Dual valve springs into an eta head? Cam options?

[EtaSport]

I like the idea of dual valve springs in the eta head while keeping the e cam. My questions is once the motor has reached about 5k, wont the powerband start to fall off based on the e cam's grind? Since it was designed to run to about 4700, will it be starving around 5500-6000? Too bad its pointless for a cam manufacturer to build a cam for the eta that will extend the powerband up top but keep the same low end.

I think I am going to build my head, do some port work, and shave it down to increase compression a tad. Will the e motronic be sufficient with a chip that has a raised rev-limit?

[Jand3rson]

Will the e motronic be sufficient with a chip that has a raised rev-limit?

The ECU will compensate and adapt.

[RedBaron86325]

Here is a picture I just took. It shows the difference between an 86 325e cam cog and an 89 325i cam cog that I have. I've talked to a couple of other people (very trusted mechanics) who swear that they are the same, but the two cogs that I have are very different. I took both of these cam cogs off their respective e30's myself. I guess a little more research needs to be done. I hate being told one thing and actually having physical proof another. Bring on Scooby Doo and the Mystery Machine.

[rs4pro3]

Red I think you're looking at a wrong mark. On the eta gear you have the dist. mounting side up and on the 325i gear you have it down. Flip them both with the dist up and the marks should line up.
here is an 84 325e cam gear and an 87 325i cam gear

The TDC mark on both is the exact same number of teath away from a line drawn threw the center of the middle hole and the center of the locating pin.

[Jand3rson]

So then they are the same? Is the i cam gear lighter, since it has the "spokes", and the eta gear is solid?

If they are the same, would it make sense to either swap an i cam gear onto an eta cam (if I keep the eta cam) or to swap in a whole i cam and gear? Or just leave the eta cam and gear as is?

[rs4pro3]

By hand the eta cam gear actualy feel lighter as it's made out of a thinner material even though it's solid. I think Red and myself have agreed there the same as he has been running and eta cam gear on an I cam with no problems.

[modifiede30]

If there are any differences, and Red is using an eta ecu, it would make sense that there are no problems since the ecu is matched to the timing of the eta cam gear. I'll do a little more investigation tomorrow when I begin the install, checking cam lobe location in reference to crankshaft position.