[grivera]

Does anyone know if there is a difference between Kaufman's CNC ported heads and SD's? From looking at their sites it appears they both offer comparable CNC packages? What am I overlooking?

KRE: http://www.krepower.com/Pontiac%20Al...er%20Heads.htm

SD: http://www.sdperformance.com/listPro...?categoryID=49

[steve25]

Info wise you want the flow numbers of course and then get them to offer up how much there porting work increases the minimum square inchs of port area by over the stock amount , then you can compare Apples to Apples!

[gtofreek]

Keep in mind that KRE doesn't use a Superflow bench, so the flow numbers will show higher than they will be on a Superflow bench. Makes it hard to compare flow numbers.

[steve25]

Yup that's true by some 6 to 8 numbers in general, but if you get those port area numbers in hand, and along with tge build details on the motor at least you can pin down within 300 to 400 rpm where your peak rpm hp will take place by the velocity factor.

[Steve C.]

Even though different benches are used and one has slightly higher numbers would comparing the area under the curve be helpful ?


http://www.wallaceracing.com/area-under-curve.php



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[Tom Vaught]

Dave at SD does OUTSTANDING port work for the money and has cnc programming for the KRE high ports and all of the E-Heads.

The info posted by GTOFREEK is true. The typical flow bench is a orifice bench (Superflow design) with individual calibration sheets for each bench based on a industry standard.

The other benches, using a pitot tube (velocity bench) measure the airflow in a different manner. Most of the guys posting on the Flow Bench Forum (including the owner of the Forum) have moved away from the pitot tube bench to a orifice style bench design.

The old guy who made the pitot bench for the other guys was not a big time flow bench guy (and never claimed to be). Superflow is a multinational flow bench corporation.

All that being said, if someone says they improved your flow by "x" percent you can decide whether to believe the data or not.

The Super Flow Bench Guys on the Flow Bench Forum did a "master orifice" using three orifices on benches all over the country. The data is available on the forum. Most of the shops with Superflow equipment were very close including Larry Meiux.

The master bench was a 7 Million Dollar flow stand owned by one of the OEMs.

So do you believe Joe Bubba's back yard bench or a 7 million dollar bench?

Some will still say that Joe Bubba's back yard bench is the equal of the 7 million dollar bench. Whatever.

Just saying, guaranteed the numbers (as was said WILL be different).

Tom V.

The data is here, but would take some looking: http://www.flowbenchtech.com/forum/viewforum.php?f=5

[gtofreek]

I do a lot of R&D work on valve jobs on Dodge Super Stock heads for a guy in Sweden. He also has a Superflow 600 bench just like ours. He says that our numbers almost duplicate his exactly over in Sweden. Ours is also almost exactly the same as a friends Superflow bench[never varies by more than 1-2 CFM], so I feel the Superflow benches are really close to each other.

[Tom Vaught]

During the testing no one knew what the orifice plates actually flowed.

The guys with the benches bolted each orifice plate on the bench and tested it at an agreed upon range of test points and submitted their info. At the end of the testing around the country the data was published. As you said, the vast number of Superflow benches were within 3-4 cfm of each other.

If all of the Superflow benches read similar and then you test a different brand bench and it is off by a large amount, then whose bench(s) do you assume is/are right?

just saying.

Tom

ps DO NOT START a urination contest about a home built bench vs a Superflow bench as several of the people on the forum were very close in data with their home built ORIFICE flow bench. The question is the measurement apparatus.

Tom v.

[vtxman]

I haven't purchased from KRE, so I can't comment on their work. I have purchased from Dave at SD, and his port work is like Art. I could hang them on the wall. I would take them to bed if my wife would let me.

Anyways, you won't be disappointed with Dave's work.

[Big Injun]

I think it funny that no one wants to start an argument here and make a statement. IMO, Dave at SD Performance provides a better product.

[mechanickeith]

Originally Posted by Big Injun

I think it funny that no one wants to start an argument here and make a statement. IMO, Dave at SD Performance provides a better product.

Oh man,,, now ya did it Dave!!!

[Will]

I would trust any flow bench to give me relative results. That is, test the head before porting and then again afterwards. That will show the percentage of flow increase and where in the lift range the changes occurred (did the heads lose flow at any lift or gain at all lifts, or only in a range of lifts, etc.) That info combined with port volume info from before & after would be fairly meaningful. But, comparing the actual numbers between different types/styles of flow benches seems problematic, just like comparing different dynos.

