Specs on the stock "i" cam?

[klrskies]

Does anyone have specifications on the stock "i" cam?

[Insanity]

I've been wondering that myself. It seems pretty well designed though from what I've seen with stock dynos..

[klrskies]

Yeah, I'd like to see how it compares to what's being used from the aftemarket. I'd like to plug it, and other aftermarket cam specs into my Desktop dyno software too....

[Insanity]

I wouldn't trust software like that. Most of the stuff of that sort that I've used seems to be about as accurate as a random guess of how the performance will increase. I remember trying to get the thing to show a high-end power increase by having a really late intake closing and a plenum/intake manifold that would only be good at the high end, and the results didn't make any sense at all. I think my power band shifted towards the mid range or something according to the program.

[nando]

I think it has 252* duration and 10mm of lift.. but I'm not positive (I've seen many conflicting figures).

[Insanity]

Well, even if the 252 spec is correct, 252 is pretty ambiguous when it comes to cams. Considering there's "advertised" duration (which pretty much means nothing), "seat" duration, which most OEM manufacturers use, and @.050" duration, which is a baseline due to the ambiguity of the other two, but you'll rarely find specs from manufacturers given in .050".

For example, a certain nissan engine I worked with has a "248" degree camshaft, but it's seat duration, and all the aftermarket cams are rated in advertised duration. When someone measured the aftermarket cams using seat duration, they found that the aftermarket cams which were advertised as 276* were actually only about 254* using the Nissan OEM method, which accounted for their very paltry gains.

[xLibelle]

b27 = 236 code B
b25 = 260 code K

[Scott314]

I think it has 252* duration and 10mm of lift.. but I'm not positive (I've seen many conflicting figures).

I've heard 256. But I've heard so many conflicting variations, that it pretty much carries no weight.

[xLibelle]

Did i stutter?!
260 came out of my shop manual... i'll go check the lift now... 6.5mm on a slightly worn cam

[Mitch M]

Re:

Here's what I measured on a used but nice stock "i" "K" grind. Measured @ the same lifts and as the Cat Cam web site.

0.010" lash, lift @ valve
0.10 mm 266 deg
1.0 mm 217 deg
Lift @ valve 10.08 mm

American spec comparison
212 deg @ 0.050"

Same basic spec intake and exhaust.

[xLibelle]

scratch the word slightly

[klrskies]

Mitch M,

Did you record any lift values? Thanks for the info!

[Low Level E30]

Here's what I measured on a used but nice stock "i" "K" grind. Measured @ the same lifts and as the Cat Cam web site.

0.010" lash, lift @ valve
0.10 mm 266 deg
1.0 mm 217 deg
Lift @ valve 10.08 mm

American spec comparison
212 deg @ 0.050"

Same basic spec intake and exhaust.

Can you explain these numbers to those of us that don't speak "Camshaft" ? :D

Is there a difference between the US-spec and Euro-spec camshafts, for 325i's?

[StereoInstaller1]

Can you explain these numbers to those of us that don't speak "Camshaft" ? :D

Is there a difference between the US-spec and Euro-spec camshafts, for 325i's?

He means metric to english...basically.

Insanity, how much have you messed with Desktop Dyno? IMO, using the SBC's that I have been beating on for years and years, that shit is always just about perfect. Lookig at the database, I see just about nothing euro...hard to believe all the techies there are and none uses DTD.

Good to see someone working on this.

Luke

[Insanity]

I haven't used desktop dyno. I tried engine analyzer pro and some other one. I'll see if desktop dyno is any better. Do they have a trial version?