Originally Posted by itguy

Water-air heat soaks, so is typically used for glory runs. Since F1 went back to turbo, they are using air-air from the same company we are sourcing these cores from. The only way to make an water-air setup work effectively would be to run cores of the same efficiency as these out front to dissipate the absorbed heat. The cores BBI used look like Bell, and I doubt they put aerospace grade cores in the front bumper, rather relying on an iced water tank. Would be cool to see more info on that build, likely running a large ice tank.

Originally Posted by pwdrhound

Earl,
10 m/s equals 22.4mph. Are you saying that a vehicle traveling at 140-160mph only has 22.4mph of air flowing throughout the IC duct? Out of curiosity, where did you get that data? That does not seem right as the ducting is generally very efficient. I would see some losses but not an 80% loss in airflow through the core. 50% loss would seems more realistic which would equate to a vehicle traveling about 50mph. Just thinking out loud.. Thanks for all your contributions over the years!

Originally Posted by Setrab

Cooling air face velocity

The table below can be used to estimate the air speed through the cooler depending on vehicle speed and inlet size.



<table border="0" cellpadding="0" cellspacing="0"> <tbody> <tr height="22"> <td colspan="3" height="22" width="64">
</td><td class="xl82" colspan="4" width="256"> m/s (Va) </td> </tr> <tr height="22"> <td class="xl65" height="22"> Vvehicle </td> <td class="xl65"> Vvehicle </td> <td class="xl65"> Vvehicle </td> <td class="xl72" colspan="4"> Front inlet area size in % of cooler area </td> </tr> <tr height="20"> <td class="xl71" height="20"> m/s </td> <td class="xl71"> km/h </td> <td class="xl71"> mph </td> <td class="xl66"> 30% </td> <td class="xl67"> 50% </td> <td class="xl67"> 70% </td> <td class="xl81"> 100% </td> </tr> <tr height="20"> <td class="xl68" height="20"> 13.9 </td> <td class="xl68"> 50 </td> <td class="xl69"> 31 </td> <td class="xl72"> 2.1 </td> <td class="xl73"> 2.2 </td> <td class="xl73"> 2.3 </td> <td class="xl74"> 2.4 </td> </tr> <tr height="20"> <td class="xl68" height="20"> 27.8 </td> <td class="xl68"> 100 </td> <td class="xl69"> 62 </td> <td class="xl75"> 4.7 </td> <td class="xl76"> 5.4 </td> <td class="xl76"> 5.6 </td> <td class="xl77"> 5.7 </td> </tr> <tr height="20"> <td class="xl68" height="20"> 41.7 </td> <td class="xl68"> 150 </td> <td class="xl69"> 93 </td> <td class="xl75"> 7.3 </td> <td class="xl76"> 8.2 </td> <td class="xl76"> 8.5 </td> <td class="xl77"> 8.7 </td> </tr> <tr height="20"> <td class="xl68" height="20"> 55.6 </td> <td class="xl68"> 200 </td> <td class="xl69"> 124 </td> <td class="xl75"> 9.7 </td> <td class="xl76"> 10.9 </td> <td class="xl76"> 11.4 </td> <td class="xl77"> 11.7 </td> </tr> <tr height="20"> <td class="xl68" height="20"> 69.4 </td> <td class="xl68"> 250 </td> <td class="xl69"> 155 </td> <td class="xl75"> 12 </td> <td class="xl76"> 13.6 </td> <td class="xl76"> 14.2 </td> <td class="xl77"> 14.5 </td> </tr> <tr height="20"> <td class="xl71" height="20"> 83.3 </td> <td class="xl71"> 300 </td> <td class="xl70"> 185 </td> <td class="xl78"> 14.3 </td> <td class="xl79"> 16.3 </td> <td class="xl79"> 16.9 </td> <td class="xl80"> 17.3 </td> </tr> </tbody> </table>
For example, if vehicle speed is 150 km/h and the relation between front air inlet opening and the charge cooler area is 50% you will have roughly 8.2 m/s cooling air face velocity.



The cooling air face velocity is on average 15-18% of vehicle speed in the table above. These values can be better or worse depending on intercooler installation in the vehicle and vehicle aerodynamics.

Originally Posted by earl3

Its been a blast, thanks! I'll be glued to this thread for a while

Affirm on the ram air speed through the IC core vs vehicle speed -it slows way down with the core in the way. The ram air pressure drop gives it away. Using Bernoulli's eqn for incompressible flow and assuming a perfect duct with no losses gives a 59m/s (~130mph) freestream flow speed. Add in some losses and you're looking in the mid 100 mph region to get 10m/s across the core. This is probably why they gave you specs at that cooling air speed. When GTRNick had his Marstons tested at a facility that does F1 IC testing, they measured at 3, 6 and 9 m/s across the core which corresponds to a fairly wide range of vehicle speed.

Setrab posted some nice rules of thumb on their website using non-perfect ducts:





As you know, this is somewhat difficult data to actually measure on the car, but to prove I'm not out to lunch, this guy actually did some testing and got similar numbers (note the effects of adding a fan!):


http://www.sccoa.com/articles/cwintercooler.php



I imagine the reason the theoretical cooling flow vs vehicle speed is a little lower through your core is because its more dense than a Setrab core.


