Intercooler ratings (CFM)???

[AnArKey]

Hopefully someone here can clear this up for me. Let's take the Spearco 2-170 core (2-230 assembly) ratings as a example. This will (at least initially) only address the determination of pressure drop, without covering efficiency (how much cooling occurs).

CFM PSI Drop
700 .18
1100 .37
1500 .70

Also mentioned is the test was conducted at 30psi with 400F air.

Now, this begs the question, at what point are we considering the CFM? CFM is a measure of volume, and the turbo has a way of making the same mass occupy a smaller volume. So the question is, does the CFM number they use assume atmospheric air at say 80F at the inlet of the turbo, or is it the 30psi air at 400F entering the intercooler? The same volume has drastically different mass, depending on which you use.

Specifically, my turbo maxes out at ~1100CFM, at the inlet. At 29psi, the air would be compressed by a factor of 3x by compression, but expand by a factor of ~x1.48 from heat. (1100/3)*1.48=542.66CFM. So, again, the rating means nothing unless we know where they are thinking of the volume of the air.

So, anybody know?

 

[azgn]

well basically who cares? (unless you are going to build your own IC)

the IC is not the block in the air flow.....the motor is! (and the charge air temp)

what are you looking for?

 

[AnArKey]

Knowing for sure allows me to calculate ahead of time how much pressure drop I will see, given a certain boost, CFM, and temp.

One place said they are rated at the intercooler. Haven't asked Spearco yet.

 

[azgn]

and what does that give you?

you gonna get a bigger IC or a bigger turbo or maybe put it in a cold box?

I still can't figure out what you are after.......

maybe you should chat with Bruce, he went from the turbo to the TB (no IC)

I'm interested, but only in real world results........

 

[postal]

well basically who cares? (unless you are going to build your own IC)

I'm not a rocket scientist but it looks like the guy asking the question cares! I think it’s a good question whether you’re building your own IC or not. Its pretty general knowledge what helps and hurts a motor as far as power goes. The hard part is trying to figure out how much some thing will help or hurt. One way is get out the $$'s and do real world testing. The other way is to try to find out as much detailed data about a part like an IC and then use some engineering calculations to try to determine the potential result. A little computer time and some math can help determine if a part or project is worth pursuing or not before dishing out the $$'s.

As far as the question goes I don’t know the answer. You’re basically asking if the cfm is standard temp and pressure or if its cfm at 30 psi and 400 degrees right? I take it you've been looking into density ratio type equations. Maybe you could call Spearco and ask to talk to an engineer. I doubt some one who takes orders would know the correct answer. If you find out the correct answer post it I'm sure you and I aren't the only ones who would be interested in this.

Jason

 

[mec108]

I'm not going to build my own intercooler either. But ,I would like to know the answer to a good question. knowledge is power?

 

[azgn]

I was not trying to demean the gentleman that asked the question.......it just seems to me that the cfm rating on an IC is irrelevant.....the important things are pressure and temp drop across the IC...I think, but I certainly am no rocket scientist either!

this ASSumes the IC is well enough designed to not be a significant restriction to air flow....I am certain that the IC's we all use can easily flow more air than our engines can use....the trick is to get the air cooler and keep the pressure up

 

[ijames]

I don't "know", but if they say the test is conducted with 30 psi air at 400 F, to me that means that that is the state of the air entering the core.

 

[postal]

it just seems to me that the cfm rating on an IC is irrelevant.....the important things are pressure and temp drop across the IC

I would think the last part of that statement is exactly right. BUT the second part is effected by the first part (CFM). Itercooler efficeincy drops as the air flow through it goes up. The pressure drop across it also goes up as cfm increases. Basically the more hot air that you force through the IC the less it will cool it and the higher the pressure drop across it d/t the restriction of trying to flow through it. In the cfm and psi drops listed it shows that if you just over double the flow then your psi drop goes up almost 4 times. That is pretty consitent with fluid flow theories. Basically with fluid flow if you want to increase the flow through some thing by a factor of 2 then you need to increase the pressure by 2 squared which would be 4. Anarkey left out the IC outlet temps that should be listed with those flow and psi numbers. If he had included them you would see the outlet temps go up as the cfm went up. Its pretty common sense that the more air you have to cool the harder its going to be to do it. The other thing that makes things hard is if you look at spearcos core the 3.8 is kind of a "tweener". The one core is recommend for up to around 4.1 and the the other one goes from like 4.1 to 7 liters or so. The price between those 2 cores is doubled if I remember right. I'm guessing thats why he's asking this question.

Jason

 

[GNVYUS 1]

You are looking at a Air/liquid cores (just making sure you knew that)

By the time you get through with everything you need, money wise, it would not beat mat temps of a V1 and razors prog alky kit. Total of those two parts, $1600.

And look at the liquid temps on the test, it might start at 45 degrees at the line, but sure the hell does not stay there at the end. No way you get 45 degree water with a turbo pushing 1100 cfm at the finish line. If they showed water temps changing along with cfm and timed it in seconds, that would be a better picture of whats happening as you go down the track.

Temp out on that core with 110 (finish line water temps) and 1100 cfm is 161 degrees. Not very good IMHO for what its gonna cost ya. Core assembly 2-281 would fit a buick in the front and cool better than 2-230. If I were to go this route, thats who I would buy.

 

[gnx7]

This is a good thread and I'm not trying to hijack it....
but...
I'm running a Spearco 1080cfm intercooler thus far with a T-70BB turbo. I haven't run the combo yet. The 760 hp/flow rating of the turbo is about the same as the intercooler however I know I'm cutting it close if not surpassing the flow and efficiency of the intercooler.

Here is the intercooler I have:
3.5"Dx18.48"Wx6"H 760hp 1080cfm 2-221 2-115

it is a dual core spearco unit with their highest flowing core. Do you guys think a larger intercooler will be worth the additional cost and fabrication trade off cost?

-Mark

 

[postal]

You run a T-plus and an LS1 MAF sensor right? I've read that on that set up you can move your air temp sensor from your air filter to the up pipe. Some thing to do with the LS1 style MAF haing built in temp compensation so the T-plus set up doesn't use it. You will then be able to monitor air temps right before the throttle body. Once you do this you should be able to determine how much room for improvement there is. I'm not 100% sure about moving the temp sensor but I'm pretty sure I've read this. Do a search and see if you can find some thing on it.

HTH: Jason