The truth about aftermarked intakes vs. stock...

[Robin-535im]

Does anybody know it?

I only ask because my car came with an aftermarket k&n / tube intake, but the car is faster with the stock box. My kester isn't real sensitive, but the stock setup had noticably more power in the 2k - 5k range than the tube setup.

Some very esteemed members of the board have the k&n intake tube setup, which makes me think mine was just set up wrong if the stock gave me more power.

There was no heat shield and the tube gets super hot under there. Does a heat shield make the difference? How about forcing the air into the tube with some sort of modified cold air flange?

Anyone want to throw in their $0.02?

Robin

[Gary M]

x

[Jeff N.]

Robin - try to find an aftermarket intake system from any reputable tuner for the M30. Basically, you can't. Sure makes you wonder why, huh? :D I think even the Hartge and Alpina versions of the E34 run the stock airbox.

[Robin-535im]

Robin - try to find an aftermarket intake system from any reputable tuner for the M30. Basically, you can't. Sure makes you wonder why, huh? :D I think even the Hartge and Alpina versions of the E34 run the stock airbox.

If you got some dyno runs I'd love to see them, by the way. Do you ever use thye g-tech to get estimates on mods? Seems to me, anything with a RPM vs. time plotting capability can tell you if you got more power from a modification... E.g., if you get from 2000 to 2100 faster now then before, you must have more power there.

Did the fan clutch work?

[AllanS]

Exactly- you get hot underhood air which is less dense that colder air from the front where the headlights are, which is where the stock airbox gets it from.

[Jeff N.]

Well...got the g-tech but haven't really setup a good "run" location for the tests. Maybe help if I lived out your way.

Getting ready for the big tune.. :) Have some plans up my sleave. Likely will end up at the dyno one of these days in the not to distant future, haven't been there yet. Still trying to learn about enough about my car to be able to really work with them vs. sit there like potted plant.

Yes - fan clutch seems to work well vs. the old one! Whoohoo!


If you got some dyno runs I'd love to see them, by the way. Do you ever use thye g-tech to get estimates on mods? Seems to me, anything with a RPM vs. time plotting capability can tell you if you got more power from a modification... E.g., if you get from 2000 to 2100 faster now then before, you must have more power there.

Did the fan clutch work?

[MicahO]

Well...got the g-tech but haven't really setup a good "run" location for the tests. Maybe help if I lived out your way.


I got my GTech Comp delivered last Friday, tried a few runs last night. Unfortunately I had problems with launch and traction. Most of the roads around me were tarred and chipped about 2 weeks ago and have yet to scrub clean in those areas that are not frequented. i.e. the roads where I could get a good clean surface for launch are flanked by houses, the roads that are flanked by onion fields are covered with gravel. Maybe in a couple more weeks...... Maybe after tonight's forecast for torrential rains.....

[G Feller]

the best times you did get on a slippery surface--with traction control on?


MicahO: tried a few runs last night

[MicahO]

I gave up - was too traction-limited in second gear even on the moderately clean surfaces. It was evening and the only non-travelled areas were out in the agricultural backwaters of my town - too many commuters on the nice roads, so I had to give up.

Wifey's out of town Saturday night and Sunday, so I should get some time for some runs this weekend. Actual ET's to 60 etc will be some time coming as I feel I really need to work on the launch. I do want to start with some power runs through second to get some model of net HP from the thing.

But as I get numbers and techniques, I will definitely post.

(wow - freudian slip - when I typed that last sentence, my fingers typed "pose." Really!)

[G Feller]

Look forward to hearing about it.


(wow - freudian slip - when I typed that last sentence, my fingers typed "pose." Really!)

[1992 BMW 535i]

Come on, Dinan has one and shows the performance improvement...

[rickm]

Come on, Dinan has one and shows the performance improvement...

So do their badges and floormatts. :)

[Jeff N.]

Got a link?


Come on, Dinan has one and shows the performance improvement...

[Martin in Bellevue]

I tried telling yoy that was a bad work around that could cause other problems.

Again, please don't persue that avenue of modification.

[George M]

maybe mixing apples and oranges. Dinan sells a high flow intake "manifold" which I think is of dubious value anyway and in typical Dinan fashion much over priced. As to the air-box...the stock air-box flows great and very difficult to improve upon or most of us would have upgraded. There is little value added in going to an exposed cone even with a head shield which will only make more noise and let more dirt in and not add any horsepower. As Martin said...spend your money elsewhere or donate it to me.
George