Stock airbox pipe size?
#1
Tech Contributor
Thread Starter
Stock airbox pipe size?
Quck question, what is the stock intake air filter box outlet pipe size. Is it 4 inches or 4.5 inches Inside Diameter? Can someone go measure please.
#2
Race Director
Member Since: Mar 2001
Location: Bonneville Salt Flats, 223mph Aug. '04
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Only since no one hasyet deemed to reply at all, I just looked at mine. However, I'm not going to pull it apart to measure I.D. but if it helps, I measured right next to the air-box after the tapered-down section where it seems to be actual "tube." Measuring across the outside at the top was 4.5" and measuring at the back, top-to-bottom was 4.25". So, if the choices are 4" or 4.5" I.D., I'd say it must be 4" since 4.5" doesn't seem physically possible. Btw, base '18. All the best.
#3
Le Mans Master
If nobody else measures I'll go up into my attic and pull my stock airbox out.
#4
Tech Contributor
Thread Starter
that would be really nice of you. I threw my old one away, like an idiot, and now am trying to go back to stock airbox intake style it but will need to make up custom intake tubing for my supercharger. It sounds like it tapers from 4.5" to 4" (basically if you cut a couple of inches off it will now be a 4.5" tube)
#5
Le Mans Master
4.5" od
#6
Instructor
that would be really nice of you. I threw my old one away, like an idiot, and now am trying to go back to stock airbox intake style it but will need to make up custom intake tubing for my supercharger. It sounds like it tapers from 4.5" to 4" (basically if you cut a couple of inches off it will now be a 4.5" tube)
#7
Tech Contributor
Thread Starter
I did some testing with a bunch of thermocouples and in short, we are pulling in air at least 10 degrees above ambient. Temperature inside the fender is ambient the entire time during testing. Plus, no restrictions really.
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Max Bet (08-20-2018)
#9
Le Mans Master
#10
Tech Contributor
Thread Starter
by the way, I called Procharger and they want 700 for the piping and filter to go back to stock air box style. No thanks. I have emailed A&A and will email ECS to see if they are willing to sell me those parts. Otherwise I'll be going to Jegs / Summit and just getting a 30° or 45° 4" ID pipe and a 30° 4.5" > 4.0" coupler. Maybe I'll find a stock airbox in a junkyard. People want way too much for those. I have to verify the angles and lengths of piping but I'll either make a new thread or keep this one updated. Trying to get it done relalitely soon before my next track day.
When I get some time I'll post full results of my intake temp testing. In short (#2), the fender hole provides 100% ambient air up to at least 220 coolant temp(didn't test any higher) and doesn't get heat from the engine bay unlike some have theorized. Maybe when you start pulling supercharged air from only there , it may.
If you take off the radiator to hood shroud, the into-filter temps will drop 5-10 degrees as the intake actually starts pulling cold air into the engine bay from the hood vents. This may decrease efficiency of the radiator as now your pulling air into the area behind the radiator, possibly blocking flow through the radiator. I'll test this at the track.
Last edited by BrunoTheMellow; 08-20-2018 at 11:25 AM.
#11
Le Mans Master
Just a thought, but if you're going through the trouble of custom making a new intake pipe, why not try do it with the much larger AFE or Chevy Performance airbox & filter? With an AFE intake along with your current Procharger race inlet pipe, I bet you could custom fab something together easy enough with a little cutting and a coupler.
Last edited by Kracka; 08-20-2018 at 11:49 AM.
#12
Tech Contributor
Thread Starter
Just a thought, but if you're going through the trouble of custom making a new intake pipe, why not try do it with the much larger AFE or Chevy Performance airbox & filter? With an AFE intake along with your current Procharger race inlet pipe, I bet you could custom fab something together easy enough with a little cutting and a coupler.
Last edited by BrunoTheMellow; 08-20-2018 at 03:05 PM.
#13
Tech Contributor
Thread Starter
Just a thought, but if you're going through the trouble of custom making a new intake pipe, why not try do it with the much larger AFE or Chevy Performance airbox & filter? With an AFE intake along with your current Procharger race inlet pipe, I bet you could custom fab something together easy enough with a little cutting and a coupler.
I could buy the Vararam airbox if I want in the future Since it's about identical outlet to stock but I've proven that air inside the fender is ambient when I ran the open filter. just have to test it again now with the stock intake to make sure it's not pulling air from engine bay now with the extra vacuum.
