anyone have a good eta camshaft suggestion? - BMW Forum

the jeepman · 03-25-2006, 12:27 PM

i need some quick power and am having some problems coming up with a good cam. I have never done one before but i have mechanic friends that are more than willing to help out.

If you guys could point me in the right direction and give me some pointers or links that would be great.

This forum seems like a small one and i like that so lets see what my eta can do!

E30crazy · 03-25-2006, 06:17 PM

Honestly, a cam in your eta is a waste of money. The eta has a very poor single valve spring design in comparison to the dual spring design in the "i". A somewhat aggressive or even mild cam could cause the valves to float. Your best bet is to just throw a chip in your eta, and save up until you can buy an m20b25, or an m/s50. Hell you can probably buy a used m20b25 for less than a new cam.

JoeMadoo · 03-25-2006, 08:31 PM

I completely agree with E30crazy, a chip is THE best back for you buck. A combination "i" cam and dual valve springs will allow you to raise your revs and give you some more top end, sacrificing some of the low end torque the eta has. You can even get a custom chip to go with your new cam and springs to take full advantage of the high end cam.

the jeepman · 03-25-2006, 09:15 PM

Ive already got a dinan chip, exaust, and intake done.

what next?

E30crazy · 03-26-2006, 01:03 AM

Quote:

Originally Posted by the jeepman

Ive already got a dinan chip, exaust, and intake done.

what next?

Save up for an engine swap. Trust me, you can go m20b25 retardedly cheap and stock it will perform better than your eta with chip, exhaust and intake. I drive an '84 "e" and I picked up a used m20b25 complete with wiring harness, ecu, and a couple boxes of parts for 200 cdn. That is far cheaper than even a reground cam.

325eXTATIC · 03-26-2006, 11:56 AM

Okay, this kind of dove tails into a question I have had for a long time... Doing an i head swap on my eta motor. I know someone on one of the other boards has done it (was it r3vlimited, or e30tech?) either way, I know it can be done... What you would end up with is a stroker i motor, but the swap isn't cheap or easy. So the question is this... is it easier/cheaper to swap the head/cam/ecu etc... necessary for the head swap? Or would it be cheaper/easier to just do an M20B25 swap from a junkyard?

Werd!

Josh W.

JoeMadoo · 03-26-2006, 01:46 PM

Well an I head on an E block will actually give you less compression because the shape of the E pistons.

A 3.71 Rear End will pep an eta up like you can't believe.
You will be in "IS" KILLER!!!

This is an awesome site that will answer your questions jeepman:
http://strictlyeta.net

E30crazy · 03-26-2006, 05:47 PM

Quote:

Originally Posted by JoeMadoo

Well an I head on an E block will actually give you less compression because the shape of the E pistons.

A 3.71 Rear End will pep an eta up like you can't believe.
You will be in "IS" KILLER!!!

This is an awesome site that will answer your questions jeepman:
http://strictlyeta.net

Correct, the 2.7i stroker that 325exstatic is talking about uses either an eta crank with "i" connecting rods, pistons, and head. Or an eta crank and connecting rods with "i" pistons and head, I cannot recall exactly which it is right now. The straight "i" head on an eta block and bottom end will lower compression to around 8.4:1. The only time this would be benificial is if you were going with forced induction.

Yes, a rear end swap will pep up an eta, but calling it an "IS" killer is a stretch. Keep in mind your 4800 rpm fuel cutoff. You may take an "IS" off the line but if you both have the same rear-end you will have to do alot more shifting than the "IS". I think an eta with a 3.73 rear end would more accurately be dubbed a "gas mileage killer" or a "top speed killer"

ldsbeaker · 03-26-2006, 09:26 PM

Quote:

I think an eta with a 3.73 rear end would more accurately be dubbed a "gas mileage killer" or a "top speed killer"

I'm not even going to mess with my eta. I'm just going to pop it out and put in an S50B30. Double the horsepower=

:

JoeMadoo · 03-26-2006, 11:54 PM

Well with a chip, the Rev limiter is at 5300. Add an "I" cam and springs, that should bring it up to about 5800 with a custom chip. The torquey eta will take an IS off the line, the top speed is not as high as an IS, but the eta will reach its top speed of about 140 (believe me). An IS will not likely make it up that high. I'm not putting the "IS" down in anyway, If i were to buy another E30, i would get an 325is, but the ETA is by no means dull or not worth working on.

325eXTATIC · 03-27-2006, 12:24 AM

But it isn't as simple as just puting double wound springs and a cam in though is it? I thought there was some machining on the head necessary to allow the springs perch properly. Once you have done that, you are starting to approach the cost of rebuilding an i motor. Or am I completely off base with this?

Josh W.

JoeMadoo · 03-27-2006, 11:07 AM

Yes you do need to drill more oil journal holes. I dont think that cots very much for a shop to do though...

JoeMadoo · 03-27-2006, 11:12 AM

This reply goes out to E30crazy: The theoretical top speed of an eta is about 160. Its real top speed is about 110. With a chip its about 120. With a differential its theoretical top speed and actual top speed it reaches becomes the same number, 145. Tell me how thats a top speed killer...

E30crazy · 03-27-2006, 07:22 PM

Quote:

Originally Posted by JoeMadoo

This reply goes out to E30crazy: The theoretical top speed of an eta is about 160. Its real top speed is about 110. With a chip its about 120. With a differential its theoretical top speed and actual top speed it reaches becomes the same number, 145. Tell me how thats a top speed killer...

That is bull, my bone stock eta has exceded 120 with a 2.79 rear. All I am saying is in my opinion a 3.73 rear is far to steep for a car with a 4800 rpm fuel cut-off. A 3.25 is a different story however.

ldsbeaker · 03-28-2006, 11:25 AM

Can we just agree to disagree? (unless you guys want to put "pinks" on it)

I'll mediate.