Imput on these head flow numbers

[boostmaster]

Hi fellas I bought these heads from another board member a little over a year ago. No complaints they work flawlessly. I can run the same numbers @ 18psi I used to have to run 26 psi to run. He included the flow sheets with these and I was just curious about the flow numbers since I'm no expert at reading theses and don't know what is the normal flow range to look for. Stock ported 8445 heads 1.77 intake 1.50 exhaust. I attached a copy of the flow sheet.

 

[turbobob924]

I dont see the attachment

 

[boostmaster]

Sorry the original file was to large had to resize it.

 

[boostmaster]

Anybody?

 

[KEVINS]

Here's some flow numbers you can compare them too.

Stock:
garage-chat.com - Stock Turbo Buick Head Flow Numbers

Champion's:
garage-chat.com - Champion Turbo Buick V6 Cylinder Head Flow Numbers

GN1's:
garage-chat.com - Turbo Buick GN1 Head Flow Numbers

ks

 

[turbofabricator]

Be sure the flow benches are the same (in this case a Super Flow 600) when comparing numbers. Look carefully at flow numbers BELOW .500" lift, as the valve stays in this range the longest. Low lift flow is VERY important. Just because a ported head flows killer numbers at .700" lift, doesn't mean the car will make more power! There is soo much to head porting that DOESN'T meet the eye. Big flow numbers across the board USUALLY makes better power, but NOT always! What happens in the combustion chamber? How big is the port volume. Turbo engines LOVE port volume, as long as it doesn't kill low lift flow. Five diferent head porters will give you five different views on port shape, valve shape, chamber shape.......... All of them plausible. Do NOT buy heads based on flow numbers. Just like buying an engine based on horsepower numbers. This (head porting) is a VERY lengthy conversation. If you really want to numb your mind, try reading this website for about 2 hours and then try and sleep : General Engine Tech :: Speed Talk - Auto Racing Forum

 

[boostmaster]

Be sure the flow benches are the same (in this case a Super Flow 600) when comparing numbers. Look carefully at flow numbers BELOW .500" lift, as the valve stays in this range the longest. Low lift flow is VERY important. Just because a ported head flows killer numbers at .700" lift, doesn't mean the car will make more power! There is soo much to head porting that DOESN'T meet the eye.

Thanks for the input, but givin all these variables I'm still left with the question of whether theses flow numbers are good or not. No question they out perform the stock heads my timeslips show that. I'm just wondering if there's more left on the table.

 

[Cheeseburger]

I would not worry about flow numbers unless you like to bench race..........

 

[VadersV6]

On a naturally aspirated engine, low lift numbers arent as important as people think. You have to consider the fact that the piston is heading upwards, and just beginning to head downward with very low speed, when the valve is at low lift. There isnt much of a signal to "suck" the air in, because of piston velocity. Low lift numbers/average flow number across the curve, is pretty important on a forced induction motor because the air is being pushed in, and isnt relying on piston speed or the cross sectional are of the port (producing velocity) to get a good flow signal. There are reversion waves and all that to deal with as well, which a flow bench cant reproduce. Plus the cylinder isnt creating a 28" pressure differential. Its all over the place, during the intake and compression cycle. But for a static, basic flow number, sure, why not? they're great for that. Reher Morrision was writing articles in national dragster for awhile. There was a long article about flow benches, and how much they lie. They had 2 sets of heads which produced the same flow numbers, end to end, but one set of heads produced 150hp more than the others. It all has to do with flow velocity, which keeps the charge moving after the piston starts heading back up and the intake valve is still open, and signal strength...how quickly the flow can react to changing conditions in the cylinder. But for a forced induction motor, flow numbers can mean alot. Especially low lift. The moment that valve cracks open, air is being crammed in. The shape of the chamber also has alot to do with swirl (which can cram alot more air in...like lowering a string in a can and letting the string randomly tumble ontop of itself...how many feet of string will end up in that can?...or spin the string while lowering it in, and let the string wind up like a coil...you can fit many more feet of string inside that can if you swirl it...hope that makes sense. its just how I picture it)
The shape of the chamber has alot to do with how much timing you can run. Hemi chambers can run with 40+ degrees of total advance..well, not can run, but HAVE TO run with that much, because the chamber produces the burn so slowly. A fast burn chamber requires much less advance. Theres alot more to it than this, but as you can see, the data is just beginning with flow numbers.
By the way, I cant tell which numbers are intake and which ones are exhaust...its really too dim to read. But I see no numbers in the 200's. They arent very good numbers. But you never know. The heads can still produce great power.

 

[GNandGS]

My guy spent very little time outside the bowl area. Even then they arent "hogged out". I think for what they are, my numbers are good and the heads work great.

Those are my numbers in the first link Kev gave. Still on the car (and car is for sale, heh).

We had a long discussion about it and we had zero concern about upper lift numbers given the cam I was running. Wanted to keep velocity up or some such.

He said an interesting thing though... exempting turbo apps and all its variables the heads, in his view, were just right for a NA 3.8. Not too big or too small.

Ive seen heads with more work on cars faster than mine that didnt flow much better so dont worry about it. Your flow numbers seem consistant and similar to other flow "curves".

 

[turbofabricator]

You probably have what is commonly called the $25 "smokey" port job. Smokey Yunick spent MANY hours developing the Buick V6 cylinder head. He said that 80+% of the gain in the Buick head was found in the valve bowl. By enlarging the Buick port as big as you can get it (with out killing low lift flow) will reward you in power gains under high boost. These heads are pretty darn small! If you look at the CSA (cross sectional area) of the intake port, you wonder how they can even make 650 hp.? A good flowing head for N/A WILL make great power with a turbo attached to it. There are gains to be had porting the head specifically for a turbo vs. N/A. Port volume is one way. There is alot of work that can be done in the valve bowl that will improve high boost performance but will NOT show up on a flow bench. If you were to test a port simulating 20 psi boost, you would have to have a air flow source capable of 500+ inches of water The power required to supply THAT would be tremendous! About 25 years ago we had a performance cylinder head company want to purchase one of our superchargers off of a Rolls Royce Griffon V-12 (2,240 cid) for their air flow source for a high end flow bench. We asked them what they were going to use to turn the blower, they said they had a HOT Small block Chevy that they would try temporarily untill they could get BIG electric motors to drive it. You could, after all, turn the blower by hand (14" centrifigal impeller). Well, they hooked it up and as soon as they came off idle and started to make boost, it would KILL the poor small block. We had told them that it took 1,200 hp. to make 130in./hg (60-65psi) Well,....... they just didn't believe us!
If you are happy with the performance of your car, keep the heads the way they are. Or, just when you get them back from whomever you send them to, there WILL be a better set out there! That's just the nature of the beast! Save your money and buy a set of CNC GN1's or TA aluminum heads and be done with it. No Iron head will compete with the aftermarket stuff. ALTHOUGH, any good porter can port you a set of heads that WILL break your 109 block. So, how fast do you want to go? The only limit is M-O-N-E-Y!:smile: