Cylinder heads & flow bench discussion

HOW MANY HAVE GONE TO A FLOW BENCH. I WAS EDUCATED RECENTLY. I HAD A SET OF PORTED HEADS FROM 70's, and a Set of Virign Camel Hump Fuelers.

...The stock fuelers out flowed the Ported heads with minor mods and smaller ports........$$ well spent.

...The one set was done by a local speed shop.....wrong valve angles...? 10% flow loss......wow...$$ well spent.

...Will dyno my 302 next..............all day for $450........unlimited pulls.

Track test and tune March 2010.........how well did my $$'s work.

 

I think it would be cool to build your own flow bench, something that would show real world improvements.

 

my buddy is a machinist and has drag raced since he was a kid. he built his own flow bench in his shop, building is easy it's the gauges and knowlage of how it all works and where to make the changes that takes time to learn.
also every flow bench is different so yours might flow a diff # then another one but it gives you a baseline for you improvements or losses.
i'll leave the porting to him because it's not as easy as it looks and experiance is priceless, go a little to far and bingo you hit water.

 

The flow bench is always a good indicator....but a lot of people get caught up in the peak flow numbers....you have to look at the numbers across the board ....average flow. A lot of crappy porting jobs are due to the porter thinking that removing as much material as possible will make a better cylinder head....it may flow more at peak lift but it won't perform as well...you lose port velocity, fuel atomization. It's all in the port shape and size for your cubic inch...too big an intake port will hurt a small motor. An experienced porter can remove the right amount of material in the right areas and improve a not so good port design. Overall its hard to compete with CNC porting these days....no hand porter can replicate the consistency of a CNC port job....the modern port designs and CNC programs outperform older designs hands down....AFR (airflow research heads) are some of the best engineered heads on the market...I've used them...CNC ported right out the box.....sometimes the money is better spent on buying a better cylinder head...then spending it on hand port work to improve an inferior cylinder head.

 

I built my own in the 90s . I started with an article in Superstock magazine but they never finished it. They did however put me in touch with the author and he helped me finish it and encouraged me. It was made from Schedule 40 abs pipe, a toilet flange kit , two 3 inch gate valves and i used a pair of leaf blowers, plumbing the suction side to the pipes. I would use a couple or three inexpensive shop vacs if I made another one. I had one commercial manometer and made the other , The slant tube. It was easy and it now seems pointless to buy one since they are so easy to make. I built mine on a work bench kit with plywood. I painted it and spent $20 for a professional sign as well. (Money well spent when you make your own equipment) Here it is testing progress on a set of Stage six mopar heads I was working on.
I have tested a set of pro ported heads by a famous shop on this for a friend. I found also they hadnt a clue what they were doing but were just making stuff pretty. A full lift they flowed only 60% of what stock heads did. They were at the time being sold as professionally ported for $2500 I believe i was told. Many folks unfortunatley think they know how to port heads but i am afraid they dont really. The flow bench at first will break your heart. After a bit you begin to understand some things about air flow. You learn often where NOT to grind , places where even a small radiusing will kill airflow 10% or more. Often you discover the valve pocket is where al the horses are hinding, not the ports as you may have thought. You also learn that what the flow bench teaches you is NOT popular. EXPERTS who are a dime a dozen often believe they were born with the instinct to port although most "EXPERTS" have yet to do their first set of heads. Unfortunaltely the flow bench doesnt know this and just gives the actual results. Often what looks good doesnt work good.
Another big advantage besides learning how to port heads for power rather than appearance you learn instantly how much valve lift a certain head can stand. Some heads lose flow at high lifts and a lot of it. Dropping 25% or even 30% once, say .540 lift, is reached. I found this factor alone to be a huge advantage to me in my racing. Being able to pick a cam that matched the heads characteristics exactly. Once i dropped from .613 lift to .540"and picked up 6 tenths of a second. The flow bench told me that up front but i got sucked in by all the hype how this new cam was the most powerful ever. I hunted around for a cam with the exact same duration and opening and closing spots and happened on two believe it or not that had within 1 degree the same duration specs and lobe centres but were .540 lift instead of .613". The flow bench hadnt lied. The extra power and et was instantly there. (Both those cams ran exactly the same et BTW. One was a Lunati and one a Racer Brown. )
I had to sell it with all my equpment when i sold the shop equipment but have often thought about making another. It is not hard. A couple of days work will do it. I could draw the plans up if you want. It will change your life and your perfomance.
Don

 

I am interested in the plans

 

Well i am no artist but here is the design. If slant tube runs the wrong direction simply reverse the hoses.
Don

 

What did you seal the combustion chamber to the flange with?

