Intercooler upgrade comparison
#31
04-02-2013, 03:51 PM
I don't claim to be an expert in fluid dynamics, but here's a thought. If the ducts have been removed, it may be causing some problems.
The upper and lower ducts serve as a conduit to promote the Venturi effect. The pressure outside the car directly in front of the side vent and the pressure of air behind the rear bumper serve to create a pressure differential in the long channel inside the fender (the narrow part of the upper ductwork.) This restrictive channel is should have lower pressure and higher velocity air used to cool the intercooler before the diameter expands once again through the lower duct and out the rear bumper.
This is from Christophorus (issue 300 specifically discussing wind tunnels and the 996.)
For your setup, at higher speeds, I have a feeling even nitrous cooling sprays won't help as there isn't enough flow because the Venturi channel/shape is gone.
The upper and lower ducts serve as a conduit to promote the Venturi effect. The pressure outside the car directly in front of the side vent and the pressure of air behind the rear bumper serve to create a pressure differential in the long channel inside the fender (the narrow part of the upper ductwork.) This restrictive channel is should have lower pressure and higher velocity air used to cool the intercooler before the diameter expands once again through the lower duct and out the rear bumper.
This is from Christophorus (issue 300 specifically discussing wind tunnels and the 996.)
For your setup, at higher speeds, I have a feeling even nitrous cooling sprays won't help as there isn't enough flow because the Venturi channel/shape is gone.
#32
04-02-2013, 04:02 PM
I use the 997.2 ICs on the track for hard 20 minute sessions in a K24 600hp car and they are excellent at quick thermal recovery. Using data acquisition for timing and speed along various points on the track, my car is running just as strong at the beginning and end of a 20 min session in 100+ degree temps. Additionally they are feather light at around 7lbs each from what I recall. For street use, drag strip and stop light bragging rights you might be better off with a lower restriction higher flow core but for track work the 997.2s are great.
#33
04-02-2013, 09:42 PM
My concern is that people throw fancy terms like pressure drop and efficiency around and assign great looking (& impossible) numbers to them and to the average customer that may not understand or has better things to do than worry about these things, it seems like the best thing since sliced bread and they end up with something that may be worse or no better performing than stock. Hopefully this isn't the case here. That's why I like to see data to back up the specs, something Markski offers openly on his website and something I've done for the .2s and ETS, hence my recommendation for the OP to treat option 3 with some caution.
Hope that clears it up!
Last edited by earl3; 04-02-2013 at 09:48 PM.
#34
04-02-2013, 09:47 PM
Now that is interesting, I would have expected an appreciable drop the instant the nitrous hit the cores -bbywu may be onto something with regards to the ducting.
#35
04-03-2013, 12:39 AM
JSBear, great point and fair enough, I should have better explained my words of caution. I too enjoy reading Chris and the USP crews' well documented builds and was surprised when I read the specs on the coolers. The specs are written exactly like every brand of knockoff cooler I've seen (AP, Blownsix, Godspeed, the other ebay units popping up like weeds lately), which caught my attention. Take a look at the AP cooler specs and compare, the wording and semi-broken English is all there, and though the specs are slightly different, they still make no sense. 89% (or 85 with AP) efficiency on a 996? under what conditions? No log produced from any cooler has come anywhere near that. 750cfm (or 620) per side? useless without the pressure drop used to achieve that flow (I could put 2000cfm through a set of coolers with a high pressure loss). Less than 1% pressure drop? meaningless.
My concern is that people throw fancy terms like pressure drop and efficiency around and assign great looking (& impossible) numbers to them and to the average customer that may not understand or has better things to do than worry about these things, it seems like the best thing since sliced bread and they end up with something that may be worse or no better performing than stock. Hopefully this isn't the case here. That's why I like to see data to back up the specs, something Markski offers openly on his website and something I've done for the .2s and ETS, hence my recommendation for the OP to treat option 3 with some caution.
Hope that clears it up!
My concern is that people throw fancy terms like pressure drop and efficiency around and assign great looking (& impossible) numbers to them and to the average customer that may not understand or has better things to do than worry about these things, it seems like the best thing since sliced bread and they end up with something that may be worse or no better performing than stock. Hopefully this isn't the case here. That's why I like to see data to back up the specs, something Markski offers openly on his website and something I've done for the .2s and ETS, hence my recommendation for the OP to treat option 3 with some caution.
Hope that clears it up!
