Well, one of the patches on my Starion intercooler blew off yesterday. (I relocated the inlet/outlet to the sides.) So that gave me the oppurtunity to see what type of pressure drop in was causing by temporarily replacing it with a straight piece of pipe. I was reading .60kg/cm2 (8.53psi) with the intercooler in place. Without it I'm reading .61kg/cm2 (8.68psi). This is with 2"od (1 7/8" id) pipes. I was actually hoping for a slightly higher pressure drop. Now I'm concerned that air is passing though too fast and not losing enough heat. Maybe that's why the original pipes were something like 1 3/4" od (don't recall id). Well, I know it's somewhat effective. After heavy boosting the inlet side was hot to the touch and the outlet was stone cold (scientific measuring huh )

Just thought I'd share.

 

Wow, it seems that an IC that size would cause more pressure drop than that! Hmmmm.......

 

It seems like my Mitsu Galant VR4 intercooler is the same as a starion intercooler (as some people have told me) and even though it does seem like a smallish intercooler, it does seem to hold up to its duties. I live in a very hot country, and push my car hard. Its never seemed to fail me. There have been one or two times where the intercooler piping has popped off the sides, but nothing serious. Boosted my car heavy, even done several runs to 5th gear redline, and it hasn't heated up (most probably due to my radiator). But I dont think its gonna hold up to my upcoming B18C engine, so its time to upgrade to something a little big bigger. But the Starion/VR4 intercoolers are good for their money, and they work well

 

Don't sweat the low pressure drop - this is a GOOD thing.

First: heat transfer laws say you get more convective heat transfer between a moving fluid and the wall as the speed of the fluid increases. Fast = good.

Second: if you were fighting, say, 2 psi of backpressure in the IC, that means the turbo has to do 10 psi worth of work to make 8 psi for the intake. So the turbo would be raising the temps even more (would guess another 10-15 degrees) so even if the IC were hypothetically a little more effective, you would still have higher intake temps (and a little more backpressure on the exhaust since the turbine's working harder).

Your "non-scientific" test told you what you need to know.

Unless of course you have a boost controller or wastegate reading a boost signal AFTER the IC, in which case you have no idea how much IC pressure drop there is, because it's just keeping the wastegate closed longer until it reaches your desired boost pressure.

 

Yeah, that's what I figured. I didn't expect anything like a 2psi differential, but a little more than .15psi. Hey, if it works, it works

FYI: my wastegate signal comes straight off the compressor housing

 

its an extruded tube core intercooler

 

Yeah, it's a very well designed IC, and compared to something like the DRAG kit ICs, it has more flow area and shorter tubes, so it should have a lower pressure drop. The "long and skinny" drag style ICs may do a little more cooling but I am pretty sure they have a higher pressure drop, which can take you back to the tradeoff that I mentioned above.

 

This is good to know. I cant wait to see how my starion works for me. I wonder if 2.25" piping rerouted to the sides is gonna have an effect on cooling?
Tomorrow starts the turbo install---wish me luck!!

 

That's how DSF and I both have ours setup (I have 2.25 in and 2.5 out)... so if it worked for him, you and me should both be in good shape.

 

Wait though, I think you need to measure the actual drop across the IC, at its inlet and its outlet. IMO there's basically no way that with the IC in place there's only ~ 0.1 psi drop at full boogie. Unless there's also ~ no flow I mean it's probably dropping the temperature by some 50 deg at least; that factor alone is probably going to represent more than a .1 psi drop IMO. There's no free lunch when pumping fluids (air) around You are just quoting the boost gauge reading before the test pipe install and after, right?

Understand, I'm not trying to knock you personally, I just think the test method needs some careful thought. I have ~ 0.5 psi loss through 2' of 5" cold air hose, a 14" K&N filter and ~ 2.5' of 4" pipe! That's at about 75 lbs/min of flow though.

JMO.

TurboTR

 

Check it!

http://home.earthlink.net/~turbogus2/intercoolers.html

 

So your measured results indicate a pressure drop of 4.15" H20, which compares pretty well with that guy's results although it seems a little bit TOO low.

 

Ok, work with me here...

But where is your wastegate reading pressure from? Indicated boost on your boost gauge has nothing to do with pressure drop across the intercooler. Either way, the test is not scientific enough to produce useful results.

.01 kg/cm^2 is probably within the acceptable range of calibration for your boost sensor, so as far as I'm concerned your test shows no "pressure loss".

Given your pseudo-exact boost readings, I assume you are using some sort of digital boost gauge... on an EBC? If it is the AVC-R, then not only does it change actuator solenoid duty on the fly to maintain boost... but it usually does not hold boost constant except within a range of +- .02 kg/cm^2 anyways.

Dustin

 

What is the absolute best place for the boost controller to read pressure from?

 

>Check it! http://home.earthlink.net/~turbogus2/intercoolers.html

Well that's interesting that you measured all those coolers, but to get a handle on what the real world drop is we really need the real world flow rate through them. Like 20-30 lbs/min (200-300 hp) or more. With only a leaf blower for a flow source I'd be surprised if it could put even 5 lbs/min through there. OTOH I guess we still have some good relative data for comparison. Cool.

TurboTR

 

would 2.5 in and 3 out be too much for that intercooler???

 

And DSF what did you patch it with???

 

Ok, remember this is my beater car and all funds are being concetrated on my Civic. I patched the original inlet/outlet holes using plate aluminum and JB Weld. The JB is what seperated. (Prepare for upcoming ghetto talk) So I reinforced the aluminum patches by running some sheet metal screws through the patch and intercooler and using JB Weld to glue and seal it all. So far so good. This entire project (car, turbo, engine, etc.) has cost me less than the price I paid for my at the time bone stock high mileage Civic CX.

Dustin: My wastegate source comes directly off of the compressor. My boost reading comes off the manifold. Along with my VDO boost gauge, I'm using the AFC hack, so that is where my digital reading is coming from (VAFC). I have no form of boost controller. And my reading were taken during the same day at roughly equal environmental conditions. I never meant this to be a totally end-all scientific read. Just sharing that my compressor was able to generate a reading in the manifold of .15psi more boost pressure without the intercooler in place. I know there are much more variables like heat gain, air density and such. I'm actually surprised at how stable/repeatable my boost readings are. But I am glad this turned into a technical thread instead of one of those "dude you must be a renob" thread


[Modified by DSF, 7:40 AM 4/22/2002]