BBC output overview.

[user-17438]

FRANKSHAFT COMMENT:-
In response to the bold, if that is true, why do they use multi angle intake seats? Call Richard Maskins, CfE, mbe,etc, they will tell you the same thing.


AND WHAT EXACTLY WOULD BE :- 'the same thing' ?
DV

I can answer that.. they simply don't work. Especially with any amount of overlap. You can fix them by using sharp top cuts and undercuts. Then it is no longer a radius seat.

X2 with my experience

[gruntguru]

Hi David. I am sure I can speak for the majority here in saying the following.

I look forward to every post you make. Your vast experience in this field and your passion for passing on that knowledge (whether by selling books and seminars or FOR FREE on forums like this) are legendary. I bought my first David Vizard book nearly 50 years ago.

Imagine my disappointment when I find a new post from David Vizard and it contains none of that. Responding to haters and fools is a waste of your VERY VALUABLE time. Please ignore them.

[user-17438]

Hi David. I am sure I can speak for the majority here in saying the following.

I look forward to every post you make. Your vast experience in this field and your passion for passing on that knowledge (whether by selling books and seminars or FOR FREE on forums like this) are legendary. I bought my first David Vizard book nearly 50 years ago.

Imagine my disappointment when I find a new post from David Vizard and it contains none of that. Responding to haters and fools is a waste of your VERY VALUABLE time. Please ignore them.

I'm not a hater or a fool, and I have a lot more experience than most at very high levels. So just because I, like others disagree. We are wrong? Or haters? Or fools?

I would be more disappointed if everyone ignored and didn't learn from others. There are a lot of very talented people on these subjects, yet some people just ignore their posts and replies because they would rather drink the kool-aid and not respect differing results.

For the record I disagree with what David has been saying on this subject. I havent posted much because I fear everyone calling me out because I don't agree. But from what I have seen in stock BBC to spread port or symmetrical race heads, his data does not jive with mine. so call me a hater, or a fool. But I build engines for a living and also crew chief. I know the builders that are winning and losing.

I'm not disrespecting David at all. And that is not my intention. I just do not agree on what he has said.

Question to David. I am confused at what is going on. You referenced a BBC edelbrock head, then posted a different one.

As far as port bias, if you don't have the room, a bias can be a bandage. I have found that putting bias in the floor opposite to what you think the port wants can increase flow. But I found it did not equate to HP when I did it on a stock 26degree

[randy331]

Last couple weeks project.IMG_20181007_141730515~2.jpg

Just in case you don't understand I actually do this for a living.

Is that the one you had at the central Illinois street car race?

Or is a different project ?

Randy

[Kevin Johnson]

Just got on to Edelbrock's site to find the part# of that head.

What a deal - they have changed it for the worse when it's a question of finding out what you have got/need. All I can tell you is what is on the ends of the heads - Performer 100 cc.

That should identify it if you call Edelbrock. As for finding it in their catalog - best of luck.
DV

I went to the Internet Archive and looked at a snapshot of Edelbrock's site in 2004; this information was copied from the site:

vizard.gif

[MELWAY]

Hi David. I am sure I can speak for the majority here in saying the following.

I look forward to every post you make. Your vast experience in this field and your passion for passing on that knowledge (whether by selling books and seminars or FOR FREE on forums like this) are legendary. I bought my first David Vizard book nearly 50 years ago.

Imagine my disappointment when I find a new post from David Vizard and it contains none of that. Responding to haters and fools is a waste of your VERY VALUABLE time. Please ignore them.

I'm not a hater or a fool, and I have a lot more experience than most at very high levels. So just because I, like others disagree. We are wrong? Or haters? Or fools?

I would be more disappointed if everyone ignored and didn't learn from others. There are a lot of very talented people on these subjects, yet some people just ignore their posts and replies because they would rather drink the kool-aid and not respect differing results.

For the record I disagree with what David has been saying on this subject. I havent posted much because I fear everyone calling me out because I don't agree. But from what I have seen in stock BBC to spread port or symmetrical race heads, his data does not jive with mine. so call me a hater, or a fool. But I build engines for a living and also crew chief. I know the builders that are winning and losing.

I'm not disrespecting David at all. And that is not my intention. I just do not agree on what he has said.

Question to David. I am confused at what is going on. You referenced a BBC edelbrock head, then posted a different one.

As far as port bias, if you don't have the room, a bias can be a bandage. I have found that putting bias in the floor opposite to what you think the port wants can increase flow. But I found it did not equate to HP when I did it on a stock 26degree

MTengines. Now that’s some interesting info. Can you share any pics or more info on your findings . Cheers

[Frankshaft]

Last couple weeks project.IMG_20181007_141730515~2.jpg

Just in case you don't understand I actually do this for a living.

