Aftermarket vs oem valves

[Tehnation]

Any thoughts??

 

Rebuilt my motor, find out one of the heads are cracked, so its back at the machine shop. Its got forged internals and bc stage 3 cams, goal is to be able to spin to 8k rpm.

 

Something tells me I should put in aftermarket valves, but I don't know a good brand. I was thinking of getting at least exhaust valves.... I'm not to up to date on the subject. No idea of what material or brand is better.

 

Any helpful info would be appreciated. I search for valves and all I get are post on retarded bovs... I need to order something quick, so I don't really have time for much research.

 

I'm willing to invest like $350-400 for both intake and exhaust.

 

GSC, BC, Supertech or ???

[Max Capacity]

What are the younger guy's over on NASIOC using ?

[Tehnation]

Its all over the place! I made a post over there, hopefully someone can shed some light. The more I read the more I realize I'm just going in circles lol!! I emailed tuner, maybe they have a proper answer.

[Tehnation]

But I'm pointing towards Manley and BC. Why? My piston and rods are Manley, and I know they are good quality parts, and all the stuff in my cylinder head are BC, so I may just go with BC all the way.

 

Also wondering if I should get bigger valves?!?

 

Options for manley valves on page 9 of pdf or page 7 of actual catalog page.

 

http://www.manleyperformance.com/sc/Manley_SportCompact.pdf

 

 

BC stuff

 

https://briancrower.com/makes/subaru/ej257_valvetrain.shtml

 

 

I remember when things were simple and correct...... way to much science and marketing.... makes my head hurt...

Edited June 26, 2020 by Tehnation

[Max Capacity]

The way the machine shop answered the same question many years ago about oversized valves. It's much cheaper to run one more pound of boost.

 

You're not building a race car are you ?

 

I did have them do some porting around the valve pocket. Be careful there as you want someone who knows what they are doing. If you port in the wrong area you can loss HP.

 

Not sure if it made a big difference, but I feel my wagon pulls pretty good in the midrange.

Edited June 26, 2020 by Max Capacity

[DaveWaters]

Check out Headgames in NJ. Iirc their website has a lot of info on subaru builds. You could also give a call. Dave (the owner) is a cool dude and loves talking heads. I had them do my heads (stock refresh) 1 week turn around in 2018. A little pricey but I felt more comfortable with them because I got answers from other machine shops that made me feel like the others knew heads but not subaru so much.

[Max Capacity]

Headgames, I have heard good things about them over the years. Even back around 2007 when we were racing.

[boxkita]

the original sodium filled valves are actually better than anything else. The extra 1mm width doesn't really matter, especially if you don't port to match, even then you need to be pushing alit of air to be worth it.

 

I put ferrea titatium & inconel +1mm valves on my v25b heads. Then used oem cams. In the end, getting to 8500rpm (my goal) turned to be more hassle than it was worth. Technically it'll turn 8500 however not for very long and certainly not lap after lap.

 

Getting the valvetrain balanced so there is no friction got expensive really fast.

 

Headgames, c&d machine (bellevue wa) are two of the most common places Ive heard about for doing high-end work. There's a guy in Portland Oregon but you have to be a shop to get in. There are definitely others, but finding a shop that is willing to do the fussy work to get everything balanced is difficult. Mostly because the average customer doesn't want to buy 100 valves to find 8 that are exactly the same.

 

Is your quest to see 8500 on a dyno sheet or see it on your rpm gauge (daily)?

 

I used to bang the rev limiter every time I drove it, repeatedly. I reset the redline to 7000 because I knew I was going to do that. If I left it at 8000, Id have blown it up more than I did.

 

Changing to a plateau curve instead of a sharp peak on the torque curve is hella fun on the street, as yer always at max power. I went from 396tq to 335tq. But I dont drag race. ymmv

[Tehnation]

I mainly just want more range, I want to move the power to the right. Its way more fun on the street having a wider range, 6k and 5 gears annoys me. Ideally I want power up to around 7k and flatten to 8k, for daily use. These motors don't seem to be designed for high rpm, so I duno.

 

Engines already done so I missed that boat, oem it is!

 

I will have to see where the cards fall at this point. I plan on bringing it to a good tuner, they tuned subracabra, and are within an hr of my house. Hopefully I can get it on the dyno by the end of July.

 

[boxkita]

generally, 8k isn't considered daily driver. I'll be interested to see what happens. Revving from 2500-8000 is a long time.

 

I found making 4000-7000 a plateau provided alot of fun in 3rd & 4th gears. Adding a fart can exhaust would have been more fun when backing off 3rd at 7000. Area under the curve is lots of fun. Be on boost instead of seeking it

[Max Capacity]

^ X2

 

with some porting in the valve pocket area, I'm very happy with the vf52 stock fueling and the tune from tuningalliance@gmail.com

 

Mike did a awesome tune.

 

The engine pulls all the way 7000rpm. great power in 3rd & 4th. Every now and then I find I run out of fuel MAP in 1st gear. 7000rpm comes quickly.

[boxkita]

First gear frustrates the heck out of me, I try to get into 2nd as soon as possible