Being generous, the stock inlet to core face % on a 996 is about 25 + the denser core and you're well into triple digits to get the advertised efficiency numbers. The good news is those efficiency numbers are f'n awesome and I'm confident you still see massive gains at lower speeds.

Originally Posted by proTUNING Freaks

Many people will attempt to go on a quest in solving heat issues by introducing better intercooling when in fact they should really take a step back at times and review their system as a whole to begin with starting with the tune on the car.

First and foremost you have to review what sort of driving you're building your particular setup for, what are your goals. One goal listed above is a power goal and that's a great start. You have to first look at the efficiency of your turbos given where your current tune is sitting. The reason I say this is that people will try running their non-purpose built non-road course type tunes on road courses in 20-30 minute sessions and will heat soak whatever they have on the car whether it is the most efficient intercooler core on the market today or not. Once you have the tuning (boost/airflow levels required to support your power levels) then you start on the quest to build the ultimate intercooler solution and you may be lucky to pull it off with an air/air setup that will fit your goals.

My opinion is that there really is no so called 'ultimate' hardware unless its backed by a goal and purpose built to fit that specific scenario in the best way possible. Exactly the same principles apply to tuning.

Any and all of the above options can be ultimate solution if they satisfy your needs from the performance point of view. Personally I'm a huge fan of water/alcohol injection. I have tuned race teams around the world with it where the rules would allow for it but I also realize that a water/alcohol injection system isn't part of your goals here so there really isn't any point discussing it as the system needs to be built to your goals not mine

What is your current setup on the car, how much boost are you running, what octane, what type of road course, average speeds, how long are the sessions, altitude, is it flat level or hill climb, are you making sure you're running your turbos in their peak efficiency?

Dzenno@PTF

Originally Posted by Bobbyfali

I truly applaud you & SRM with your under taking of this project, as it can only help the 911 community, but I am surprised that someone like yourself that needs consistent, reliable HP for what you do, that this isn't a foundational part of your build plan. For fractions less and miles better performance then ANY ultra NASA core, water meth would be better performing. Even if you wanted to still do these serious coolers, having the water / meth would only bring your cooler to another level on top / coupled together with these new cores.


Again, I am still following this thread as it is advancements for our platform and am glad someone is pushing the envelope!


Thanks


Bobby Ali


ba

Originally Posted by xbox_fan

Anyone ever tried fitting fans under the IC's?

Originally Posted by GTRNICK

Nice to see someone thinking like I did. Good luck in moving forward and I am subscribed

p.s. when I fitted my aerospace cores I did a back to back test against 997.1 cores and saw over 20* drops in IAT's in certain gears, you just cant beat aerospace cores.

Originally Posted by earl3

To prove I'm not completely out to lunch, this guy actually did some testing and got similar numbers (note the effects of adding a fan!):

Originally Posted by pwdrhound

There are many aftermarket choices available but very few if any have proven to surpass the performance of the OEM 997.2 for those looking for all around performance for moderate power (up to 650whp or so). This has been proven repeatedly in real world testing as reported by Earl who has tested them against many aftermarket options out there.

Originally Posted by pwdrhound

This is a like shopping for the best wine but people wanting to sell you cheap whiskey instead because it'll get you drunk quicker. It's apples and oranges. I am well aware of the concept and benefits of meth injection. There are definitely applications where meth has its place and where it shines. I'll say it again, it is just not an option I want to entertain and deal with due to the added complexity, weight, and constant servicing requirements. This is all about creating the best air to air intercooling solution possible that surpasses any other air to air offering available. Simplicity is part of my build plan. A simple, lightweight, ultra reliable, zero maintenance solution that provides a quantifiable reduction in IATs (without drawbacks) over anything currently available. Why does Porsche Motorsport use the ultra expensive Secan heat exchangers instead of meth which could provide even better results? Probably the same reasons, it doesn't fit their goals. The 997.2s were originally designed for a 530hp TT so it's not surprising they fall short in the 612hp 7GT2RS the same way they fall short in my case. Not all the time and not by much, but they do fall short. Hence the aerospace solution...

Originally Posted by stevemfr

I don't know, Earl. The effects of the fan that this guy claims to have seen go against everything I've ever read or heard about fans in relation to cooling air flow based on vehicle speed (my info was generally on the effects of fans on AC condensers).

In general, consensus is that as of around 30mph or so, fans are more of a restriction than an aid in cooling air flow (standard vehicle configuration with the radiator(s)/AC condensers at the front and relatively unrestricted air flow). The guy in the link you posted seems to have measured a reduction in cooling all the way up to 100mph based on the fan. I find this hard to believe. Either the lower temps were due to the lower starting temps (the fans cool the ICs at idle) or his measurements are off in some way.

Originally Posted by oldbooster

I hope you realize that your point of view is just like my point of view, a reference point. We are solving the same issue different ways and although they are indeed apples and oranges in terms of approach the end result is what matters. A more appropriate way of describing this would be different ways to skin the cat. For me you are just drinking a super expensive bottle of rare wine that tastes no better than a really tasty mass produced $20 bottle. In fact many will argue the $20 bottle tasted far batter and for the cost difference they got a really nice bottle of cognac too!