the machine shop said i have a couple bent valves so im going to get a set of supertech valves for it. now my question is should i get oversized valves? and how much will it really help if i do? my setup is going to be a little different with a holset hx40 pro which flows about 71lbsmin im looking to about max this turbo out on e85. my goal is 600hp on a MD at stm.

 

any input fellas?

 

I always thought oversized valves would help alot with letting more air in and getting exhaust out but i was told by my tuner that the difference isnt even noticable and not worth doing unless your at the end of your build and your just looking for that little edge

 

i just got my head back from David at Head Games Motorworks n the way he explained it to me was unless i was planning on maken 900-1000whp stock sized valves are fine. larger valves from the way he described it can make the turbo more lazy. He said he does john shepheards heads uses 1mm oversized but hes maken in the area of 1500whp. Now not that i dont trust Dave but i called AMS n asked chris just for s second opinion and he pretty much said the same thing so i just got Ferrea comp series valves, guilds, seals, locks with kiggly valve springs.

 

ok thanks for the input guys

 

As what Dave at headgames said, a larger valve actually has more surface area which can hinder spool. A standard valve is fine in nearly every application. A friend of mine got his head done by Headgames and told me exactly what was mentioned above, so I decided to read up on it. It makes sense from a physics stand point.

 

Thanks for the info guys, I was wondering if it was worth it myself.

 

we cut a 1mm oversize valve into a lightly ported stock port and it lost flow.

stick with stock size.

 

From a leader in the industry. What more can you ask for?

 

I was wondering if i can get away with using the stock valves on my build?

 

stock valve size or stock valves themselves?

 

Stock valves themselves, but upgrade springs and retainers.