[335is_miami]

Just got a 335is and Im having a bms dual head intake system installed on tuesday. Some people have been saying this will hurt the performance on this car. If so, why is this?

also, does it make the car sound alot nicer?

[e92bmw]

I already told you why in your last thread....
It sucks in hot air which is less dense and therefore makes less power. The only time you need one is when you run over 15psi and the stock air box cant provide enough oxygen. Also the dci raises the temperature on an already hot(335i's run hot) car.

They sound nice though...

[enrita]

Originally Posted by beemw

I already told you why in your last thread....
It sucks in hot air which is less dense and therefore makes less power. The only time you need one is when you run over 15psi and the stock air box cant provide enough oxygen. Also the dci raises the temperature on an already hot(335i's run hot) car.

They sound nice though...

[Mike@N54Tuning.com]

A DCI has been proven to make power. There have also been member tests that showed marginal increases in IAT, post FMIC.

Mike

[e92bmw]

Originally Posted by Mike@N54Tuning.com

A DCI has been proven to make power. There have also been member tests that showed marginal increases in IAT, post FMIC.

Mike

Then why do most people report a loss of low end torque?
Also there was a thread of a guy who recently switched back to the factory air box and reporter a bump in low end power. Its way different in the real world then on a dyno with fans blowing(hood up or down).

[jb's335]

The only problem with the "real world" is that it is all by personal judgement, i.e. "butt dyno".

If it is proven on the dyno then there isn't much you can say to refute it. Being stuck in traffic with no airflow might create heat-soak more on the DCI's but we still have a relatively efficient stock intercooler to take care of this extra heat. Also, if the turbo's don't have to work as hard to suck in air then there is less heat that is created, which is what the DCI's do. They might not be in the perfect spot for grabbing cold air but a lot of people forget that most turbo cars these days still have means of cooling air post turbo...

[boom]

I found they lost power at the track.

http://www.e90post.com/forums/showthread.php?t=491005

Open hood single run on the dyno does not reflect how they'll perform when driving....

[Black Gold]

^^^^^^^^^^^^^^^

good info in that thread. I also removed my dci (tune + fmic) and felt if anything the car ran smoother stock.

I would say only get a dci if you like the look and/or the sound. Im back to stock intake and happy that way. JMO

[Ilma]

Originally Posted by beemw

Then why do most people report a loss of low end torque?
Also there was a thread of a guy who recently switched back to the factory air box and reporter a bump in low end power. Its way different in the real world then on a dyno with fans blowing(hood up or down).

Perception?
Placebo?
Nuclear fallout?.....

In fact I just took off my DCI today and switched back to the stock airbox.

I did not notice any improvement in low end torque.....but then again, I am not in the real world very much.

But a couple of intuitive observations if I may:

It certainly makes sense that one would be sucking in more hot air with DCI's and the hotter thinner air would reduce the amount of fuel and power.

When I was running the DCI's I monitored and measured post intercooler intake temps on my car, and there was only a significant temperature rise when you were sitting at a stop light for a long time.

At a stoplight I would watch intake temps would rise by 40 to 50F above ambient, but quickly cool back down once you got on the throttle and provided airflow to the intercooler.

On average, with normal cruising I sit about 20 to 25F above ambient.

On WOT intake temps drops to around 15 to 18F above ambient at the start of the run.

Would be interesting to see how a stock airbox compares on intake readings relative to ambient. I would bet the cooler air is still going to be at least 10 to 15F higher than ambient just passing over those hot turbos.

If I get a chance this week, I will do some logs with the stock airbox and see how it compares.

[BobS]

I'm not sure what the alternative should be. I run higher boost so I need the DCI. I elected not to get a Cold air intake because many of the intakes on the market aren't really CAI's at all. They have metal tubing that heats up and the air going in becomes hot just like the DCI. I think the dinan works well but its to expensive and really the 5 hp increase you may get from it, isn't worth it.

I suppose you could modify the stock intake but even that doesn't make that much of a difference from what I can see.

To me the BMS DCI is the best bang for the $

[Justang]

Fwiw, I just installed mine 2 weeks ago. Immediately I noticed the car was smoother when taking off from a stop... Does this mean less tq? I don't know. When I go from cruising to WOT the car appeared to do so with less effort. The sound is nice, but I only hear it when the windows are down. Overall I thought the car was much smoother with the dci intakes. I live in the desert and temps here reach 120+ in the summer, so I'll report back in the summer.

What convinced me to get this intake was it was inexpensive and it reduces the duty of the turbo... But I negated that with the JB+. Lol. I put the JB+ on 5 days ago, so I got a good feel for the car with just the intake.

Interesting to note, with the JB+ and dci intake I saw an increase in gas mileage. I frequently travel from Yuma to El Centro, roughly 120mile round trip. Prior to the mods, if I cruised there at 80mph with the AC on I'd get 28-29mpg. I did that drive today, same speed with AC on and outside temp at 77f and I got 30.9mpg! JB+ is set at 75%. I freaking love this car. Well over 300hp and I get awesome mileage....

The downside of the JB+ is the power delivery isn't as smooth. I can feel minor dips and surges in power. I have only had it on for 5 days, and on day one it sucked... I thought the car was gonna stall or die between 2-3k rpm at about 75% throttle, but it's smoothed out and runs better now. I may reduce the JB+ to 50% given the summer coming and only having 91 octane. That and I seem to keep engaging the traction control at 25mph when I mash the gas and the rear wheels start to break loose. LOL. I can't imagine it at 100%. LOL.

