turbo/carrera heads, different valves?

[89turbocabmike]

Are the intake/exhaust valves on the turbo heads dimensionally different length-wise (they have the same diameter 41.5/49mm)as opposed to the 3.2 heads or is there some other reason they are much more expensive?

The reason I ask is I'm rebuilding 3.2 heads for Turbo use.

Thanks, Mike

[racing97]

Different Alloys, you know 50 cents worth of material 50 dollars more in price.
When increased strength or temperature resistance is required, the higher nickel alloys are typically preferred. With more than 70% nickel content.

Best regards

[89turbocabmike]

Thanks racing97, as usual there is no free lunch. I was hoping that the price difference was due to the 3.2s being dimensionally different and high production volume, but I should have known better. Oh well, turbo valves it must be, I'm already a bit nervous about using the 3.2 heads with their different alloy, but I've got to take some risks

[Bill Verburg]

930 valves are Na cooled on the exhaust side and use different alloys on both sides.

if you think they are expensive , price a club sport valve

[adomakin]

i think many people use stainless steel in turbo applications.

[hobieboy]

Originally posted by Bill Verburg

if you think they are expensive , price a club sport valve

Can the club sport valve be used on turbo engines? To be sure - you are talking about Intake?

[adomakin]

is it that important? i always thought that turbo and n/a cars had similar head temps unless you are running too much boost/comp etc.....or you are running a race car. but for a street car?

[Bill Verburg]

Originally posted by hobieboy
Can the club sport valve be used on turbo engines? To be sure - you are talking about Intake?

Sure, a better bet though would be Na filled 964 intakes, light and heat effective.

Most exhaust valves are 2 part anway, w/ a magnetic ss alloy for the stem and a non magnetic heat resistant ss alloy head welded on

Mahle won an award in 2004 for their hollow, nickle alloy valves. but they are just going into production now and Toyota has a trick Ti mmc alloy that they use.