Please educate me on CAI, RAI, & SRI
January-27th-2005, 10:13 PM
#1
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Join Date: Nov 2003
Location: Columbia, SC
Posts: 239
Please educate me on CAI, RAI, & SRI
Well the old P5 just passed 50 K miles and guess what! I'm hoping to do what I've been reading about here all this time. Please explain to me the differences between CAI, RAI, and SRI. I would like to learn the basic differences in
1. Architecture (a pic of each would help with this).
2. Pros and cons of each...
For instance, many of you have written that you lose low end power but gain high end performance. Does that mean the power peaks at a higher area on the tach? I like where the power curve is now, so I can shoot around town at 3k to 4500 RPMS using 2nd and 3rd gear and be ready to jump through traffic when I romp on it. I'm not interested in lowering ETs, (I do that in a 600 hp Camaro on the weekends), I just want to comfortably blast through traffic.
3. Can I just remove the air box and mount a cone filter in front of the MAF, and if so, what about that sensor inside the air box (what is it anyway?)? Would that be a waste of time?
Maybe there's a link to all this info I'm asking for.
Thanks for the help, I only get one shot at getting it right as I'm poor, moneywise anyway.
PS: This colder weather really woke it up. Feels like 15 more hp when the air is 30F. Reminds me of how we used to pack a cooling can with dry ice to chill the gas on my old '67 Camaro SS that I raced back in the 80s. 350 4-bolt with a Muncie 4 speed rockcrusher.
1. Architecture (a pic of each would help with this).
2. Pros and cons of each...
For instance, many of you have written that you lose low end power but gain high end performance. Does that mean the power peaks at a higher area on the tach? I like where the power curve is now, so I can shoot around town at 3k to 4500 RPMS using 2nd and 3rd gear and be ready to jump through traffic when I romp on it. I'm not interested in lowering ETs, (I do that in a 600 hp Camaro on the weekends), I just want to comfortably blast through traffic.
3. Can I just remove the air box and mount a cone filter in front of the MAF, and if so, what about that sensor inside the air box (what is it anyway?)? Would that be a waste of time?
Maybe there's a link to all this info I'm asking for.
Thanks for the help, I only get one shot at getting it right as I'm poor, moneywise anyway.
PS: This colder weather really woke it up. Feels like 15 more hp when the air is 30F. Reminds me of how we used to pack a cooling can with dry ice to chill the gas on my old '67 Camaro SS that I raced back in the 80s. 350 4-bolt with a Muncie 4 speed rockcrusher.
Last edited by Rusty; January-27th-2005 at 10:16 PM. Reason: misspells
January-28th-2005, 07:29 AM
#2
Registered User
Join Date: Jul 2002
Location: Maryland
Posts: 999
Well, what i did was mount the cone filter to a duct (from a Neon intake box i found in the trash!) to the MAF.
It picked up a little pep (it was worth it) and was way cheap (only the cost of the K&N filter!)
Word of caution, when i moved the MAF, i stretched the maf sensor wires and eventually broke them. Once i spliced in some wire to remove the stress - all good to go!
It picked up a little pep (it was worth it) and was way cheap (only the cost of the K&N filter!)
Word of caution, when i moved the MAF, i stretched the maf sensor wires and eventually broke them. Once i spliced in some wire to remove the stress - all good to go!
January-28th-2005, 07:45 AM
#3
Registered User
Join Date: Aug 2002
Location: New Jersey
Posts: 349
I'll try to answer some of your questions.
CAI = cold air intake: The filter is located outside the engine compartment, typically in the wheel well and consequently ingests ambient temperature air. Actually a misnomer, it should really be called an AAI since in the summer your're not drawing in 'cold air'.
SRI = short ram intake: The filter is located inside the engine compartment and consequently ingests underhood temperature air.
Since HP varies as the square root of the change in ABSOLUTE temperature and since ambient temperature air is always cooler than underhood temperature air, a CAI might be better than an SRI in terms of increasing power output. This is why your car feels peppier in cold weather. For more info, go to:
www.clubprotege.com/forum/showthread.php?t=995
It's generally better not to mount an air filter directly to the MAF as this sometimes causes turbulent flow into the MAF affecting the accuracy of its reading. A length of pipe between filter and MAF will help smooth the air flow.
The sensor inside the air box is the intake air temperature sensor (IAT) and is an essential part of the intake air system. Along with the MAF, it sends data to the PCM that is used to determine injector pulse duration. The IAT has to be incorporated into any aftermarket intake system you install.
Many people who remove the stock air intake system in favor of a CAI or an SRI report a loss in low speed torque, although with some gain in power at higher RPM's. This is due to the fact that the OEM air intake system contains a Helmholtz resonator (the piece that hangs down below the inlet to the air box) that functions to increase and maintain low speed torque.
Check out: http://www.grapeaperacing.com/GrapeA...ionsystems.pdf
You can find pics of the SRI at the AEM website and of the CAI at the Injen website.
In other words, you pay your money and you take your choice.
CAI = cold air intake: The filter is located outside the engine compartment, typically in the wheel well and consequently ingests ambient temperature air. Actually a misnomer, it should really be called an AAI since in the summer your're not drawing in 'cold air'.
SRI = short ram intake: The filter is located inside the engine compartment and consequently ingests underhood temperature air.
Since HP varies as the square root of the change in ABSOLUTE temperature and since ambient temperature air is always cooler than underhood temperature air, a CAI might be better than an SRI in terms of increasing power output. This is why your car feels peppier in cold weather. For more info, go to:
www.clubprotege.com/forum/showthread.php?t=995
It's generally better not to mount an air filter directly to the MAF as this sometimes causes turbulent flow into the MAF affecting the accuracy of its reading. A length of pipe between filter and MAF will help smooth the air flow.
The sensor inside the air box is the intake air temperature sensor (IAT) and is an essential part of the intake air system. Along with the MAF, it sends data to the PCM that is used to determine injector pulse duration. The IAT has to be incorporated into any aftermarket intake system you install.
Many people who remove the stock air intake system in favor of a CAI or an SRI report a loss in low speed torque, although with some gain in power at higher RPM's. This is due to the fact that the OEM air intake system contains a Helmholtz resonator (the piece that hangs down below the inlet to the air box) that functions to increase and maintain low speed torque.
Check out: http://www.grapeaperacing.com/GrapeA...ionsystems.pdf
You can find pics of the SRI at the AEM website and of the CAI at the Injen website.
In other words, you pay your money and you take your choice.
January-28th-2005, 09:31 AM
#4
031 - Deathtech
Join Date: Aug 2002
Location: Petawawa, ON. Canada
Posts: 401
From experience there is really not much difference in gains between a SRI and a CAI. And between those there is no differnce between Injen, AEM, Ractice or e-Bay. I've had all of them. The only noticable difference aside from price is that a SRI is a little louder than the CAI.
Most of your 2-4 hp gain will be around 3500rpm and the CAI may have a little more low end torque.
As for filters, you will only see a fraction of a hp gain between the brands. Personally I'd go with one that filters the crap out of the air the best. Foam filters are notoriously bad when it comes to filtering out crap.
Most of your 2-4 hp gain will be around 3500rpm and the CAI may have a little more low end torque.
As for filters, you will only see a fraction of a hp gain between the brands. Personally I'd go with one that filters the crap out of the air the best. Foam filters are notoriously bad when it comes to filtering out crap.
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