Please stop putting words in my mouth, it makes you sound dumb. I was saying why doesn't top fuel use sodium filled if its better than inconel? I never said that since top fuel uses it, that its good for my engine!

To your point about weight... The stainless intake valves are still bigger and therefore heavier than the solid inconel exhaust valves, and the valve springs are the same spring rate for both intake and exhaust valves, so doesn't matter.

You are probably correct about the sodium filled running cooler...but only to a point. Does the inconel get hot enough to cause det., thats debatable imo.

I'm glad we agree.. yes, inconel can handle more heat. thank you very much!

You said I am making 450hp... wow, i didnt know drivetrain losses in AWD cars is only 7.5%! haha don't we all wish.

BR will be shipping my 2.3L very soon and eventually I will go FP black eventually, so I will be much higher later. I am thinking ahead for that as well... but i guess as you say "running a 4g63 at even 900hp you will be no near failure thresh holds due to heat"... do you personally have a 900hp evo with stock valves? If so, how many miles do they last? How can you be sure that a 900hp evo's sodium filled valves "will will be no near failure thresh holds due to heat"?

 

So Im just asking, but then wouldnt the inconel be better material for keeping heat inside the combustion chamber? wouldnt it be better to keep the heat in vs something that will absorb the heat out and heat the cylinder head itself more? Higher exhaust temps means more velocity-more power, no
Im just trying to understand this better.

 

I think the amount of heat that exhaust valves can absorb from the combustion chamber and transfer to the head is negligible for what you are talking about, no matter what material they are made of.

You can have situations of really high exhaust temps due to retarded ignition timing where the fuel is still burning in the exhaust which doesn't mean more power (less actually), but it does mean high EGT's and velocity which will spool a turbo quickly (i.e. anti-lag).

In most cases for a given engine, more power = higher EGT's. the more air and fuel you can cram into the cylinder and light off, the more heat you are making as well.

 

For anyone interested in reading more about valves, I found an article that is a good read:

https://www.aera.org/engine-professi...ve-technology/

 

I for one am not quick to discard anything mitsubishi gave you from the factory. dsm 4g63 engines did not come with sodium filled exhaust valves. they only came with the evo series. and if anyone remembers the evo literature in 2002 before the evo was here they were also supposed to come with hollow intake valves, but anybodies guess why it didnt happen. my guess would be either cost cuts or reliability. but I am sure the sodium filled design was a nice improvement over the previous valve. designed to be lighter and run cooler. the factory valves are also nitrided for longevity. in 2004 I started buying wrecked evos and was pleased to find all the improvements made to the valves train. I installed all the evo stuff in my 600whp dsm where they still remain today. I run the stock evo valves, springs, retainers, and cam followers with crower 280 cams. I spin the engine as high as 9300rpm (aem verified) and have had many tuning mistakes where egt reached 1000-1100c. no damage to valves. keeping the valve train light is of high importance to me. It allows lighter spring pressures which is extremely important for engine longevity.. if you ever built an engine and felt how hard it is to turn the engine over on the test stand after you install stiff springs you would have a very good understanding of why so many oil pumps fail on the 4g63. over springing the engine puts additional side load on the pump gears. very evident problem that leads to very expensive engine failures and disappointment.

my simple advice. dont fix whats not broke. the stock valves work very, very well for many many hard miles..

 

This is correct, more hp = more heat 100% of the time. That means more heat is conducted through the valves, pistons, oil, cooling system, etc.

If this head is just getting a valve job, mild hand grinding, and the valvetrain won't be subjected to considerable stress, then your options are more flexible. This is especially true for a street setup, and even more so if E85 is used. In such cases, there is no external condition that forces you to ditch the factory valves - any of them. Many persons generate 500+whp in street cars with a medium sized turbo and a bone stock head, with no apparent track record of valve failure. The factory Na-filled valves hold up well in such instances.

If this were a situation whereby you were determined to get every last bit of flow from the head and best possible power from a given turbo PR ratio, you'd want aftermarket valves not only to satisfy size and durability requirements, but for another valid reason - they outflow the factory valves. In this case, an aftermarket Inconel exhaust valve is a solid option that provides superior flow and better durability than the factory pieces.

If you stick with the factory exhaust valves in your mild setup, you should be fine. And if you decide to go with an Inconel exhaust valve, the world won't end and your dog won't die.

 

If it's so important why don't you get titanium intake valves or hollow stainless? You do realize that I am not having to go with a heavier spring due to the inconel exhaust valves and that they are still lighter than the solid stainless intake valves right?

Are you saying that all the guys out there running higher spring rate springs for bigger cams are making a mistake and should all go back to mild or OEM cams so that we can use the factory spring rate?

 

Hahaha! thanks TedB

 

I wish I still had that pm saved when I contacted GSC and asked questions about aftermarket vs oem valves when I was building my head. What GSC bascially told me was what TedB touched on. There is a benefit in better flow with the aftermarket valves vs oem, of course he was talking about his, but he actually said for ANY,not just GSC brand. He had written alot more info as to the details but this was a while ago so I really cant rememember everything. I went with aftermarket valves due to his recommendation. I also happend to contact MAP who gave me similar information as well. ymmv

 

Well, just thought I would report back. Tom at Port Flow Design really took care of me. Super nice guy and he does beautiful work. I went with the Supertech inconel exhaust valves. He did a nice radius valve job and then went back and knocked down all the sharp edges in the combustion chambers. He put supertech viton valve seals all the way around. I put a Kiggly HLA on as well.

BEFORE:


AFTER:

 

Beautiful!

Please post result!

 

So after reading this thread I'm wondering why everyone was suggesting OEM valves instead of something aftermarket like ferrea. I put GSC +1mm valves in my head when I did it, is this a bad thing? I did exhaust and intake valves, I had alot of detonation in my head because I got a bad tune and it melted a spark plug which broke the valve and shot out the exhaust side and ruined my turbo as well. The tune was from when I blew a different turbo on the dyno and left without a solid tune (my fault) http://www.extremeturbosystems.com/G...m-1mm-Set.html

 

I know I am bringing this thread out of the dead, but just want to thank for the GREAT information.

I am currently making this kind of work on my Evo 5 JDM, due to my timing belt snapping and ruining valves

I was about to go with Supertech nitrided, sodium-filled.... but now, I am trying to find out of pre-8/9 evos also have oemn sodium-filled exhaust valves. If so, I will try to go OEM

 

Just use the OEM sodium filled exhaust valves, cheaper, longer life, and your engine won't see enough heat to cause them to fail.

 

Thanks for the advice, that was pretty much my choice after reading this post and many other sources of info about the topic