#14
Tech Contributor
Thread Starter
I haven't looked at the data yet but so far car feels the same. Which is good. I'll be at the track next weekend so I'll have lots of IAT/ECT data to compare. Before this, IAT1 rose and dropped linearly with ECT. Which makes sense if you're pulling engine bay air from a hotter engine bay.
Btw 123Sugey. I cut the stock airbox outlet down to just 1" in length. Follwoing A&A supercharger install instructions. Below is how much I cut off from the long side of the Procharger pipe. Also used a 3.5" to 4.5" coupler from Amazon and cut 2" off the 4.5 " side. You have plenty of wiggle room so it's not hard.
Btw 123Sugey. I cut the stock airbox outlet down to just 1" in length. Follwoing A&A supercharger install instructions. Below is how much I cut off from the long side of the Procharger pipe. Also used a 3.5" to 4.5" coupler from Amazon and cut 2" off the 4.5 " side. You have plenty of wiggle room so it's not hard.
Last edited by BrunoTheMellow; 09-01-2018 at 08:06 PM.
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123sugey (03-11-2020)
#16
Tech Contributor
Thread Starter
Yep. My hypothesis has been proven! See below for quick rough pictures of coolant vs intake air temp. Red/green graph is with open to engine bay filter. Blue graph is stock air filter location.
On the first graph notice how iat rised linearly with ect as it sucks hotter and hotter engine bay air. On the second graph, 1/4 to about 1/2 of the x axis is what you're looking at. Once I get going and ECT starts to rise, IAT levels off.
Stock airbox:
102 ambient,
102 iat min
135 iat max
open filter:
90 ambient
110 iat min
145 iat max
On the first graph notice how iat rised linearly with ect as it sucks hotter and hotter engine bay air. On the second graph, 1/4 to about 1/2 of the x axis is what you're looking at. Once I get going and ECT starts to rise, IAT levels off.
Stock airbox:
102 ambient,
102 iat min
135 iat max
open filter:
90 ambient
110 iat min
145 iat max
Last edited by BrunoTheMellow; 09-19-2018 at 10:23 AM.
#17
Dig
Member Since: Jan 2006
Location: Port Saint Lucie FLORIDA & HONDURAS
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I haven't looked at the data yet but so far car feels the same. Which is good. I'll be at the track next weekend so I'll have lots of IAT/ECT data to compare. Before this, IAT1 rose and dropped linearly with ECT. Which makes sense if you're pulling engine bay air from a hotter engine bay.
Btw 123Sugey. I cut the stock airbox outlet down to just 1" in length. Follwoing A&A supercharger install instructions. Below is how much I cut off from the long side of the Procharger pipe. Also used a 3.5" to 4.5" coupler from Amazon and cut 2" off the 4.5 " side. You have plenty of wiggle room so it's not hard.
Btw 123Sugey. I cut the stock airbox outlet down to just 1" in length. Follwoing A&A supercharger install instructions. Below is how much I cut off from the long side of the Procharger pipe. Also used a 3.5" to 4.5" coupler from Amazon and cut 2" off the 4.5 " side. You have plenty of wiggle room so it's not hard.
Bruno any chance you have the part # for the coupler from. Amazon ?
That would complete this thread 😃 and help me after I’ve put this mod on the back burner for over a year 😉
#18
Tech Contributor
Thread Starter
old thread but worthy of posting back up. The Procharger race inlet/filter sux. I bought a Vararam last year to do exactly what Bruno has done in this thread. He’s moved on to another car but this mod has to be one of the cheapest and well rewarding mods on a supercharged C7.
Bruno any chance you have the part # for the coupler from. Amazon ?
That would complete this thread 😃 and help me after I’ve put this mod on the back burner for over a year 😉
Bruno any chance you have the part # for the coupler from. Amazon ?
That would complete this thread 😃 and help me after I’ve put this mod on the back burner for over a year 😉
Click the link ^
Last edited by BrunoTheMellow; 03-17-2020 at 01:32 PM.
#20
Dig
Member Since: Jan 2006
Location: Port Saint Lucie FLORIDA & HONDURAS
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Well the Vararam I tried modifying today. A no go. Between the Vararam itself and the Procharger tube it will not work. The intake box is just a little to long and the angles couldn’t be made with what I have. Oh well I’ll just do what Bruno has already done and worked