Head flow testing.

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Ok Jim your reports of poor results with oil as engine coolant back up what I've gleaned w/o near the adventure though. Research shows it takes .6 L/min to get 100'F reduction in our size pistons in normal use engines and up to 3 gal/min per piston in racer applications. Ugh. Leaves just air surface, fuel type, anti-detonation fluids and maybe direct water or C02 fin spraying to sustain fuel burn amounts to make much over 100 hp. Would this count as a water cooled Commando?

Still I'd think it good to avoid some oil cooking, if more flowed through the exhaust side of head, where it can get 500'F.

In my crazy Peel I'm using 750 'big' port Combat head, with hopes its on the small size of ports/valves for 920 to help the low end and tame the drag cam with a bit faster intake flow. Also the rim to surface area of stock 750 valves has better heat transfer seat area. Further hope the Drouin's slight blowing in at idle and low throttle will tame the drag cam for mild creeping around use at ~8:1 effective CR.

BTW what are the chamber volumes range you have found?
Any notice of size of chamber vs performance?
 
Well here are flow results from Ken's Maney stage 3 head. Big flow numbers for sure. Huge ports and 1.690 inch valves for big inch high RPM use only. The red line is the Maney head . Green is a standard Fullauto and blue is a RH4 that has been flowed by persons unknown. I went all the way to .500 lift although few cams lift beyond .420 or so. Jim

Head flow testing.


Here are the velocity numbers. They are what matters if you want a wide powerband.

Head flow testing.
 
Impressive velocity in FullAuto compared to the others, way to go. Almost 400 fps = almost .36 mach number-speed of sound. http://www.unitarium.com/speed

Anyone fit a Fullauto to a 920 yet? Many limits his to 7200 rpm to race, he says.
 
comnoz said:
My experiences . . . . to cool the oil.

I also recall in the mid 80's when racing a GSXR which was mainly oil cooled that we could not keep it cool after we installed high compression pistons along with flatslides and a pipe. We installed larger "kit" oil coolers but after each race the engine and oil would be smoking hot. It was impossible to restart until it cooled for a bit.

. . . . Jim
Click to expand...

I think is was Formula USA at Willow Springs in the late 80's . . . .? maybe I misremember . . . . anyway . . . . it was an anything goes "outlaw" format and the GSXRs in an overbored 12 or 1300 cc high compression configuration . . . . ran methanol.
 
Might be missing something here, but i would have thought a head with high velocity figures, is going to mean a bike which is going to be an awful lot nicer to ride on the road, than something with very high flow figures, which is going to mean a very narrow power band at high rpm?
 
Carbonfibre said:
Might be missing something here, but i would have thought a head with high velocity figures, is going to mean a bike which is going to be an awful lot nicer to ride on the road, than something with very high flow figures, which is going to mean a very narrow power band at high rpm?
Click to expand...

That is the general idea. Why do a port job that starts to work at about the mechanical limits imposed by the long stroke? Fine if you are building a full on race motor [salt flats] but then it is only good for one thing. Jim
 
I spent some time on the flowbench this evening playing with the Fullauto head that is going on my bike. I installed a .070 larger valve in the RH port and did a radius valve job which included tapering the seat up to the larger valve. I also relieved the area around the valve guide boss. I did not increase the area of the port as I did not want to hurt the velocity. This is about as large a valve that I could fit without re-angling the intake guide and it will limit the amount of overlap the cam can have- so no race cams. The main gain is from the improved seat geometry allowed by the larger valve and not because of the slight increase in valve area from the increase in valve size.

The red line is the Maney stage 3 head I tested last week. The blue line is the left hand port that I tested with stock parts right after I tested the RH port. The green line is the RH port with the valve job and minor port work. Note that the reading at .050 lift is not accurate but is correct at .100 and up.

Head flow testing.


Here is the head on the bench

Head flow testing.


And here is the work done around the valve guide boss.

Head flow testing.
 
