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#14397 - 01/25/18 09:20 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
fordboy628 Offline
Professional

Registered: 06/30/14
Posts: 322
Loc: NE Illinois
Since a picture is worth a thousand words . . . . here are 10,000 words for viewers.

Flow bench version.






















No captions or explanations. Use your imagination and fabrication skills.

Oh, one thing though, photo subject is a Briggs & Stratton "Animal" head. But the ideas can be adapted to pretty much anything.

Cheers
_________________________
Fordboy628

Without "data", you are just another guy with a theory or an opinion . . . .

Someone who thinks logically is a nice contrast to the real world . . . .

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#14398 - 01/25/18 09:39 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
fordboy628 Offline
Professional

Registered: 06/30/14
Posts: 322
Loc: NE Illinois
Since a picture is worth a thousand words . . . . .

Dyno version. Part 1














Again, no explanations, just visuals.

Cheers
_________________________
Fordboy628

Without "data", you are just another guy with a theory or an opinion . . . .

Someone who thinks logically is a nice contrast to the real world . . . .

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#14399 - 01/25/18 10:01 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
fordboy628 Offline
Professional

Registered: 06/30/14
Posts: 322
Loc: NE Illinois
Since a picture is worth a thousand words . . . . .

Dyno version. Part 2














Readers with older eyes will find it helpful to set the zoom to 175% or higher for this photo:


For competitors that still think that they do not have to dyno test, the only comments I'm going to make are these:

A/ Dyno run #4 was the test where the state of tune was "generalized", based on years of track tuning with good results. Bhp & Tq in black.

B/ Dyno run #20 was what the engine "wanted". In stark contrast to conventional experience. Bhp & Tq in red.

C/ If you don't think the type of dyno, the technicians or dyno operators make a difference . . . . well, you might want to re-evaluate that conclusion.

Viewers, you be the judge . . . . .

Cheers


Edited by fordboy628 (01/25/18 10:07 AM)
_________________________
Fordboy628

Without "data", you are just another guy with a theory or an opinion . . . .

Someone who thinks logically is a nice contrast to the real world . . . .

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#14439 - 02/11/18 12:49 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43


Couple of pics of my new EFI setup

Aaron Kelley

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#14440 - 02/11/18 05:44 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: AVP Heads]
fordboy628 Offline
Professional

Registered: 06/30/14
Posts: 322
Loc: NE Illinois
Aaron, thanks for sharing!!

Titan Series 2 oil pump?

What's it going to go into?

Cheers,
M
_________________________
Fordboy628

Without "data", you are just another guy with a theory or an opinion . . . .

Someone who thinks logically is a nice contrast to the real world . . . .

Top
#14441 - 02/11/18 09:48 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
Aaron,

That's awesome!

Can you share the good, the bad, and the ugly of your trials and tribulations to get there (I'm assuming you didn't nail it in your first shot)? How did you end up with a common plenum as opposed to individual throttle bodies?


Edited by hoffman900 (02/11/18 10:59 AM)

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#14442 - 02/11/18 11:49 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43
It's my development motor for my GT-L car. TDC 3 stage oil pump, combined with rear main seal kit, for pulling a vacuum on the crankcase.

It was a ton of work, but it was combined with 2 years of power development.

2 plenum designs, 3 different cams, 2 different rocker ratio's, along with custom towers for addl stability. Switched to belt drive on cam, which had it's own set of failures. CNC chamber design. Switched to h13 tool steel adjusters with a smaller ball on them, and pushrods to match. Larger lifter diameter (.875" with latest cam), 2 different styles tried.

Looking at the the dyno software, I made over a 170 pulls. I think I tried everything.

The main reason for the plenum vs individual throttle bodies was cost, and ease of connecting to the cold air/ram air pickup from the left headlight. Also looked to have a slight edge in avg hp in EAPro simulations.