[steve25]

Airflow and port velocity go hand and hand!
A given head that flows more air but at a greater peak velocity can end up and will make less HP at a given rpm that another head flowing less air but also at a smaller port velocity number.

[Chadmokc]

Originally Posted by Big Injun

I think it funny that no one wants to start an argument here and make a statement. IMO, Dave at SD Performance provides a better product.

I think Jeff Kauffman has better customer service and that's more important to me. If I have an issue or question, I like someone that answers the phone or calls back at least when you leave a message.
Last year when I built my engine and needed to order parts, I tried every avenue of contact with Dave at SD for over 2 months. I still have never heard from the man. So that $6500 order went to KRE.
I run a business too and I am Very Busy and still answer my phone & emails.

[Steve C.]

CFM and Velocity

Darin Morgan: "Make no mistake, velocity is the primary variable in the design of the entire induction system. I often say that my job title should be Velocity Manager instead of Cylinder Head Designer. Air speed is 10 times more important than raw flow numbers. If you kill the velocity by 10 percent, you will kill almost 40 percent of the wave and ram energy that dynamically fills the cylinder! Raw airflow cfm is an important variable as well; it's just not as important. If you buy a cylinder head that is properly sized for a flow of 400 cfm and your engine is only asking for 350 cfm, you will not only fail to achieve the power potential that the 400 cfm would have given you, you will also fail to reach the power that the 350 cfm would have given you. That's because you killed all the air speed in the induction system. If your engine is asking for 350 cfm and you give it a properly sized cylinder head flowing 350 cfm, your airflow demand is matched and your air speed is matched. You then have a chance of achieving the power potential that 350 cfm can give you.How much power potential can 350 cfm give? Well, that depends on a host of variables such as engine speed, overall induction system design, and piston speed. To put it in basic terms, the less restriction you have in the induction system and the more freedom you have to attain increased engine speeds, the easier it is to extract the full potential of the 350 cfm available. Most people don't know how much airflow their engine is actually asking for! This leads to builders wanting to purchase cylinder heads with way more airflow than their engines can possibly use. The end result is a low air-speed induction system that can't properly fill the cylinder by means of dynamic inertia and harmonic supercharging, which means the engine will never reach its full power potential.
"That said, a good cylinder head port design will flow a lot of air for its valve size. The bad news is that a bad port design will flow just as much if not more air! Airflow alone won't tell you if a port design will reach its power potential with 100 percent certainty. Everyone knows that it's easy to compare two 23-degree small-block Chevy heads with 220cc ports. Just pick the one with the most flow, right? That's about all the average builder can do, and in a lot of cases it's hit-and-miss. There are multitudes of ways to achieve that 220ccs. You can have a big pushrod pinch section and a very small bowl area, or a huge bowl area and a super small pushrod pinch area. One 220cc port can actually be choked off at the pushrod, short-turn radius, or throat area, hurting top end power. Another 220cc port design can have too small of a bowl area and too large of a choke and hurt power and torque equally across the entire power range. Having extra airflow isn't always bad, but it can't come at the expense of air speed. The ports must be sized properly. The amount of air Pro Comp Eliminator engines are asking for are exactly how much the heads flow, and that's not a coincidence. People want to make cylinder head design simple, but it's not. It's very complex and interdependent on a massive amount of variables."



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[Steve C.]

"I hink Jeff Kauffman has better customer service and that's more important to me."


Your opinion. There are a large bunch of previous customes who received poor service and/or defective produts that if they has the balls to speak up would disagree !

Onward...........
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[70f400]

Here is the flow sheet from the set I just got from KRE. Mabye some one has one from SD performance


[IMG][/IMG]

[PAUL K]

Originally Posted by Big Injun

I think it funny that no one wants to start an argument here and make a statement. IMO, Dave at SD Performance provides a better product.

Lol....I was taught if you have nothing nice to say, don't say anything. I can say, I've had heads from both vendors pass through my shop and I will say their flow numbers provided with the heads seemed to be accurate.

[Formula8]

Originally Posted by 70f400

Here is the flow sheet from the set I just got from KRE. Mabye some one has one from SD performance

[PAUL K]

Form', that's a nice flow chart. Very informative.