[jonm42]

I've seen lots of talk about one or the other, but nothing weighing the relative merits/issues with each option. Comments and discussion from those in the know, please? Off we go. Thanks.

[ragingclue]

I don't believe you.

[Former_Boosted_IS]

Originally Posted by jonm42

I've seen lots of talk about one or the other, but nothing weighing the relative merits/issues with each option. Comments and discussion from those in the know, please? Off we go. Thanks.

I did a very extensive test recently on the "DCI" versus "CAI". There is a ton of info in there. Here is a link:

http://www.e90post.com/forums/showth...cai+versus+DCI

[Drakos]

There are proven power gains on both. They both sound different. There have been posted comparisons between the BMS DCI and Stett CAI. The CAI showed better AIT temps than the DCI. DCI's are significantly cheaper though. The Stett unit in a really nice design built with very nice materials but costs several times more. It is kind of a PITA to remove and re-install the stock air box for service or warranty. I frankly am going to wait for the Dinan CAI when it is released. Should be anytime now.

[jonm42]

Originally Posted by Former_Boosted_IS

I did a very extensive test recently on the "DCI" versus "CAI". There is a ton of info in there. Here is a link:

http://www.e90post.com/forums/showth...cai+versus+DCI

And then his search skills proved faulty... Thanks! I only saw one remark in that thread regarding airflow -- did you (boosted_IS) happen to measure (or even notice) anything related to airflow?

[Zeph]

Originally Posted by jonm42

And then his search skills proved faulty... Thanks! I only saw one remark in that thread regarding airflow -- did you (boosted_IS) happen to measure (or even notice) anything related to airflow?

he concluded that since the JB3 met boost targets on both intakes that he believes airflow is sufficient with both setups. Which flows more air or if one would choke at higher power/flow requirements we don't know.

[Curt2000]

Hard to guage the gains of the DCI since it benefits from open hood dyno's...all in all I would say that your looking at a maximum of about 5 HP delta between any intake. I have had a CAI but switched to DCI because the CAI was a PITA to take off and put back on for service apointments.

[Zeph]

Originally Posted by Curt2000

Hard to guage the gains of the DCI since it benefits from open hood dyno's...all in all I would say that your looking at a maximum of about 5 HP delta between any intake. I have had a CAI but switched to DCI because the CAI was a PITA to take off and put back on for service apointments.

agreed, since the FMIC makes or breaks AIT's I still think DCI is the most practical since it costs a fraction of the CAI price and cleaning is so much easier. I just can't justify CAI costs/hassles to drop my AIT's on constant back to back WOT's from like 109 to 102 or something... negligable difference there and atleast you aren't 150+ like on stock FMIC. Plus I think DCI "can" flow more air if ever needed.

I gotta say Helix+BMS DCI+?BOV=my complete "intake" package.

[HB335]

Are you deciding between purchasing one of the two or just trying to cause a ruckus? lol

You're gonna have people who argue for either side. I read this a while back and decided on DCI because it makes sense to me.

Originally Posted by shiv@vishnu

What about cold air ducting?
The truth behind the matter is that lack of restriction is far more important than "cold air ducting". Especially in intercooled turbo systems. In such a system, the only temperature that matters is that of the air as it enters the intake manifold. But this air has already been on a long journey. It originally entered the system at the air filters. Then it travelled through the turbos, through a bunch of piping, then through the intercooler, through more piping and only then to the intake manifold. With the exception of when it passed through the intercooler, the air picked up heat at every stop. The largest heat gain occurred in the turbo during the compression stage. Here, air temps can easily rise by 150 deg F. A whole lot more than the 10-30 deg F gained from drawing air from under the hood (and not through a cold air box.)

With the vast majority of heat generated in the compression stage, it makes sense to address this stage and see what we can do to cool things down. First of all, we can actually reduce the amount of compression. And yes, we can do this without reducing boost pressure simply by eliminating the negative pressure (vacuum) at the turbocharger inlet. This reduces the pressure ratio which makes the turbo spin slower and generates less heat. And not only is there less heat generated through the reduction in compressor RPM, the amount of exhaust backpressure is also reduced. Add both effects together and you get a car that makes more power with less stress on the turbo. In fact, at 14-15psi of boost, our Dual Intake system offers a 15-25whp advantage over the stock cold air ducted airbox. And not only that, intake temps at the intake manifold is measurably cooler (that's what datalogging is for!).

I hope this helps your decision.

[JoeyFiasco]

Originally Posted by HB335

Are you deciding between purchasing one of the two or just trying to cause a ruckus? lol

You're gonna have people who argue for either side. I read this a while back and decided on DCI because it makes sense to me.

Originally Posted by shiv@vishnu

What about cold air ducting?
The truth behind the matter is that lack of restriction is far more important than "cold air ducting". Especially in intercooled turbo systems. In such a system, the only temperature that matters is that of the air as it enters the intake manifold. But this air has already been on a long journey. It originally entered the system at the air filters. Then it travelled through the turbos, through a bunch of piping, then through the intercooler, through more piping and only then to the intake manifold. With the exception of when it passed through the intercooler, the air picked up heat at every stop. The largest heat gain occurred in the turbo during the compression stage. Here, air temps can easily rise by 150 deg F. A whole lot more than the 10-30 deg F gained from drawing air from under the hood (and not through a cold air box.)

