racer7088

Raughammer,

""Again... you were not the target of my query at all. I was merely asking if SAM's 350 cfm was flowed on a 3.9" bore. And if they were'nt. What bore are those fantastic numbers from? what do they flow on a 3.9" bore? I would like to know... because I found them AWESOME.""

Those numbers are the real deal and they are not welded or anything. Just good porting and attention to detail. Of course since these were for our own shootout car they are not for a 346 inch street engine and are sized for our 418. They are flowed on a bigger bore.

In case you didn't know and I assume you don't the LSx heads in general do not like bigger bores unless they are reworked a lot. They tend to go turbulent and actually flow less or back up at higher lifts when overly unshrouded and so do a lot of ported ones I've seen. They do NOT always flow more on a larger bore.

LSx heads aren't the only ones that do this although most heads do indeed pickup on a bigger bore. TW ford heads are kinda like the LS1 being very picky about how much they're unshrouded by unless you re-engineer the whole port. If you design something to be optimized for a small bore like the 99mm LS1 it's not always a win/win situation to make it bigger at first.

Sporadic

[quote]Originally posted by SpeedDemon:
<strong>

Only one reason. I would rather be honest. I woudl hate to have to explain what kind of tactics I used to sell a customer to that customer once he wised up. I guess I am just honest like that... <img src="images/icons/smile.gif" border="0"> </strong><hr></blockquote>

What exactly is dishonest about stating flow numbers on a standard bore, and when it's disclosed to the customer? How can a customer compare flow numbers between vendors when they are on different bores? What I think is dishonest or shady is when you don't get flow sheets of your heads. And most LS1 vendors don't flow every set of heads! What a crock!

just me

[quote]Looking at several pics, It appears the ls1 swirl dam area near the valve guide is completely removed on the higher flowing heads.
Are there any negative effects of removing this area in the port ?

<hr></blockquote>

Don't any of you guys know anything about this?

just me

Speeddemon,
[quote]Steve. We do not take the swirl out of the head at all! That is not the correct way to get power out of a set of heads. <hr></blockquote>

I was not talking about creating a port with no swirl, but rather removing the big physical swirl vane as it is called.
I know a lot of porters are now removing it but some leave it in to some degree.

Looking at this pic I copy /pasted from your own website it sure looks as if you have removed the swirl vane to me.

Very nice porting work by the way <img src="images/icons/smile.gif" border="0">

Again,my motor is not N.A. It is supercharged. I doubt the swirl vane even works as intended now that the port is under pressure.
Once supercharged the ports and intake are basically storage tanks of pressuerized air/fuel vs a flowing/drawing portway into a N.A. cylinder.
This is not to say you can get lazy on the port dynamics but the blower will do most of the work. Having a big vane/or dam intended to increase swirl N.A. that is also a defenite restriction to flow makes no sense to my engine combination anymore.
I am removing it <img src="images/icons/wink.gif" border="0">
Steve

SpeedDemon

[quote]Originally posted by Sporadic:
<strong>

What exactly is dishonest about stating flow numbers on a standard bore, and when it's disclosed to the customer? How can a customer compare flow numbers between vendors when they are on different bores? What I think is dishonest or shady is when you don't get flow sheets of your heads. And most LS1 vendors don't flow every set of heads! What a crock!</strong><hr></blockquote>

Sporadic,
Maybe I misunderstood your comments, but it soulds like because some tuners flow with a 4.00" bore or larger to inflate their numbers, we all should from a marketing standpoint. To that is what I commented on. <img src="images/icons/smile.gif" border="0">
We send flow sheets with EVERY set of heads we port. We also flow EVERY port, not just one port just to get a flow number. It is very important for every port to be very similar in characteristics. This takes a lot of time and energy, but I really think it is worth it.
Chris

SpeedDemon

We have removed the swirl vane in some heads and left it in on some. We are currently removing a part of it, not all of it. This is a set of heads that was sent in for a tune up. This car has gone FAST!!! <img src="images/icons/smile.gif" border="0"> <img src="images/icons/smile.gif" border="0">

Thanks for the compliments on the heads. <img src="images/icons/smile.gif" border="0">
Chris

HouseofSpeed

I realize that this may fall on deaf ears...but other than an alleged "apples to apples" comparison....why even worry about flow sheets? For that matter cam specs?

The flow numbers and/or the cam specs tell a very small portion of the story....to say that two heads from different shops pull the same numbers at the same drop, at the same lift doesn't mean that there aren't differences in the chamber, perhaps a different back cut on the valve, different runner cross sectional dimensions.

Yes, I agree we need to have standards (28" test, std bore for a std bore application, etc.)...but in the end, saying that your heads are the same or different from the graph on a piece of paper is about the same as comparing dyno graphs from two cars to find out what porter did the work on the heads. There are just too many variables.

I think if the customer really wants to know the differences, line it out for them. The shop should KNOW the differences between their head and a competitors. If the customer wants cam specs....give them ALL of the cam specs, put the cam in question on a Cam Pro or a Cam Doctor and get a print out.

