2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Intake tube

Thread Tools
 
Search this Thread
 
Old 10-07-06, 11:18 AM
  #1  
Senior Member

Thread Starter
 
cls6888's Avatar
 
Join Date: Nov 2005
Location: Ohio
Posts: 316
Likes: 0
Received 0 Likes on 0 Posts
Intake tube

im lookin to make my intake tube bigger , I was just wondering whats the best thing to use and does anyone have any good pictures...
Old 10-07-06, 11:26 AM
  #2  
yes,thats me \/

iTrader: (1)
 
cdaleracer669's Avatar
 
Join Date: Mar 2006
Location: Eaton, CO
Posts: 861
Likes: 0
Received 0 Likes on 0 Posts
bigger? the stock one is quite big. search for CAI prelude intake. a 92-94 (i think thats the year) prelude intake can be made to fit qutie easily. do that, heat wrap it, make a box around the filter, and your set!
Old 10-07-06, 12:30 PM
  #3  
Senior Member

Thread Starter
 
cls6888's Avatar
 
Join Date: Nov 2005
Location: Ohio
Posts: 316
Likes: 0
Received 0 Likes on 0 Posts
I have a s4 TII, 720 secondarys,rtek 1.7,ported wg,3" turbo back exhaust,sbc-id boost controller,safc, few other mods . From whhat ive read theres a big diffrence in a bigger itnake tube . . . How do I go about making one etc. and was wodnering if anyone had any pictures.
Old 10-08-06, 10:30 AM
  #4  
Engine, Not Motor

iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes on 91 Posts
Go to the plumbing store and buy an assortment of ABS pipe. Get 3" to fit the filter, a few 45 degree bends and then a 3" to 2.5" coupler to connect to the turbo and a 3" coupler to mount to the AFM. Mock it all up in the car before gluing, making sure to keep the AFM level.
Old 10-08-06, 10:57 AM
  #5  
Lives on the Forum

iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,596
Received 9 Likes on 5 Posts
Originally Posted by cls6888
From whhat ive read theres a big diffrence in a bigger itnake tube.
The tube is already bigger than the AFM, but if you want to make a bigger one go for it. Also, post the results afterwards.
Old 10-08-06, 11:18 AM
  #6  
This is my social media.

iTrader: (22)
 
dwb87's Avatar
 
Join Date: Jan 2006
Location: WA
Posts: 2,744
Likes: 0
Received 0 Likes on 0 Posts
Auto Zone sells a $10.00-$12.00 mock-up kit.
Old 10-08-06, 01:31 PM
  #7  
Strength and Honor

 
stevej88na's Avatar
 
Join Date: Apr 2006
Location: CA bay area
Posts: 391
Likes: 0
Received 0 Likes on 0 Posts
ABS starts to bend around 200F and melts at 220F, so ABS is probably best for mockup only.

PS: aren't those popup movie ads annoying?
Old 10-08-06, 01:43 PM
  #8  
Lives on the Forum

iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,596
Received 9 Likes on 5 Posts
Originally Posted by stevej88na
PS: aren't those popup movie ads annoying?
You got spyware, buddy. Download adaware (www.lavasoft.de) or spybot: search and destroy and run them on your comp. Both have a free version, but you might have to look a bit to find it.
Old 10-08-06, 02:08 PM
  #9  
Strength and Honor

 
stevej88na's Avatar
 
Join Date: Apr 2006
Location: CA bay area
Posts: 391
Likes: 0
Received 0 Likes on 0 Posts
Try mousing over the word "car" in Aaron's post above! Thanks for the link though, I'm pretty sure I'm clean.
Old 10-08-06, 02:33 PM
  #10  
Clean.

iTrader: (1)
 
ericgrau's Avatar
 
Join Date: Mar 2005
Location: Huntington Beach, CA
Posts: 2,521
Received 2 Likes on 2 Posts
I can tell you from my fluid dynamics classes (fluid = gas or liquid, not just liquid) and from my job involving both water and air piping that a bigger pipe will not make any significant difference. If the intake pipe were 50' long it would help, but it isn't. Worry about the AFM, etc. Each of those counts as several yards of pipe.

There is exactly X HP of losses in the stock intake. Your "gains" cannot exceed X no matter how unrestrictive you make the intake. Only higher airflow will increase X. There is only A/B/C/etc. HP of losses in each part of the intake (A + B + C + etc. = X; I am simplifying things a bit, since there is some interaction between A & B, B&C, etc., but this is approximately true). Your "gain" for each segment cannot exceed A/B/C/etc. So you can't "gain" any real HP from upsizing the pipe because there is hardly anything lost in the pipe. Your HP "gains" come from recovering what's lost in the stock intake. You can't create more HP out of nothing with an intake.

