im building a b18a1 head. im port matching it. but do i need to go with over sized valves to make more power. and can i use gsr valves ?????

 

look for a p8r non vtec head.They already have the 33 mm intake valve in it.

 

Having the head professionally ported is much better than simply installing larger vales which will accomplish very little. Once the head is done, you'll need to select cams, intake manifold, header, exhaust, pistons, tuning system....all the things that COMPLIMENT each other and power will be made.

After saying all that, there's a reason why people go LSVTEC, which is because those heads stock out flow your current head and have the potential to flow more than your current head ever will.

 

yeah i got crower dual springs steel retainers, skunk 2 mani, bdl 68mm TB, crower 404s. ready for the head




I HAVE A BUILD ON HERE.... N/A NON VTEC B18A1

 

if the chamber is opened up, the throat is and the rest of the port is tailored for it than they will work but just putting the valves in a stock head isn't worth it

 

yeah true... but i know i can make that head flow good and run harder then a vtec....

 

No you cannot use GSR valves the have a different stem diameter.

Non-Vtec builds are great they just arent great drag race motors, I use one for my autocross car and it works fantastic.

 

well am draging mine... i wont at least a 13.4 ill be happy with that

 

[QUOTE=Natural Aspirations;41485227]No you cannot use GSR valves the have a different stem diameter.


ok i was just asking cuz i might get a gsr head... yeah i know not use that n go ls/v... cuz i already got **** for my ls head. i might the gsr head too. if anydody wants it. 450. full head no dizzy tho. and a edelbrok mani for 150

 

No you cant with equal mods a vtec motor of similar displacement will always out perform one with a non-vtec head. Its not that they wont perform great but there are some limitations of the head and rocker designs. One thing I have herd of was someone who had their p75 (or p8r I forget) head cnc machined with PR3 ports achieving better flow but you still have the rocker limitations.

 

horrible price on the head decent price on the manifold.

 

idk ima cn if i dnt like it ill go vtec i guess n be like everybody else ugh!!! that said can i use a gsr head with p30 pistons ??? n have VTP clearance ???

 

the head is fresh man w/ cams

 

I have a question. Has anyone ever just go bigger on the exhaust side like 1mm over and just leave the intake alone. B/c getting the exhaust out better raise the potential of the hp/tq almost like retarding the exhaust cam only. Alot of people do that when using nitrous.

 

The difference is that during the exhaust cycle, the burned mixture is under pressure to escape. As long as it has a reasonable exit available and it's open long enough, it'll get out. In an NA motor, the intake charge must be sucked in and isn't pressurized like it would be in an FI setup. Using a longer intake pipe/longer runner IM/larger intake valves/better valve job/etc are all ways of increasing volumetric efficiency. Adjusting cam timing on the exhaust can help but so will a well designed header and free flowing exhaust.

 

No you wont

 

A good rule of thumb is that you see about 10 cfm for every 1mm increase in valve size. There are other ways to get flow, but usually when you go to the larger valve you run a larger throat and bowl as well, so you can considerably increase flow if you know what you are doing.

 

Understable so do u think that u would get good gains from increasing exhaust side only to help exhaust scavenge the cylinder just like a big long tube race header and 3 inch exhaust i mean if u can make power all the way around the power band hp/tq with just changing exhaust from 2.3 to 3 inch and a good race header thats stepped in the right places it does make sense. maybe even better than changing both sides b/c the honda intake flows pretty damn good from the jump. But just some assumptions i was thinking on the subject.