raiden571

im ordering my new valvetrain pretty soon and wanted to know if it would be worth it goin gwith oversized valves.secondly, is it even worth buildign the non-vtec head. later on i plan on buying the crower turbo cams for it too. im just worried that it will be a limiting factor.

BoostCraze

i Have herd that those heads flow like ----, you might look into getting a port and polish job in the bitch

Guy-Fast

stock form not the best.valave job/good port gonna outflow a stock dohc vtecaa head. Chris aka xencron made good whp on his set up

Tom-Guy

Good valvejob, but no portwork, and you'll flow as well as OMG VTECH.

It's all a stupid numbers game. Just go with some nasty cams, rev to 8K, and boost the ---- out of it. Portwork is not needed, compared to the cams.

If you want the oversized valves, go for it, but if you go too big you end up with the bowl/seat being mismatched to the valve and you don't get any more flow off of the valve size. Intake valve is the bottle neck at big boost.

Jcushing

for once i agree word for word with you! valvejob gets you 90 percent of your gains, but you cant see it like you can a bling *** port job so you wont get much respect on HT. in a FI motor i dont honestly think OS valves arent really needed, i dont think the gains you will get will be worth the machining and money. honestly to quote jdavis just crank the boost up a little extra. cams however seem to make a huge difference so for sure invest in those.

to give you an idea of what a valvejob can do MAXCFM on hondatech is getting 300cfm out of a h22 head with only a valvejob.

Tom-Guy

o/s intake valves net 30-40 increase in "hp-psi" at 300-350 whp range. Same as running a JG Edelbrock IM at that power range. Demonstrative of flow, nothing more. As for them actually being *needed*... well, althought plenty of people have gone lots higher, I'd halfassed guess based on nothing around 450-500 whp you'd want o/s valves to prevent unwanted restriction/friction/heat. If you wanted to spend $1.9 million dollars and try to make a 500whp ride "reliable" wtf that is in turbo Honduh fantasy land.

H22 gets 300 cfm because it's essentially a K20 without a ****** intake cam that flops around like a limp wrist.

Jcushing

take another look at the 2 heads.... theres a few things different besides just that. the h22a head is actually closer to the f20c head.

mycrx

any write ups on valve jobs?

Slo_crx1

So essentially a better cam set is what it all boils down to? I'm gonna be doing a b18a1 swap over the next few weeks so i'd like to see what are the best things to do flow wise to this motor before i get my turbo slapped on it. Is it possible to use a different non-vtec head to achieve close to the same results as vtec head?

Tom-Guy

You can drop the $$$ for a P8R head that has 33mm intake valves, like the V-Tech rides.

I think the chamber is already opened up on those to accomodate 84mm B20B/Z bores. I could be wrong. I do know for sure that it is a different cc combustion chamber.

Personally, I'd grab a good set of cams, boost that biotch, rev to 8 grand, and call it a day.