BMS DCI poll above/below 50F(10C)

[Little1er]

Using your butt dynos, what do you think? Debating whether to go back to my stock air box. Love the sound of the turbos, but I hate the look. Performance is going to be the deciding factor.

[bigEC]

I have the BMS DCI and I have to say i LOVE the sound of it and install was very easy (about 20min give or take). Performance wise I havent noticed anything, but I didnt buy mine hoping for performance gains, I just wanted to hear those turbos! Oh and right now it is like 20 degrees in NY and its the same shit as when i installed it in 70 degree weather in the fall LOL

[SlicktopTTZ]

The DCI reduces waste-gate duty cycle, even in warm weather, which means your turbos are not having to spin as fast as they would with the stock airbox to hit target boost.

The stock airbox creates a turbo inlet restriction at higher than stock boost levels.

[HondaGoneRogue]

Originally Posted by maxnix

As anyone who listened during 8th grade general science will know, hotter air is less dense than colder air. If the air under your hood isn't hotter than the outside air, then you car's radiator and FMIC are not working.

Your point? Hold on lemme do that for you:

If there are gains from the increased efficiency of the turbos spooling, it may be negated by the loss of density caused by the warmer air, meaning the turbos may still have to work just as hard to hit target boost. So, the DCI at first glance and without imperical evidence may be benificial only according to the weather.

However, when there are significantly raised boost levels, I would go for the best flowing intake (DCI) over the stock airbox in any case.

Originally Posted by maxnix

Even if this were true (data, please), what percentage of time does your engine spend above "stock boost levels"?

Mine spends a lot of time there. Yours doesn't?

[thez99]

I would think below 50 degrees its a no brainer, DCI is open no restriction with less hot air induction due to the cooler ambients. And even when its warmer out, yes the air under the hood is hotter, but the open zero restriction DCI has got to have more pros than cons over stock, yes the air is hotter going thru the intake, but for a FI engine the intake temp matters less and the intake air flow matters more. If you have a 6.0L NA V8, then shit ya you want a CAI to bring the coolest air into the engine as you wouldnt have an FMIC or turbos to require one. All the heat then would be on the engine. Our engines performance relies much heavier on the turbos which are cooled by oil coolers and the FMIC. If you have a DCI in the hotter temps and really worry about the temps being an issue, get an aftermarket sexier FMIC, period.

[Jeef Beef]

Originally Posted by thez99

I would think below 50 degrees its a no brainer, DCI is open no restriction with less hot air induction due to the cooler ambients. And even when its warmer out, yes the air under the hood is hotter, but the open zero restriction DCI has got to have more pros than cons over stock, yes the air is hotter going thru the intake, but for a FI engine the intake temp matters less and the intake air flow matters more. If you have a 6.0L NA V8, then shit ya you want a CAI to bring the coolest air into the engine as you wouldnt have an FMIC or turbos to require one. All the heat then would be on the engine. Our engines performance relies much heavier on the turbos which are cooled by oil coolers and the FMIC. If you have a DCI in the hotter temps and really worry about the temps being an issue, get an aftermarket sexier FMIC, period.

+1

There's always someone in these threads who inevitably counters with "OH but the IATs do matter, our cars feel much stronger on cold days and heat soak on warm days!"

The fact is that the air entering the intake is heated up massively by the spinning turbos anyway, so the difference between CAI and DCI should be negligible. The difference between cold days and warm days lies in the fact that the FMIC is able to cool the charged air from the turbos to the engine much more efficiently when the ambient temperature is low.

[thez99]

Originally Posted by Jeef Beef

+1

There's always someone in these threads who inevitably counters with "OH but the IATs do matter, our cars feel much stronger on cold days and heat soak on warm days!"

The fact is that the air entering the intake is heated up massively by the spinning turbos anyway, so the difference between CAI and DCI should be negligible. The difference between cold days and warm days lies in the fact that the FMIC is able to cool the charged air from the turbos to the engine much more efficiently when the ambient temperature is low.

Springtime comes, im going BMS DCI and HPF FMIC and booyah

[escobar929]

oh gawd, here we go again

[HondaGoneRogue]

Originally Posted by Jeef Beef

+1

There's always someone in these threads who inevitably counters with "OH but the IATs do matter, our cars feel much stronger on cold days and heat soak on warm days!"

The fact is that the air entering the intake is heated up massively by the spinning turbos anyway, so the difference between CAI and DCI should be negligible. The difference between cold days and warm days lies in the fact that the FMIC is able to cool the charged air from the turbos to the engine much more efficiently when the ambient temperature is low.

