# Can't Decide!!!!



## Ågent99 (Jan 7, 2002)

DanB said:


> P.S. Hey lazy, are you going to wait till I come up for Thanksgiving to install that thing??? :rofl:


I'll get together with the E39 crew up here some weekend and take my bumper off as I have to replace that little air dam under there plus another plastic item I tore up. Also, I want to fart around with the stock snorkel intake near the radiator. I was thinking to just leave it in there but cut it near the fender well in hopes of using it to provide air to the CAI. What do you think? Actually, this was an idea Tej has...sounds good to me.

Also, I got a buncha stainless steel brake lines to install along with a buncha new Axxis D+ pads thanks to prompt shipment by Senor Zeckhausen. :tsk:

Chris


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## bmw540i (Mar 30, 2003)

What do you guys think of the Gruppe M intake.


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## Ågent99 (Jan 7, 2002)

jvr530i said:


> Do you make an aluminum version for the 530i? I'm not hung up on the CF look, prefer a better value for the same performance gains.
> 
> Also, what's the risk of water infiltration under normal rainy season driving?
> 
> Damn this board! I've got MOD FEVER again!!!


Jeff, I'm told it is damn near impossible to ingest water unless the front end is dunked in a lake and you've got other problems if that is the case but I'm sure it _could_ happen. BFP does sell a water sock but Dan talked me out of it.

Shoot, now I'm thinking I want the 4" diameter...if BFP makes one for the 530i...I may have to trade "up". I think the Al is cheaper than the CF one!

Chris


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## e39540i6 (Oct 9, 2003)

Hey Greco... What is the GruppeM's diameter? Leaning more towards this one. If the diameter is 4", I'm sold. Where did you get yours? And how long did it take to arrive?


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## bmw540i (Mar 30, 2003)

e39540i6 said:


> Hey Greco... What is the GruppeM's diameter? Leaning more towards this one. If the diameter is 4", I'm sold. Where did you get yours? And how long did it take to arrive?


What do you mean by diameter, the diameter of the K&N filter? you can get one from REnn-sport.net


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## jvr826 (Apr 22, 2002)

Ågent99 said:


> Jeff, I'm told it is damn near impossible to ingest water unless the front end is dunked in a lake and you've got other problems if that is the case but I'm sure it _could_ happen. BFP does sell a water sock but Dan talked me out of it.
> 
> Shoot, now I'm thinking I want the 4" diameter...if BFP makes one for the 530i...I may have to trade "up". I think the Al is cheaper than the CF one!
> 
> Chris


I don't see an Al version for the 530 on their site, but I'm going to check on it. Thanks too for the info on the water issue. I tend to over-engineer things when I build, so it's natural for me to want that water sock too.


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## e39540i6 (Oct 9, 2003)

Ågent99 said:


> :lmao:
> 
> Actually, I just reread the thread. Dan's CF CAI is 3.5" dia. and the Al one is 4" dia.
> 
> ...


bmw540i, I was referring to this. I guess it is the inner diameter that feeds in the air? Bigger is better, No?


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## Ågent99 (Jan 7, 2002)

e39540i6 said:


> bmw540i, I was referring to this. I guess it is the inner diameter that feeds in the air? Bigger is better, No?


I think I've convinced myself that bigger is better. Really, you want to have NO tube restricting the air entering the engine but that is plain dangerous and stupid. You'd like to filter that air to make sure you aren't putting stuff into the engine that won't be good for it. Makes sense, no?

Okay, so you need to filter the air...fine.

Next, you want to try and bring in as low a temperature air as you can. It gets pretty hot under the hood as we all know. This means you'd like to bring in cooler than under-the-hood air.

Okay, so we want filtered, cooler than under-the-hood air...fine.

Added to that, BMW wants to measure air flow into the engine using a little transducer so that needs to be added as well.

This necessitates, in our case, a tube to feed the air into the engine, have an air filter on the tube, and place the tube to draw in cool air and incorporate the MAF (mass air flow) meter.

Might as well make the *inside* diameter of this tube as large as, if not larger than, whatever BMW has chosen for our engines. Also, it needs to fit reasonably well into the engine bay using more or less the stock mounting and routing. I used the _outside_ diameter when comparing the areas of the various tubes out there therefore all my numbers will be a tad less than what I stated but not significantly so.

Chris


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## e39540i6 (Oct 9, 2003)

This is why I can't decide. Will I be gettin colder air by gettin an intake that sits low in the bumper (Dinan) than one like the GruppeM? Decisions, Decisions.


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## Ågent99 (Jan 7, 2002)

e39540i6 said:


> This is why I can't decide. Will I be gettin colder air by gettin an intake that sits low in the bumper (Dinan) than one like the GruppeM? Decisions, Decisions.


Some temperature probes need to be placed at the intake of each CAI and at the intake to the throttle body and the difference between the two should be noted along with the ambient temperature.

Warm air rises, cold air falls due to density. However, a hot road could distort readings close to the pavement.

To that end, I might just go with the largest tube available that draws air as much from the outside of the engine bay as possible. Then factor in cost and see where you end up. In the end, you probably won't notice much difference between different brands. :rofl:

Chris


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## dadtorbn (Oct 3, 2003)

Regarding CAI's... This is the most independant review of their value and impact on performance. It's fairly technical and on an E39 M5. However, I'm sure the conclusions apply to our cars as well.

http://www.m5board.com/vbulletin/showthread.php?s=&threadid=34815

Mike


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