Switching from 45 to 50 deg seats - done some testing

[steve cowan]

cant wait for the results,she is going to be one of the baddest cast headed Holden V8 around.

[KnightEngines]

Yeah, I had an aggressive 45 seat in there that behaves pretty close to a 50, 38/45/65/80 with a big throat. Gone to 45/50/65/85 with similar throat.

You've done reverse-flow testing w/ that 45* seat config vs a "less aggressive" 45* seat config? If so, anything you could post? Thanks - Brad

No, I haven't yet, most of the serious stuff that justifies spending the time has the aggressive seats. Only milder stuff gets a regular 45 seat.

[bob460]

What car?
What doe's it weigh?
What times and mph in 1/4?

[KnightEngines]

What car?
What doe's it weigh?
What times and mph in 1/4?

Vs SS commo in street trim, irs rear, only 2x shakedown passes before the track closed, back out soon.

Weight was something like 3800lb, maybe heavier, it'll be lighter next time out.
Ran mid 10 @ around 128mph or thereabouts from memory, short shifting & still plenty of suspension setup to do - fresh car, those 2 passes are it's only 2 passes.

[bob460]

What car?
What doe's it weigh?
What times and mph in 1/4?

Vs SS commo in street trim, irs rear, only 2x shakedown passes before the track closed, back out soon.

Weight was something like 3800lb, maybe heavier, it'll be lighter next time out.
Ran mid 10 @ around 128mph or thereabouts from memory, short shifting & still plenty of suspension setup to do - fresh car, those 2 passes are it's only 2 passes.

Only 2 passes, that's pretty good, if you reach the 700hp range at that weight 9.9s @134 could be had. Good work.

[KnightEngines]

It'll be a lot lighter soon, those 2 passes it had the spare, stereo equipment inc sub & amp & even the factory tool kit & jack in it, along with full exhaust system etc.

Last I heard it was below 3400lb now.

[steve316]

With that much of a weight reduction & 670 HP to 680 HP would put him in the 9's

[Protech Racing]

My class is limited to a max of .425 Valve lift . The cam duration is unlimited. Thus my cam is high rate to max lift. I picked up about 4-5HP , mostly over 6200RPM on my VW 1.8 non cross flow engines with 50 degree seats.
I think that my combustion chamber shape shrouds the the valves in such a way that high velocity air bounces off of the back of the valve into the wall. The 50* seats might move the bounce angle further down the wall and run a little tiny bit better . IMHO

[KnightEngines]

Started on the real heads, that R&D was worth it.

As they came of the engine:

20191115_163931 by tony knight, on Flickr

After 50 deg seats, 5/16" stems & a little grinder time:

20191118_162626 by tony knight, on Flickr

Graph of as they were Vs R&D port Vs current

20191118_163529 by tony knight, on Flickr

20191118_143854 by tony knight, on Flickr

20191118_143903 by tony knight, on Flickr

20191118_143909 by tony knight, on Flickr

20191118_143914 by tony knight, on Flickr

[steve cowan]

Damn Tony very nice work as per usual
bye bye low lift and nice gains on the mid-high #s
i bet you did not really gain much cc on the port either.
they got plenty of meat at the pinch ??i set my PR pinch today on my 180cc Darts @ 2.3'' pushrod paper thin and took a bit of material from the common wall as well.
any thoughts you would be willing to share on valve events now with the cylinder head mods and the updated application for this engine

[KnightEngines]

Maybe 3cc out the port, bugger all!

Pinch is about 2.45", there is a little left, but bigger on the mcsa overwhelms the turn & they tend to go turbulent at high lift, this is dancing that fine line, you can see it backs up a cfm at .900".
Cam is staying, it's 268/274 on 109, but rocker ratio change from 1.65 to 1.8 will change valve events.
Haven't decided if I'll change icl yet.

[cjperformance]

Very nice result

[RevTheory]

Wow. That should turn out really well.

[ClassAct]

Wow. That should turn out really well.

I hope there will be some dyno numbers for both valve jobs. The 50 should beat up the 45 everywhere.

[RevTheory]

Wow. That should turn out really well.

I hope there will be some dyno numbers for both valve jobs. The 50 should beat up the 45 everywhere.

I agree.