A
#36
04-03-2013, 03:24 AM
Guys are referring to what's known as the Bernoulli Principle. This is a inversely proportional relationship between air speed and it's relative pressure. Basically faster= lower pressure, slower=higher pressure.
Blackhorse, I think, with what little I've read, that you have an airflow problem that's related to your ducting. It's possible you have stagnation or reversion going on inside your ducting. I think it's interesting that you don't see any change to your temps with your nitrous. Do you happen to have any pictures of your ic setup?
Oh, btw I'm running Markski's ic and I'm very happy with them.
Blackhorse, I think, with what little I've read, that you have an airflow problem that's related to your ducting. It's possible you have stagnation or reversion going on inside your ducting. I think it's interesting that you don't see any change to your temps with your nitrous. Do you happen to have any pictures of your ic setup?
Oh, btw I'm running Markski's ic and I'm very happy with them.
#38
04-03-2013, 12:02 PM
Rep for you, bbywu, RnH, et al. - that's good (and useful) info to have.
#39
04-03-2013, 12:48 PM
I have Markski's intercoolers and they work very well at keeping IATs low down here in South Texas where temps easily and routinely get into the 100-110 F range most of the year. Also, Markski's customer service was exceptional when I was installing his IC's by myself in my garage. Can't say enough good things about his willingness and enthusiasm in working with you when you have questions or problems that need to be resolved. Lastly, his intercoolers are visual works of art.
Good luck with your choice of IC.
Good luck with your choice of IC.
Last edited by Valley996TT; 04-03-2013 at 12:50 PM. Reason: correction
#40
04-03-2013, 05:30 PM
Basic Sponsor
I The intercooler ducting and a good seal at the intercooler to ducting junction is absolutely critical to creating a Venturi effect which effectively draws air over the intercoolers. The set ups that butcher or eliminate the IC ducting severely degrade the airflow over the ICs. No way to get around that, plain and simple.....
with all that said, Im guessing majority of the HIGH HP cars including mine that ran 9s is done just like that... but it has to be done right...
and lastly, for the those running a MAF and your not grabbing air from the top of the ICs you have absolutely no reason to get rid of the upper duck...
This is our 4.5" direct replacement version.... hand made in house with one piece molded end tanks pressure tested to 35 psi with cnc machined flanges we make and test for leaks on bench with hoses... We also offer free duct trimming and even will put it in the bracket and send it ready to be installed..
__________________
2001 996TT 3.6L and stock ECU
9.66 seconds @ 147.76 mph 1/4 mile click to view
160 mph @ 9.77 seconds in 1/4 mile click to view
50% OFF ON PORSCHE ECU TUNING BLACK FRIDAY SPECIAL
2001 996TT 3.6L and stock ECU
9.66 seconds @ 147.76 mph 1/4 mile click to view
160 mph @ 9.77 seconds in 1/4 mile click to view
50% OFF ON PORSCHE ECU TUNING BLACK FRIDAY SPECIAL
#41
04-03-2013, 08:39 PM
I fly jets for a living so I'm fairly familiar with fluid dynamics. The intercooler ducting and a good seal at the intercooler to ducting junction is absolutely critical to creating a Venturi effect which effectively draws air over the intercoolers. The set ups that butcher or eliminate the IC ducting severely degrade the airflow over the ICs. No way to get around that, plain and simple.....
#43
04-04-2013, 05:45 PM
just curious as to no one mentioning the EVOMS IC. It is what i currently have on my car. Are they outdated, too pricey, knockoff, heavy... or something else I'm missing? I run them with W/M and have been happy so far, but I am also getting ready to throw on some A3076 next week... so any input is appreciated.
#44
04-04-2013, 05:53 PM
Basic Sponsor
just curious as to no one mentioning the EVOMS IC. It is what i currently have on my car. Are they outdated, too pricey, knockoff, heavy... or something else I'm missing? I run them with W/M and have been happy so far, but I am also getting ready to throw on some A3076 next week... so any input is appreciated.
__________________
2001 996TT 3.6L and stock ECU
9.66 seconds @ 147.76 mph 1/4 mile click to view
160 mph @ 9.77 seconds in 1/4 mile click to view
50% OFF ON PORSCHE ECU TUNING BLACK FRIDAY SPECIAL
2001 996TT 3.6L and stock ECU
9.66 seconds @ 147.76 mph 1/4 mile click to view
160 mph @ 9.77 seconds in 1/4 mile click to view
50% OFF ON PORSCHE ECU TUNING BLACK FRIDAY SPECIAL
