50 degree valve seats in modern hot street builds: is it finally time?

[randy331]

You want others to accept the conclusion of your testing but I am not allowed to draw a conclusion off of someone else testing?

Gary, I want to take this time to apologize for our real world testing not agreeing with your theories .
And I think the rest of our group that tests and dynos engines together would agree with me.

We are Sorry Gary.

Randy

[GARY C]

You want others to accept the conclusion of your testing but I am not allowed to draw a conclusion off of someone else testing?

Gary, I want to take this time to apologize for our real world testing not agreeing with your theories .
And I think the rest of our group that tests and dynos engines together would agree with me.

We are Sorry Gary.

Randy

My theory's are drawn from test results just like yours.

[Warp Speed]

You want others to accept the conclusion of your testing but I am not allowed to draw a conclusion off of someone else testing?

Gary, I want to take this time to apologize for our real world testing not agreeing with your theories .
And I think the rest of our group that tests and dynos engines together would agree with me.

We are Sorry Gary.

Randy

My theory's are drawn from test results just like yours.

Can you post a link, I must have missed them?

[GARY C]

Gary, I want to take this time to apologize for our real world testing not agreeing with your theories .
And I think the rest of our group that tests and dynos engines together would agree with me.

We are Sorry Gary.

Randy

My theory's are drawn from test results just like yours.

Can you post a link, I must have missed them?

I'm sure you have far better data you could post than I do, I am not going to try to duplicate everything I have put forth over the past year just because you choose not to be part of the thread.

[GARY C]

If the cam was correct for the 45° seat, it would seem logical that a couple of degrees more for both IVO and IVC could be required with a 50° one (and thus no change in ICL or LSA) to compensate for the reduced low lift flow.

This would be a good investigation for someone with a recent version of Dynomation or a similar/higher level simulation software program. m ke I believe is one Speedtalker with same..

I did some Dynomation 5 simulations testing some steep seat flow curves and ran the cam iterator to find what it wants but the sim always showed less power with the steep seat flow curve, no matter the cam events. Makes me doubt the accuracy of the info.

Rick

Interesting Rick! Disregarding the lower predicted power, how were the similarly-optimized cam specs affected?

PS: How did your steep seat flow input data compare to the 45° values? If it exhibited the commonly-reported reduced low lift flow, less power would be the opposite of the conclusions noted in the "too fast over SSR" thread...

I had a 357 saved in Cam Master with a 2.08 valve and for the heck of it I changed it to a 2.02 and reduced flow accordingly between .100 to .250 only and it added 2 degrees on seat, reduced LSA by 1.3 and increased overlap from 55 to 60... For what it's worth.

[Warp Speed]

My theory's are drawn from test results just like yours.

Can you post a link, I must have missed them?

I'm sure you have far better data you could post than I do, I am not going to try to duplicate everything I have put forth over the past year just because you choose not to be part of the thread.

Ok

[Warp Speed]

I did some Dynomation 5 simulations testing some steep seat flow curves and ran the cam iterator to find what it wants but the sim always showed less power with the steep seat flow curve, no matter the cam events. Makes me doubt the accuracy of the info.

Rick

Interesting Rick! Disregarding the lower predicted power, how were the similarly-optimized cam specs affected?

PS: How did your steep seat flow input data compare to the 45° values? If it exhibited the commonly-reported reduced low lift flow, less power would be the opposite of the conclusions noted in the "too fast over SSR" thread...

I had a 357 saved in Cam Master with a 2.08 valve and for the heck of it I changed it to a 2.02 and reduced flow accordingly between .100 to .250 only and it added 2 degrees on seat, reduced LSA by 1.3 and increased overlap from 55 to 60... For what it's worth.

How would the smaller valve data apply to a change in valve seat angles?

[GARY C]

Interesting Rick! Disregarding the lower predicted power, how were the similarly-optimized cam specs affected?

