Building my own cold air intake

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bommy261

Golden Member
Dec 17, 2005
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just be sure your don't run over a big puddle of water or drive in horrible rain and carefully monitor engine temps .
 

exdeath

Lifer
Jan 29, 2004
13,679
10
81
just be sure your don't run over a big puddle of water or drive in horrible rain and carefully monitor engine temps .

This is high up at the hood of the car, this isn't like the kind where the filter is in the fender well by the tire 3" off the ground.
 

bommy261

Golden Member
Dec 17, 2005
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This is high up at the hood of the car, this isn't like the kind where the filter is in the fender well by the tire 3" off the ground.

granted he doesn't have to worry about mud puddles, but heavy rain could drown out his air filter and that could cost big $$$ if water got into his engine.
 

EightySix Four

Diamond Member
Jul 17, 2004
5,122
52
91
Ram air works? Yeah, on a SR-71, sure.

One last piece to nitpick, the air inlet on SR-71's purposely slowed the air down, not rammed it in. RAMJET engines airflow has to be subsonic or the engine will flame out due to the shock waves. You're thinking of experimental SCRAMJET engines.

I like the work Rambler, keep updating us.
 
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Apex

Diamond Member
Oct 11, 1999
6,511
1
71
www.gotapex.com
http://g35driver.com/forums/tuner-dyno/203301-stillen-intake-dyno-test.html
7rwhp 10rwlb.ft

http://www.vetteweb.com/tech/vemp_0612_c6_corvette_intake/dyno_test_results.html
2rwhp 12rwlb.ft

http://forums.corral.net/forums/s-1...11-gt-jlt-cai-dyno-results-vs-k-n-filter.html
15.82rwhp 8.8rwlb.ft

Oh look, it works on motorcycles too, and S2k's, mmmm... Audi. The Audi received 12awhp and 10awlb.ft, and even the tiny little S2k motor put up an extra 11.6rwhp.

You will make more power from a new intake, period. While they do not produce huge gains, they're invaluable when combined with the other major bolt-ons and a proper tune to create a complete package which outflows the stock parts. Just because JDM motors built for gas mileage in little toasters don't receive huge gains from an intake, doesn't mean other cars don't, so you go play with your little toys and let the big boys talk mkay?

And FYI, before you go running your mouth again, I actually tune cars... Where I actually, you know, see the MAF numbers right in front of my face. Have you ever even seen a dyno run?

Here's another one:

CIMG4534A.jpg


Vehicle: 2007 BMW M6, Normally Aspirated 5.0L V10
Dyno: DynoDynamics 2WD
Fan: Patterson High Velocity 30" 12,000CFM 1hp fan.

Fan placement (distance and angle) was fixed. Ram air intake was installed on the vehicle on the dyno, so the strapdown pressure was not changed (how tightly a vehicle is strapped down can change the dyno reading). Hood was down during dyno tests. 1 Dyno operator used for runs. Same gear used for runs. Same rate of throttle application used for runs. Other supporting mods (filter change, charcoal filter removal, blockoff plates) NOT installed for this test.

About as apples to apples as it comes.

The dyno is one of the most conservative ones on the market. M5 and M6 on that dyno show roughly 370-380hp to the wheels stock, from the 500hp to the crank manufacturer rating. Most Mustang Dynos show an average of 405-415hp, and most DynoJets from 420-430.

Gain showed 22hp to the wheels, but more importantly, substantial gains through the entire powerband.
 

dug777

Lifer
Oct 13, 2004
24,778
4
0
Here's another one:

CIMG4534A.jpg


Vehicle: 2007 BMW M6, Normally Aspirated 5.0L V10
Dyno: DynoDynamics 2WD
Fan: Patterson High Velocity 30" 12,000CFM 1hp fan.

