http://www.slip-angle.com/hosted/dyno2.jpg

for $1 you can touch me

Naw, I`ll pass

Ohh Ohh first in line!!!

:disco: :banana:

~v6

Do I see timing being pulled at 5K? :)

Do I see timing being pulled at 5K? :)

nope, something else is amiss, perhaps vanos

Good starting point :thumbsup

Do I see timing being pulled at 5K? :)
makes it look more like a vtec dyno. haha.

vanos = BMW's variable cam timing. So that makes some sense. :)

Holy super lean afr batman! Here's my 1 dollar advice, richen it up i swear to god you'll gain a few more hp. I bet your egts are through the roof! Who tuned your car?

Non-turbo BMW...

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I thought you didnt need as much fuel NA

Jmott,

Whats the mods on that? Are you doing 9+:1 compression before turbo/supercharging?

We have the Lexus 2.0L NA 3S-GE doing almost that there to the ground, but you would know that the torque would not be as broad as the 2.8L

nope, something else is amiss, perhaps vanos


Change the intake piping and I bet that dip moves to a different RPM.

It's probably just a resonance in the system somewhere. With no turbo to cram air into the cylinders it's going to be a lot more sensitive to the acoustic tuning of the intake tract...

From here: http://www.bmwworld.com/technology/vanos.htm



The VANOS system is based on an adjustment mechanism that can modify the position of the intake camshaft versus the crankshaft. Double-VANOS adds an adjustment of the intake and outlet camshafts.

[...]

At idle, the cam timing is retarded. Just off idle, the DME energizes a solenoid which allows oil pressure to move that cup gear to advance the cam 12.5 degrees at midrange, and then at about 5000 rpm, it allows it to come back to the original position.


(emphasis mine.)

Nothing is amiss. You might be able to tune that out, but it's unlikely. Just like vtec.

WI and race gas? that's a very lean AFR line :eek:

WI and race gas? that's a very lean AFR line :eek:


Yep.... Definitly!!! Were your headders glowing?? :lol:

I don't think it is really that lean, that was from a tailpipe guage. My own AEM gauge up closer to the headers reports a streay 13:1 AFR across the board, with no spike at the end.


Vanos is not "just" like VTEC, vtec has a discrete switchover point where valve lift change. Vanos does not change lift, just cam timing, and it is continuous so there shouldn't really be a anomoly like that.

It isn't a big deal though, I don't notice it driving.

this is just a stock BMW 2.8L 6 cylinder with bolt ons, no changes to heads, cams, or compression ratios.

Nice. I think you lay more power down then my stock 330ci hehe

the thread title made me think it was one of those crawford 2.8l blocks with out a turbo running. i was doing this : :eek:

Get a low boost add on, turbo or supercharger, and 5 psi will add 50-80 hp!

its not the vanos. Its something acoustic in the intake manifold i think...

the topic has been discussed ad nauseum @ e46fanatics.com

the thread title made me think it was one of those crawford 2.8l blocks with out a turbo running. i was doing this : :eek:

hate to admit it, but at first glance i thought the same lol

hate to admit it, but at first glance i thought the same lolx3 :huh:

x3 :huh:


yeah that was kinda the idea =)

no turbo or anything crazy until after solo2 nationals this year.

then maybe I'll go nuts