You do know that there are dyno's that disprove everything you just said right? But hey, whatever helps you sleep at night. I won't take this any further.

[Jeef Beef]

Originally Posted by HondaGoneRogue

You do know that there are dyno's that disprove everything you just said right? But hey, whatever helps you sleep at night. I won't take this any further.

Huh? I thought you were in support of the DCIs.

I've never personally done a dyno or seen one (not saying they don't exist, I'm just a lazy bastard and don't look around) but I was just using some basic logic. Cold ambient temp = intercooler is better at doing its job, rather than colder air entering the intake, since all air has to pass through the spinning blades of the turbo regardless of whether it was hot or cold in the first place. The efficiency of the intercooler is what determines the temp of the air entering the engine.

If I am wrong, meh I learn something new everyday

[HondaGoneRogue]

I'll entertain once more for clarity's sake. I am in support of the DCI, in short duration applications. If your on a long course or driving in traffic on the southbound I-15 from Vegas to Cali in 115 degree heat, you will get heat soak (and yes, it will be worse than with the stock airbox). Common sense says that the cooler (denser) the air entering the turbos the better. Regardless of how much they heat it up.

In short, the first couple DCI dyno pulls were stronger than a stock box (cooler air). But after the heat soak (by logging IAT's) they were less efficient than the stock box.

So it's a give and take. Depends how/where you drive. I don't have them because the summer means instant heatsoak .

[infinitekidM2C]

Originally Posted by escobar929

oh gawd, here we go again

+1...put whatever the heck u want to in your engine bay...there's no compelling evidence one way or another so don't act like ur psuedo-science is better than anyone else's

[HondaGoneRogue]

See you at the track .

[thez99]

Originally Posted by HondaGoneRogue

I'll entertain once more for clarity's sake. I am in support of the DCI, in short duration applications. If your on a long course or driving in traffic on the southbound I-15 from Vegas to Cali in 115 degree heat, you will get heat soak (and yes, it will be worse than with the stock airbox). Common sense says that the cooler (denser) the air entering the turbos the better. Regardless of how much they heat it up.

In short, the first couple DCI dyno pulls were stronger than a stock box (cooler air). But after the heat soak (by logging IAT's) they were less efficient than the stock box.

So it's a give and take. Depends how/where you drive. I don't have them because the summer means instant heatsoak .

Dude...if you're driving in that kind of weather, you are going to get heatsoak under spirited driving no matter what goddamn intake you have, this all has to do with the efficiency and size of your FMIC. Why bother even bringing 'heatsoak' into an intake discussion?

[HondaGoneRogue]

Did I say I avoid heatsoak alltogether with the stock intake? So cooler air fed into the system has the same effect as hotter air? Really? If you put a frozen potato in the microwave for 3 mins and a warm potato in for 3 mins what happens? Are you saying that the air temps exiting the turbo's are the same regardless of the air temp that went into them? If anything is unfounded, stretched or psuedo-science, that theory is.

Whatever. Have fun. I don't get paid to teach.

Here's some pro bono:

Originally Posted by alextremo

I recently did a few baseline data logs completely stock, then repeated after adding DCI but before adding tune.

I'm sure this has been done before, but results were consistently slower FATS score (albeit a very small difference) and a consistently higher IAT of ~6 deg F in 3rd gear WOT pulls (ambient temps of 30 deg F, starting IATs were identical) with DCI.

I will be repeating the test with a higher boost tune installed to see if the increased flow characteristics outweigh the hot air ingested by the DCI.

Again, I'm sure this has been done - just testing with my car to see with my own eyes

Originally Posted by GeorgiaTech335coupe

I have been in turmoil over what is better as well. I think it depends on a lot of other factors as well, especially the climate you live. The hotter the climate, the worse DCI will perform. DCI will definitely lower WG %, so that in itself might be worth it. At the drags I believe the stock box kept my IATs about 10-15 lower than DCI. I think with tune only, its a close call. If you have FMIC or meth, DCI is probably the way to go. Having said all that, I still use DCI and am located in a very warm climate.

Originally Posted by R1000K3

You can probably find extreme situations like I mentioned in the previous post where the STD intake may be slightly better but a DCI or even better the Mr.5 CAI, will almost always perform better. Another situation where the stock intake should be ahead for a while is directly after take off when the car has been idling for some time when it is very warm outside and frigging hot in the engine bay. But these are not typical driving situations for most people unless you are in a real hot climate and the traffic is jammed and slow.

