Im guessing a 4.5" would be good...

 

Heavy you will make more power over a longer period of time with a better intercooler a 4.5 will produce cooler air and fight heat soak much longer then a stock sized intercooler. whatever you loose in your weight loss quest you would gain in forward momentum of not loosing the horsepower you are loosing by the means of thermal heat soak.

i wouldn't sweat the weight different at all for a track car id rather have the bigger more efficient cores.

 

+1.... and no brake boosting is so 2009...

 

I can weigh my 3.5s and 4.5s... I can also weigh stock ICs...I think for most applications 3.5s with 14x9 sizes are more then enough.. I just tested yesterday on dyno my 3.5s and on one run there was 20 rwhp difference on a 18g car at 1 bar.. nothing else changed....

http://www.youtube.com/watch?v=1vv9RV60AUk

 

the question for the road racer is though how much faster does a 3.5 heat soak versus a massive 4.5-6" core. drag racing id say 3.5 or northern state driving 3.5 southern state and track weapon is say go bigger.

 

My car used to have the Evo 3.5's w/ the old hybrid GT28's (K16 hotside...absolutely zero lag but of course they would die out up top). that was a perfect track set up/ The Billet 16's would also be good.

can't have any lag exiting corners.

 

We like the 4.5" as well, At the Texas Mile, we saw the IAT plateau and stay stable, but we were going at a high rate of speed. It is just as important to have adequate air on the ambient side of the cooler to exchange the heat form core. Some times the center of a core that is too thick will not see enough moving air to avoid core heat saturation. Core design is also huge. Look at the 959 IC,s they have to be 5.5" but core technology has come along way in the last 25 years.

 

Hey Mark! Is your 3.5" IC good enough for K24/20G turbo application? Thanks!

 

yes they are!

 

Heavy, I have some new results for our a28 package, with our Monster IC's and stock airbox setup, that I should have ready sometime tomorrow.

All of this talk about responsiveness for the track and you are talking about doing k24s? The 28's spool faster than a stock K16 car! Not to mention the top end power that is there as well...

 

Please reread my last two sentences. I'd worry more about the weight and cost than I would the "lag". I didn't use my *** dyno to measure the difference in spool I used datalogs that measured multiple times in a second and overlaid two graphs in a package designed to analyze the information. This was internal logging on a standalone EMS that I tuned not some slow *** OBD-II logger.

The stock intercooler on a 3liter Supra is about the size of a shoebox but thinner. Probably the size of a single 996 intercooler - maybe. I moved to a 4row Greddy - about the face size of 4 shoe boxes and about 3.5inches thick. In other words much more volume and piping too. Graphs didn't differ noticeably when I measured pressure at the intake. This after all sorts of people moaned about how it would be SO laggy. Bull, my data didn't bear that out and the car felt great to me all data aside. We're pressurizing and moving 3.6liters+ of air at thousands of RPMs in these cars. Ponder the airflow and volume of that and then look or measure how much is in a pair of even the largest intercoolers for these cars. Sorry, I don't think the turbo will have any trouble filling it!

Weight, yeah that's an issue. If you're on a road course in the heat though the more MASS an intercooler has the better. When it reaches heatsoak it will reject heat both into the cooling airstream and into the engine intake air. You can see this sometimes coming off a hard pull and then going part throttle or stopping - air temps can sometimes go up before dropping. Autospeed magazine tested and noted this while creating some of their water sprayer setups over in Australia. Check out their testing - it's online. And yeah I'd consider the Swain stuff - it's cheap and worth a shot if it gains any efficiency...

 

I would say so... Todd Knighton used the 3.5s on his high HP cars a few years ago... we use the 4.5s on 1000 rwhp cars and that is working well... I made the 4.5s 4 years ago on my car... I currently made the 6 inch cores... we will see how they perform very soon....

going back to the 3.5s....
remember we're coming from a 2.5x8.5in core from stock or only 21.25 square inches of flow area and that's not even that because the tube/fin design has smaller channels than the bar/plate design to 30.8 square inches in bar and plate 3.5x8.8inch....so we're already 100% increase on the example I'm showing, or the equavalent of two or more stock cores stacked!
However, as far as radiant area, we're nearly 50% better and have
76% more flow area through the cold side for ambient air to cool it better!

as far as core thickness... they use thicker "brick size" cores for lest say 1/4 runs because they will cool better for short periods of time.... for long term driving too thick may not be the way....

 

No, I was saying I already have K24's.

Faster than 16's huh? Any comparo Dyno's?

 

Hey Mark thanks for your response! From above, it sounds like 3.5" is good enough for me.
But I wonder why thicker core is not really good for drving long time? Do you mean thicker core of IC is not necessary better for long term driving under WOT condidtion?

 

Are you running stock k24's?... I ran them 3/4 years back and found them to be too aggressive when they kick in (depending on your tuning of course) maybe this is why you are finding the car not as responsive to a NA car... you need to be in the sweet spot with the Turbo and have boost building smooth power through the corner.