Author Topic: Intercooler Plumbing Size  (Read 5128 times)

January 20, 2008, 10:21:46 pm

jasonsansfleece

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Intercooler Plumbing Size
« on: January 20, 2008, 10:21:46 pm »
A subject that has received some attention recently but I cant answer my question.
A K14 is 2" off the compressor and the intake manifold has a 2" port as well. Intercoolers are available with a variety of port sizes including 2".
Would it be preferable to keep all ducting at 2" or is there some advantage to increasing the diameter even though the air must still pass through a 2" port at either end?
2" ducting through would maintain a constant pressure? (what effect would the intercooler have?)
Larger ducting would give a pressure drop after the compressor port and perhaps better flow but would experience a restriction at the intake manifold with losses due to re pressurization ? (as well as the effect of the IC)
I am experiencing analysis paralysis due to pressure caused by to many IC choices on ebay and not having a high school diploma let alone a degree in fluid dynamics :lol:
What do you guys say?
Guy



Reply #1January 20, 2008, 10:32:58 pm

blkboostedtruck

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« Reply #1 on: January 20, 2008, 10:32:58 pm »
I'm no rocket scientist either but staying with 2 inch i don't think you can go wrong? but i'm sure someone with more experience with I.C. piping will chim in? thats my opinion! i as planning on using 2" also i balieve just adding a I.C. is a benaficial improvment anyways!
thanks Duane
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Reply #2January 21, 2008, 04:58:44 pm

spencebm

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« Reply #2 on: January 21, 2008, 04:58:44 pm »
2" is what I used and it is good because like you said, the outlet of the turbo and the inlet of the intake manifold are a little less than that so I wouldn't go any bigger than 2.  Plus if you make it bigger, you still have to pressurize that space.  2 is plenty big enough for the K14.
Ben Spencer

Reply #3January 21, 2008, 05:34:07 pm

zukgod1

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« Reply #3 on: January 21, 2008, 05:34:07 pm »
What about a K24
dan

99 Golf TDI (now CNG powered) , 82 TD Caddy

Reply #4January 21, 2008, 06:44:04 pm

spencebm

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« Reply #4 on: January 21, 2008, 06:44:04 pm »
use 2" for that too unless you are pushing ungodly amounts of boost which is possible.  I run less than 20lbs so I use 2"
Ben Spencer

Reply #5January 21, 2008, 07:19:13 pm

Black Smokin' Diesel

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« Reply #5 on: January 21, 2008, 07:19:13 pm »
Anything between 2" and 2.25" is big enough. Any bigger and you lose efficiency (what a lot of people using an intercooler don't care about with their 3" piping pushing 8psi).
91 Passat syncro 1.8T swapped.

Reply #6January 22, 2008, 02:49:09 am

OM617

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Intercooler Plumbing Size
« Reply #6 on: January 22, 2008, 02:49:09 am »
Stick with 2". Going bigger will add significant lag and wastes energy.

According to Corky Bell, Maximum Boost pg 61, 304 MPH or 0.4 mach is the point at which airflow meets increased resistance (drag) and flow losses are experienced.

0.4 mach = 304 MPH

2" piping
1.57 x 2 = 3.14 sq in
300 cfm = 156 mph = 0.20 mach
400 cfm = 208 mph = 0.27 mach
500 cfm = 261 mph = 0.34 mach
585 cfm max = 304 mph = 0.40 mach


2.25" piping
3.9740625 sq in = 1.98703125 x 2
300 cfm = 123 mph = 0.16 mach
400 cfm = 164 mph = 0.21 mach
500 cfm = 205 mph = 0.26 mach
600 cfm = 247 mph = 0.32 mach
700 cfm = 288 mph = 0.37 mach
740 cfm max = 304 mph = 0.40 mach


2.5" piping
4.90625 sq in = 2.453125 x 2
300 cfm = 100 mph = 0.13 mach
400 cfm = 133 mph = 0.17 mach
500 cfm = 166 mph = 0.21 mach
600 cfm = 200 mph = 0.26 mach
700 cfm = 233 mph = 0.30 mach
800 cfm = 266 mph = 0.34 mach
900 cfm = 300 mph = 0.39 mach
913 cfm max = 304 mph = 0.40 mach


2.75" piping
5.9365625 sq in = 2.96828125 x 2
300 cfm = 82 mph = 0.10 mach
400 cfm = 110 mph = 0.14 mach
500 cfm = 137 mph = 0.17 mach
600 cfm = 165 mph = 0.21 mach
700 cfm = 192 mph = 0.25 mach
800 cfm = 220 mph = 0.28 mach
900 cfm = 248 mph = 0.32 mach
1000 cfm = 275 mph = 0.36 mach
1100 cfm max = 303 mph = 0.40 mach


