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Engine Specific Info and Questions => IDI Engine => Topic started by: jasonsansfleece on January 20, 2008, 10:21:46 pm
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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
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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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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.
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What about a K24
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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"
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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).
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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
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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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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
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If you price shop on eBay there are several good deals on tubing "kits" and individual tubes.
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steel tubing is cheaper and easier to find but is a little heavier
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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.
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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
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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?
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Who is the maker of the intercooler, what is it rated for, and what do the end tanks look like?
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Got it from Just Intercoolers on E Bay.
The End tanks are Cast (thick).
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=015&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=250219901631&rd=1
That's the one I bought.
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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.
?
From the Ebay add:
"Working Pressure: 10~30PSI:"
"Pressure Drop 1~4psi@35psi"
Looks like its doing exactly what its advertised to do.
Its too small for your application.
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I agree, a 1-4psi drop is terrible. If you see more than a 1psi drop its too small.
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So crap,,,
I dont think I can fit a larger one..
Looks to me like they put the same info on dang near all thier IC listings.
Kinda like a generic form..
I could prob fit a taller one if I went behind the front bumper. like a 11" tall one, but the listing as to pressure drop is the same..
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Put one behind the bumper as well. Run 2 in parallel.
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Put one behind the bumper as well. Run 2 in parallel.
Why not just run a taller single?
Way less plumbing.
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Well I thought you said you couldn't fit a larger one. If you can go taller, then by all means, that's the way to go.
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I mean really, I dont mind buying a larger IC (if I can fit it).
The one I have now will work fine for a stock engine just doesnt work like I want for the amount of fuel I'm pushing through.
I need to go out there with a tape measure I guess..
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Well I thought you said you couldn't fit a larger one. If you can go taller, then by all means, that's the way to go.
I have a Sawzall, if I REALLY want to I can fit a larger one :twisted:
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Hehe, that's what I did to my entertainment center when I wanted a bigger tv. :lol:
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So it's the general opinion then if I get a larger IC (more internal capacity that I will lessen the problems I'm having now correct?
I'm going to go see if I can get a larger one in there somehow, thinking of a 27x12x3.
Not to sure how I'm going to get from my 2" piping to a 2.5 or 3" inlet/outlet,,??
If it was a straight shot it wouldn’t be a big deal I don’t think but I have a 45deg bend in the inlet..
SH*T!!
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Ta-Da!
http://cgi.ebay.com/ebaymotors/2-2-5-90-DEGREE-REDUCER-SILICONE-HOSE-1YR-WARRANTY_W0QQitemZ160231318531QQihZ006QQcategoryZ33601QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/2-5-3-90-DEGREE-REDUCER-SILICONE-HOSE-1YR-WARRANTY_W0QQitemZ150239146426QQihZ005QQcategoryZ33601QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/2-3-90-DEGREE-REDUCER-SILICONE-HOSE-1YR-WARRANTY_W0QQitemZ160231318591QQihZ006QQcategoryZ33601QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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Close, I need 45deg not 90deg..
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just do a search then as I have seen 45 and other degree silicone bends on e-bay. If you want it, it is there. :lol:
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just do a search then as I have seen 45 and other degree silicone bends on e-bay. If you want it, it is there. :lol:
I know I know, I'm just lazy and cant do E Bay @ work so I have to wait till later tonight when I'll certinally get busy and forget till I get to work tomorrow when the cycle starts over :(
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Ta-Da x2
http://cgi.ebay.com/ebaymotors/45-Degree-reducer-elbow-2-to-3-4-PLY-SILICONE_W0QQitemZ270228521776QQihZ017QQcategoryZ33742QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/45-Degree-reducer-elbow-2-to-2-50-4-PLY-SILICONE_W0QQitemZ310043588393QQihZ021QQcategoryZ33742QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/45-Degree-reducer-elbow-2-5-to-3-4-PLY-SILICONE_W0QQitemZ310040928028QQihZ021QQcategoryZ33742QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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To Cool!!
Thank you much sir :D
I'll get out there and do some measureing ASAP so I can get what I need ordered ASAP..
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Well I need to be able to crawl under there a bit better but it looks like I can fit a 12" tall IC in there. the bottom 6-7" or so will be exposed the rest will be behind the bumper.