Quote:
Originally Posted by KennyP
Also on the heatsoak part... intake air gets heated up by the turbos anyway. A good intercooler is here what is needed to cool it down... so this is more important part to concentrate on... not which intake, filter you are using?
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I am not going to comment on the filtration part of it as that is like arguing about oil makes, it's a very long deep discussion for another day lol.
However on the heat soak side of things, I have tested this as I stated above and I used logs to gather the data to do accurate comparisons. On a single run it's is fine, but after the 2nd 3rd, 4th 5th and so on the difference in intake temps are quite literally staggering and I would go so far as to say that you are actually hurting the motor by running a DCI setup in an N54 with the standard placement of the filters.
Many will argue this point and that's fine, we are all entitled to our opinions, but log's don't lie! Dyno results don't count as it's a very controlled environment and in no way shape or form depicts what happens on the road. In a very cold country the differences might not be so bad but in countries closer to the equator like south Africa etc during the summer months you are just putting tons of performance on the table and quite literally hurting the motor. Not only do intake temps go up, oil temps go up and coolant temps go up, dct oil temps go up etc, heat Soak smashes performance because it is a knock on effect on the motor. Slapping a big intercooler to mitigate this is silly in my opinion, rather run a better setup where you run plumbing to the cavity inside the front bumper and run the DCI in there, That way you actually get a true cold air intake. This is quite a popular mod on the M4's it's a bit harder on the Z4 but it can be done.
One thing you need to also take into account is that road driving is extremely variable and unpredictable in nature, you can put foot and do a little traffic light to traffic light run against another car, then get stuck at a big intersecion or get stuck in traffic for some time, in that time that motor is now heat soaking a ton, After that it takes quite a bit of time driving in some free air to get temps down and even then you might not get them down enough before the next intersection etc and if that's on a very hot day it's just compounding the issue and once everything is heat soaked it's done, the car becomes a sluggish thing and pushing it in that state is hurting the motor in my opinion and destroying the oil much faster as well.
With my car personally I did everything to get my intake temps low, I fitted hybrid turbos(This is obviously not for cooling, I just wanted bigger turbos) , charge pipe with duel nozzle water/methanol as well as direct port water methanol, so 8 x water/methanol nozzles in total as well as a 7.5" stepped intercooler. All this with the stock airbox and a K&N drop in filter (Think it's K&N but might be BMC, I have since forgotten and must check lol) for the stock airbox. with MHD stage 2+ I saw no gain in performance with DCI on a dyno vs the stock airbox and I would equate that to the water/methanol cooling the intake temps so much that the air density would increase substantially. There are many variables involved here. No methanol + high boost = hot intake temps, means much less dense air so then no lid on the air box or DCI or Mr 5 Mod on the dyno will definitely help as every little bit of extra air will help, but it simply can't be compared to actual cold air going into the motor from a water/methanol setup. You can also easily see the differences in your logs by looking at timing corrections, as the car heat soaks with DCI etc you will notice the car pulling more and more timing after each consecutive run (hence why I say you are actually physically hurting the motor and the motor is in turn trying its best to protect itself). This was also why I ran water methanol, there are almost zero timing corrections in my logs no matter what time of day it is or how many hard pulls I have done in 3rd or 4th gear etc, the water/methanol + 7.5" intercooler simply overcome the hot air easily.
There is allot to consider when trying to up boost and make more power but make no mistake DCI causes heat soak on a hot day and especially in slow moving traffic etc. you are being fooled by placebo due to the intake sounds.