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Bench Data

General engine tech -- Drag Racing to Circle Track

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SpeierRacingHeads
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Bench Data

Post by SpeierRacingHeads »

Working on a set of 195cc Pro-Filers for my IROC build. I was going to do the port much like a Super Stock head. The head flows lots of air, and not sure it what I want to do. However, some interesting data to share.

Both ports have the same valve job, same SSR height and shape, same LS 8mm valves.

One port is oval and raised. Notice the flow curve difference. The raised port is 30 fps on the floor vs the standard height port.

Image

Image

Image
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Re: Bench Data

Post by Outlaw383 »

Chad do you think the approach leading to the SSR is more responsible for the difference
Or do you think it's the Oval shape. I guess I'm curious what you think the difference would be (if any) if you raised the runner and kept the roof shape squared or out of the box shape so to speak.
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Re: Bench Data

Post by ClassAct »

Chad, have you ever done any port development with the opposite shape?? As in, have you ever raised and made the roof of the port square, while leaving the floor round? Just curious as to what you think.
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Re: Bench Data

Post by SchmidtMotorWorks »

The raised port is 30 fps on the floor vs the standard height port.
Could you add a little detail to this line?
I don't get what you are saying.
Which line is the raised port?
Where is it measured?
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Re: Bench Data

Post by swampbuggy »

I was thinking the same as Jon, ??? Mark H.
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Re: Bench Data

Post by nhrastocker »

Chad,

Many of the fast Chevy Super Stock cylinder heads have been ported and epoxied into an oval intake port.
The first Heads-Up, Dave Layer, cylinder heads I took a look at in the early 1980's, had oval port heads and the car was a record holder in its class.
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Re: Bench Data

Post by SpeierRacingHeads »

ClassAct wrote: Sat Aug 31, 2019 6:34 pm Chad, have you ever done any port development with the opposite shape?? As in, have you ever raised and made the roof of the port square, while leaving the floor round? Just curious as to what you think.
no I have not.
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Re: Bench Data

Post by SpeierRacingHeads »

SchmidtMotorWorks wrote: Sat Aug 31, 2019 8:48 pm
The raised port is 30 fps on the floor vs the standard height port.
Could you add a little detail to this line?
I don't get what you are saying.
Which line is the raised port?
Where is it measured?
The raised line is the oval port. The floor speed with the oval and raised port is 30 fps faster with the pitot on the floor straight across.

It's well over 400 fps.
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Re: Bench Data

Post by SpeierRacingHeads »

nhrastocker wrote: Sat Aug 31, 2019 10:55 pm Chad,

Many of the fast Chevy Super Stock cylinder heads have been ported and epoxied into an oval intake port.
The first Heads-Up, Dave Layer, cylinder heads I took a look at in the early 1980's, had oval port heads and the car was a record holder in its class.
Every Super Stock head that I do is oval and raised. That is why I wanted to try it on this.

However these flow way too much air to be this small and oval, IMO.
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Re: Bench Data

Post by RevTheory »

SpeierRacingHeads wrote: Sun Sep 01, 2019 1:14 pm
nhrastocker wrote: Sat Aug 31, 2019 10:55 pm Chad,

Many of the fast Chevy Super Stock cylinder heads have been ported and epoxied into an oval intake port.
The first Heads-Up, Dave Layer, cylinder heads I took a look at in the early 1980's, had oval port heads and the car was a record holder in its class.
Every Super Stock head that I do is oval and raised. That is why I wanted to try it on this.

However these flow way too much air to be this small and oval, IMO.
So what's the fix; aside from less duration and lift, which can't be a terrible thing for a street engine?
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Re: Bench Data

Post by Carnut1 »

They look great and I expect they will make a serious street sweeper. The fast floor doesn't bother me if it has a low speed gradient across the floor and has a smooth sound at higher depressions. Please share some cfm and shortblock specs. Thanks, Charlie
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Re: Bench Data

Post by Mikej26 »

[/quote]
However these flow way too much air to be this small and oval, IMO.
[/quote]

What do you mean? How is this a bad thing? Or am I not picking up on sarcasm?
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Re: Bench Data

Post by SpeierRacingHeads »

RevTheory wrote: Sun Sep 01, 2019 1:24 pm
SpeierRacingHeads wrote: Sun Sep 01, 2019 1:14 pm
nhrastocker wrote: Sat Aug 31, 2019 10:55 pm Chad,

Many of the fast Chevy Super Stock cylinder heads have been ported and epoxied into an oval intake port.
The first Heads-Up, Dave Layer, cylinder heads I took a look at in the early 1980's, had oval port heads and the car was a record holder in its class.
Every Super Stock head that I do is oval and raised. That is why I wanted to try it on this.

However these flow way too much air to be this small and oval, IMO.
So what's the fix; aside from less duration and lift, which can't be a terrible thing for a street engine?
Head doesn't have enough cross section. Need to slow it down
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Re: Bench Data

Post by SpeierRacingHeads »

Mikej26 wrote: Sun Sep 01, 2019 3:40 pm
However these flow way too much air to be this small and oval, IMO.
[/quote]

What do you mean? How is this a bad thing? Or am I not picking up on sarcasm?
[/quote]

Too fast IMO.
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Re: Bench Data

Post by SpeierRacingHeads »

Carnut1 wrote: Sun Sep 01, 2019 1:36 pm They look great and I expect they will make a serious street sweeper. The fast floor doesn't bother me if it has a low speed gradient across the floor and has a smooth sound at higher depressions. Please share some cfm and shortblock specs. Thanks, Charlie
Port is about 188cc. 2.08 LS valve. Flows 300@.500 and 305@.600, and 308@.700

4.165 x 3.48
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Weisco Pro Tru pistons
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.580 lift
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