All of the heads really do look awesome. While i dont agree with Alaniz customer service or pricing, they look the best. I plan to build my motor for big power in the following months, and i just cant justify 3k on a head for 50hp-75hp.

-Alex

 

I still dont see how you can get 50hp from just headwork.... ENDYN

 

Do you have a flow sheet? How much did the exhaust flow increase with the headwork?

Exhaust flow is the limiting entity and good headwork should pick up the flow about 30 cfm.

 

I think it has to do with % increase in flow. If you have a car that is 350rwhp vs. a car that is 500+rwhp, the HP pickup from the headwork will vary. 50rwhp should be attainable in the higher HP realm. Not sure about the 300-350 "mild" FI applications... Maybe 30-40rwhp for those applications...

John

 

I don't blame you. I wouldn't even consider headwork on an S2000 unless it was the last thing I hadn't touched, I had not reached my power goals, and couldn't reach them in an easier way. The factory head is just already so damn good.

Also... Don't read too much into the port pictures. Pictures don't show nearly enough of what's going on in a ported head to be able to make a judgment on which is "better". There's several differing ideas on how to arrive at basically the same point with headwork, and they all work, yet they also all look completely different in a picture.

What looks fantastic in comparison shots can also result in a head that won't last 20k miles, won't make enough power down low to drive on the street, and won't idle. The inverse can also be true, I've seen a head that looked like it wouldn't make any real power at all, but it managed to flow 800hp worth of air into a 2.0 liter motor through ports I could plug completely with two fingers.

 

So, everyone had talked about the porting, what about the other parts.

If someone was wanting to run 15-22 PSI, will the valves hold up? Do the springs need to be upgraded?....................

 

great info

 

Valves are good. Springs and retainers need upgrading. While you are in there, might as well get a new set of guides installed (why not? They are not expensive, and can be swapped quickly/easily with the other stuff being replaced). Some people say that when going 20+psi, that ARP headstuds are a good investment ($100 for the parts, plus no additional install time compared to the OEM bolts vs. risk of lifting the head and having to have it planed). Currently available cams are worthless, IMO...

Just my $.02.

John

 

Porting runners, bowl shaping, valves, guides, seats, springs, retainers, keepers.

Upgrading in these areas allow either more power directly or more rpms safely.
More rpms = more power.

Actually the factory head will work fine with boost in the 15 to 22 psi range.

Over sized valves may improve breathing but they require bowl shaping and porting to get the best results. Since the exhaust is the limiting side most will go with a greater increase in size with the exhaust valve.

There are many trick valve springs available in the market place. Most built heads get a dual spring setup. Springs are upgraded to avoid valve float. None of them will prevent damage if you miss the shift from 5th to 4th and end up in 2nd.

If you use light weight valves and titanium retainers the factory springs are good too.
I'm currently running ap1 intake springs on the intake and exhaust and redlined at 9500 rpm.