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Dyno Runs--DCI vs OEM air box (Hood Closed)
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08-12-2009, 01:10 PM | #46 | |
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Of course you are ignoring the most important thing, and it has nothing to do with horsepower. It is how hard the turbos are working to hit a boost target....BMS' testing showed less strain on the turbos. Mike |
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08-12-2009, 01:17 PM | #47 |
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Thanks for the info Mr. 5. I have been thinking about going DCI, but after seeing this....and driving around in the SoCal heat, I think I am going to stick to the stock air-box with a drop in.
Any DCI systems that use a large heat sheild design? What about a hybrid design that uses the DCI piping and filters in a stock-style air box? Would that help turbos in terms of less strain and lower heat soak? |
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08-12-2009, 01:19 PM | #48 | |
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I had a good discussion with Terry on the other forum about this and you can read about it if you'd like. We were talking about what to do with further testing, which is also what I have mentioned in my post above.
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08-12-2009, 01:22 PM | #49 |
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I also think that it's interesting to find that in the other thread, most people agree with the other test and in this thread most agree with what I did.
It's interesting how it works that way.
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08-12-2009, 01:33 PM | #50 |
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Hood latched but not completely closed ..
just to give an idea to everyone how much space is actually available for wind/cooling when the hood is latched, but not completely closed:
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08-12-2009, 02:57 PM | #51 | |
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Nice test Mr. 5, I am sorry I missed this on its first go around. But then, I have to do actual work sometime right? The results seem to square with what we know about these cars, that the engines run fricken hot. So with a DCI you are going to be sucking a lot of really hot air if the engine has been running. Not a big deal if you have been icing the intake between drag runs in the staging lanes, but a little more important if you are daily driving. That it only took 2 dyno runs to make the DCI substantially under perform the stock set-up seems indicative of what will actually happen driving the car. I would love to see the results you get with this test:
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08-12-2009, 03:02 PM | #52 | |
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08-12-2009, 03:03 PM | #53 |
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Mr. 5, thanks for the good work and write-up.
One facet I believe that's missing from this discussion is the effects of ram air charging that are lost on the DCI's. I come from the superbike world where RAM air setups are common, and in particular from racing Kawi's for a while, who had/have arguably the best ram air system. The OEM setup I believe is a ram air system. I confirmed this when talking to Steve Dinan (in person) and thier testing of the 335i also concluded that at speed the OEM box is a pressurized system. This reduces the compression ratio required by the turbo's and thus reduces the rpm required. This effect isn't represented by these tests because, as already pointed out, the fan speed is measured at the fan and unless it was a 15' 100mph fan, the frontal pressure on the car is going to be very little compared to actual road conditions. As you already pointed out, this indicates that the OEM box is better at the track (the one with turns, my playground), where the RAM effect is much more important for both reducing the load on the turbo's, and isolating the charge air from the engine bay air thus reducing and stabalizing the IAT's. For dyno numbers and 1/4 mile runs (with lots of time to cool down in between) the DCI's appear to give higher initial numbers. But IMO the effect of heat soak, and loss of RAM air, will create increasingly higher IAT's and thus lower HP, and after only a few runs (or a couple laps) the DCI's may have less power than the stock box. And with a tune that is asking for more boost the DCI's may actually end up with a higher load on the turbo's than the OEM box. And I agree with you on the hood sealing. With the hood completely down, there's much less air "washing" over the engine, flushing out the hot engine bay air, and thus reducing heat soak shown with the DCI's. In this case, a 1/2" makes a difference! ;-) Just look at the seal all around the hood and you realize how little air is flushed through, especially with the panels on the bottom of the car. Basically just what's flowing through the radiator, which is, of course, heated by the rad, plus the heat added by the engine block. The ideal solution would be a design similiar to the stock box, simply with a larger filter and possibly straighter flow lines. Interesting that in the new S1000RR BMW sport bike they make a point of the fact that thier air filter is oriented vertically as opposed to all the other bikes where it's horizontal, and that this reduces the pressure loss of the intake air, which means it reaches the intake manifold at a higher pressure. Something like the Gruppe or Simota is in line, but the Simota filter doesn't actually look like it's got that much more filter area than the stock filter. Or Dinan's approach of piping a CAI into the downstream side of the filter, keeping the ram effect but supplying additional volume. At this point I picked up the Helix drop in along with the Rev. 2 FMIC, because I just haven't seen anything that I feel is a great improvement over stock. That having been said, the results of the initial runs on each certainly show that the flowrate of the OEM with a drop in is restrictive enough vs the DCI's for a that boost to produce almost 15 less hp, which is significant. Anyway, just my thoughts. Great work! |
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08-13-2009, 08:53 AM | #55 |
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I didn't. That's one thing that Terry did that I didn't.
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08-13-2009, 08:57 AM | #56 |
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We can log that on BT though can't we? If indeed the wastegate DC is higher, then regardless of what any dyno shows, you are overspinning your turbos to equal the same boost of an aftermarket intake at higher boost. To me that alone is worth the expense.
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08-13-2009, 08:58 AM | #57 |
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I wonder why AMS says that they saw no gains with the intake removed and no filter yet people are posting dyno gains with a DCI?
AMS said this yesterday - and that its why they arent goign to produce an intake. I tend to belive them.... |
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08-13-2009, 08:59 AM | #58 | |
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I may test this after I do the FMIC testing. |
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08-13-2009, 09:11 AM | #59 | |
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It's harder on the turbos to make 14 psi rather than 13 psi, but if people want more power then they will take the 14 psi. Based on this statement, you would rather take the 13 psi because it's easier on the turbos?
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08-13-2009, 09:14 AM | #60 | |
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This coupled with a FMIC, should serve to LOWER IAT and reduce wastegate duty cycles. Also - it seems the Stett could do this on its own, although the addition of a good FMIC increases IAT reduction exponentially. Why settle? |
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08-13-2009, 09:26 AM | #61 | |
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08-13-2009, 04:54 PM | #62 |
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Oh my goodness that car again...up goes my underhood IATs; rpms; boost; cycles...more than enough psi...yip!!! Want one now!!!
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08-14-2009, 08:55 AM | #64 |
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08-14-2009, 08:57 AM | #65 | |
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08-14-2009, 10:48 AM | #66 | |
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I routed the tack wire up towards the windshield and routed it over the passenger mirror so it would stay. If you do this then you could slam the hood without crimping anything. Edit...you must have had a fun time last night to post at 2:30 in the morning.
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