Last edited by ericgrau; 10-08-06 at 02:46 PM.
Old 10-08-06, 03:00 PM
  #11  
Strength and Honor

 
stevej88na's Avatar
 
Join Date: Apr 2006
Location: CA bay area
Posts: 391
Likes: 0
Received 0 Likes on 0 Posts
...and increasing the cross section decreases velocity. I'm not sure how turbos would respond, but in N/As, many shorten the intake length to increase throttle response - there's less air mass to speed up and slow down.

I took a fluid dynamics course way back when, but I dropped it after the first midterm - that was my first and last ME course! In my defense it was upper division.
Old 10-08-06, 04:28 PM
  #12  
Lives on the Forum

iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,596
Received 9 Likes on 5 Posts
Originally Posted by stevej88na
Try mousing over the word "car" in Aaron's post above! Thanks for the link though, I'm pretty sure I'm clean.
Oh, the forum advertising, gotcha. I thought you meant true popups.
Old 10-09-06, 10:23 AM
  #13  
Engine, Not Motor

iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes on 91 Posts
ABS is fine. Many people make TIDs out of ABS (including me) and have never had an issue.
Old 10-09-06, 11:54 AM
  #14  
Alcohol Fueled!

iTrader: (2)
 
J-Rat's Avatar
 
Join Date: Jan 2002
Location: Hood River oregon
Posts: 11,093
Likes: 0
Received 2 Likes on 2 Posts
I also did it for a while, and it worked fine..
Old 10-09-06, 12:34 PM
  #15  
Strength and Honor

 
stevej88na's Avatar
 
Join Date: Apr 2006
Location: CA bay area
Posts: 391
Likes: 0
Received 0 Likes on 0 Posts
Well, I can't argue with experience - I was just going off a datasheet for ABS bending and melting points. Here's a more detailed one that lists the temps recommended for the injection molding machine (400 - 500F) and maximum service temp in air (140 - 223F). I would still be inclined to use it for mockup only, but if it works, it works!
Old 10-09-06, 12:43 PM
  #16  
Alcohol Fueled!

iTrader: (2)
 
J-Rat's Avatar
 
Join Date: Jan 2002
Location: Hood River oregon
Posts: 11,093
Likes: 0
Received 2 Likes on 2 Posts
I am not advocating its use, but it WILL work..
Old 10-09-06, 01:50 PM
  #17  
Clean.

iTrader: (1)
 
ericgrau's Avatar
 
Join Date: Mar 2005
Location: Huntington Beach, CA
Posts: 2,521
Received 2 Likes on 2 Posts
They recommend no higher than 140-223F because ABS gradually gets softer past 140. You could probably go much hotter if it's not under pressure. Your intake air probably won't get that hot anyway. Ditto on what J-Rat said.
Old 10-09-06, 02:08 PM
  #18  
Senior Member

Thread Starter
 
cls6888's Avatar
 
Join Date: Nov 2005
Location: Ohio
Posts: 316
Likes: 0
Received 0 Likes on 0 Posts
So basically its not worth doing this mod...What about a cai on a turbo?
Old 10-12-06, 03:24 PM
  #19  
Clean.

iTrader: (1)
 
ericgrau's Avatar
 
Join Date: Mar 2005
Location: Huntington Beach, CA
Posts: 2,521
Received 2 Likes on 2 Posts
Should be worth it. - cheap and significant gains. Though in theory a ginormous intercooler could replace a cai, since temps after the intercooler are all that matter.

Universal gas law:
PV = nRT: Pressure * Volume = (amount of air) * (constant) * Temperature

More air = more power. So there are two ways to increase air:
1. Increase pressure.
2. Decrease temperature.

It gives about 5-6HP on on N/A. You'd have to ask around to see what people get with a cai in a turbo, since I don't feel like doing the math and it depends on your intercooler. If it weren't for the intercooler, it would be a flat ~4% increase to your existing horsepower.

Last edited by ericgrau; 10-12-06 at 03:27 PM.
Old 10-14-06, 06:38 PM
  #20  
I'm a boost creep...

 
NZConvertible's Avatar
 
Join Date: Jan 2002
Location: Auckland, New Zealand
Posts: 15,608
Likes: 0
Received 8 Likes on 8 Posts
Originally Posted by ericgrau
Though in theory a ginormous intercooler could replace a cai, since temps after the intercooler are all that matter.
In theory and in practice the colder the air is when it enters the intake, the colder it is when it enters the intake, no matter what happens along the way. No matter how good an intercooler is, a proper CAI will lower the intale air temp further still.

As for the TID, it's absolutely worth upgrading. Again, experience has provided overwhelming proof of that. The stock TID is very restrictive because of it's two very tight bends, and the bottom bend causes poor turbo entry conditions that reduce compressor efficiency.

Here's mine. https://www.rx7club.com/showthread.p...27#post4702327
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Shainiac
Single Turbo RX-7's
12
07-17-19 02:20 PM
NotMrButts
1st Generation Specific (1979-1985)
23
09-15-15 09:46 PM
armans
Single Turbo RX-7's
1
09-06-15 09:02 PM



Quick Reply: Intake tube



All times are GMT -5. The time now is 07:45 PM.