3.0" piping
7.065 sq in = 3.5325 x 2
300 cfm = 69 mph = 0.09 mach
400 cfm = 92 mph = 0.12 mach
500 cfm = 115 mph = 0.15 mach
600 cfm = 138 mph = 0.18 mach
700 cfm = 162 mph = 0.21 mach
800 cfm = 185 mph = 0.24 mach
900 cfm = 208 mph = 0.27 mach
1000 cfm = 231 mph = 0.30 mach
1100 cfm = 254 cfm = 0.33 mach
1200 cfm = 277 mph = 0.36 mach
1300 cfm max= 301 mph = 0.39 mach

Reply #7January 22, 2008, 05:25:28 am

gldgti

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« Reply #7 on: January 22, 2008, 05:25:28 am »
i also agree, stay with the 2" piping.

when you change pipe sizes up and down, you lose energy that cannot be gained back - thermodynamics will never let us have perpetual motion so to speak.

if the piping increases in size, the airflow must decelerate. then, if it has to go back to smaller again, it must accelerate once more. these actions do not cancel eachother out. thus, there is energy lost, and loss of efficiency.

if someone would like to change this law, i'm sure many physisists would pay you well. ;-)
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Reply #8January 22, 2008, 07:39:46 am

moTthediesel

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« Reply #8 on: January 22, 2008, 07:39:46 am »
On the same subject (sort of):

Does anyone have a good North American source for aluminum tubing and bends for fabbing up intake systems?

Thanks,

moT
'82 LandCruiser Diesel Conversion
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Reply #9January 22, 2008, 07:51:11 am

OM617

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« Reply #9 on: January 22, 2008, 07:51:11 am »
If you price shop on eBay there are several good deals on tubing "kits" and individual tubes.

Reply #10January 22, 2008, 08:47:28 am

spencebm

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« Reply #10 on: January 22, 2008, 08:47:28 am »
steel tubing is cheaper and easier to find but is a little heavier
Ben Spencer

Reply #11January 22, 2008, 10:05:00 am

jimfoo

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« Reply #11 on: January 22, 2008, 10:05:00 am »
Too bad that when I was doing my engine, everyone I talked to said to go as big as I could. So I went 3". Maybe I will redo it with the new engine. The only problem is my Saab IC is 3", but I doubt that will matter that much.
Jim
1966 Land-Rover 88" with 1.9 AAZ which has been transformed to an M-TDI
GT1749V, IC , and 2.5" exhaust.
Driven daily

Reply #12January 22, 2008, 10:16:56 am

moTthediesel

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« Reply #12 on: January 22, 2008, 10:16:56 am »
Quote from: "spencebm"
steel tubing is cheaper and easier to find but is a little heavier


When you're hanging an iron block diesel off the a$$ end of a swing axle Tub, every ounce counts  :lol:

moT
'82 LandCruiser Diesel Conversion
4Cylinder 3B/KKKturbo/AudiIntercooler(gone, BNF)
'92 Dodge/Cummins D350 Getrag Dually
356 w/Quantum 1.6TD (73 mpg!)
'85 BMW 524td (Der Komisar) 
'00 Jetta TDI 5spd

Reply #13April 21, 2008, 05:36:55 pm

zukgod1

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« Reply #13 on: April 21, 2008, 05:36:55 pm »
Bumping a old thread up..

Just for reference I installed a FMIC on my Jetta a few weeks back and thought I would post some findings for all to read.

I used a FMIC that was 26" x 5.5" x 2.5" with 2" inlet and outlets.
Also used all 2" mandrel bent alum piping.

Before IC I was hitting 40spi (spikes) and would hit 30psi regularly, pulled way hard.
Post IC I can hit 25 if I REALLY try, seems to be restricting the air flow as before IC @ 30psi there was a slight haze out the back and now there is a black cloud at the same gear/RPM.
It still pulls hard but it's obviously running out of air on the top end, EGT's climbing fast and engine just sputters like it's hitting a rev limiter.

I did get the bar and plate type IC no tube/fin construction here.

I'm wondering if the 2" inlet/outlet in the IC is what’s causing my restriction.
I've taken it all apart to make sure all the joints had a smooth transition and same deal.

Right now my clutch is slipping so I cant do any further testing until I get it replaced with a better system but for now this is the info I have available.

Thinking about going with the same sized IC and maybe jumping to a 2.5" inlet/outlet and keeping the 2" piping.

Anyone have thoughts?
dan

99 Golf TDI (now CNG powered) , 82 TD Caddy

Reply #14April 21, 2008, 06:01:43 pm

subsonic

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« Reply #14 on: April 21, 2008, 06:01:43 pm »
Who is the maker of the intercooler, what is it rated for, and what do the end tanks look like?
2009 Jetta TDI Loyal edition, 6-spd. 16V 2.0CR


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