worth reading thru

grumpyvette

Administrator
Staff member
I THINK YOULL FIND THIS LINK VERY INFORMATIVE....open and read thru the linked info
http://www.circletrack.com/enginetech/c ... ady_spark/

Distributor Comparison
Timing set at 36 degrees at 5,000 rpm - Dyno Pull from 4,000 to 8,000 rpm
Low High Variance Average % Change
Crane Pro Curve Billet 30.4 37.4 7.0 34.288 4.99
Crane Pro Race 32.7 37.2 4.5 35.850 0.42
Crane Pro Race Optical 34.0 39.1 5.1 36.217 0.60

Distributor Gear Comparison
Timing set at 36 degrees at 5,000 rpm - Dyno Pull from 4,000 to 8,000 rpm
Low High Variance Average % Change
Standard Brass Gear 32.7 37.2 4.5 35.850 0.42
Brass Gear +0.020 Inch Oversize 33.6 38.7 5.1 36.196 0.54

Analog vs Digital Ignition Comparison
Timing set at 36 degrees at 5,000 rpm • Dyno Pull from 4,000 to 8,000 rpm
Low High Variance Average % Change
Race Pro w/ HI-6N (Analog) 32.7 37.2 4.5 35.850 0.42
Race Pro w/ HI-6R (Digital) 36.2 38.7 2.5 37.941 5.39

Crane Pro Curve Billet Distributor Test
Engine Configuration: V-8 - Cylinder Configuration: V-8
Cylinder Ordering: Left Bank - 1 - 3 - 5 - 7 - Right Bank - 2 - 4 - 6 - 8
Firing Order: 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2
Cylinder Rotation: 0.0 - 90.0 - 180.0 - 270.0 - 360.0 - 450.0 - 540.0 - 630.0
Cylinder #1 Timing: 36.0
RPM Cyl #1 Cyl #8 Cyl #4 Cyl #3 Cyl #6 Cyl #5 Cyl #7 Cyl #2
4,000 35 36 35.4 35.2 35.4 35.8 35.4 35.2
4,100 36.1 37.1 36.3 35.6 35.7 36.3 36.1 35.7
4,200 35.6 37.1 36.6 35.6 35.6 36.4 36.1 35.6
4,300 33.5 35.6 35.5 34.7 34.6 35.2 34.9 34.4
4,400 33.4 34.4 34.2 33.8 33.5 33.7 33.7 33.8
4,500 34.1 34.4 33.4 33.1 32.8 32.8 33.2 34
4,600 35 35 33.5 33.3 33.2 33 34 34.6
4,700 34.7 35.4 34.2 34.1 33.8 34.1 34.7 34.7
4,800 34.4 35.5 34.5 34.5 34.4 34.5 34.4 34.5
4,900 34.6 35.4 34.6 34.4 34 34.5 34.2 34.4
5,000 34.8 35.4 34.7 34.1 33.7 34.7 33.9 34.4
5,100 34.7 35.4 34.7 33.7 33.8 34.7 33.6 34.3
5,200 35.3 35.3 34.3 33.5 34.4 34.7 33.6 34.7
5,300 35.4 35.2 34.4 33.6 34.4 34.9 33.5 35
5,400 34.8 35.8 34.4 33.5 35 35 33.4 35.3
5,500 34.7 35.8 34.7 33.7 34.8 34.4 33.7 35.3
5,600 34.7 35.1 34.5 34 34.5 34.1 33.9 35.1
5,700 35.1 34.4 34.4 33.6 34.5 34.2 33.4 34.9
5,800 36 34.1 34.8 33.3 34.9 34 32.9 34.9
5,900 35.5 34 35.1 33 34.6 33.6 33.2 34.9
6,000 35.8 33.5 35.4 33 34.6 33.7 33 35.3
6,100 37 32.9 36 33.3 34.8 34.7 32.3 35.8
6,200 37 32.2 36 33 34.3 35.4 31.4 35.3
6,300 37.3 32.2 36.2 33 34.2 36 31.2 35.5
6,400 37.7 31.8 36.7 32.9 34.3 37.1 31 35.8
6,500 36.3 31.6 37.8 32.1 34.7 37.3 30.6 36.7
6,600 33.9 32.7 37 31.2 35.8 36 30.7 37.4
6,700 32.5 34.9 34.6 32.3 36.6 34.2 31.8 36.9
6,800 31.9 35.3 33.9 33 36.2 33.6 32.2 36.4
6,900 30.7 35.8 33 33.2 36.1 32.7 32 36.6
7,000 31 35.5 33 33.3 35 32.6 32.5 35.3
7,100 33 34.9 33.8 33.6 33.8 33.7 33.7 33.4
7,200 33 35 33.7 33.8 33.8 33.8 34.1 33.5
7,300 32.6 34.8 33.1 33.7 33.5 32.9 34.5 33.4
7,400 32.4 35 32.9 33.3 33.7 32.9 34.2 33.3
7,500 31.7 34.3 33.1 32.6 33.5 32.6 33.6 33.1
7,600 31.1 33.7 33.4 32.2 33.1 32.5 33.4 33.4
7,700 31.1 33.9 33.6 32 33 32.8 33.3 33.5
7,800 31.3 34.2 33.4 31.8 33.2 32.9 33 33.5
7,900 31.5 34.1 33.4 31.9 33.2 33.1 33.1 33.9
8,000 31.6 34.2 34 31.7 33.5 32.2 33.6 33.9