Is that the one you had at the central Illinois street car race?

Or is a different project ?

Randy

Yes, that's the one. The one we won the race with, against all the turbo and nitrous cars, naturally aspirated. But I know nothing about this subject.

[Frankshaft]

FRANKSHAFT COMMENT:-
In response to the bold, if that is true, why do they use multi angle intake seats? Call Richard Maskins, CfE, mbe,etc, they will tell you the same thing.


AND WHAT EXACTLY WOULD BE :- 'the same thing' ?
DV

About using multi angle vs radius intake seats.

[RevTheory]

Hopefully I'm not alone here in wanting to give the man a chance to address the matter before he gets tarred and feathered for a response he's yet to give.

[Frankshaft]

Unfortunately, David obviously doesn't want a technical discussion. He only wants to make technical statements....?
Any questioning of his views is taken as an attack on his intelligence, and is rescued by the faithful. Hard to progress that way........imo

That being said, I have NEVER seen a full radius intake seat be better on the intake side on a running engine......
EVER!

I'm out

But it flows better on the flow bench.

[Warp Speed]

Unfortunately, David obviously doesn't want a technical discussion. He only wants to make technical statements....?
Any questioning of his views is taken as an attack on his intelligence, and is rescued by the faithful. Hard to progress that way........imo

That being said, I have NEVER seen a full radius intake seat be better on the intake side on a running engine......
EVER!

I'm out

But it flows better on the flow bench.

Of course it does, every time. Dynamically, it never shows a positive power gain.

[Frankshaft]

Unfortunately, David obviously doesn't want a technical discussion. He only wants to make technical statements....?
Any questioning of his views is taken as an attack on his intelligence, and is rescued by the faithful. Hard to progress that way........imo

That being said, I have NEVER seen a full radius intake seat be better on the intake side on a running engine......
EVER!

I'm out

But it flows better on the flow bench.

Of course it does, every time. Dynamically, it never shows a positive power gain.

If you haven't gathered, I am not a radius intake seat guy. I have tested it numerous times back to back, and I have concluded the same thing. BSFC's go up, fuel flow goes up, and power goes down. They are all tied together. My testing has shown ME, that the engine wants to be richer, and it wants more total timing. To make less power. That's why the bsfc's go up, along with fuel flow. This is a good discussion subject, but not really about bbc's in general.

[user-17438]

But it flows better on the flow bench.

Of course it does, every time. Dynamically, it never shows a positive power gain.

If you haven't gathered, I am not a radius intake seat guy. I have tested it numerous times back to back, and I have concluded the same thing. BSFC's go up, fuel flow goes up, and power goes down. They are all tied together. My testing has shown ME, that the engine wants to be richer, and it wants more total timing. To make less power. That's why the bsfc's go up, along with fuel flow. This is a good discussion subject, but not really about bbc's in general.

x2 thats what i have seen. but put a top and bottom angle and power is up and bsfc goes down

[PRH]

Just got on to Edelbrock's site to find the part# of that head.

What a deal - they have changed it for the worse when it's a question of finding out what you have got/need. All I can tell you is what is on the ends of the heads - Performer 100 cc.

That should identify it if you call Edelbrock. As for finding it in their catalog - best of luck.
DV

I went to the Internet Archive and looked at a snapshot of Edelbrock's site in 2004; this information was copied from the site:

vizard.gif

If you look at the shape of the intake ports in that pic you see they are basically “square”.

The pic of the intake port at the start of this thread looks to have started out as a traditionally shaped “oval” port.
I’ve never seen an Edelbrock head that had a traditional “oval” port.
And, if they did come that way at some point....... I’m pretty sure the current offerings come with ports shaped like what’s in the pic from the Edelbrock site.

In the pic at the beginning of the thread, are we looking at some old Edelbrock head, or some other head?

[David Vizard]

Hi David. I am sure I can speak for the majority here in saying the following.

I look forward to every post you make. Your vast experience in this field and your passion for passing on that knowledge (whether by selling books and seminars or FOR FREE on forums like this) are legendary. I bought my first David Vizard book nearly 50 years ago.

Imagine my disappointment when I find a new post from David Vizard and it contains none of that. Responding to haters and fools is a waste of your VERY VALUABLE time. Please ignore them.

I'm not a hater or a fool, and I have a lot more experience than most at very high levels. So just because I, like others disagree. We are wrong? Or haters? Or fools?

I would be more disappointed if everyone ignored and didn't learn from others. There are a lot of very talented people on these subjects, yet some people just ignore their posts and replies because they would rather drink the kool-aid and not respect differing results.