 

rubber mat
Don

 

Good comments................there was a lot of focus on the 0.250 lift point, and my ported were worse than stock......this was resolved........I cannot wait to see how the power feels. Next is the headers................I plan on adding a "goilet" in the collecter to merge the exhaust flow.

 

check out www.flowbenchtech.com

 

So if any want to build this design I will hang around the thread till you have it up and going. Like i said everything can bebought ff the shelf at Lowes or Home Depot.
How well does it work?
I wil tell you this story i heard ths summer. A wealthy guy nearby hired an guy torun his shop. they bought a superflow flow bench. He told someone this summer that they had to close the business because Dulmage's bench was available cheaper . Now Dulmage (Thats me. Dolmetsch + Dulmage are the same name. One is original German Spelling, One Canadian spelling ) just built his bench fo his own use but did let others run it with experimental stuff after hours. Personally i dont think it was a money making venture regardless but the concept that a homebuilt bench could give megabunch bench competition should encourage those who want to build one.
Don

 

I have directions to build one using a vacuum cleaner for flow. Its an old article from the '60s or late '50s. Probably not as accurate as todays stuff but it would work for comparisons sake.

One of the things on my list to do just because I can.

 

Accuracy is in inches of water. Unless your ruler has changed or water has accuracy will be the same for all. Once made calibration can be dne from a know plate or head but really you want to measure more flow or less so the actual figure doesnt really matter. if you improve a set heads by 40% and all ports are within 3 percent of each other. That is waht is important. De ifference in CFM which is mathimatically caculated can vary as much as 20% between machines (even of the same manufacturer So i have been told. Flow increase or decrease is all you need. You will see once you get it going.
Don

 

I helped build one years ago, probably from the same article, I would treat it as a toy because the best flowing heads quite often do not make a car the fastest.There are so many variables that sometimes making or leaving them alone makes better results. For instance ,because of shrouding of the cyl wall,the fixture always need to be Exacually the same bore size as the motor its going on.The longer the stroke on the engine the faster the piston moves, the faster the velocity of the air past the valve. How are you going to compensate for that between a 331 cu.in and a 482.If you run headers with a collector a flow bench can not simulate the scavagening effect of the collector from the other cyls.
AS far as I'm concerned a fun toy ,but don't be surprised a after hundreds of hrs haveing little on no actual performance increase.

 

A flow bench by it's self is only a device to move air. How you use it will tell you volumes of info. Have a few tools to go with it, and the understanding of what they tell you can open a world of info.

Simple things like a piece of string will tell you how the air is flowing in any area of the port. There are other tools (bought or home made) when used correctly can point you in the proper direction and save you many hours of wasted time and $$$$$.

It pays to do your home work before you buy or build a flow bench. This is also true when taking your heads/manifold to be flowed. If you just get max flow numbers the money was wasted. It is important to know the correction(ed) numbers, entry and exit shapes (manifold/header) used with the ports, repeatability of numbers, and the back flow percentage of each port.

I guess what i'm saying is; A flow bench used with the understanding of what they can tell you, using the right tooling, in the right way can be very useful and informative.

Just my .05 worth, inflation.

 

I'll be watching this thread to see if anybody else has some input as far as hands-on flow bench building. I ported some 452 heads for my 440, but the thing just doesn't seem to smoke the tires like it should and I think it's in the heads. It would be pretty handy to see if I actually did them any good when I ported them.

 

Should of read my book.
I found it to be a huge benifit. BTW if you used the templates you did probably ruin them. They were not developed on a flow bench. I tested them as well when I had my bench. I think you want to be very careful calling a flow bench a toy. I certainly wouldnt. It will teach you things you will never know otherwise and it will produce power and show up in your timeslips. Not minor gains either. It will also teach you things you dont want to know. That is the hardest part of owning one and you have to be man enough when you discover a common conception or idea is wrong to follow through and correct that. Many folks can not unfortunately. Some people do not think in a manner that a flow bench can help them. It is only for the serious engine guy who actually wants to know. The rest usuaully just follow the herd and of course as any farm boy knows you willl be always stepping in Poo if you just follow the herd. Anyway If anyone wants to build It I will help you. if not . That is Ok too. its your dime.
Don

 

Gee that would be my site! Happen to be a FNG here on the HAMB even though I've been a member for some time.

If you have any interest in learning about flowbenches don't miss my flowbench forum. Lots of good info on building and using your DIY flowbench.

Don't be fooled into thinking a home-built flowbench can't be as good as a commercially produced bench, we pretty much have broken that myth . . .

