I read your post to begin with and acknowledge what you said that the newer design should be somewhat improved but that doesn't answer my question why you would not have checked/qualified the performance against the .2tt coolers prior to putting to market, least of all quantify the actual gains achieved over the previous version. Just seemed odd to me especially from a marketing sense. Using P as an example it'd be a bit like them releasing the newer .2tt version car without providing any qualitative and quantitative data showing the buyers the factual improvements over the previous model .1tt car, giving reason for buyers to change up.

And re you saying "if im happy with my .2 intercoolers" you have not read my post as nowhere did i say i have bought .2tt coolers. In fact i'm a potential buyer but after reading skands thread i'm skeptical of anyones claims unless they are supported with factual data. You may be right that yours are not for me but at this at this stage without you providing anything tangible to consider then i'm not in any position to make that decision. Or should i just take your word for it

 

great post! so often people try to correlate pressure drop to boost pressure when reading flow bench charts. Honestly I was surprised that ALL these coolers had this much pressure drop at the given cfm, especially given how short and wide the cores are (~14"x3.5"). EVOMS did a similar test on a 996 core and on their coolers and came up with roughly 350 & 480 cfm @ 2psi pressure drop. CMS's flow results look consistent, so I don't doubt them, they just all seem low. Would love to see the pressure drop on these coolers moved up to get the flow into regions we care more about (like 400-500cfm).

TTdude, we're looking for pressure loss (or drop) across the intercooler at flow levels that would represent the airflow you would see with turbos running at xx psi. 400-600cfm per intercooler would correlate pretty well to the airflow produced by most 997 turbos (stock and upgraded) running typical boost levels. Hope that made sense... Edit: just saw your response above, and yes, they all seem to be trending to a somewhat high pressure drop (assuming pdrop vs flow stays linear), especially given the relatively low cfm they were tested at.

In addition to better flow, one other thing the CMS coolers probably offer is more of a true bolt-on type deal with customer support during the install -there is some work involved in making the .2s fit properly and that time is worth some $$ for many folks.

 

Thanks Earl. I understand that a difference of 2 psi is producing the flow indicated but I'm questioning the validity of this type of measurement since most race-quality ICs have purported pressure drops <1 psi. So the estimation of 3-4 psi drop to get 480 cfm seems too high, imeo (enthusiast). What I meant to say is doing a different type of test at 25-30 psi which what the boost pressure is. That is use a differential pressure gauge measuring the pressure at the inlet and outlet.

 

ahhh, yep, with you on all counts. As someone mentioned, I'd be curious to see boost requested vs actual boost on a few cars -may be sort of a real-time way to see it.

 

Yeah, something seems off with 3-4 psi drop. I was told when I purchased my ICs that the pressure drop was 0.25 psi at 900 cfm. They are larger, however.

 

Guys, that chart shows the pressure you lose on the IC when you are flowing a given amount of cfm.
So, rather than "applying 30 psi", one should "flow" the desired cfm that's supposed to be needed for a given power level, and then measure the pressure drop on the IC.

As for requested boost vs actual....if your wastegates are maxed out and you still don't reach requested boost, then yes, going to an IC with less drop will help you to reach the desired boost.
But if the wastegate can handle it, it will simply compensate and bypass less exhaust gas so to spin the turbo to higher revs, giving you the desired boost.
Actual boost is measured after the IC and piping, so the relative pressure at the comp discharge is BOOST+ IC drop+ Piping drop. If your IC and piping drop is bigger, to achieve the same boost the compressor will spin a bit more to raise the pressure at its discharge. That's it, imo.

TTdude is correct on the 1 psi figure, as even on Garrett website is said that a 1psi drop is a good value, and "restrictive factory" IC and piping can lead to 3-4psi drop IF you are trying to flow more air than stock.....

 

Agreed but without knowing the testing parameters and method (i.e what is the head pressure?), it's hard to evaluate how accurate those numbers are especially since they seem too high for what is supposed to be efficient ICs. Maybe their pressure gauges need calibration. All I know based on the chart, it shows high pressure drops and that the .2IC is worse than the .1 which seems to go against all the real world experiences people have demonstrated recently. You have to give them credit, however, since they are at least providing some kind of data which is nice to see and allowing folks like us to comment/speculate on it. Ideally, it would be nice to see a graph for thermal efficiency and pressure drop at different flows but I guess you would have to go directly to the core manufacturer for that type of information.

PS Look what I pulled out of my OEM .1ICs. No wonder thermal efficiency is down.

 

You are right...
A bit of theoretical speculation is always fun though!
I would love to build a proper pressure measurement for my next round of mods...being able to measure pressure before and after IC's, as well as temperature before and after.....Imagine how cool it would be...







PS:What's that stuff ?

 

They appear to be plastic "passed inspection" tags. I pulled them out of the fins. They have barbs on them so they were meant to stay planted. Not sure why P would do this.

I agree a little theoretical speculation is fun. I remember reading somewhere that pressure drop will increase as the square of the cfm so it's a hyperbolic relationship rather than linear. For example, a 100% increase in flow would correlate to 2^2 or 4x increase in pressure drop rather than just double. You may have to check me on that one.

 

Right, this is how it works usually....H= p + (v^2)/g where H is "height in meters, an expression of pressure like mmHg" , and I was pretty surprised when I saw some graphs on the AWE website showing a linear relationship betweer pressure drop and rpm..

 

Keep in mind... the chart is only charting one variable - flow. Thermal efficiency isn't shown. The .1 IC could very well flow more air at a given psi than it's younger brother, but have much lower thermal efficiency than the .2 IC... making the .2 IC better overall for applications that require greater-than-stock thermal efficiency improvements.

 

So true and if you extrapolate that reasoning to the CMS IC then that would imply their IC is worse than the .1IC with regard to thermal efficiency. As has been demonstrated, the .1ICs have a lot be desired. I just can't see how they could flow that much air either if you take a look at them, especially the end tanks. So one cannot really conclude too much from the graph alone.

 

Its the open channel space within the core, there's at least a 1 in^2 area of straight shot (no turbulators) to the other side of the core on the .1s.

 

I'll have to take a closer look. I just noticed the end tanks and even though I'm no expert, they looked a bit restrictive especially the exit side. Are the open channels running along the edges?

 

You're correct. The .1 coolers are missing a row of turbulators along the edge, which definitely contributes to their increased flow over the .2 units.

The .2 coolers do not have the open channels along the edges. They also have much denser core material then the .1's. This was done because (again), the .2 was never intended to run as much boost as the .1 turbo.

Now to answer a few questions from the page before:

The equipment we use to test the coolers flow is called a SuperFlow SF-1020. Why didn't we test pressure above 2psi? Simply put, because the machine does not support it. It does, however, support testing under vacuum, and we did test at 40 inches of mercury, which is roughly equivalent to 19.5 psi. At that level, the difference in results was too great, and the graphs could not be scaled, so we opted for the more realistic and consistent 2psi results. The results that you see from the graph we posted would only be exaggerated further if pressure was increased, so to see such a drastic difference at only 2psi is encouraging for our intercoolers.