Fan placement (distance and angle) was fixed. Ram air intake was installed on the vehicle on the dyno, so the strapdown pressure was not changed (how tightly a vehicle is strapped down can change the dyno reading). Hood was down during dyno tests. 1 Dyno operator used for runs. Same gear used for runs. Same rate of throttle application used for runs. Other supporting mods (filter change, charcoal filter removal, blockoff plates) NOT installed for this test.

About as apples to apples as it comes.

The dyno is one of the most conservative ones on the market. M5 and M6 on that dyno show roughly 370-380hp to the wheels stock, from the 500hp to the crank manufacturer rating. Most Mustang Dynos show an average of 405-415hp, and most DynoJets from 420-430.

Gain showed 22hp to the wheels, but more importantly, substantial gains through the entire powerband.

What speed does that pressure equate to? I would suggest it's impossible to see the same gains throughout the powerband because...wait for it...yup, you can't possibly move at the same speed in every gear all the time ;)

Now if that pressure equates to some daft speed like 100mph, then it's nice and all, but real world application it ain't ;) Of course, if it's 20mph then that's rather more useful :)
 

Apex

Diamond Member
Oct 11, 1999
6,511
1
71
www.gotapex.com
What speed does that pressure equate to? I would suggest it's impossible to see the same gains throughout the powerband because...wait for it...yup, you can't possibly move at the same speed in every gear all the time ;)

Now if that pressure equates to some daft speed like 100mph, then it's nice and all, but real world application it ain't ;) Of course, if it's 20mph then that's rather more useful :)

12k CFM from this 30" fan at an 8' distance equates to roughly 60-70mph of airspeed, though the overall volume of air being pushed (because the frontal area of the vehicle is much larger) is arguably closer to the 40-50mph range. In other words, this 22 hp at the wheels gain from just the ram air intake change without even the change of air filters is happening just out of 1st gear. Once you're out of 2nd gear, the real world gains are higher than shown in this dyno.
 

dug777

Lifer
Oct 13, 2004
24,778
4
0
12k CFM from this 30" fan at an 8' distance equates to roughly 60-70mph of airspeed, though the overall volume of air being pushed (because the frontal area of the vehicle is much larger) is arguably closer to the 40-50mph range. In other words, this 22 hp at the wheels gain from just the ram air intake change without even the change of air filters is happening just out of 1st gear. Once you're out of 2nd gear, the real world gains are higher than shown in this dyno.

Forgive me but you will have to explain that more simply ;)

How does the bolded part work? Surely airspeed is airspeed is airspeed? I get that the fan is only targeting the air intake, but just because the whole car is pushing through the air in real life doesn't increase the air pressure over the intake, does it?

In addition, from the graph it looks like you might get 22hp (as a maximum) at the upper end of that a pretty insane rev range. Most of the time it looks more like 10hp or less from a casual glance.

What's the source for that graph, out of idle curiousity? Be interesting to understand the backstory (and forgive my scepticism, but I am interested to see if this is a marketing effort for a CAI ;)). A conflict of interest is a conflict of interest, after all ;)
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
Forgive me but you will have to explain that more simply ;)

How does the bolded part work? Surely airspeed is airspeed is airspeed? I get that the fan is only targeting the air intake, but just because the whole car is pushing through the air in real life doesn't increase the air pressure over the intake, does it?

In addition, from the graph it looks like you might get 22hp (as a maximum) at the upper end of that a pretty insane rev range. Most of the time it looks more like 10hp or less from a casual glance.

What's the source for that graph, out of idle curiousity? Be interesting to understand the backstory (and forgive my scepticism, but I am interested to see if this is a marketing effort for a CAI ;)). A conflict of interest is a conflict of interest, after all ;)

Science aside as this is clearly where the argument breaks down with many using concepts they do not understand.

While CAI's do not work in all applications it has been PROVEN to result in a significant improvment in esp quarter mile and top speed type runs.

I don't think anyone is trying to target the 0-45mph commute speed with any performance mods :)
 

dug777

Lifer
Oct 13, 2004
24,778
4
0
Science aside as this is clearly where the argument breaks down with many using concepts they do not understand.

