" - 18" in a moderately tuned engine. The throttle butterfly is only open 6% to 9% at those cruise speeds. The atmospheric pressure supplies plenty of air under those conditions......the engine does not "suck in" air: the atmospheric pressure pushes it in depending on throttle opening.

CadillacSTS42005
09-06-08, 01:26 PM
want ram air
buy a Trans AM and hit 100+ mph for it to actually be worthwhile
period

stngh8r
09-08-08, 07:24 PM
As promised, pics. One change that I plan to make: repaint the part behind the grill a flat black, to make it really inconspicous.

I got the inspiration for this from the following articles:

http://autospeed.com/cms/A_107824/article.html
http://autospeed.com/cms/A_107825/article.html
http://autospeed.com/cms/A_107826/article.html
http://autospeed.com/cms/A_107827/article.html
http://autospeed.com/cms/A_107828/article.html

Read through the articles, they're a quite interesting read.

Man, thanks for the article links. I went through the homepage and found multiple articles of interest. I admire your intake efforts. Most mods are quickly ridiculed around here.

I have ported my intake box, but made no mods to improve flow to it.

FYI to everyone- While using a data scanner, I noticed that my IATs stay right at ambient as long as the car was moving.

Happy Hot Rodding

Eric

Submariner409
09-09-08, 08:11 AM
IAT, regardless of what system you use, (Seville/Deville) will hover around ambient to maybe 6-8 degrees above while driving on the open road because the cars are already equipped with an external intake system. When in town, stopped, or parked the IAT temps soar to 120+ because there's very low flow either through the system or over the piping which allows underhood heat to make everything toasty, chrome or not.

stng, It's not the FWD vehicle/engine modifications themselves that are questioned frequently, it's the unrealistic expectations of vast amounts of power gains from idle to redline which have proven to be pure fantasy.

stngh8r
09-09-08, 06:45 PM
stng, It's not the FWD vehicle/engine modifications themselves that are questioned frequently, it's the unrealistic expectations of vast amounts of power gains from idle to redline which have proven to be pure fantasy.


I'm cool with that (agree).

Even on the LS1's, most of the free mods and boltons only offer small power improvements. Most people accept that as the truth and are fine with it. There is an improvement though and for those of us hoping to get an extra 1-10hp here or there (not detectable by the SOTP dyno), its fun to discuss.

Happy hot rodding

Eric

NHRATA01
09-10-08, 04:07 PM
I'm cool with that (agree).

Even on the LS1's, most of the free mods and boltons only offer small power improvements. Most people accept that as the truth and are fine with it. There is an improvement though and for those of us hoping to get an extra 1-10hp here or there (not detectable by the SOTP dyno), its fun to discuss.

Happy hot rodding

Eric

LS1s with as little as an airbox lid and an exhaust cutout can pick up a good 10-15 at the wheels. With a few other bolt ons and a tune, 20-30 is not unheard of. Seen quite a few bolt-on cars put down 330-340 range at the wheels, a pretty good improvement over the 300-310 stock they'll put down.

Happy hot rodding

Another Eric :)