[boom]

@ justang and bobs, those are just your impressions. I honestly felt the sam way and was convinced of the dci until I tested it at the track. I logged the runs and showed that the dci only hurts performance. Wgdc is not substantially different and in my experience, the mileage isn't either. I'm holding out for a true turbo inlet pipe/cai replacement for the stock parts.

[BayerischeMW]

Originally Posted by Mike@N54Tuning.com

A DCI has been proven to make power. There have also been member tests that showed marginal increases in IAT, post FMIC.

Mike

This dyno is useful only if the runs using the stock airbox also used a high-flow filter like the ones used in DCIs. Else we have a paper based filter vs a high-flow filter.

It's widely known that the stock paper filters (like Mahle filters) are more restrictive than the high-flow filter found in DCIs (often K&N filters) because they're stricter on filtration than high-flow filters. This means that the stock filter allows less particles into the engine, but also less air.

High-flow filters let through larger particles than the others, which in the long run will contaminate the internal components of the engine more than the stock filter. But in return, the high-flow filter allows more air.

Then we have the problem of the DCI not being shielded in a very hot environment like the N54 provides.

[///M3THOD]

OP.. do your research based on the information you have available to you. In threads like this there will always be people who cannot be persuaded one way or the other, regardless of all the information put in front of them.

IMO, and really thats all that matters when its your car.. The DCI may suck in warmer air, but there's no way it flows less efficiently that the stock unit. IAT's going up or down 10~15 degress pre IC is not a big issue on a turbo car. The reason the FMIC is there is to cool down air.

The real argument is whether the stated possible slightly increased IAT post FMIC is enough to negate the increased flow of the DCI intake. My opinion.. No.

Finally, TQ loss due to the DCI is just BS. Its a freaking turbo car, ideally you put 2 horns on the turbo and let them work unimpeded. Every molecule of air in the engine is force induced, improving t/c efficiency by removing intake restrictions only helps the car breath better.

[vase330]

IMO only CAI or intake you should put on your car is Dinan CAI. Do as I say and do. And no, I am not a fanboi, had their tune and ditched it for something else, but fact is fact, its the best and only intake worth putting on our cars. Planning on BMS JBD when I get a diesel soon, so offense or BMS hater here. Forget the label and just buy good products from whoever. In the end its your car, do as you like.

[vase330]

Originally Posted by BayerischeMW

This dyno is useful only if the runs using the stock airbox also used a high-flow filter like the ones used in DCIs. Else we have a paper based filter vs a high-flow filter.

It's widely known that the stock paper filters (like Mahle filters) are more restrictive than the high-flow filter found in DCIs (often K&N filters) because they're stricter on filtration than high-flow filters. This means that the stock filter allows less particles into the engine, but also less air.

High-flow filters let through larger particles than the others, which in the long run will contaminate the internal components of the engine more than the stock filter. But in return, the high-flow filter allows more air.

Then we have the problem of the DCI not being shielded in a very hot environment like the N54 provides.

Dinan CAI solves all your mentioned issues elegantly while also having model-looks to boot.

[Justang]

Originally Posted by boom

@ justang and bobs, those are just your impressions. I honestly felt the sam way and was convinced of the dci until I tested it at the track. I logged the runs and showed that the dci only hurts performance. Wgdc is not substantially different and in my experience, the mileage isn't either. I'm holding out for a true turbo inlet pipe/cai replacement for the stock parts.

Did you log IAT temps?
Is your car an auto or manual?
Did you do the runs back to back stock vs DCI?
Because unless you have imperial data, your statement is purely subjective as well.

[WWM3]

Look at FBIS's comparison w/ the Stett CAI and the DCI. Stett absolutely outperforms the DCI and is much less $$ than the Dinan. I have the DCI and I will be definitely getting a Stett before summer.

[Mike@N54Tuning.com]

Originally Posted by maxnix

With the hood up on a Dynamometer? Just like on the street?

Did you actually look at the graph? One of the plots is with hood down??

Mike

[FoShizzle]

AFIK I'm the only one currently running the Injen DCI on the 335is. The dci debate is as old as time.
My .02: Looks, feels, and sounds great. (Performed great on the track too)

[BobS]

Originally Posted by WW330

Look at FBIS's comparison w/ the Stett CAI and the DCI. Stett absolutely outperforms the DCI and is much less $$ than the Dinan. I have the DCI and I will be definitely getting a Stett before summer.

WHere is that comparison?

Boom - Do you have a link to your info? I would like to look into that further.

Like is said, I don't think the bms dci is the absolute answer but I don't see a better alternative that is also cost effective. I will run the bms until something better comes out. Right now, besides dinan, there isn't anything that is going to give you true cold air. IMO of course.

[WWM3]

Originally Posted by BobS

WHere is that comparison?

Boom - Do you have a link to your info? I would like to look into that further.

Like is said, I don't think the bms dci is the absolute answer but I don't see a better alternative that is also cost effective. I will run the bms until something better comes out. Right now, besides dinan, there isn't anything that is going to give you true cold air. IMO of course.

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