While CAI's do not work in all applications it has been PROVEN to result in a significant improvment in esp quarter mile and top speed type runs.

I don't think anyone is trying to target the 0-45mph commute speed with any performance mods :)

Hang on, are you insulting me? :thumbsdown:

Give me the courtesy of trying to answer my questions first please :) If I still don't get it, then go right ahead! :)

I haven't been anything other than perfectly courteous to you, and I don't think any of those questions are so dumb. It can't be that hard to hook me up with a link to the post or article that graph came from either :)

Do you randomly accept things people tell you without attempting to understand it? ;)
 

EightySix Four

Diamond Member
Jul 17, 2004
5,122
52
91
Forgive me but you will have to explain that more simply ;)

How does the bolded part work? Surely airspeed is airspeed is airspeed? I get that the fan is only targeting the air intake, but just because the whole car is pushing through the air in real life doesn't increase the air pressure over the intake, does it?

In addition, from the graph it looks like you might get 22hp (as a maximum) at the upper end of that a pretty insane rev range. Most of the time it looks more like 10hp or less from a casual glance.

What's the source for that graph, out of idle curiousity? Be interesting to understand the backstory (and forgive my scepticism, but I am interested to see if this is a marketing effort for a CAI ;)). A conflict of interest is a conflict of interest, after all ;)

If I blow through a straw the speed of the air may be high, but the volume of air going through the straw is low.

What he was saying was that the fan's air output was smaller than the amount of air the intake would normally have being forced into it when driving. So while the airspeed was 60-70mph the VOLUME of air that the car was taking in was closer to the amount of air that would be taken in at 40-50mph
 

Apex

Diamond Member
Oct 11, 1999
6,511
1
71
www.gotapex.com
If I blow through a straw the speed of the air may be high, but the volume of air going through the straw is low.

What he was saying was that the fan's air output was smaller than the amount of air the intake would normally have being forced into it when driving. So while the airspeed was 60-70mph the VOLUME of air that the car was taking in was closer to the amount of air that would be taken in at 40-50mph

This is correct. Basically, the issue is it's tested with a fan. It's a good one, but it's still simply a fan. A wind tunnel would give you a better approximation.

While the airspeed is the airspeed, airspeed alone does not determine the power gain by relieving the pressure zone ahead of the air filter. Sufficient volume also plays a part. In this case, we're talking a 30" round fan, and dual intakes on the left and right side of the nose of the vehicle.

22hp is partially a matter of RPM, but horsepower is really that, just a matter of RPM. If you look at the torque gain, it's a substantial amount throughout.

The source of the graph is from my in-law's shop, during one of the "open house" dyno sessions. Customers are allowed to watch the procedure from beginning to end, from roll up and strap down, to the runs, installs, more runs, and the roll off, including the computer operation.
 

dug777

Lifer
Oct 13, 2004
24,778
4
0
If I blow through a straw the speed of the air may be high, but the volume of air going through the straw is low.

What he was saying was that the fan's air output was smaller than the amount of air the intake would normally have being forced into it when driving. So while the airspeed was 60-70mph the VOLUME of air that the car was taking in was closer to the amount of air that would be taken in at 40-50mph

aha, makes sense now. I had assumed only one intake in which case if the fan was much similar in size or larger than the intake that made little sense. Assumption is a dangerous thing!

I still don't see anything other than a guesstimate for an equivalent real world speed but with dual intakes I guess that is not an unreasonable guesstimate :)

Having access to a dyno could be a lot of fun!

Edit: understanding the physics is fine - the context of the comments was not clear to me ;) hence my question :)
 
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AMCRambler

Diamond Member
Jan 23, 2001
7,715
31
91
Man you guys are getting nerdy on this, lol.