I'll see if I can post a pic of the dyno sheet later, with Nigel's 2014 FP dyno sheet for comparison. Since my dyno could be reading a bit happy.

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#14443 - 02/11/18 12:09 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
Alfaromeo1 Offline
Enthusiast

Registered: 10/27/12
Posts: 97
Loc: IL
Can you be more specific. I am not understading what the engine wanted was after doing some different things despite conventional methods you were able to achive much better results?

Do not undertand the part about the type of dyno or dyno operator. I assume by tech mean knowledgable and able to get more power is that correct?
_________________________
Terry R. Stahly
Bloomington, IL 72 Alfa GTV 2000
Grp 8 VSCDA, SVRA, Midwest Counsel, HSR

www.stahly.com
www.4qte.com

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#14444 - 02/11/18 12:25 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: AVP Heads]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
Originally Posted By: AVP Heads
It's my development motor for my GT-L car. TDC 3 stage oil pump, combined with rear main seal kit, for pulling a vacuum on the crankcase.

It was a ton of work, but it was combined with 2 years of power development.

2 plenum designs, 3 different cams, 2 different rocker ratio's, along with custom towers for addl stability. Switched to belt drive on cam, which had it's own set of failures. CNC chamber design. Switched to h13 tool steel adjusters with a smaller ball on them, and pushrods to match. Larger lifter diameter (.875" with latest cam), 2 different styles tried.

Looking at the the dyno software, I made over a 170 pulls. I think I tried everything.

The main reason for the plenum vs individual throttle bodies was cost, and ease of connecting to the cold air/ram air pickup from the left headlight. Also looked to have a slight edge in avg hp in EAPro simulations.

I'll see if I can post a pic of the dyno sheet later, with Nigel's 2014 FP dyno sheet for comparison. Since my dyno could be reading a bit happy.



Aaron,

Looking forward to it.

I've pretty much spent the last year immersing myself in cam and cam designs, playing with my own designs in simulation as well without resorting to an entire Blair software suite.

Spent a lot of time reading and studying everything Harvey Crane, Mike Jones, and Harold Brookshire have left scattered around the internet, as well as conversing with Billy Godbold.

I always felt like the Harold Brookshire style of delayed opening intake designs would suite the A-Series quite well. Only problem is his stuff is designed for a .842" lifter at minimum. Not an issue with an A-Series in vintage or GT-L.

Also, Billy said the lobe needs to be tempered some on a 4 cylinder due to higher fluctuations in velocity compared to a bent crank V8. I know Harold's stuff can tend to be on the more aggressive side. Anyway..

I'd be interested to hear your thoughts and what you have found. You can email me if you'd like to keep it off the forum.

Fordboy is profiling some cams for me. In total, I have 4 aftermarket and an OEM grind to compare figures from. Spent some money getting the cylinder head measured up accurately and have everything in CAD now. Expect a thread when I get everything measured up and have a chance to digest it.

Cheers,
Bob


Edited by hoffman900 (02/11/18 12:36 PM)

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#14445 - 02/11/18 12:35 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: Alfaromeo1]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43
I did make more power than before, but I have no comparison on how accurate my dyno is compared to a perfectly calibrated dyno. I have calibration technique that was setup by an engineer, but my weights are not certified. But I do think it's in the ball park, and my progression with addl weight converted to torque is within .02 lb ft. It also repeats very well.

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#14446 - 02/11/18 12:54 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: hoffman900]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43
Could you please clarify "tempered" for me? Pretty sure I know what you mean, and that was the reasoning for switching to the belt drive, to reduce/smooth out the accel/decel of the cam that comes with each power stroke.

Ended up with cam from Mike Jones, it works very well. Very good guy to work with, although he gets so busy at times he can be hard to get on the phone.

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#14447 - 02/11/18 01:17 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: AVP Heads]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
Originally Posted By: AVP Heads
Could you please clarify "tempered" for me? Pretty sure I know what you mean, and that was the reasoning for switching to the belt drive, to reduce/smooth out the accel/decel of the cam that comes with each power stroke.

