Engine Drivetrain 3rd Gen Introducing the Helix DDCâ„¢

Discussion in 'Tuning and Performance' started by Eric@Helix, Feb 25, 2016.

  1. Eric@Helix

    Eric@Helix New Member
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    Introducing the Helix Dual Density Coreâ„¢

    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.

    [​IMG]

    -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.
    Method/ Testing
    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.

    [​IMG]
    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.

    [​IMG]
    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. DONâ€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.
     
  2. Eric@Helix

    Eric@Helix New Member
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    Today I'd like to talk about the development of this specific intercooler and more on why we developed the DDC.

    We actually are on our version 2 of the F56s intercooler. We designed, modeled and prototyped our first version last summer. The design was based upon what had worked in our past coolers, with improvements in end tank design. Here's a redacted PDF of version 1:


    [​IMG]

    Once we installed the prototype in the test car, we were a little disappointed with the results. They were an improvement over stock, especially in higher boost conditions, repeated use and at high RPM, but not the dramatic improvements that we had seen in the R series MINIs. Part of that was due to the bigger stock core, but a big part of it was due to an inherent design limitation: our fin density through the core was too tight, dropping pressure between the ferrules more than we wanted. This is very difficult to measure utilizing OBD-based datalogging software, since the factory engine control management operates using what are called torque targets. The DME (the engine's brain) asks for certain levels of boost, based upon the condtions. When you are in sport mode, at wide open throttle (giving it the ol' stick!), the DME asks the turbocharger (By controlling the wastegate) for as mush boost as possible until it reaches a pressure threshold. Then it starts bleeding boost to maintain the target pressure. If you have an intercooler that is very thermally efficient (drops temps well) but also creates a larger pressure drop from end tank to end tank, the DME has to keep the turbo on the roil for longer. Spool up is slower, meaning that your initial burst of torque is slower to happen after you stomp on it, and you're working the turbo harder. Here are some of the data we collected on our version 1 cooler.


    [​IMG]

    These two third-gear pulls were done on subsequent days. The first day was the stock cooler, the second day, our prototype. Weather conditions weren't perfectly consistent, unfortunately. The second day was several degrees higher with 30% more humidity. As you can see the boost levels are pretty consistent, but if you saw the wastegate duty cycle numbers (not shown on this graph) the turbo was working harder with the prototype, which raised the intercooler inlet temperature). Both pulls were the first of a series of 4, so this graph represents the least heat soaked runs. The prototype's greater thermal mass and increased frontal area kept it consistent run-to-run.

    So what we had was a cooler that performed well enough, but didn't solve the problem of pressure drop. Back to the drawing board it was. We came up with two tricks to increase efficiency through the core: end tank design, and fin density. To be continued in a later post...
     
  3. Dave.0

    Dave.0 Helix & RMW Powered
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    So what is the Over / Under # of days until ALTA, Forge, WMW copy this. :rolleyes:
     
  4. Savvy

    Savvy Well-Known Member
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    They couldn't even copy the original right... people smart enough to see the differences know this.
     
  5. vetsvette

    vetsvette MINI Alliance Ambassador

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    After getting in on the pre order for the R56 unit and seeing the quality of said unit, I'm in for one of the F56 DDC Interthingies. Order placed! :D
     
  6. packimocity

    packimocity New Member

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    Order placed.

    The Helix 2nd gen FMIC got swapped thru 3 different MINIS of mine....guess I got my moneys' worth. (It's still in my Countryman.

    Go Helix!!

    pac
     

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