Which is better - CAI or SS Hood Airbox??
03-02-2004, 10:46 AM
#32
Registered User
Join Date: Mar 2002
Location: O'fallon, mo
Posts: 236
im still using my stock SS airbox. 1. because i can take it off and put it on in less than 2 minutes 2. it looks better than any CIA i have seen. it must not be too restrictive if i am able to trap right at 110 in the middle of jusly with boltons only
03-02-2004, 11:38 AM
#34
Registered User
Join Date: Mar 2003
Location: Fairfield, ca
Posts: 1,623
Like was said before i beleive that the CAI and SS airbox are pretty equal with the CAI being a little better. I have seen a dyno that shows this but i can't seem to find it. So if you already have a CAI on your car its not worth it to change to a functional ram air. Just leave it alone. The same goes if you have already have a functional ram air hood. Just leave it alone because the difference in hp is not worth the money imo.
03-02-2004, 02:40 PM
#35
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Join Date: Sep 1999
Location: Grand Rapids, Michigan
Posts: 1,550
Ok to get back to the point of the original post. If your looking for which of the two makes more hp, it's about an equal battle. So that parts settled. If your looking for the cheaper of the two, the CAI wins hands down. Less than $200 bucks new compared to over $300 is just rediculous. I know it's all about preferences and this is just my opinion. But for something like this that changes nothing on the car that you'd see OR hear it's a waste of money. But then again I never understood why people spend $700-$900 bucks on a catback when they can get one that makes the same hp for under $300. That's something that even sounds and looks different too.
I'm probably gonna get flamed for that comment.
I'm probably gonna get flamed for that comment.
03-02-2004, 02:51 PM
#36
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Join Date: Jan 2003
Location: Greenville, SC
Posts: 1,217
A dyno will not be able to prove which is better because it is in a building where the air at the CAI is at the same temp as the air at the RA. It is indisputable in my opinion and many others, that the ram air is a "colder" induction in the real world, not on a dyno. It also does not "RAM" air, it is merely a colder induction than a CAI.
CAI, like Moroso, K&N, etc experiences more heat soak from the engine bay than RA, because it has more piping, thus increasing its surface area therefore increasing the heat transfer from convection it experiences. The RA will experience less heat transfer from convection, so it is already providing colder air. Next, the CAI takes air from only a few inches off the ground, which will be hotter, due to heat transfer from the asphalt. I am sure you have seen heat waves somewhere on TV. The RA setup takes air from 2 feet or so off the ground, in which the nose of the car is a barrier to the ashpalt, again dcreasing intake temps over CAI. The one downfall to the RA is heat transfer by conduction from the hood. However, a fiberglass hood will reduce this heat transfer, because fiberglass has a MUCH lower thermal conductivity. Fiberglass is around 0.036 (W/m-K) at 300K and steel (not sure what the steel of our hoods is, so heres a range) is between 38.0 - 58.0 (W/m-K) at 400K. I didnt have any values at 300K, but thermal conductivity decrease with increasing temp. So, the heat transfer rate is DRASTICALLY larger with a steel hood.
Some rough calcs:
Rth=L/(k*Ac)
where, Rth=thermal resistance
k=thermal conductivity
Ac=cross sectional area, assumed 1m^2
L=length or thickness in this case
(assumed 0.5 cm)
Q=changeT/Rth
where, Q=heat transfer rate
Assuming a temperature difference of 75degC, just picked a number. Increasing this temp difference only acsentuates the results.
Steel hood= 750,000 J/s
Fiberglass hood= 540 J/s
This does not take into effect convection on either surface or radiation effects, so it is very rough, but you get the idea.
Click here to read more:
http://web.camaross.com/forums/showt...5&pagenumber=1
The Ram Air also looks much nicer in the engine bay and you dont have to deal with those darn elbows tearing.
CAI, like Moroso, K&N, etc experiences more heat soak from the engine bay than RA, because it has more piping, thus increasing its surface area therefore increasing the heat transfer from convection it experiences. The RA will experience less heat transfer from convection, so it is already providing colder air. Next, the CAI takes air from only a few inches off the ground, which will be hotter, due to heat transfer from the asphalt. I am sure you have seen heat waves somewhere on TV. The RA setup takes air from 2 feet or so off the ground, in which the nose of the car is a barrier to the ashpalt, again dcreasing intake temps over CAI. The one downfall to the RA is heat transfer by conduction from the hood. However, a fiberglass hood will reduce this heat transfer, because fiberglass has a MUCH lower thermal conductivity. Fiberglass is around 0.036 (W/m-K) at 300K and steel (not sure what the steel of our hoods is, so heres a range) is between 38.0 - 58.0 (W/m-K) at 400K. I didnt have any values at 300K, but thermal conductivity decrease with increasing temp. So, the heat transfer rate is DRASTICALLY larger with a steel hood.
