Vertical flow vs. horizontal flow FMICs - interesting read

Discussion in 'Mazdaspeed 3/6 Engine' started by dale_gribble, Feb 21, 2017.

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  1. dale_gribble

    dale_gribble Greenie Member

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    I already posted all this somewhere else, but seeing as it's helpful I thought I would post this here.

    I had a curiosity about vertical vs. horizontal FMICs for our cars.

    I've been reading papers/articles/forums regarding vertical flow/horizontal flow front mount intercoolers.

    The general consensus regarding flow aligns with a whitepaper from treadstone (below)-

    Vertical and horizontal flow cores that are manufactured exhibit different internal fin design characteristics. Horizontal flow coolers have long runner lengths which translate higher pressure drop through the core, while the vertical cores have short runner lengths and lower pressure drops. Inversely, vertical flow intercoolers have lower cooling efficiency compared to a longer runner horizontal flow.

    In laymans terms:

    shorter runs (vertical flow) = better flow/lower pressure drop/lower thermal efficiency
    longer runs (horizontal flow) = lower flow/higher pressure drop/higher thermal efficiency

    These general rules can be negated by the core design of course. A vertical flow core may be made more dense to increase efficiency and a horizontal flow core may be made less dense to increase flow/lower pressure drop.

    Treadstone goes on to say the following; these statements generally align with what I have read in automotive tech articles and decent forums threads and it seems quite logical. That, and pretty much all small displacement turbo cars you see have OEM horizontal flow intercoolers.

    Regarding vertical flow

    Many vertical cores that we manufacture are designed for larger displacement motors that do not require high boost pressures, therefore we need a dense internal fin design to extract all the heat we can, as the airpasses through 6-10” of core length.
    Regarding horizontal flow
    Many smaller displacement motors 1.6L to 3.0L will require higher boost pressures 15psi and above, to achieve the power levels one is looking for. With this higher boost pressure means higher compressor outlet temp, and we need to cool this air over a longer runner length of intercooler. Making the runner length longer means higher pressure drop through core, and this is something that robs us of power. Manufacturing a slightlyless dense core than our vertical flow cores, we can still have low pressure drop through core, while still extracting as much heat as possible.

    For my final act in this FMIC saga, I picked up a treadstone TR82 horizontal flow Intercooler. It has a similar size core (600^3in) to the existing TR1859 I'm using (582^3in). Although the core size is similar, the vertical flow TRV1859 is rated to 720HP and the horizontal TR82 to 500HP. The TR82 doesn't flow as well but will be much more thermally efficient.

    TR82 below. Since my TRV1859 is same side inlet/outlet, I opted for the TR82 to reuse all of my piping.

    [​IMG]
     
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  2. dale_gribble

    dale_gribble Greenie Member

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    I used my 0WG maf cal map for before/after comparison of intercooler impact.

    The results are predictable. For similar IATs and conditions, the TR82 horizontal cooled the air ~15F cooler than the TRV1859 vertical (graph posted). This comes at a cost of flow however. You can see in the attached boost graph, the TRV1859 hit 1.5-2psi higher boost throughout the run under 0WG. This extra 1.5-2psi resulted in about 5% higher mass air flow, up to 295g/s vs. 280g/s at redline.

    [​IMG]

    [​IMG]

    So, again, the question remains, what happens after I tune up the new IC? Will the gains in lower BATs with the horizontal flow IC allow me to push past the flow advantage of the vertical flow IC?

    I'll dial the boost back up and then it's just a question of whether I can add more timing also.
    [doublepost=1487727342][/doublepost]I had an interesting tuning session. So, if you recall, with the vertical flow IC the car was hitting ~345g/s (~46lb/min) @ ~ 26psi at IM(~2.8 pressure ratio). Considering a PSI in pressure drop, the BNR boost was more at 27psi at IM (2.9 pressure ratio). This is essentially PUSHING the BNR S3 (2871) past the 2871 turbo map.

    After installing the horizontal flow IC, I decided to up the wastegate to compensate for the additional pressure drop. So, I dialed the boost back up to 26psi at IM (~29psi/3 pressure ratio) to compensate for the 2-3psi pressure drop of the horizontal. The turbo/motor was not having it. At all. I got KR consistent >2 from 5k on.

    The phenomenon did not show up at the BATs; that is to say with meth spraying, the BATs were comparable which makes sense since the sensor is getting hit with meth, however, I am certain the EGTs must have gone up pretty good to result in the KR. I have an EGT sensor/gauge, but I don't have the datalogger hooked up which I wish I did.

    I had no choice but to back the boost back down to 24-25psi at IM (335g/s - 44lb/min). As soon as I did this, the KR all went away and I'm back on sure footing.

    Guess who just left 20whp/20wtq on the table? This guy. Here's a vdyno comparison (SAE adjusted of course) of what the extra flow does for power so far.

    [​IMG]
    [doublepost=1487727418][/doublepost]FML, the KR threshold for spark advance isn't any higher, at least in the 5-5.5k range. I can build up the ignition advance curve a little to the left and right but it's unchanged in that region. So there it is.

    When the dust settles on optimizing spark advance, I'll update with results.

    LMAO, most people mod for more power, I mod for less apparently. On the plus side, the TR82 looks SIIIICKK.

    [​IMG]
     
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  3. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    As i was reading this and hadnt gotten to the part where you already tested it i was going to tell you that california gas is too weak for you to push the timing and get the power back.

    Plus you dont have hot enough temperatures or the heavy track use that would make you lean towards the new intercooler


    Plan on switching it back?
     
    Easter Bunny, via a HTC device, Feb 22, 2017
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  4. Maisonvi

    Maisonvi Platinum Member

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    I love all the data, super interesting stuff here. How did you go about having the vertical one fit? I think another reason people use the horizontal is just do to packaging constraints. (and to feed peoples inner ricer)
     
  5. Chpspd

    Chpspd Greenie Member

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    Meh, I'm sticking with my cpe tmic.
     
    Chpspd, via a mobile device, Feb 23, 2017
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