But in the end, will all that really matter? What matters is the performance....not the conjecture and supposition surrounding the parts.

Patrick G

iTrader: (14)

Raughammer and all...The SAM heads flowed 350 cfm at .600 lift on a 4.100 bore. They flowed 330 cfm on a 3.900 bore because of increased valve shrouding. They did all the flow work using the 4.100 bore because Jud's motor is a 4.080 bore (didn't have a 4.080 sleeve for flow bench). Since they are LS6 heads with 2.085 intake valves, they also have incredible flow numbers at .400 and .500 lift. The solid lift cam is close to .700 lift so flow numbers at .600 and up matter to them, but are pretty worthless for us street guys.

On a side note, speaking with Judson, he said that the new 6.0L aluminum truck heads are the best flowing heads at mid-lifts of anything made by Chevrolet...even better than the LS6 heads. They're easily getting 275 cfm at .400 lift (3.900 bore) which is un-freaking believable when you consider how much airflow that can be when coupled with a stock cam. <img src="images/icons/shocked.gif" border="0"> They fall behind the LS6 heads above .500 lift, but for a savvy street racer, the new truck heads look like the fast ticket for speed.

The Alchemist

iTrader: (19)

All I have to say is, any time you're performing a test to produce one desired result, there are to many variables that can be 'adjusted' to meet that result.

If you want a head that flows 400 cfm, Im positive it can be done without much difficulty.

That is why people must be very cautious when falling into the mentality of bigger is better. Just because a cylinder head flows 20cfm better (you define the parameters) doesn't mean it will make more power if you can't sufficiently fill the cylinder.

To summerize, ever try drinking a soda with a garden hose? Kind of tough. In the end, you'll drink more over any period of time using a normal straw because you get a greater velocity of fluid through the straw than with the garden hose.

[ November 21, 2001: Message edited by: Pewter_00_TA ]</p>

Terry Burger

iTrader: (4)

My favorite is when guys with 3500+rpm torque converters start talking about low end, as if they don't realize they're completely mooted the power they make under their stall speed. <img src="images/icons/wink.gif" border="0">

You see it a lot with SY3500 people running a LS6 cam, so they don't lose the low end power. <img src="images/icons/wink.gif" border="0">

2quick4u

[quote]Originally posted by Terry Burger:
<strong>You see it a lot with SY3500 people running a LS6 cam, so they don't lose the low end power. <img src="images/icons/wink.gif" border="0"> </strong><hr></blockquote>

Terry, I take it that you are not concerned with part throttle driveability and throttle response when the car is in OD with the converter locked up.

On a street/strip car there is a whole lot more to the equation than building an engine for the most Hp and quickest ET. I challenge anybody to build an 11.72 sec, N/A, no nitrous, 3,500# car that has better street driving manners than mine. <img src="images/icons/smile.gif" border="0">

ChrisB

[quote]Originally posted by Pewter_00_TA:
<strong>To summerize, ever try drinking a soda with a garden hose? Kind of tough. In the end, you'll drink more over any period of time using a normal straw because you get a greater velocity of fluid through the straw than with the garden hose.
[ November 21, 2001: Message edited by: Pewter_00_TA ]</strong><hr></blockquote>

It you move the same massflow through a garden hose it takes less work. The reason you are thinking it's harder is if you "suck" as hard you move a greater volume - hence you do more work.

I think I replied in the intake/exhaust thread to roughly the same idea.

Basically if your premise was correct then there would be no purpose to going to larger heads - since XXX depression with a smaller head would give us more velocity and make things easier. That's obviously wrong.

To extend your analogy, try drinking the same amount of water / time through a coffee stir as you do through a drinking straw. It's easier to suck up water through the stir, but that's because you are moving less water.

Velocity is important, but not for the reasons you put forward.

Chris Bennight

racer7088

Flow numers are certainly very important. Flow is what power is all about. If you burn more air and gas per unit time then you make more power in general. As Kyle said though you have to know a lot to understand flow sheets.

If you're getting the flow by sheer port and valve size the port may be too lazy and make less power even though it flows more at the same drop. It may be so big however that the motor will never be able to acheive that drop on it though! You want small ports that flow a lot basically. Big ports that flow a lot won't make power until high rpm or never if they are way too big and we don't want that on a street engine.

If you know cylinder heads very well, like someone such as Judson or Greg Good at SAM, you can tell a lot from a flow sheet just by looking at it and the head but you also need to know the port volume and minimum cross sectional areas as well as valve sizes. With this info you can make a pretty good educated guess about whether the heads will make power on a certain size engine turning X rpm. It's all about power and where you want to make it.
<img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

Terry Burger

iTrader: (4)

[quote]
Terry, I take it that you are not concerned with part throttle driveability and throttle response when the car is in OD with the converter locked up.

<hr></blockquote>

No, because I know that even with a 240/240 cam when the converter is locked up above 2000rpm (normal cruising speeds), you won't have any problems. I used to lug my 220/220 112ls cam around at 1100 rpm all the time in OD.