Ended up with cam from Mike Jones, it works very well. Very good guy to work with, although he gets so busy at times he can be hard to get on the phone.


That's exactly what I meant. I don't think Billy meant in terms of velocity, it would be the acceleration and jerk curves.

Go to the last half of Billy's presentation here:
http://www.aetconline.com/wp-content/education/2017/Billy_Godbold.pdf

It's measured, discussed, and remedies developed here:
http://www.f1-forecast.com/pdf/F1-Files/Honda/F1-SP2_09e.pdf

Kevin Cameron's articles:
Quote:
TIOC May 2005
Eaten Alive by Parasitic Oscillations
by Kevin Cameron

As a new hi-fi amplifier is designed by an electronic engineer,
particular care must be taken to be sure that unforeseen combinations
of resistance, inductance, and capacitance do not permit so-called parasitic
oscillations; to build up, destroying the music.

Each property of electrical circuits has a mechanical analog, and one
mechanical system that is often rife with its own parasitic
oscillations is the valve train. Rocker arms bend, pushrods compress
and expand, camshafts deflect between their bearings, and valve stems
flop from side to side while valve heads deflect like trampolines or
floppy disks. All of this is invisible to us. Its symptoms are valve
seat recession and valve spring and valve breakage. In many cases,
after tests with a new cam that gives really good power, we have to
reluctantly back up to a previous, less powerful set-up because we
can't afford the DNFs and breakages that the hot set-up
produces. Valve train failures are hit-and-miss, trial-and-error, a
mystery. Lighter valve train parts and stronger springs sometimes just
seem to make everything worse. Is there any truth?

Back in the 1920s Percy Goodman decided it was time to put aside
clattering pushrods and adopt trendy OHC valve drive on the TT
Velocettes he manufactured. Soon he was driven crazy by erratic valve
motion and sensibly resorted to the use of a strobe light to reveal
what was happening. But naming the illness is not the same as a cure.

When I was recently at the NHRA drag nationals in Houston, I had the
opportunity of conversation with Byron Hines, whose purpose-designed
giant 160-cubic-inch V-twin engine has recently begun to win Pro Stock
races. I asked what had made the difference after some uncompetitive
seasons.
The Spintron, was his answer. It showed us that our valve
motion was nothing like what was in the cam profiles.

When I was recently at the NHRA drag nationals in Houston, I had the
opportunity of conversation with Byron Hines, whose purpose-designed
giant 160-cubic-inch V-twin engine has recently begun to win Pro Stock
races. I asked what had made the difference after some uncompetitive
seasons.
The Spintron, was his answer. It showed us that our valve
motion was nothing like what was in the cam profiles.

Spintron use a big electric motor to spin your engine while a variety
of instrumentation is used to measure the actual trajectories of the
parts you are interested in. This is different from using a
strobelight in that the information you get is detailed enough to
allow the flexing of each part to be isolated and understood.

Byron went on to say that valve train dynamics are particularly
difficult to control in big twins because of the large variations in
crank speed as each cylinder fires. The cam profiles were originally
developed to work at a particular maximum rpm, provided that the
camshafts turn smoothly. They do not turn smoothly because the crank
does not turn smoothly; it advances in a series of fairly violent
jerks. 80 percent of the recoverable energy in the hot combustion gas
does its work between 10-deg ATDC and 80 ATDC. Out of the 720 crank
degrees in the engine cycle, power is given during only 10%. This
means that the instantaneous speed of the cam can often be much higher
than its average speed. This also means that as a cylinder fires and
the crank accelerates suddenly, an open valve in the other cylinder
may be tossed right off its cam profile, or dropped prematurely onto
its seat.