In the end, the IC+Meth makes more of a difference and will compliment the DCI's nicely. But thats where DCI's belong. With FBO's. Why do you need to flow more if you are running stock boost anyway. At the point where you NEED DCI's this conversation will be pointless anyway because the pro's (flow) will outway the con's(heat).

Done. For real now.

[Alext]

I found the stock airbox better than the DCI esp in hot weather. I did several swaps and just by feel it was superior. I think the DCI may give slightly better throttle repsonse.

[bryce]

.....this topic has been beat to death and proven with actual data. the dci's are best suited for cars running higher boost levels.


maxnix- please read the two threads below (or at least the first few posts). yes, one of the threads is from terry @ bms, who sells these intakes. the other is from mr.5, who has no personal investment either way. they both say the same thing basically- heat soak is not as important as lower wastegate duty cycles to keep the turbo's from over-spinning, over-heating, wearing out quicker, etc etc etc.

thread #1
thread #2

[AZ135]

these dci vs. stock intake threads are always gems. who knows and who cares? intake shouldn't be a performance mod on this car. Do it for sound or look. people will argue til death which is better for performance in real world driving, but no one has proof that one is better than the other.

[Jeef Beef]

Originally Posted by HondaGoneRogue

I'll entertain once more for clarity's sake. I am in support of the DCI, in short duration applications. If your on a long course or driving in traffic on the southbound I-15 from Vegas to Cali in 115 degree heat, you will get heat soak (and yes, it will be worse than with the stock airbox). Common sense says that the cooler (denser) the air entering the turbos the better. Regardless of how much they heat it up.

In short, the first couple DCI dyno pulls were stronger than a stock box (cooler air). But after the heat soak (by logging IAT's) they were less efficient than the stock box.

So it's a give and take. Depends how/where you drive. I don't have them because the summer means instant heatsoak .

That makes sense, thanks for clarifying. I'm inclined to swap my DCIs out for the intense summer heat we get over here, but again I'm too much of a lazy bastard

So from that then it should mean a stock airbox would be better for consistent lap times?

Originally Posted by thez99

Dude...if you're driving in that kind of weather, you are going to get heatsoak under spirited driving no matter what goddamn intake you have, this all has to do with the efficiency and size of your FMIC. Why bother even bringing 'heatsoak' into an intake discussion?

Yeh, I always thought the best mod would be to change the FMIC. Gets rid of most of the heatsoak problem.

Originally Posted by bryce

.....this topic has been beat to death and proven with actual data. the dci's are best suited for cars running higher boost levels.


maxnix- please read the two threads below (or at least the first few posts). yes, one of the threads is from terry @ bms, who sells these intakes. the other is from mr.5, who has no personal investment either way. they both say the same thing basically- heat soak is not as important as lower wastegate duty cycles to keep the turbo's from over-spinning, over-heating, wearing out quicker, etc etc etc.

thread #1
thread #2

Thanks for the links bryce. Interesting reads, I guess keeping the turbos less stressed is more important to me than getting a few less hp after some heavy driving.

[micha3l]

I dont know about all the technical aspects of intakes, all I know is practical experience.

2 cars with the same mods at the same drag strip.

In winter the DCI car had the edge, as soon as it got hotter (25 degrees +) the car with the standard air box was quite noticably faster.

[D335I]

I am running a GIAC S1/stock air box/filter and overall the car runs very, very nice and 2nd/3rd pulls pretty strong to 7k. I repeated this every chance I got and the cars always smooth and strong not matter what the temps were outside.

Dropped in the DCI and felt pull back from the start and thought "what the hell", kept it in for 2 weeks and it never felt as smooth, I could feel a little pull back but left it in thinking the car would adapt and get better. Two weeks later not much difference.Temp also seemed to be a tad higher.

Reinstalled the stock box today and right away could tell the difference. Took her out a few times throughout the day/night and I'm totally convinced the car runs better.

I think if I had S2/FMIC and DP i would have to go with the DCI but Im convinced my S1 flash performs better with the stock box.

[MarkRacerX]

I have swapped back forth a few times. If car sitting at drags nice and cool the DCI pull much harder in upper RPMS than stock airbox.

However daily driving in Heat of summer the lowend/throttle response/TQ isn't as good as stock airbox.

It is nice to hear some air flowing, but I clearly noticed loss of lowend/throttle response w/ DCI vs stock airbox seemed more TQ/Responsive in Hot summer weather.

my .02cents

So depends on what ya want/needs are from the mod...

Thanks!