Read more: http://www.circletrack.com/enginetech/c ... z2RRCNGoRr
 
Be interesting to compare all popular makes & types of electronic ignitions & CD capacitive discharge analog & digital boxes Grumpy.
Let the race ignition boxes heat up from room temp to 240 F like actual underhood temps are on a hot summer day or in a race car running flat out to win.
All electronics have circuitry tolerance levels & different methods to control thermal changes, and different methods to control dwell & expand dwell as RPM increases.

Make a check of Old Vertex Magnetos too.
Some favor yet as I do.
Get the neon strobe light unit going in my SUN 400 Distributor machine, new electrolytic capacitors came this week.
Testing of my own.

I like the high resolution inferred optical counter setup on Dortons engine dyno he used for testing.
Pretty neat.
 
Firing Order Swaps: What’s Best For Your Engine?


http://www.enginelabs.com/engine-tech/cam-valvetrain/firing-order-swaps-whats-best-for-your-engine/

A firing order swap is one of those modifications that has become popular based on the potential of an often-corroborated performance upgrade; however, its true value to the engine builder may be obscured by those power promises.



I knew the driver and I wasn’t going to see him get killed.–Billy Godbold, Comp Cams
quote2.png


“The main reason people like the 4-7 swap or the 4-7/2-3 is really about cooling and torsion of the crankshaft,” explains Billy Godbold of Comp Cams. “Other issues involving air and fuel distribution can be addressed with manifold design or in the fuel system. If you hear someone say, ‘I picked up 30 horsepower,’ then they just had the air-fuel all wrong.”


The topic of firing-order swap is rather narrow in the high-performance and racing industry. It’s usually limited to 90-degree V8 engines, both gas and diesel. You rarely hear Nissan GT-R or Buick Grand National owners asking engine builders if there’s a better firing order for their V6 engines. And if they did ask, the answer is likely to be “no.” Same for straight-6s, straight-8s and I4s.

Just what is a firing order swap?

First, we know that a conventional V8 engine is designed to generate a power stroke every 90 degrees of crankshaft rotation. Remember, it’s a 4-stroke engine, so, a full cycle of eight firings requires two complete crankshaft rotations, or 720 degrees (8 x 90 = 720).




Firing order choices in a 90-degree V8 engine are driven by crankshaft design. This is the standard configuration for almost all V8 engines with a cross-plane crankshaft. The #1 and #4 pins are 180 degrees apart, and the #2 and #3 pins are 180 degrees apart. Some race teams have experimented with swapping the position of the #2 and #3 pins, which would generate different firing order possibilities, but no significant advantage was ever discovered. Below is the Ford flat-plane or 180-degree crankshaft found in the GT350 engine. Note the up-down-up-down or ‘snake’ profile. Flat-plane cranks are also available with an up-down-down-up profile for the pins. Again, each change generates different firing order possibilities.



Eight possible firing orders

Most V8 engines have a cross-plane crankshaft, which phases the connecting rod pins at 90-degree intervals. This compares to a flat-plane crankshaft where the pins are phased at 180 degrees. The flat-plane crankshaft style will be discussed later since they’re used only in high-end racing and exotic production vehicles.

Based on an engine configuration of a 90-degree V8 block spinning a cross-plane crankshaft, there are only eight possible firing-order combinations. Actually, there are 16 because GM and Chrysler engines are left-bank forward and the automakers number their cylinders differently than Ford, which is right-bank forward. With a little math and comparison mapping, we can find the common ground for the eight firing orders (see chart below) available to the manufacturers.


The chart shows the eight possible firing orders for a GM V8 engine, with the exception of a Cadillac Northstar–which is right-bank forward for packaging reasons and has a different firing order. The firing order with the asterisk is the one used most often when attempting a bank-to-bank configuration.

Four of these possible combinations are generally thought to be ineffective in performance applications, as they fire four cylinders in various sequence orders on one bank before the four cylinders on the opposing bank are fired. Such a bank-to-bank combustion cycles would create considerable engine shake and therefore is rarely used by engine builders. That doesn’t mean they haven’t been tried. Godbold knows of former a Pro Stock Truck racer and a NASCAR team experimenting with such an order–most likely 1-8-4-2-6-5-7-3. And a Top Fuel team once asked Godbold for a bank-to-bank camshaft, but he was understandably hesitant to turn a 25-foot-long digger into a 10,000-horsepower, 300-mph vibrator.

“Think of all the downforce the exhaust produces on a Top Fuel engine,” reminds Godbold. “Four massive pulses from one side, then four from the other. I knew the driver and I wasn’t going to see him get killed.”


Ford V8 engines typically are right-bank forward and number the cylinders sequentially down the right side and then the left. Most GM engines are left-bank forward and number their cylinders by alternating from bank to bank, going front to rear.
 
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