This reveals why tuners of singles and twins found that their bikes
top-ended better and faster the heavier their cranks were made. A
younger generation of tuners has rejected this idea as turn-of-the-century
dirt-track nonsense, reasoning that physics requires lighter flywheels to
result in faster acceleration.
Vintage racer Todd Henning learned the heavy crank truth
in back-to-back testing of his highly tuned Honda twins, as did Rob
Muzzy in 1981-83 with 1025-cc Kawasaki in-line fours. The heavier the
crank, the smoother its rotation becomes, and the less power stroke
disturbance, or is transmitted to the cams. Where
does the lost power go when a light crank is used? Erratic valve
motion is one answer, and big valve bounce after closing is another.

Power pulsing is not the only disturbance to the valve train. Consider
a parallel twin, a flat twin, or an in-line four. In all of these, all
the pistons stop simultaneously. This means that as pistons decelerate
to a stop, the crank must accelerate rapidly because there is nowhere
else for the pistons' energy to go ; its conservation of
energy. Peak piston speed is about 1.5 times mean piston speed. This
means that all the kinetic energy in the pistons, moving at near 100
feet per second, is suddenly dumped into the crank. This is especially
bad for in-line fours, which have small-diameter cranks and little in
the way of flywheel mass. This sudden crank deceleration/acceleration
cycle is performed twice per revolution. No wonder new engine
development usually involves coping with cam drive breakage. No wonder
there are mystery failures of valve train parts.

Allan Lockheed is the man behind the engine design software Engine
Expert, and he talks to engine people all over the world. He has
tales of engines whose valves were stable with a chain or belt cam
drive, but which mysteriously began to break valve springs as soon as
a much more rigid gear drive was put in its place. The slight
flexibility of chain or belt took the sharp edge off the sudden crank
speed variations, preventing high frequency motions from reaching the
valve train. This may be why Yamaha retain a chain cam drive in their
M1 in-line four MotoGP race engine. The oil film between each of the
cam chain's pins, bushings, and rollers can be thought of as a kind
of viscous damper. Such fluid film damping is one of the motivations
inclining the designers of rocket engine turbopumps to give up rolling
element shaft bearings in favor of plain journal bearings. A gear cam
drive has fewer than 10 oil films between the crank and cam, but a
chain has a great many more.

Phil Irving, designer of Vincent motorcycles, suggested construction
of parallel twins with crankpins not at the traditional 360 degrees,
but separated by 76 degrees. With usual rod ratios, the piston reaches
maximum velocity at about 76-deg ATDC. At this point, the crank arm is
at right angles to the con-rod; the condition for maximum piston
velocity. This crankpin angle would therefore cause one piston to be
stopped when the other was at maximum speed. The result would be that
the two pistons would exchange their kinetic energy only with each
other, and not with the crankshaft, eliminating one important source
of cam drive disturbance.

Wide-angle Vee engines are better in this respect than parallel twins
but even they have their problems. The classic Cosworth DFV V8 GP car
engine of 1967 was estimated during design to have no more than a 35
pounds-foot torque peak in its cam drive, but actual testing revealed
peaks ten times greater; leading to drive failure. As the engine
was already near production when this was discovered, designer Keith
Duckworth had to scurry around and design a compact spring drive
(analogous to what is found in clutch cush hubs) that could be
incorporated into one of the gears in the drive.

Another approach is that seen on certain WW II German V-12 aircraft
engines, and on late race versions of Honda's RC30. In these and
other cases, small flywheels have been attached to the cams
themselves.

It is interesting to note that both Velocette and Ducati have found
that changing the stiffness of cam drive towershafts can be used as a
tuning measure to adapt an engine to a given race track a stiff
towershaft on short courses, and a more limber one for longer
tracks. The parts seem stiff and strong only in our imaginations and
in our not-very-stiff protein hands. In fact, at speed, everything in
engines is flexible because the amounts of energy moving from part to
part can be so large.

Byron Hines noted that as useful as Spintron's instrumentation is,
even more so is the experience and advice of Spintron personnel. One
of the first things they suggested was that he replace his aluminum
rocker arms with steel, for accurate motion depends more on stiffness
than on weight. He also said that full benefit from Spintron requires
making several laps through their process. A first lap involves re-configuring
the cam profiles and valve train to settle the motion and eliminate float
and excessive bounce. A second lap becomes necessary when it is realized
that after lap one, the engine's power curve has sagged in some places.
This is because before, cam timing and lift had been unwittingly chosen to
at least partly compensate for the uncontrolled valve motion. Once the valve
motion is settled, timing and lift are wrong. Now lap two consists of finding
new optimum cam timings and profiles to again maximize power. That, in turn,
brings to view new dynamic problems to be solved in lap three, and so on.
The people with the greatest sophistication in all this are, naturally, NASCAR engine
builders.

As an extreme example of what can happen, airflow
pioneer Jerry Branch was once called upon to dyno a special V-twin
that was conceptually a slice off a small-block Chevy, crank and all.
Being intended as a motorcycle engine, it had no flywheel other than
its little piece of V8 crankshaft. Branch said that although the engine
had plenty of displacement and hot tuning parts that suggested an
easy 100-hp, it never made over 35 horsepower. Each time it fired,
with almost no flywheel mass to smooth the pulse, it launched its
valves into orbit.

Another aspect of unplanned valve motion is the vibratory modes of
valves themselves. Particularly with rocker-arms (which exert some
side-thrust), a valve can be excited laterally as it lifts, the head
of the valve whipping from side-to-side on the stem; the stem
possibly made more flexible by undercutting to squeeze out that last
CFM of airflow. When this flopping valve approaches the seat, one edge
can hit first, causing a motion not unlike the final stages of a spun
coin's motion. Or, approaching its seat squarely, the rim of the
valve stops but the stem and center of the valve head keep right on
going; the trampoline mode of valve flex. When the motion
at the center finally stops, the valve head is quite deformed and it
now snaps back, tossing itself back up off the seat in a cycle that
can make several hops; with considerable lift being reached in the
process. This is a cautionary tale for those who wish to carve away
valve head mass in search of ultimate lightness. Or for those who wish
to replace existing valve shapes with something quite different. Think
about it if things don't go right. You may have made transformed
those elegant chunks of metal from valves into springs.

Spintron is not cheap but all of us can afford imagination. If you
have valve or spring problems, think about what has worked in your
experience with your particular engine, and what has not. Careful
mental sorting here can reveal a lot. Besides, what else is a body to
think about while waiting for a dental appointment? Sit with the
engine and rotate it through its cycle, thinking about what is
happening at each point. Over time you can develop a mental picture of
what may be happening and what might correct the problems. There is
more to valve trains than light parts and heavy springs."


Quote:
Early computer-controlled engines had cam position sensors to tell the computer which cycle they are on. Now they do without - they just use the speed difference in the crank to tell them (I guess the engine sparks at every TDC during start-up). So, yes, there are very large speed variations, especially with singles and twins - enough that they give the two cylinders different fuel and ignition maps. Enough, for example, to toss the valves prematurely because the instantaneous cam speed is high. One speed variation comes from the actual cylinder firing, and others come from the steady exchange of kinetic energy between the pistons and the crankshaft (which is twice per revolution).

Nearly every race engine in history has had to have special attention given to the cam drive during development, because crank/cam interactions, through the flexibility of the drive (or lack of it, just as often) create problems. Cosworth make a trick torsion spring that goes in their gear cam drives, and has with it a stack of tiny clutch plates compressed by a diaphragm spring, to absorb the oscillatory energy at the speeds where it tends to get out of hand. Ducati found they had 32nd-order torsionals in their camshafts. They made a big improvement when they changed from ball bearings to plain - every plain bearing is also a hydraulic shock absorber. The oil pump refills it and the thumps of valve acceleration squeeze the oil out of the bearing.