PS: How did your steep seat flow input data compare to the 45° values? If it exhibited the commonly-reported reduced low lift flow, less power would be the opposite of the conclusions noted in the "too fast over SSR" thread...

I had a 357 saved in Cam Master with a 2.08 valve and for the heck of it I changed it to a 2.02 and reduced flow accordingly between .100 to .250 only and it added 2 degrees on seat, reduced LSA by 1.3 and increased overlap from 55 to 60... For what it's worth.

How would the smaller valve data apply to a change in valve seat angles?

Probably the revers swirl polish.

[Warp Speed]

I had a 357 saved in Cam Master with a 2.08 valve and for the heck of it I changed it to a 2.02 and reduced flow accordingly between .100 to .250 only and it added 2 degrees on seat, reduced LSA by 1.3 and increased overlap from 55 to 60... For what it's worth.

How would the smaller valve data apply to a change in valve seat angles?

Probably the revers swirl polish.

So, you have nothing huh?!?
At least your consistent!

[GARY C]

How would the smaller valve data apply to a change in valve seat angles?

Probably the revers swirl polish.

So, you have nothing huh?!?
At least your consistent!

So that means you have less than nothing? Feel free to post up some info... I will be waiting.

[Warp Speed]

Probably the revers swirl polish.

So, you have nothing huh?!?
At least your consistent!

So that means you have less than nothing? Feel free to post up some info... I will be waiting.

It was a serious question. You've been stating that a change in valve seat angle would require a change in lobe separation angle (which has never showed in our testing) and gave simulation data from a change in valve size. How would that data apply when they are vastly different scenarios?
BTW, you know why I can't post data, what is your excuse?

[Stan Weiss]

If we were to look at this using Blair's time area. The great the seat angle the less time area we would see in these areas (looking at intake only).

Intake BTDC (IVO to TDC)
Intake Ramming (BDC to IVC)
Intake Overlap (IVO to EVC)

Stan

So in this case difference in time area do not come into play?

Intake Valve Seat Angle = 45.0 Intake Valve Seat Width = 0.035
Exhaust Valve Seat Angle = 45.0 Exhaust Valve Seat Width = 0.055

Intake BTDC (IVO to TDC) = 3.412
Intake Pumping (TDC to BDC) = 58.947
Intake Ramming (BDC to IVC) = 7.365
Intake Overlap (IVO to EVC) = 14.751

Using Valve Seat Angle and Width for Area Calculation
Intake BTDC (IVO to TDC) = 2.644
Intake Pumping (TDC to BDC) = 54.061
Intake Ramming (BDC to IVC) = 6.081
Intake Overlap (IVO to EVC) = 12.793

---------------

Intake Valve Seat Angle = 55.0 Intake Valve Seat Width = 0.035
Exhaust Valve Seat Angle = 55.0 Exhaust Valve Seat Width = 0.055

Intake BTDC (IVO to TDC) = 3.412
Intake Pumping (TDC to BDC) = 58.947
Intake Ramming (BDC to IVC) = 7.365
Intake Overlap (IVO to EVC) = 14.751

Using Valve Seat Angle and Width for Area Calculation
Intake BTDC (IVO to TDC) = 2.429
Intake Pumping (TDC to BDC) = 53.409
Intake Ramming (BDC to IVC) = 5.775
Intake Overlap (IVO to EVC) = 12.398

Stan

[RevTheory]

Thanks for putting numbers to the difference in time/area during the overlap phase between various seat angles, Stan.

[GARY C]

Food for thought in a different direction, If all things being equal a 45 degree seat provides more window area and more average cfm than a 50 for the entire induction stroke but it does not increase power or looses power, what is preventing the engine from taking advantage of the extra widow area and CFM?

[KnightEngines]

Where the flow demand is highest 50 deg seats move more air.
Pretty simple.

Looking at average flow is BS, look at average flow between mid lift & .100" past peak lift to get a better idea.

Move more air at peak demand & you build more inertia in the charge, that improves fill at the end of the induction stroke.