Interestingly enough fitting a larger valve and keeping the port size std, has the effect of increasing gas speed, and is something thats doesnt cost anywhere near as much money as a costly "gas flowing" job, and will make bikes a lot nicer to ride on the road.
 
Actually 98% of the increase in flow from a professional gas flowing job is gained in the valve seat and bowl area. That generally will apply to any head. When you are looking at a strait round tube like a port you can flow enough air for over 200 horsepower through a single 38 mm hole. It is when you start bending the airflow that things get tricky. Jim
 
Jim,
Thanks once again. Looks like we have some data to go along with the reports of improved low and mid-range grunt with the Fullauto Heads.
Russ
 
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Unread postby Carbonfibre » Tue Mar 29, 2011 10:19 pm
Interestingly enough fitting a larger valve and keeping the port size std, has the effect of increasing gas speed, and is something thats doesnt cost anywhere near as much money as a costly "gas flowing" job, and will make bikes a lot nicer to ride on the road.
Click to expand...

AlrightY! This little tid bit may be great value to Ms Peel and her vulnerable fiberglass tank. Smallish ports air ram help tame excessive over lap cams. Most pleasing combo I can think of is hi-ish CR cammy big block with smallish ports for the low rpms w/o boost then no end in sight as boost builds to blow up rpms'. So far seems JIm's Fullauto hi speed porting might be my best investment after a TT gearbox. Then the thermal flowing issue gets in the way.
 
Nice work, Jim. As you have surmised, the Maney Stage 3 head is going on an engine destined for the Bonneville salt flats. It's all about high flow on the top end. The engine is an ultra sort stroke 750, with 75 mm stroke. The cam is Megacycle 480. I haven't settled on carbs yet, but probably a pair of 38 mm Mikuni flat slides.

I'll get another head off to you this week to measure, probably a Maney Stage 2 head.

Ken
 
lcrken said:
Nice work, Jim. As you have surmised, the Maney Stage 3 head is going on an engine destined for the Bonneville salt flats. It's all about high flow on the top end. The engine is an ultra sort stroke 750, with 75 mm stroke. The cam is Megacycle 480. I haven't settled on carbs yet, but probably a pair of 38 mm Mikuni flat slides.

I'll get another head off to you this week to measure, probably a Maney Stage 2 head.

Ken
Click to expand...

Great I will be looking forward to it. I am interested in seeing if it is better over .350 lift. As you see on the graph the flow hits a point were it dives and it it because the air is lifting from the port floor at the short side radius. I was able to see it clearly with the V probe and you could hear it as the the flow suddenly got very loud and raspy sounding. The probe could find no flow on the short side of the valve once the airspeed got over 300 FPS. Jim
 
Carbonfibre said:
How well do bikes fitted with these high flow heads work on the road or track?
Click to expand...

The only one I ever used was on a long stroke 750 and it was the slowest thing on the track. It was on a three main engine and was cammed and tuned for 9000 rpm but even then it would not work. Steve builds them for high rpm big bore motors and reportedly they produce good horsepower in that application.
The port turbulence over .350 lift does not mean they can not make good power as the flow is there. Port turbulence and short side flow problems are something that is hard to avoid when you re-angle the valve. It is hard to make up for the fact that you have to turn the air a couple more degrees. It tends to put a limit on high velocity flow in trade for the higher mid lift flow you can get from a bigger valve. Jim
 
I quizzed Steve Manney to find out he runs his race 920's to 7200 on standard stroke and crank dyno showed 100.4 hp peak.
 
If heads which make high figures on the flow bench dont work on the road or track, I wonder if there is any real point in this thread?
 
Carbonfibre said:
If heads which make high figures on the flow bench dont work on the road or track, I wonder if there is any real point in this thread?
Click to expand...

As has been said many times before. High flow is not necessarily better. The correct flow for the engine is. Flow and velocity figures can tell you a lot if you know how to use them.
One way to use the figures is to know how a particular engine performs and look at the flow and velocity figures from that head and after looking at several of them you will see what works and what doesn't.
 
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