With the vast majority of heat generated in the compression stage, it makes sense to address this stage and see what we can do to cool things down. First of all, we can actually reduce the amount of compression. And yes, we can do this without reducing boost pressure simply by eliminating the negative pressure (vacuum) at the turbocharger inlet. This reduces the pressure ratio which makes the turbo spin slower and generates less heat. And not only is there less heat generated through the reduction in compressor RPM, the amount of exhaust backpressure is also reduced. Add both effects together and you get a car that makes more power with less stress on the turbo. In fact, at 14-15psi of boost, our Dual Intake system offers a 15-25whp advantage over the stock cold air ducted airbox. And not only that, intake temps at the intake manifold is measurably cooler (that's what datalogging is for!).

I hope this helps your decision.

?

[HB335]

Not sure what you confused about.... Cold Air Ducting is referring to Cold Air Intake. Dual Intake is referring to Dual Cone intake. Do I need to spell it out more for you Joey?

[jonm42]

Originally Posted by HB335

Are you deciding between purchasing one of the two or just trying to cause a ruckus? lol
.
.
.

Yes, trying to make a decision. I like the the CAI look much better and am trying to determine if there is close enough airflow between the CAI and the DCI. That being said, how often do I look under the hood .

[shifterboy45]

if i did do an intake, it would be between the injen and UR CAI. but i have a question that I think is important in my decision process.

with the CAI - what are the chances of the inlet drawing in water, or other fluids? I live in a area where there are fast floods, they are not frequent, but possible. if the CAI is mounted in the lower fender area it seem really susceptible to drawing in water and stuff -- and that would be a complete catastrophe -- hydrolock is not a pretty sight and quite expensive to repair.
whats the word on that ?

[longodj]

Former_Boosted_IS I think mentioned that your entire front end would essentially need to be submerged in order for hydrolock to occur with the STETT...

[Sniz]

Originally Posted by shifterboy45

if i did do an intake, it would be between the injen and UR CAI. but i have a question that I think is important in my decision process.

with the CAI - what are the chances of the inlet drawing in water, or other fluids? I live in a area where there are fast floods, they are not frequent, but possible. if the CAI is mounted in the lower fender area it seem really susceptible to drawing in water and stuff -- and that would be a complete catastrophe -- hydrolock is not a pretty sight and quite expensive to repair.
whats the word on that ?

you would have to be driving through some pretty deep water to hydrolock w the UR CAI. My car was lowered on coilovers and it was never an issue for me. If I had to guess, I'd say the filter are is still at least a foot off the ground w the UR.

[Former_Boosted_IS]

Originally Posted by Zeph

agreed, since the FMIC makes or breaks AIT's I still think DCI is the most practical since it costs a fraction of the CAI price and cleaning is so much easier. I just can't justify CAI costs/hassles to drop my AIT's on constant back to back WOT's from like 109 to 102 or something... negligable difference there and atleast you aren't 150+ like on stock FMIC. Plus I think DCI "can" flow more air if ever needed.

I gotta say Helix+BMS DCI+?BOV=my complete "intake" package.

Zeph, I do respect that opinion, but this is a cumulative effect. The single best thing you can do to cool IATs is buying an aftermarket intercooler. Now if have the stock intercooler, then difference between the CAI and DCI will be a whole lot more than the 9F I tested. You will not be anywhere close to 102F. On hard runs your IATs will go over 150F with the DCIs. I suspect the difference on the stock intercooler will be closer to 15-20 degrees because of the 40% difference in efficiency between the Active Autowerke intercooler I tested and the stock intercooler.

[Former_Boosted_IS]

Originally Posted by longodj

Former_Boosted_IS I think mentioned that your entire front end would essentially need to be submerged in order for hydrolock to occur with the STETT...

You are correct. The bumper would have to be under water all the way over the fog lights to get water into the STETT CAI. Basically, your IC plumbing would be under before the intake would be under water.

[Zeph]

Originally Posted by Former_Boosted_IS

Zeph, I do respect that opinion, but this is a cumulative effect. The single best thing you can do to cool IATs is buying an aftermarket intercooler. Now if have the stock intercooler, then difference between the CAI and DCI will be a whole lot more than the 9F I tested. You will not be anywhere close to 102F. On hard runs your IATs will go over 150F with the DCIs. I suspect the difference on the stock intercooler will be closer to 15-20 degrees because of the 40% difference in efficiency between the Active Autowerke intercooler I tested and the stock intercooler.

Good point, and it brings up another issue where really the most restrictive part of our intake is the stock FMIC (connectors atleast) and so that gives me 2 reasons NOT to get a DCI without upgrading the FMIC 1st... for both heat and limited flow reasons. If you are determined to keep the stock FMIC for whatever reason, then it might be worth getting a CAI

[Former_Boosted_IS]

Originally Posted by Zeph

Good point, and it brings up another issue where really the most restrictive part of our intake is the stock FMIC (connectors atleast) and so that gives me 2 reasons NOT to get a DCI without upgrading the FMIC 1st... for both heat and limited flow reasons. If you are determined to keep the stock FMIC for whatever reason, then it might be worth getting a CAI

Replacing that stock intercooler is absolutely a must. It is probably the weakest link of any stock part we have.

[jonm42]

So is getting a good CAI (whatever that means) air flow equivalent to getting DCI?

[longodj]

did your (whatever that means) mean what does the acronym stand for? Cold Air Intake vs Dual Cone Intake.

Former_Boosted_IS logged boost levels for the CAI and DCI and marked no difference. That means the JB3 did not correct boost levels for a drop in pressure, which means at JB3 HP levels, they are air flow equivalent.

[jonm42]

Originally Posted by longodj

did you (whatever that means) mean what does the acronym stand for? Cold Air Intake vs Dual Cone Intake.

Former_Boosted_IS logged boost levels for the CAI and DCI and marked no difference. That means the JB3 did not correct boost levels for a drop in pressure, which means at JB3 HP levels, they are air flow equivalent.

Just trying to confirm that as a statement instead of an inference.