For the record I disagree with what David has been saying on this subject. I havent posted much because I fear everyone calling me out because I don't agree. But from what I have seen in stock BBC to spread port or symmetrical race heads, his data does not jive with mine. so call me a hater, or a fool. But I build engines for a living and also crew chief. I know the builders that are winning and losing.

I'm not disrespecting David at all. And that is not my intention. I just do not agree on what he has said.

Question to David. I am confused at what is going on. You referenced a BBC edelbrock head, then posted a different one.

As far as port bias, if you don't have the room, a bias can be a bandage. I have found that putting bias in the floor opposite to what you think the port wants can increase flow. But I found it did not equate to HP when I did it on a stock 26 degree

MT,

I want to thank you for demonstrating how to disagree in a polite and respectful manner. You are setting the bar for those not so well endowed with such social skills.

Also you have raised some tech points that with what has so far been said could well do with addressing. Though I don't doubt the validity of your findings for one second there may be some issues I can present that better justify my claims. (BTW congrats on your win a week ago at Cordoba.)

First the radius seat designs I am using are far easier to get accurate than seen from a typical S&G machine unless a two or three cut approach is adopted. I owned a Serdi for years and have better than 20 years experience of their use. I loved what they could do but I was also very aware of aware of their short comings.

Cutting a seat form that ran at or near the full length of the cutter was not even close to producing the normally desired seat concentricity. Now if you want accuracy of seat concentricity the Newan single point machine such as used by AFR and most cup teams is the answer.
AFR has a gang of these machines doing seats each representing an investment of about 80 grand apiece.
My seat can be fully machined on a CNC machine during the porting to an accuracy of 0.0005 readout on position thereby eliminating about an hour’s worth of seat machining and at least an $80,000 S&G machine. And, for what it is worth, this seat design, in it's ultimate form, cannot be cut on a Serdi, Newan, or any other conventional S&G machine.
Note:- it is almost certain that none of the cylinder head sources quoted earlier even know of this technology. Only my class attendees know of this and they are sworn to secrecy.

Now let’s address the functionality of these radius seats.

• I think I can safely say that we are, more or less, all agreed that a well-proportioned radius seat will outflow a multi-angle seat. I first started using radius seats on 'A' Series heads back in 1965 and since then the flow bench has only ever confirmed their flow supremacy. Any contradictions here??
• How many of you reverse flow test your heads? Those who do will already know that, unless catered for, any intake will flow better in reverse. A radius seat is even better at reverse flow than a regular seat and we don’t want that.
This is just one aspect of a radius seat that if unchecked, will cause such a seat to produce less output than a conventional seat. If any such tests were done I will wager that it is unlikely that any of the heads specialists mentioned earlier, including Hendricks and RCR, tested with this reverse flow factored in.
• Valve heights: - the better the low lift flow of the intake valve is the higher it needs to be in relation to the exhaust valve. Again another factor rarely considered in a seat test.
• If radius seats are used on both the intake and exhaust and produce the typical flow bench CD numbers then, what happens in the engine, is that the cylinder re-acts to the intake seat as if the cam has been advanced about 5 degrees (so a 4 degree advance would look more like 9 degrees) and that the intake duration has increased by a similar amount. The increased CD of the exhaust valve during the first 200 thou lift has no measurable effect on the blow down but it does during the overlap period. The overlap period is altogether another story. If the headers are well selected and the scavenge signal is high then the radius seat looks like a bigger exhaust valve throwing yet one more factor into why an A-B-A test of these seats gives the negative results so often seen.
• MT do the following figures look about inline with any A-B-A tests you might have done? :- Test engine – one of my 87 octane street build 383’s. Stock Dart seats – 536 lbs-ft and 592 hp. Cam power timed in with Jesel setup – optimal at (as it happens) 4 advance. Same Dart heads with my seats on and nothing else changed:- 525 lbs-ft 586 hp. Idle vacuum was less and the motor responded at low speed as if it had a bigger cam in it. These are the kind of results that I suspect end up condemning my seats. It is also proof that A-B-A tests fall far short of what professional grade engine builders should be doing to advance their technology.
• Next test – engine same as above but the cam advance/retard power timed. Original best timing with regular seats was +4 degrees. Best with radius seat -1. Output 542 lbs-ft and 611 hp. Just for the record can any of my regular critics tell me where I could have done better here??

This is all I have time for at the moment MT but once again, I thank you for your civility and I am really looking forward to seeing what your BBC flow experiences are with those big port Edelbrock 24's. If you don't want to share universally I understand but a PM with some confidential stuff would be more than welcome. Just think - I might have something to share in return!!

DV

PS when time permits I will address the other tech points you brought up and respond to gruntguru (don't worry -it's all good stuff)