Torsionals were a HUGE issue in the development of the large radial aircraft engines. Generally they had a 4.5-order (firing frequency) and a 2nd-order (secondary vibes coming from the asymmetry of the master-and-links con-rod system) dynamic counterweight on the crank - really massive things that swung back and forth, alternately storing the excess energy from a cylinder firing, then giving it back as the firing impulse died away. When this wasn't right, pieces would vibrate off the tips of hollow steel propellers - chunks about 18" long, going about 500-ft/sec. Or the prop reduction gears would crumble, or the shaft crack, &c. It was a major part of development - hours and hours of running tests to get the crankshaft system stable.

A few years back the NASCAR guys were floating the valves in the back of their engines. This looked like cam twist so they bored some blocks for bigger bearings, increased the cam base circle, and made some experimental cams on bigger tubes. Imagine their surprise when they got LESS power. After a while they figured out that enough valve float to increase time-area, but not enough to wreck the parts, was what was happening. SO next they designed cams to float intentionally, and gradually learned how to design the ski jump so the skier didn't lose his balance when he landed after the jump. At first, these were used just for qualifying. Now they use such "lofting" cams for 500 miles, and the Europeans are calling them "Ballistic valve trains". I think it can work only because NASCAR engines don't run across a wide range of RPM. The guys at Spintron have books and books of development records of this kind.


I asked Billy about the V&H Pro Stock bike, and he mentioned you could see the effects of it on the Spintron without the engine firing. A firing engine would be worst. He said the way to deal with this is to calm down the lobe. A single and a twin would need a smoother profile than a I4, which would need a smoother profile than a bent crank V8. This wouldn't be velocity, but the acceleration and jerk curves.

From what I know of Mike's designs, his stuff is pretty smooth. He's outright said time on the Spintron made him go back and think about how to design the ramps on his cams and he's changed accordingly. I've had him measure up a cam for me before, and I agree. Nice guy, just have to remind him to check his emails occasionally, but that's everybody it seems. I would like to have him design a cam for my bike, but that would be $800 worth of design / master cutting ($400 per) and I would need to source cores for him.



Edited by hoffman900 (02/11/18 01:21 PM)

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#14448 - 02/11/18 02:21 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43
Mark,
What can you share about that a-series you posted dyno pics of? Other than a very nice dyno sheet!

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#14449 - 02/11/18 07:43 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43



Here are a couple of pics during assembly, can see the entry and injector placement better

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#14450 - 02/11/18 08:22 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
Aaron,

Those runners are slick. Did you machine them? Is there a spigot they slip over on the head side as well? It's nice to have a runner with the taper you need, and no change in csa from a venturi / booster to effect pressure waves. I would think the majority of the gains from going to EFI would be from this alone on an application like this.

How do they flow on the flowbench vs. a Weber or a SU set up?

I feel like A LOT of people mess up when going to EFI. They use individual throttle bodies on Weber spacing, so the bends in the runners remain intact. Make them straight like you have!

Am I correct in seeing two sets of injectors? Do you have them timed so they are firing for their own cylinders?

How do you think a plenum of that size will effect part throttle operation and shift recovery?


Edited by hoffman900 (02/11/18 08:40 PM)

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#14451 - 02/11/18 09:06 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43
Had a friend machine them, nothing to slip into head.

They outflow my su carbs by just a few cfm, but I was able to put the length on the 3rd harmonic. Plus the taper is exactly what I wanted. It ended up making a bigger difference than I even imagined it could.

Another mistake I see is putting the injectors too close to the head, killing the latent heat vaporization.

4 injectors, fired in groups of 2. Not timed to the cylinders, but I am able to delay/advance the injector firing which fixed the center cylinders running hotter and makes the plugs burn evenly. No longer have to have the individual cylinder timing or colder plugs in the center 2 cyls.