Like here I have forum members with various levels of flowbench experience, quite a few "Pros" stop by from time to time and offer help with airflow thoughts.

 

I found a Chassis Dyno close to me today. Now I can dyno my car, that will make it easy to Calc Baseline HP before the track.

Does flowing the intake with carb tell you anything?

 

I'm enjoying this thread, think i might have to try this, thanks.
Where in Ont. is prince ed county?

 

Yep I used the MP templates. $15 for templates compared to $1500 for Edelbrocks seemed like a good deal at the time. If I built a flow bench, it would probably be used for porting research. Flow a factory head, port it, test it and see if I make any gains or not. I have plenty of cast iron BB Mopar heads laying around, that's for sure.

 

Prince Edward County aka "The County" is located on the piece of land or island like chunk hanging out in Lake Ontario about the middle of the northern shore. It was settled in 1784 by soldiers both Britsch and Hessen who were expelled from the newly formed USA because they were fighting for that Hanover king George III. Most received land grants from the crown for their military service and almost every piece of land is of that origin. Many of those families still live here over 200 years later. It was invaded once. Battle of Pryners Cove . That was stoppped almost befoe it started. It is the home of The Hasty Pees. Hastings /Prince Edward Regiment the most decorated Regiment ever in the Canadian Army (sometimes called the ploughboys) who fought their way from the bottom of Italy to the top but stood aside for Patton's excusion into Rome. (Read "The Regiment" by Farley Mowat. ) This the birth place of the founder of Crimestoppers. Was the first law office of Canada's first prime minister John A MacDonald. Was the place where the rum runners ran from during US prohibition taking whiskey from Belleville to USA accross the lake in fast runabouts. (Booze Boats And Billions by CW Hunt) There are more ships sunk of Point Traverse here than in the Bermuda Triangle. Was the home for many many years of the Gold Cup Boat races that saw such famous race boats as Miss Supertest and Sudden Seven racing for the Harnsworth Trophy. Mrs F W Woolworth was born here. Tis the place where the Avro Arrow test models were launched and tested during the design phase of that great world beating fighter aircraft's development. In fact the Radios for that great plane were designed by a Prince Edward County native. He happens to be my father and is still living at 86 years old. The Olympic Gold Medalist Rowing champ Brian Price calls this his home. He lived here his whole life till his rowing days and in fact lived accross the road from where I am. His parents still live there. It is the home of the big Ameliasburgh Street Meet which has been going now for some 30+ years. Almost a week of Hot Rods and fun. Tis a special place this Pr Ed County . Lots of Hot Rodding locally too. One shop devoted to streetrods. Several specialized shops in out of the way places doing one brand restorations. One does Lincoln. one does Jags. another BMC cars. It is the home of Minakers Auto parts. who have several barns right full of NOS vintage parts. Some three stories high. And also Roblins Garage (online listing) in Fish lake who is a great source of what you cant find anywhere else. We have beaches that rival the Bahamas (Sandbanks Provincial Park. ) The small town of Demorestville only a few miles away had the highest race car per capital population probably in the world . A couple of years ago it was actually at least one race vehicle per household with no exceptions. It would be little different now although probably not 100% anymore. How come you havent been here? The local Museum actually has a 500 HP Goldie Coreliss Steam engine. Tis a grand place to be. Hope some of you come to see it.
Don

 

I noticed the intake bowl work on my stocker heads.......is similar to the prots on High $$ heads. Here is my first attempt at good running heads. 240CFM @ 0.550 lift.

 

Ex Port..........Modest

 

Had them flowed with this thang..............

 

Well I dunno what i was thinking, i better get my butt down there come summer. Whens this street meet, that might just be the right time. Course I'll need a guide now....

 

Link provided on flow bench and DIY head porting.

http://www.diyporting.com/

 

We have a quasi-homebuilt flowbench we use at the shop. Right now it is not up and running because we just moved and haven't calibrated it again, but soon... We use a Performance Trends Black Box II for the manometer and data recording. It works pretty well, has more info and options than you can shake a stick at and could be overwhelming for some. It does have some neat options, like port velocity measurement using a pitot tube.

We also have a Flow Performance Electronic Manometer, but either we got a pre-production unit, or the quality sucks for $500.

Here's some diagrams for a home-made bench
http://performancetrends.com/ez_flow_system.htm
http://performancetrends.com/PDFs/EZ Flow w Black Box.pdf

 

GTD
looking good!
Don
Johnod, look here
http://us.altavista.com/web/results?tlb=1&fr=tb&kgs=0&ienc=utf8&q=Ameliasburgh+Street+Meet