"e" to " i " cam swap and others

[robmespeedy]

Hey guys whats up ! i just joined today .
Now i know you guys have talked about this topic alot im pretty sure since i've heard of people doing this all the time .

I want some real performance gain so i was thinking of taking off the head on my 325e and getting it ported , but i wasnt sure about the " i " Cam
what do i have to have done to get this to work ? and is there a significant increase in power ? what else can i take from the i and swap it to my car ?

[e30Matt]

The whole head.

[chrisd]

The whole head.

No, this lowers the compression ratio and will kill what little power your car already makes.

[chrisd]

I sould have been more informative in my last post, sorry.

The I head lowers CR because the pistons come up over the top of the block very slightly IIRC. Thus the I head has a taller inside profile/more volume than the eta.

BUT!

You DO want to switch to I double valve springs, throttle body, intake manifold, and (I think) cam. You need to make sure that the cam does not have so much lift that it makes your valves hit the pistons. Please consult someone knowledgeable about this...
HTH.

[C ///M]

if you dont feel like doing the "i" head swap with either super eta pistons or custom pistons, then you can just do the cam swap.
You need:
"i" cam
dual valve springs
additional cam oil journals drilled into head (a good shop can look at the cam placement and know where to drill)
"i" intake manifold w/ new "i" gaskets
port matched head to intake manifold
"i" throttle body
full 325i exhaust
new head gasket
custom ecu chip with 6500rpm redline and tuned for the "i" cam powerband

You don't "need" the intake manifold or exhaust, but without them, you're engine won't be able to breathe at all.

[e30Matt]

I sould have been more informative in my last post, sorry.

The I head lowers CR because the pistons come up over the top of the block very slightly IIRC. Thus the I head has a taller inside profile/more volume than the eta.

BUT!

You DO want to switch to I double valve springs, throttle body, intake manifold, and (I think) cam. You need to make sure that the cam does not have so much lift that it makes your valves hit the pistons. Please consult someone knowledgeable about this...
HTH.

Yeah... that. :)

[robmespeedy]

Hey thanks a lot for all the information !!!!

if you dont feel like doing the "i" head swap with either super eta pistons or custom pistons, then you can just do the cam swap.
You need:
"i" cam
dual valve springs
additional cam oil journals drilled into head (a good shop can look at the cam placement and know where to drill)
"i" intake manifold w/ new "i" gaskets
port matched head to intake manifold
"i" throttle body
full 325i exhaust
new head gasket
custom ecu chip with 6500rpm redline and tuned for the "i" cam powerband

You don't "need" the intake manifold or exhaust, but without them, you're engine won't be able to breathe at all.

[chrisd]

if you dont feel like doing the "i" head swap with either super eta pistons or custom pistons, then you can just do the cam swap.
You need: (etc.)

Thanks, this is exactly the list I am looking for...

[C ///M]

No prob. I have a brand new set of dual valve springs available. I also have an "i" intake manifold and valve cover (w/ new valve cover gasket), both in a black wrinkle finish, and also an "i" throttle body. And I'll have a complete "i" exhaust with Bosal "sport upgrade" muffler for sale this winter. *The intake manifold/valve cover/throttle body might be spoken for by Josh unless you're willing to "significantly" beat his amount.

I was going to do this exact swap for a while, but the s50 swap came up kind of fast and I never got around to doing it because I never picked up the cam (BavAuto has the brand new "i" cam for about $250 or something while the dealership even with CCA discount is over $300. I'm sure you could find a better deal, or just find one used for super cheap.

[James Crivellone]

an ETA reving to 6500rpm? I don't think I would wanna do that

[C ///M]

an ETA reving to 6500rpm? I don't think I would wanna do that

And why not? Valve float isn't possible with the dual springs, and the crank is built to withstand sustained periods of up to 6500rpm. Along with the "i" cam, you'll need that 6500 to stay within the powerband and have the ability to hold gears.

Any reason to your statement, or do you just not have any info on the subject? :roll:
I guess even the smart ones like to make statements with absolutely no relevance or any real reason behind it... Herehere to the spread of misinformation and doubt...

[robmespeedy]

The I cam

Hey thanks for all the great info .
but i have another question ? when i install the i cam and springs , can i use my original " e " rocker arms or do i have to use the " i " rocker arms ?

also with all the mods you have suggested do you think my eta / i will be as fast as an original 325is ?

thats all

[James Crivellone]

an ETA reving to 6500rpm? I don't think I would wanna do that

And why not? Valve float isn't possible with the dual springs, and the crank is built to withstand sustained periods of up to 6500rpm. Along with the "i" cam, you'll need that 6500 to stay within the powerband and have the ability to hold gears.

Any reason to your statement, or do you just not have any info on the subject? :roll:
I guess even the smart ones like to make statements with absolutely no relevance or any real reason behind it... Herehere to the spread of misinformation and doubt...

Don't fucking roll your eyes at me, and claim I am clueless. I make one fucking comment and you jump at me? back the fuck off, jesus

I personally would not want to rev an engine with a 4800rpm redline to 6500, especially considering most of these engines have upwards of 175K - 200K miles.

If you think it is an okay risk to rev that engine higher, then by all means, prove me wrong, but I would never rev an ETA past 5500rpm, new cam/valve springs or not.


Its not about doing it cheap, its about doing it correctly, you have done this, and thats fine... would I recommend it to anybody? probably not....What are you even dynoing at?


The stroke on these motors is way different then the M20B25, and spinning at 6500rpm for amounts of time is certainly going to cause an engine failure.


And beileve me, I have considered doing this, I have all the parts for it in my damn garage, but after weighing out the pro's and con's, and discussing it with several engine builders, I decided not to do it, the general concenses was engine failure.

If it lasts fine, but when I have enough people telling me bad idea, I tend to agree with them

[robmespeedy]

valves

does anybody know ? if there is any difference between the " i " valves and the " e " valves ?

[nando]

james, if the E bottom end couldn't handle 6500+rpm, then how do people get away with using it in a stroker motor? :roll:

not that it matters anyway.. the E valves and head are much more restrictive than the i, and won't hardly make any power in the higher RPMs anyway. IMO, spend $500 on a used M20B25 and just drop it in. modding an E motor is pretty pointless (aside from a chip).