Not sure how the plenum is gonna fare yet, may require addl track tuning. The throttle response from idle is better than any 1275 I have ever worked with. Part throttle is tbd. Bigger plenum than I wanted for sure, but designed on the flow bench for minimum flow loss compared to a bare runner. The jones cam helped a lot with throttle response, seems to use less fuel. Also put less fuel out the exhaust.

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#14452 - 02/11/18 09:10 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43



Here is the dyno sheet from Nigel's 2014 runoffs motor

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#14453 - 02/11/18 09:13 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43


Here is the dyno sheet from GT-l with EFI

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#14454 - 02/11/18 09:17 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
Do you mind sharing what Mike did with the cam timing?

His stuff always looks small at first glance, but it works. He does seem to be a fan of smaller lobes and as much rocker ratio as you can give it. Judging by your post earlier, it sounds like you put a lot of effort into the rockers.

Like all cam designers, the more you can give him, the better he can do. No doubt you have no shortage of data to pull from.

Another thing about Mike is he certainly designs cams unlike anyone else I can find. Most are using polynomials, B or C Splines, Bezier Curves, etc. Mike has his own way of doing it.

I created profiles to match the specs he gave me for my bike. It was very happy with with it in the sim.

Also, I love that power curve on that FP engine! There is a lot of work there.

Edit. Holy sh*t on that GT-L engine! You did say elsewhere that you had the cfm potential to get there if only you could get the lift! That torque curve is sublime. I canít say I would have ever guessed a 5 porter A series would hit 2hp/ci!


Edited by hoffman900 (02/11/18 09:37 PM)

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#14455 - 02/11/18 09:31 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
Jay Wiles of Hendricks shared they lost horsepower going to EFI for that very reason (as did the Pro Stock engines). They got most of it back with individual coil ignitions. Since injector location was specíed by the rules, everyone was in the same boat. There were rumors of some Pro Stock builders with leaky seals on an internal fuel rail to fog the plenum, now they have to be on the outside. grin

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#14456 - 02/11/18 11:25 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
AVP Heads Offline
Novice

Registered: 02/16/15
Posts: 43
Cam was not as exotic as you might think, would like keep that info private for now.

Interesting thing is that when the carbs are on the motor, it makes 152 hp. Which is 1 less than the HL-12, and same as APT spvp5. Put the EFI on and the HL-12 loses 9hp and 8 ftlbs, APT cam was a gain of 3hp with the EFI.

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#14457 - 02/12/18 05:58 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
That just further illustrates that an engine is a system and not individual components.

What are the intake and exhaust centerlines on the HL-12 and the SPVP-5?

I believe both are around 300-306* advertised (.020Ē?)?

I really canít believe wave tuning was worth that much, but wow again. I really thought the Siamese section in the head would really break up or mess with the timing of the waves.


Edited by hoffman900 (02/12/18 06:04 AM)

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#14459 - 02/12/18 11:35 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: AVP Heads]
dcb Offline
Legend

Registered: 01/24/11
Posts: 1029
Originally Posted By: AVP Heads


Here is the dyno sheet from GT-l with EFI


Aaron,

WOW! fantastic result. Your gearbox choice will be interesting with this kind of torque. I don't think any Spridget cased box can deal with it.

I'm not very scientific, nor well read on engine development trends. But I have felt for a long time that a single throttle body/ carburetor could be beneficial for these motors. I've based that assumption on a few experiences with single carbed A-series and B-series engines - they simply run better on a single carb. I know that doesn't necessarily translate to ultimate performance, but I always thought it would be worth playing around with it.

Your results certainly show that it doesn't seem to hurt!

Dave Brown

PS I'd settle for Nigel's engine!

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#14460 - 02/12/18 07:50 PM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: fordboy628]
hoffman900 Offline
Champion

Registered: 02/03/11
Posts: 564
Loc: New Jersey
Dave,

Not speaking for Aaron, but it's my opinion the only way a single carb could work is, like Aaron's set up, is if there is a large enough plenum. You would have to do something like some of the drag racers do:







If anything, Aaron's work illustrates the point that the carburetors are choking the engine at some point. Also, as I pointed out above, never underestimate what ram tuning can do for you.


