lart951

Let say i build a custom intercooler identical to the factory but with 2.5 inlets and I get a set of 2.5 IC pipes would i see an flow improvement? any theoretical gains?

User 41221

If its truly identical to the factory intercooler, probably not. If you increase the size of the pipe, you should be reducing the velocity of the air flow through it but I am not convinced you'll see any advantage from doing so. I doubt you'll realize much of a temp drop by doing so, unless you go to an entirely different (ie Front Mount) design.

Truth be told, there are easier ways to make power. If you are commited to keeping the stock location for the intercooler, try putting a relief vent behind it (ala 968 Turbo RS) for better flow through it.

Paulyy

the idea of larger pipes is less turbulence at higher flow levels.

Good info here:
http://www.dsmtuners.com/forums/turb...ping-flow.html

333pg333

I would suspect that you'd get the greatest advantage by increasing a lot of other things in combo with a larger I/C and pipes. No real point going larger than the throttle body (which will only increase your IAT's) and then into a stock intake. Followed by a stock head, cam and headers. In other words, when you increase flow in one place you're often putting more stress somewhere down the line. Not 100% always, but in the majority of cases.

Look at JET951. Running what must be over 500bhp through the stock I/C and pipe-size. Possibly wouldn't hurt for this car to go up in size, but it's working well as it is.

Paulyy

by just changing the intercooler pipes, it wont make a difference really. Patricks right, when you increase the VE of one thing, you'll want to do the rest to see the real gain, because there will always be a bottle neck if you change one thing.

If sean is running stock ic pipe size, 2" or even 2.25" i think he should go larger, by looking at the chart he's probably getting some turbulence and loosing efficiency. He would probably gain if he went bigger.

URG8RB8

I am pretty sure that the rest of Lart's engine is not stock!

Willard Bridgham 3

If you increase the size of the pipes and they are the same configuration as stock, ie, same bends and fittings, you will have a decrease in pressure drop and an increase in VE, ie, increase in HP.

I'm not sure you can build an ic the same as stock.

lart951

Here is the IC is a Frankenstein

lart951

do you think it's more efficient than OEM?

reno808

you cant tell by picture. why do you just test it and compare to stock??

Willard Bridgham 3

A flow test will tell you if it's better.

eman930

That left end tank looks restrictice, If you look at Lindsey Racing IC, they replace the end tanks with rounder better flowing tanks, Also the welds inside the pipe look like the need to be cleaned up

lart951

Yea, maybe I'll ditch the IC and just use the 2.5" ic pipes, some people said that it's better to use a 2.25 in the ic hot side and 2.5" in the coold side anyway I found this information

*.4 Mach is the point at which air becomes turbulent and losses in efficiency start to occur exponentially. The key is to stay under that speed. You want to use the smallest piping possible that still flows enough to meet your needs. Larger than necessary piping increases lag time with no measurable gain

The velocities are in miles per hour and mach, and the flow rates are in cfm. Measurements for the piping are in inches.


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


In order to convert from Lb/Min to CFM for the equation above, you take the flow rate in Lb/Min for your turbo (generally an educated guess based on the pressure ratio and power created) and multiply it by 14.27. That will yield the CFM flow for your setup.

For Example:
T3/T04e 57trim .63ar @ 21psi makes 452 whp
This turbo is known to have a 50lb/min compressor wheel which will make ~500bhp. Since we're using whp above, we can assume this turbo is pretty close to its max of 50lb/min.

Now to convert that to CFM, you take 50lb/min x 14.27 = 713.5 CFM. When you refer to the table above, you can see that we're starting to max 2.25" piping, but we're still in the "good" range for 2.5"

but it also depends on how smooth the piping is inside... and all the bends. this i would say is " perfect piping conditions" and if you would pick a number to upsize your piping at it would be when you hit about the .3 maximum .35 mach region.

lart951

Btw I like the idea of running 21-23 psi on daily basis I have a Gt35R turbo on the 951 now, so I think 2.5" pipes is a good move

eman930

What about the T-body? If you have a stock t-body all that piping inst gonna help if it gets pinched back down. Your Math is correct on the pipes, But as far as that IC goes, I think you will have flow issues with those end tanks the way they are and the poor transisiton between pipe and intetcooler welding.