Posted on 25th Feb 2016
Introducing the Helix Dual Density Core™
When Helix introduced the world’s first stepped core intercooler, it was revolutionary in the automotive aftermarket. The design was born out of a necessity for a balance of properties in a cooler that were useful not only in track applications, but also a variety of street conditions. The goal was to produce an intercooler that had excellent charge air cooling, high end-tank flow efficiency, quick recovery rate, minimal pressure drop, and significant thermal mass. Many existing coolers could achieve one or two of these characteristics but not all of them. With our first models we were able to achieve excellent results in 3 of the 5 characteristics that we were targeting, and decent results in the other two. With our fourth-generation DDC™ intercooler, we have achieved the greatest balance ever. Here’s a breakdown:
-Temperature drop: We chose bar and plate core design with very high fin density, giving us the greatest surface area for heat exchange. Our coolers have always had the greatest fin density of any core on the market. It’s more expensive, but it gave us un-paralleled temperature drop. Other companies that copied our stepped design either chose very inefficient tube and fin design, or had poor fin density. Like all things in charge air cooling, there was a compromise with such a dense fin count: an increased pressure drop. With our 4th generation DDC™, we have addressed this compromise, by having two different fin densities: we maintain a very high fin count on the ambient side (the side of the core that is being cooled by the movement of ambient air), and reduced the density through the core, to minimize pressure drop. This innovation has given us the balance of performance characteristics that we’ve been striving for.
-End Tank Flow Efficiency: This is an area where we have made the greatest improvements throughout our 4 generations of intercoolers. First, our engineer designs our end tanks in-house using the latest design software and Computational Fluid Dynamic renderings. For each intercooler we go through multiple generations and test them before we are satisfied with the performance. We have worked sometimes as long as a week on a single tank design. Re-drawing, testing, re-drawing, testing. We’re not satisfied with something that looks good and fits. Once we have a satisfactory design we 3D print the design in-house for proof of concept and fitment testing.
I guarantee that this commitment and attention to detail is unique in the industry. Once we go to production, all of our end tanks are cast in aluminum, versus cheap and inefficient welded sheet metal. There is no comparison in flow. You can see the progression of designs through our generations of coolers, and how the shapes have changed.
-Quick Recovery Rate: This was one of the key needs when we introduced the stepped core. The advantage of a thin core with a large surface area is that it can recover quickly once it is heat-soaked (think of the R53 generations of MINIs—there’s a reason that we never released an intercooler for that application: you couldn’t improve on the factory design). With the enlarged surface area of the stepped design, we were able to get the advantage of the increased frontal area with a core volume that balanced pressure drop, flow, and thermal mass for the best overall package.
-Pressure drop: When you design a cooler with aggressive temperature drop, you get increased pressure drop. That’s because, as you cool intake gasses, they contract in volume, adding to the drop in charge air pressure. This is a natural trade-off, and if it’s moderate, we like it because a colder intake temperature is good for power and engine wear. As stated above, greater the fin density through the core added more aerodynamic drag and increased pressure drop in our older coolers. Again, we accept moderate pressure drop as a necessary limitation that pays off in ultimate motor output (The cooler air would more than offset the slight drop in engine boost). However, too much pressure drop from these two factors is not desirable, and there’s where we’ve made our biggest change to core design: with the Dual Density Core™, with greater density on the ambient side and less density through the charge core.
As I have alluded to above, our in-house engineer designs, CFD tests, 3D prints our prototypes. We then road and dyno (our in-house Mustang MD-250 dynamomoeter) test our coolers.
One of our CFD renderings demonstrating charge air velocity
It turns out that road datalogging is a very good method vs. dyno, since it is difficult to produce wind velocity and volume that mimics road or track conditions. One note about testing and datalogs: It is easy to show a single test curve which demonstrates massive performance increases. The truth is that a company can manipulate test conditions in a single circumstance to help market the product, so company-produced test results should always be taken for what it’s worth. The key to true intercooler performance is the whole package: how does it perform in a variety of conditions, and is it repeatable.
3D Printed model of one end tank produced in-house. It was printed in three sections because our print bed is slightly too small for this part.
-Production: Unfortunately, the labor intensive nature of intercooler production is such that almost all intercooler manufacturing has migrated off-shore. There are a couple of US companies who still manufacture similar type heat exchangers, but their prices and production levels are impossible for our industry, and interestingly, their quality is spotty. I am a huge proponent of American manufacturing and have done in-depth feasibility studies on re-patriating cooler production. The answer is, we’re not yet big enough to come close to making it work. All other Helix products are proudly manufactured in USA. DON”T BE FOOLED BY DECEPTIVE MARKETING! No MINI intercoolers are made in Germany or England. I know the exact factories where each of our competitor’s coolers are made. They are in China.
-Introductory Offer: We are finally ready to offer a special introductory price on our Stepped Core Intercooler for the third generation MINI. Our first production run is now under way, and we wanted to extend a one-time special price for those who have been waiting so patiently for the release of our newest intercooler. The regular retail price will be $749, but we will be running a special, one time introductory offer of $649.
Here's how it will work. If you want to get in on the introductory offer, go to our website, and select the introductory offer. It will charge a $75 deposit which will lock in your price. The balance of the price, plus shipping, will be charged when we ship the cooler. If we get 25 or more deposits, we will pay the shipping (to CONUS only, but we'll do a special deal for those outside) as well! We expect to ship introductory offer intercoolers at the end of April, beginning of May.
We will be releasing more test data as we go, and have a complete installation how-to ready.
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