benefits of sequential + WS/COP ?

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ChevelleFan
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benefits of sequential + WS/COP ?

Post by ChevelleFan »

At what point is it beneficial/not-beneficial to go semi- or full-sequential on fuel and spark? I've got my 383 SBC running very nicely on MS2-Extra and has been for a few years, but I'm just using batch-fire injection and a MS-controlled 8pin HEI & MSD 6AL setup. It has returned good ETs at the dragstrip (low 12s) and good MPGs on the road (15-18mpg) and is all-around enjoyable to drive. On the road, I'm generally under 3000 rpms, and when drag racing, I shift at 6000. What kind of benefits might I see going to wasted spark or COP, along with sequential injection? It kinda feels like it would be a make-work project, but if there would be measurable gains, I'd grab an MS3 and upgrade.

Thoughts/suggestions?

-Dave
'70 Chevelle ZZ383/700r4/3.73 MS3X, 36-1, LS Coils, Holley Stealthram -- success story
'92 Saturn 1.9 DOHC/5sp, MS3, Champcar racer success story
'79 Malibu DartSHP400/80mm/PG/3.55, MS3X/36-1/LS Coils -- success story
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DaveEFI
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Re: benefits of sequential + WS/COP ?

Post by DaveEFI »

The main difference with sequential port injection seem to be at low revs - thing like a better idle and emissions.

Changing from a distributor to a crank based sensor for the tach signal should give benefits in terms of far more accurate timing. And better reliability.

If you go to fully sequential, the normal way would be a crank sensor for the tach signal, and a modified dizzy for the cam position signal.
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ol boy
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Re: benefits of sequential + WS/COP ?

Post by ol boy »

On the spark side like Dave mentioned, COP with a crank wheel is the way to go. I'm running a 306 Ford with LSx COP in waste spark. Only draw back to waste spark is the coils pull a lot of current during dwell. Some have measured 11ish amps at 5ms at 14ish volts for each coil pack(depending on the model type). In waste spark that is 22ish amp spikes once every 90* of crank rotation. As RPM increases you will get into dwell over lap. Now the minimum current draw will be 22 amps with spikes to 44 amps during over lap. This is hard on relays and wiring. I really want to go sequential on the spark just to reduce the current demand. I have reduced the dwell as much as I dare to reduce the electrical demand on the system.
306 SBFord, Torquer II EFI intake, 60 lbs injectors, 8 LS2 coils, VS Racing 7668 turbo, 4R70W, MS3x fw1.4 w/built in trans controller.
benckj
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Re: benefits of sequential + WS/COP ?

Post by benckj »

Why not run sequential fuel with the MS2? Can activate and trim each cylinder fueling through seperate VE tables. The trick is what to adjust them to. I based my settings on 3sgte test results others have done and slightly adjusted when I changed plugs.

Benifits are with trimming each cylinder to avoid detonation. Obviously sequential spark has more power benifits but cannot be done MS2 as far as I know.

Jim
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ol boy
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Re: benefits of sequential + WS/COP ?

Post by ol boy »

benckj wrote:Why not run sequential fuel with the MS2? Can activate and trim each cylinder fueling through seperate VE tables. The trick is what to adjust them to. I based my settings on 3sgte test results others have done and slightly adjusted when I changed plugs.

Benifits are with trimming each cylinder to avoid detonation. Obviously sequential spark has more power benifits but cannot be done MS2 as far as I know.

Jim
because... MS2 only does 4 fuel and upto 6 spark outputs... he is running a SB Chevy V8. 383cid.. aka stroked 350. He could gang a pair of MS2 units together and run the motor as a set of V4's with common crank/trigger wheel.
306 SBFord, Torquer II EFI intake, 60 lbs injectors, 8 LS2 coils, VS Racing 7668 turbo, 4R70W, MS3x fw1.4 w/built in trans controller.
DaveEFI
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Re: benefits of sequential + WS/COP ?

Post by DaveEFI »

ol boy wrote:On the spark side like Dave mentioned, COP with a crank wheel is the way to go. I'm running a 306 Ford with LSx COP in waste spark. Only draw back to waste spark is the coils pull a lot of current during dwell. Some have measured 11ish amps at 5ms at 14ish volts for each coil pack(depending on the model type). In waste spark that is 22ish amp spikes once every 90* of crank rotation. As RPM increases you will get into dwell over lap. Now the minimum current draw will be 22 amps with spikes to 44 amps during over lap. This is hard on relays and wiring. I really want to go sequential on the spark just to reduce the current demand. I have reduced the dwell as much as I dare to reduce the electrical demand on the system.
Interesting. When fitting EDIS8 to my car, it was convenient to use the original single coil power wiring, from the ignition switch. (MS has its own feed) And the highest peak current I saw was 15 amps. Average more like 3 amps.
Rover SD1 3.5 EFI
MS2 V3
EDIS
Tech Edge O2
London UK.
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