Some rough calcs:
Rth=L/(k*Ac)
where, Rth=thermal resistance
k=thermal conductivity
Ac=cross sectional area, assumed 1m^2
L=length or thickness in this case
(assumed 0.5 cm)
Q=changeT/Rth
where, Q=heat transfer rate
Assuming a temperature difference of 75degC, just picked a number. Increasing this temp difference only acsentuates the results.
Steel hood= 750,000 J/s
Fiberglass hood= 540 J/s
This does not take into effect convection on either surface or radiation effects, so it is very rough, but you get the idea.
Click here to read more:
http://web.camaross.com/forums/showt...5&pagenumber=1
The Ram Air also looks much nicer in the engine bay and you dont have to deal with those darn elbows tearing.
Last edited by ZZtop; 03-02-2004 at 02:54 PM.
03-02-2004, 04:35 PM
#40
Registered User
Join Date: Jun 2003
Location: Myrtle Beach, SC
Posts: 288
I think it should just be a matter of personal opinion. It's not like the cai flows THAT much better than the ram air, if it does at all (not trying to start any fights, but I don't want to speculate since I personally haven't seen proof either way). In my opionion, the ram air hoods look bad#ss. Either way you should see a little gain over stock. If you like the looks of ram air, go for it. If you don't have the money to spend or are going to nitpick over a 1-2hp difference that you won't even be able to feel, well, then, get a cai.
I never really have thought ram air to be that much of a myth. No one said it was going to be like a major boost, but I know that when you hold your hand out the window, whether you're going 25 or 150, you can feel the pressurized air. Now the aerodynamics of the car and the location of the scoops may hinder this, but I think it should still work a little. I've seen people add a huge funnel on the carb of a 4-wheeler before and pick up about 4mph on the top end.
If ram-air was such a slouch we could all look at the sportbike world, where ram air is generally standard and not touted about, and some companies have even redesigned bikes to put the ram air ducting closer to the point of highest pressure on the nose.
I've even read books touting factory development of ram-air in the 60's, but they could be full of crap too.
Bottom line, choose what you want, you probably won't feel a difference between the two. ----J.Bird
I never really have thought ram air to be that much of a myth. No one said it was going to be like a major boost, but I know that when you hold your hand out the window, whether you're going 25 or 150, you can feel the pressurized air. Now the aerodynamics of the car and the location of the scoops may hinder this, but I think it should still work a little. I've seen people add a huge funnel on the carb of a 4-wheeler before and pick up about 4mph on the top end.
If ram-air was such a slouch we could all look at the sportbike world, where ram air is generally standard and not touted about, and some companies have even redesigned bikes to put the ram air ducting closer to the point of highest pressure on the nose.
I've even read books touting factory development of ram-air in the 60's, but they could be full of crap too.
Bottom line, choose what you want, you probably won't feel a difference between the two. ----J.Bird
03-02-2004, 08:24 PM
#42
Registered User
Join Date: Jul 2003
Location: Upstate New York
Posts: 700
SLP is clearing out their old SS stock to anyone who wants to buy it.
They sell the whole airbox now for about 200.00
My aftermarket airbox has ducting for the last bend.
I'm going to use it with the powerdyne blower I'm putting in soon.
It looks like it will work good flowing straight into the blower.
I had a K&N cai.
I like the better filter access with the SS Airbox and it stays cleaner than my cai did, which can make a difference.
They sell the whole airbox now for about 200.00
My aftermarket airbox has ducting for the last bend.
I'm going to use it with the powerdyne blower I'm putting in soon.
It looks like it will work good flowing straight into the blower.
I had a K&N cai.
I like the better filter access with the SS Airbox and it stays cleaner than my cai did, which can make a difference.
03-02-2004, 08:40 PM
#43
Registered User
Join Date: Mar 2000
Location: Fort Collins, CO
Posts: 503
Here is my solution to the whole ram air vs cai thing. I hated my elbow/slp cai so wanted to try something different. Don't konw how well its gonna work yet but should be nice. I built a little plastic heat shield between the radiator and the intake so hopefully that keeps it cool from heatsoak.
http://web.camaross.com/forums/showt...hreadid=229101
http://web.camaross.com/forums/showt...hreadid=229101
