humor me, porting a 200 head

[2mAn]

confession: i love me ETA. i want it to have as much midrange as possible. its my daily driver and i usually shift before 3k rpms, 4k if im merging or something. i rarely ever wrap it out anywhere near its 5k redline. current mods are an ebay chip, long tube headers and a 2.5" exhaust with no cat, cherrybomb resonator and a flowmaster muffler. as it is right now, i love it and probably wont be doing any more mods, except maybe a new rear end...

ive been keeping an eye out for a 731 head, but combine that with all the "I" electronics, manifold, and all the other goodies and it will get fairly expensive (relatively speaking). So, im thinking with all the cheap eta parts out there, im tempted to pick up a free 200 head and play with it. id like to keep the stock eta cam, but add dual valve springs as a safety concern. money basically would only be spent on machine work

goal would be to help optimize low end velocity. so whats the best way to approach this?

[jlevie]

While you might be able to open up the ports in the head some, the smaller valves and smaller intake manifold passages will still impose significant restrictions. I suspect the result would not justify the effort.

[nando]

get some long tube headers, like stahl, with maybe 1 3/8" primaries, at least 36" long, and a 2.5" single pipe exhaust. otherwise - I'd leave it alone, if you do any porting, you will slow down the velocity which is where all that low end comes from. the only significant improvement in torque will come from the exhaust. Everything else is pretty well optimized for low end torque as-is.

I don't think there's any point in dual valve springs on a mostly stock eta - the torque will fall off way before it becomes an issue, and the heavier valvetrain will just be less efficient.

[2mAn]

nando, thats exactly what i have. probably the only other thing ill do to this is a 3.25 LSD

[Madhatter]

Absolutely no point adding dual valve springs if you want to keep the stock cam. Also pretty much no point in doing a whole bunch of port work designed to get the head to flow better at higher rpms when the eta cam just dies off anyway. Not true that you cant do porting work that will reduce velocities significantly, you just dont want to go opening up the throat of the port at all. All the work in the bowls and seats is still applicable.

[PeteD]

This guy swapped 173 head on his eta. *Info from another thread.

**Arems87e
Member


Join Date: May 2008
Location: New England
Posts: 61

MR 325 is absolutely correct on this. I also have a 325e and did a head swap. I swapped the head with a 731 casting head (which is direct match to e bottom) 3.73 LSD and with of modifications here and there, couldn't be more happier with my car.**

I think a lot of people underestimate the headswap. I also love the eta, but not sure I spend the time porting the head and then keep a stock cam. Would you consider just getting an i motor?

[digger]

remove the guide boss and bullet the guide that is where the min CSA is and then do seat and bowl work as above.

I wouldn't be worried about too much removal as you need to remove an absolute shit load to reduce the velocity. For example port is oval about 27 x 32mm for 200. For 731 is approx D35mm and 885 more squarish and 37x35. These dimensiohns are at entry

[MR 325]

My buddy Shant (Myster-e) is working on a 200 casting head right now for an engine he is building.

He just finished porting the head today, it has been gasket matched to i intake and exhaust gaskets. Those of you who have seen the original size of the 200's ports know that this is a BIG improvement. We will be having the head machined to accept i valves and drilling it for oil supply. It will also get a reground performance i camshaft.

I'm looking forward to the outcome of this head/engine and will definitely be posting dyno results once the time comes. We will be running it with all i electronics and intake manifold.

[2mAn]

^^ nice, i look forward to seeing what it makes

[cheapshot]

My buddy Shant (Myster-e) is working on a 200 casting head right now for an engine he is building.

He just finished porting the head today, it has been gasket matched to i intake and exhaust gaskets. Those of you who have seen the original size of the 200's ports know that this is a BIG improvement. We will be having the head machined to accept i valves and drilling it for oil supply. It will also get a reground performance i camshaft.

I'm looking forward to the outcome of this head/engine and will definitely be posting dyno results once the time comes. We will be running it with all i electronics and intake manifold.

This sounds interesting! Any updates on this?

[MR 325]

This sounds interesting! Any updates on this?

The head is currently at the machine shop being machined to accept the valves from the 885 head.

[Kershaw]

why not start off with an 885 head?

[e30trooper]

why not start off with an 885 head?

Etas allready have higher comp than the b25, putting a I head will drop comp numbers. This way you keep the stock comp or higher

[MR 325]

why not start off with an 885 head?

In our case it's to do something different. Eta engines have higher compression than the i engines. The cylinder head ports (after opening them up of course) are also smoother and better flowing than the 885.

It's fun to try something different. ;)

[Killacortes]

confession: i love me ETA. i want it to have as much midrange as possible. its my daily driver and i usually shift before 3k rpms, 4k if im merging or something. i rarely ever wrap it out anywhere near its 5k redline. current mods are an ebay chip, long tube headers and a 2.5" exhaust with no cat, cherrybomb resonator and a flowmaster muffler. as it is right now, i love it and probably wont be doing any more mods, except maybe a new rear end...

ive been keeping an eye out for a 731 head, but combine that with all the "I" electronics, manifold, and all the other goodies and it will get fairly expensive (relatively speaking). So, im thinking with all the cheap eta parts out there, im tempted to pick up a free 200 head and play with it. id like to keep the stock eta cam, but add dual valve springs as a safety concern. money basically would only be spent on machine work

goal would be to help optimize low end velocity. so whats the best way to approach this?

I have a 731 head fully machined ready to bolt on if your interested. I also have some "I" accessories like manifold. Throttle body. Etc