Well I put the first layer of fiberglass down Saturday and it went pretty well except for a couple of air bubbles. I sanded it yesterday and I think I should have given it a little longer to cure. Seemed a bit sticky still. Today I tackled putting on the second layer with the thick cloth and it didn't go as good as the first layer. Problem with the thicker stuff is it's heavier and with the resin still liquid it tends to peel off the form when you flip it over to do the back side. Looks like I'll have to take two passes at the second layer. I did the top, the front and the sides today. Once that hardens(it's going to need a couple days) I'll be able to sand it and trim the excess resin and cloth, then I'll be able to do the bottom.

Anyway as promised pics:
bluelayer1.jpg

bluelayer2.jpg

bluelayer3.jpg
 

SSSnail

Lifer
Nov 29, 2006
17,458
83
86
I like how the snail hasn't returned.
LOL, while you guys are sitting here on your thumbs fretting about shits that don't matter, I spent the weekend in Monterey.

Anyways, back to my original arguments of ram air on cars. Somewhere in there, I forgot that someone here will pick on technicality about manufacturers' inefficient designs. You mean if you remove the restricted "let's put this crap where it fits Bob" school of design, and put in something that's freer flowing, you're not getting better result? Wow!!! Someone call somebody. That's not what my argument was. I simply said if any design is efficient, you won't see any "improvement" simply by introducing "ram air".

Ram air would work, if your whole front end is a funnel, and you're going fast enough to overcome atmospheric pressure. And, if you're producing any gain then, your drag will just negate that gain. That's all. Please ignore my other arguments.

Everyone knows that there could be very minute gains by changing out factory equipments with sacrifice (but not always, sometimes the effect is opposite - depends on the efficiency of design).

Anyways, feel free to experiment. It's your equipments.
 

EightySix Four

Diamond Member
Jul 17, 2004
5,122
52
91
LOL, while you guys are sitting here on your thumbs fretting about shits that don't matter, I spent the weekend in Monterey.

Anyways, back to my original arguments of ram air on cars. Somewhere in there, I forgot that someone here will pick on technicality about manufacturers' inefficient designs. You mean if you remove the restricted "let's put this crap where it fits Bob" school of design, and put in something that's freer flowing, you're not getting better result? Wow!!! Someone call somebody. That's not what my argument was. I simply said if any design is efficient, you won't see any "improvement" simply by introducing "ram air".

Ram air would work, if your whole front end is a funnel, and you're going fast enough to overcome atmospheric pressure. And, if you're producing any gain then, your drag will just negate that gain. That's all. Please ignore my other arguments.

Everyone knows that there could be very minute gains by changing out factory equipments with sacrifice (but not always, sometimes the effect is opposite - depends on the efficiency of design).

Anyways, feel free to experiment. It's your equipments.

Go look at the motorcycle link I provided, it proved you are wrong. Ram air effects do produce a benefit. This forum was a better place when you were in Monterey btw.
 

SSSnail

Lifer
Nov 29, 2006
17,458
83
86
Go look at the motorcycle link I provided, it proved you are wrong. Ram air effects do produce a benefit. This forum was a better place when you were in Monterey btw.
Well, I'm back. Get used to it. I wonder how they measured the ram air effect when they were standing still. Anyways, go back and read my post carefully, taking everything into consideration, including the physical aspects of it. In other words - resistance, is futile.
 
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EightySix Four

Diamond Member
Jul 17, 2004
5,122
52
91
Well, I'm back. Get used to it. I wonder how they measured the ram air effect when they were standing still. Anyways, go back and read my post carefully, taking everything into consideration, including the physical aspects of it. In other words - resistance, is futile.

They measured the air pressure inside the intake while it was in motion in part one, then matched that pressure on the dyno.
 

EightySix Four

Diamond Member
Jul 17, 2004
5,122
52
91
That I got, but did they take in account the resistance/drag at speed?

The added drag would be negligible. It depends on how much extra power it makes. In most of these situations the added drag is so negligible (how much force do you think the intake could impart on the car without the tubing bending/breaking?) that the power gains surpass the losses.