Titanium exh valves in turbo motor?

[norbs]

I am looking for opinions on titanium exhaust valves in a turbo motor, what would be the ill effects?


Thanks

norb

 

[Mike E]

They aren't necessary and they don't handle heat well. Ti also has lubrication problems at high heat in the guides. The only advantage to a ti valve is the light weight. More of an advantage on the large intake valve than the smaller exhaust. You likely won't turn enough rpm with a turbo motor to need anything lighter than stainless on the exhaust side. If your buying new, buy inconel (also called superalloy). It's the best choice for the high exhaust temps.

 

[Alky V6]

I did a lot of research on running Ti valves before I decided to run Ti for both intake and exhaust.
First off, in a boosted situation, especially with high exhaust back pressure to intake boost pressure ratios, the exhaust valve will be the first valve to look at for floating at high rpm limits, even though the exhaust is lighter than the intake.
Even in my situation where my exhaust back pressure to intake boost pressure ratio is very favorable, the exhaust valve will still be the valve to float before the intake.

 

[Dusty Bradford]

Ti can be used in the exhaust side. Alcohol motors dont see the temp of gas motors so they are a better fit than on gas engines. You have to run a super high quality Ti valve in a turbo engine. I personally would not spend the money to run Ti on a gas engine. You can opt for the Ferrea super alloy or Inconel from most manufacturers. The Ferrea super alloy is better than stainless and cheaper than inconel. When building an engine from scratch, I use the Ferrea.

 

[Alky V6]

Ti can be used in the exhaust side. Alcohol motors dont see the temp of gas motors so they are a better fit than on gas engines. You have to run a super high quality Ti valve in a turbo engine. I personally would not spend the money to run Ti on a gas engine. You can opt for the Ferrea super alloy or Inconel from most manufacturers. The Ferrea super alloy is better than stainless and cheaper than inconel. When building an engine from scratch, I use the Ferrea.

I agree with Dusty. The difference in my application is the alcohol. Ti does not like exhaust temps over 1400 degrees F. That's an upper exhaust temp limit for an alcohol engine. Even turbocharged.
There are heat barrier coatings you can get for Ti exhaust valves. In fact, my exhaust valves are coated for added insurance.
Just for reference, the valves that I have in the car now were installed in 2005.

 

[norbs]

Thanks everyone, so based on your comments I dont think Ti valves for exhaust are a good idea.

 

[m233roller]

I'm with Dusty on using Ferrea.!!

 

[750H.P.V6]

I discussed this with Kenny once. His advice boiled down to something like this. If you've got them then run them, if you're thinking about buying them don't spend the money there are better valves for the application as stated above.

Neal

 

[Alky V6]

What happens with Ti exhaust valves is warpage, and then improper sealing to the seat. Even at my exhaust temps of only 1250-1350 degrees F, the valve head will obtain a little warpage, even with a heat barrier coating. The valve head seems to flatten out enough to seal once seat spring pressure is realized, but I'd hate to see what a typical gasoline exhaust temp would do to the valve.
The company that supplied the valves to me were very specific in warning me not to use the exhaust valves in an application where the exhaust temps rose above 1400 degrees F. Very specific.