While I wholeheartedly agree, I'm sure the originator of these motors would say its perfectly okay to subject them to that torture, and that they would hold up just fine.

 

One of the reasons we sought to work with dave is because of his expanded knowledge on the subject. We came up with a combo that works and works better than everything I had imagined it would.
We have some interesting projects to post up shortly, that will define his work even further.
Thanks again Dave

 

I like your enthusiasm!lol one thing at a time..so we will start with the Inconel question.

this is a hard subject to keep simple...and I will admit, I really don't know how to tie it all in, because I am not that smart, , but will try!

The name Inconel is really just a name back in WW2 that was given to a material that could withstand heat. It's a Nickel alloy..And it is not something that is a constant between manufactures. Meaning every manufacture has there own "mix". In reality, all valves are Inconel, factory(some) or aftermarket, intake and exhaust.. so it can kind of be misleading. I understand to the laymen it makes it easier to say "Hey this is a inconel valve, buy it", but they all are. If you break out you periodic table of elements, valves can be a mix of of things like Chromium, Tungsten, nickel, and sometimes niobium. But I think when it is stated, they are mostly referring to a valve that has a higher nickel content then the other. Which makes it more resistant to heat.

Most after market valves are made out of what's called EV8, which is a older inconel mix.(1800 to 2000 degrees) I say older because there are some newer stuff out there like Ferrea's use of numonic 90 on there comp plus series exhaust valves that we use on heads slated for 40 psi (1200whp 2400 degrees). And for the absolute extreme temps there is pyromet(2600 degrees) that we use on our 60+psi 1400whp+ stuff. The pyromet is the same material they use in Top Fuel and Funny Car, so it has shown it can withstand some heat! Unfortunately, it doesn't have memory though. Most valves are elastic to some degree, meaning they will bend. Some bend and break, some bend and then can be bent back in shape. The pryomet is so strong it takes alot to bend, and will never find a home again if it does.

To give a example of material usage, in 04' we were doing heads for some ProRWD and Modified (NHRA and NOPI) cars. They have a 6mm stem diameter and were having issues bending valves once we tried running 70psi. I don't remember exactly, but you can imagine the exhaust temps for such a deal, and after a pass, the valves would tweak a little during shut down, they would not seal anymore and beat the seat up a little. We were using the EV8 on the intake and Numonic 90 Ferrea valves. We worked with Ferrea and after some begging and pleading they made us a valve made from the Pyromet to our specs. The problem was solved as we no longer had issues with bending unless something hit them.

 

Wow cool story! Would love to hear more.

 

Wow, great work yet again from Nick, the DTM crew, and now HeadGames!

What a team.

 

Interesting that the valves would bend during shut down.... Think it was just a matter of them cooling off too rapidly?

Besides CFM, what have you found to be most crucial in producing power through modifying heads? Do you prefer volume or velocity?

Thanks for sharing with us!

Scorke

 

great info on valve material! when do sodium filled valves come into play?

 

Thanks for the info Dave - Great results, that power band must be very fun on the track!!!

 

Question: What are you using to log boost? Can we see a boost plot?

 

Sodium filled valves conduct heat upward, and are used in engines that are expected to see high loads and therefore lots of heat in the combustion chamber.

I know the 'pros' of sodium valves, and have used them before, but I am unaware of the 'cons', if there are any. One could guess that because of the hollow portion of the valve stem, they may not be as durable to valvetrain stress. It's a good question.

 

thanks..as long as no one cares, I can share. There is alot of knowledge we gained from the race teams that you would never see on the street, but it makes it so you can build something for the street that you are absolutely sure could never break.
It was a matter of cooling down too quickly. We are talking about 215mph passes, so when the parachutes are pulled, the engine was shut down. The problem started there, and after other changes were made, we tried getting the guys to let the motor idle in the shut down area...this quelled the issue, but it did not disappear. That is when we changed valve material. Maybe it should be noted that there was also a copper berylum valve seat in the head to take heat away from the valve as well as a maganese bronze valve guide that not only absorbs the heat faster but takes the heat away from the valve and disapates the heat into the head faster then the stock cast iron..it may wear quicker, but will not break or fail like cast iron.

As far as velocity :VS: volume, I think it is a double edged sword..our philoshy could certainly be wrong, but the day that gas is so expensive that we start pulling flow benches out to the track to race, we will not worry about peak flow.(volume) We are a velocity based company, which is why we do not recommend a 1mm bigger valve for anything below 700whp on a mitsu. Let's not get confused with the real fact that it will NOT flow as well against a well prepared big valve head..so if you guys compare numbers, the small valve head will lose..but it will out run the big valve head down the track in a lower hp car. It will also make you beat the living crap out of your car, because the power feels so good everywhere though!

From what we have seen, the valve is not the restriction in the Evo head, but it is the valvejob and bowl size. It is all about the valve job, which is what most lack. We have seen heads with a good port, flow no better then stock because of the valve job. You can easily pick up 30cfm from a good one that's blended in correctly.
They are actually the most valvejob finicky head we have had the pleasure to deal with...thank baby jesus for giving up a flowbench!lol

we have never used them in a sport compact engine...

 

Thanks again for your reply, somebody with your sort of expertise and experience is a great resource to our community, I might send you a PM and come by and visit your location sometime if thats possible, would love to meet you and see your facility!

It's always nice to learn something new, besides AMS who else sells head done by you guys in our community, and or do you offer your services directly?

Scorke

 

I will admit, I am a little weird and not very inviting about people dropping by the shop unless they call first, are there dropping something off, and leaving. Not trying to be rude, just honest. So, if you want to come by and visit, it would have to be a Saturday, and it would have to be a short visit! unless your dropping something off... This is simply because when we are way to busy for anything less..I even kick friends out of my shop all the time, so please don't take offense.

And you can get our heads from a few forum sponsors like - AMS (I know they have a few on the shelf) DTM has a few, and of course from us...

 

headgames, pm sent