Flowing at higher depressions

[coulterracn]

John

My reason for posting this was the part about flowing heads at 72" of water.

I can appreciate the use of wet flow technology, however is it worth the cost and time to have that capability to do heads for bracket racing, street stock or any low budget racing engine?

I agree the track is the best test bed to prove or disapprove horsepower gains. The data gained from a flowbench and or dyno can be used to calculate performance gains at the track. If someone has a few customers that can affort the R&D for that 1/4 horsepower or .2 MPH gain then use the latest tools availible.

I'm going to keep using my PTS bench and rent a dyno when needed. The good part about paying someone for use of their dyno, you have access to their knowledge which in most cases is priceless. Word of advice to those paying for dyno time, if the person is just going to sit at the controls and pull the throttle, get your stuff and find another shop. If the person is offering advice and gives you assistance during pulls then make sure they are compensated for their service.

Us low budget guys can make horsepower in ways that baffle the deep pocket boys. Know what I mean Vern!

Ray

[jfholm]

Ray,
I agree with what you have just said. I am a budget racer and we have made quite a few high dollar guys go hmmmm......

On my heads I am doing for me, Dart 180 cc intake I could find most of what I needed just by pouring a port mold with the urethane. I used that to find the CSA and where I needed to to change the CSA of the port. But I did need the flow bench to discover that the flow went backwards at the convergence lift. I was then able to get my SSR corrected using the flow bench and velocity probe. I would love to dyno the engine, but the $500 + dollars will be spent in better places right now.

I feel the same and think the higher depression you use to flow your heads the better. The bench I am building may be able to get 40 inches with my SBC heads. At least I am hoping. And I hope that you guys don't end up reading about the man in Salt Lake that was killed with flying plywood shrapnel.

John

[coulterracn]

John

I was at Larry Meaux's shop one Saturday morning. He was helping a friend/customer with their 355 cu in Chevy with Vortec heads. I don't remember what brand intake or the spec's on the cam, etc...

The first pull was 425hp. They made a timing adjustment and second pull yielded another 20+hp. They made a second timing adjustment and the third pull yielded another 20+hp. The next modification was 18 inch collector extentions. Fourth pull made 497hp.

My friend and I had to leave and head home to Mississippi. Larry has shared a list of things they were going to do the rest of that afternoon. I don't know the final Horsepower numbers that day but to make 75hp in lease than an hour is pretty impressive.

The list of things that were to be checked that afternoon included:
two different fuels (pump gas and racing fuel)
a different carb ( I don't know if they did any jet changes in the carb)
valve adjustment (my understanding is you can go .010" +/_ with the vale adjustment, very few cams like the valve adjustment spec's on the cam spec sheet)

BTW did you flow your dart heads before and after doing any work to the valve guides? The reason I ask is I contacted Dart about reshaping the valve guides on a pair of 230cc Iron Eagles. I was told There would an increase of 1cfm and they didn'r recommend doing the work.

On your future bench get some of that polymer wrap that I've read about on the forum. That should hold 100 inches easy.

Ray

[blaktopr]

[coulterracn]

Thanks Chris,

I'll have to take back what I said about wet Flow testing being price prohibitive

Ray

[jfholm]

[coulterracn]

I didn't do any work on the guide bosses. I was cleaning up the ports and blending the short side radius where it meets the valve seat angles. I didn't find the pre machined exhaust valve seats to be very impressive for a so called top of the line head. To me the seats were set to far back on the valve face to really flow. What I am saying here is the pattern left on the valve face after lapping the valve was closer to the backside radius of the valve it's self. I like a seat that is .020" smaller than the od. of the valve. I've seen hugh gains by moving the valve seat to the outer edges of the valve.

I had another set of Iron Eagles in the shop recently with the fxhaust seats cut the same. Maybe I should get a set and flow them as they are out of the box and after doing the seats the way I like them. That would be an interesting test.

Ray

Ray

[jfholm]

Ray,
I have found the seats a little small in the throat right under the valve also. Exhaust flow has been a little anemic. I find that I like to have really good low lift exhaust flow as the blow down when the valve first opens seems to be critical.

John

[coulterracn]

[bruce]

[slracer]

Ray, I was experiencing some of the same effect with my router control, especially at lower speeds. I talked to Rick (1960FL) and he said it was common with that type of electrical control and putting a small light in PARALLEL with the motor being controlled would help. I didn't understand most of what he said as electricity and I don't get along too well. :p Start with a 60 watt and if it helps, try smaller until it doesn't help any more, then go back up 1 size. Rick, if this is wrong, jump in! I'm modifying other things on my bench right now so don't have any results to talk about, but it is on my list of changes. Just a thought. Also, I have noticed what Bruce says is that these motors do take a while to spin up or down. -- Doug

[Tony]

Yes Doug, Rick is quite right about a particular motor/controller combination sometimes going nuts at certain speeds and loads.
A suitable lamp load wired directly across the motor will fix it. You will also see the lamp flickering if the speed controller is still not happy and is misfiring with the particular motor load.

If the lamp brightness holds rock steady, then any pressure fluctuations are not going to be from the motor supply voltage from the controller, but due to some other cause.

How much actual lamp wattage load you require to calm things down can vary hugely.
You will just have to try a few things and see what happens.

[slracer]

Tony, is there some type of "variable power" resistor that could be added in place of the lamp load? Then one would just have to twist a knob to change the load. There I go again, tryingto make it easier! -- Doug

[Tony]

Once you know "how much" resistive load is required, it can certainly be replaced by a very large resistor.

But the beauty of using lamps, at least to try initially, is that you can change the total wattage very easily by just adding more lamps, or using different sized lamps.

It has the added benefit of causing the lamps to flicker if the controller starts to misbehave. It is just that ordinary domestic lamps are very cheap and convenient to mess around with when trying to diagnose or solve a problem.

[coulterracn]

Hey I like this Guy,

KISS, keep it simple stupid.
I just added a U-tube manometer on my bench. I will check the rise just for knowledge and the pursuit of power. I could use the light bulb to light the area above my bench.

Ray