Edited by hoffman900 (02/12/18 07:53 PM)

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#14461 - 02/15/18 09:55 AM Re: RACING ENGINES, A TECHNICAL EXAMINATION [Re: Alfaromeo1]
fordboy628 Offline
Professional

Registered: 06/30/14
Posts: 322
Loc: NE Illinois
Originally Posted By: Alfaromeo1
Can you be more specific. I am not understading what the engine wanted was after doing some different things despite conventional methods you were able to achive much better results?

Do not undertand the part about the type of dyno or dyno operator. I assume by tech mean knowledgable and able to get more power is that correct?


What I mean specifically is that "generalized" tuning or "track tuning" does not typically take specific data into account. At the "club" level interpretation of "improvement" is based solely on "driver's judgment" or perhaps lap times. The exception to this is when and if, the car can be outfitted with "data logging" instrumentation. "Effective" interpretation of data is "uncommon" at the "club" level, IMHO.

On the other hand, accurate and repeatable dynamometer testing eliminates many variables, thereby providing more accurate data for analysis. BUT, one can not assume that all dynos are accurate and repeatable, any more than one can assume that all dyno operators are equally talented with respect to tuning insight.

Some specific examples for you to consider:

1/ In my opinion, dyno repeatability is far more important than "absolute" accuracy. In a perfect world, both would exist, simultaneously. But "above average" engineers are "forced" to deal with the reality that "perfection" is seldom achievable. Therefore, a unit that can repeat readings +/- .3% or so is what you want to utilize. Evaluate the credibility of your dyno session results with what engineers term a "closed loop test". Try this: At the end of a dyno testing session, return the engine to the same tuning specification as the starting baseline test. You should get the same results, under the same conditions, as your baseline. If you do not, there is a problem somewhere. If you can not repeat your original baseline, the data is "flawed".

2/ What I mean by a dyno technician/operator is a person who is capable of operating a dyno, connecting your engine, running a test on the engine and perhaps printing the resultant data. Nothing more or less is implied. LOTS of these.

3/ What I mean by a "tuner", is a person who has some experience with a particular engine type and has some insight into the conditions required for the engine to produce "reasonable" power output. Should be able to suggest tuning changes, that may or may not be improvements to the engines power output. This person might or might not be capable of operating a dyno. Could be many or few of these, depending on engine type.

4/ What I mean by engineer with respect to racing engines, is really an "internal combustion" engineer. Hopefully one with a wide range of experience in racing engine data analysis. This is the person who can provide an analytical "insight" into how an engine might be performing, and may be able to suggest options, tuning or otherwise, for improving an engine's bhp & tq output. This is the rarest of the bunch. Most good IC engineers are employed at the professional level and are "unavailable" to club racers.


For the specific example engine, the results of which were posted, the engine testing began with a run-in cycle. After which some component checking was performed, and then testing began in earnest. The baseline was "under-performing" and some tuning issues were addressed and investigated in order to correct the performance. Some minor issues were identified and corrected, resulting in improved performance and the test regimen continued. Testing of additional variables eventually
resulted in performance that exceeded the owners expectations, although there were solid indications that a change in engine "specification" would result in "improved output". This conclusion was based on comprehensive data analysis of combustion efficiency, as well as other test factors. The engine's owner/builder is considering changing his "specification".

As a final note, it is important to communicate that within the testing regimen of 27 total pulls, not every test resulted in improvement. Slightly more than half the variable testing, resulted in bhp LOSS . . . .

Hope this helps to clarify things.

Cheers
_________________________
Fordboy628

Without "data", you are just another guy with a theory or an opinion . . . .

Someone who thinks logically is a nice contrast to the real world . . . .

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