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Blown-inj-alky w/msd 7al ign.?

General engine tech -- Drag Racing to Circle Track

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promachine
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Blown-inj-alky w/msd 7al ign.?

Post by promachine »

Anyone here ever try to run a blown alky engine with a MSD ignition? (7al)
Engine is a 565 Chevy , 11.5-1 , conventional head , 1471 , buzzard , Enderlie 110 , Total area is 686 , 15 lbs boost.
We started off with a fat tuneup this morning and tryed working into a nice safe tune but ended up making wholesale changes to try and clean her up.
Finally we got her to go in at 4500 rpm pretty clean , till about 5800 rpm she would go back into a fat blubber. As the fuel presure goes up she just goes to rich. Now , I know how this works , but I have taken so much fuel out of this thing that red flags started going up in my little brain.
145 main , avg. 039 nozzles in the hat , avg. 046 nozzles in the ports.
58 lbs. fuel press @ 5800 rpm , I know , I think it a little low too , but should come up to about 100 lbs. at 7500 rpm , still lower than I would like , but thats why I stoped the session .
I could add a high speed but I think it will take more than that.
So , do you all think I need the mag for the extra juice to fire this pig , be it a points mag or maybe an MSD mag. Or should the 7AL fire this thing?
Plug gap .045
timing @ 35 d
voltage to the box @ 13.8 volt constant
I think the customer should bring me a mag or let me put one of mine in it for testing.
h.p. peddler
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Dave Koehler
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Re: Blown-inj-alky w/msd 7al ign.?

Post by Dave Koehler »

Plug gap too big. Bring her down to .020
Based on your other components get a Mag20. The difference will be noticeable.
Dave Koehler - Koehler Injection
Enderle Fuel Injection - Nitrous Charger - Balancing - Nitrous Master software
http://www.koehlerinjection.com
"Never let a race car know that you are in a hurry."
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Re: Blown-inj-alky w/msd 7al ign.?

Post by revolutionary »

I have a customer who ran a 6al(!!!) on a 555 with an 8-71 in a dragster running top sportsman/super comp (6.90~200 so not near the power you are talking)and ran that for 3 years before I finally talked him into a 7AL3. That being said, I think the 7al would work ok but it is not what I'd use. Either the ICE ignition 10 amp (preferably) or an MSD 8 would work. Still I'd close the gap like was mentioned above.
Daryl

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raynorshine
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Re: Blown-inj-alky w/msd 7al ign.?

Post by raynorshine »

Dave Koehler wrote:Plug gap too big. Bring her down to .020
Based on your other components get a Mag20. The difference will be noticeable.
yes!!!!!!!!!!!!!!!
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dan miller

Re: Blown-inj-alky w/msd 7al ign.?

Post by dan miller »

Hello John

I have an MSD8 that you're welcome to borrow. Danny
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Re: Blown-inj-alky w/msd 7al ign.?

Post by In-Tech »

promachine wrote:Anyone here ever try to run a blown alky engine with a MSD ignition? (7al)
Engine is a 565 Chevy , 11.5-1 , conventional head , 1471 , buzzard , Enderlie 110 , Total area is 686 , 15 lbs boost.
We started off with a fat tuneup this morning and tryed working into a nice safe tune but ended up making wholesale changes to try and clean her up.
Finally we got her to go in at 4500 rpm pretty clean , till about 5800 rpm she would go back into a fat blubber. As the fuel presure goes up she just goes to rich. Now , I know how this works , but I have taken so much fuel out of this thing that red flags started going up in my little brain.
145 main , avg. 039 nozzles in the hat , avg. 046 nozzles in the ports.
58 lbs. fuel press @ 5800 rpm , I know , I think it a little low too , but should come up to about 100 lbs. at 7500 rpm , still lower than I would like , but thats why I stoped the session .
I could add a high speed but I think it will take more than that.
So , do you all think I need the mag for the extra juice to fire this pig , be it a points mag or maybe an MSD mag. Or should the 7AL fire this thing?
Plug gap .045
timing @ 35 d
voltage to the box @ 13.8 volt constant
I think the customer should bring me a mag or let me put one of mine in it for testing.
If you have a decent mag to throw at it, do it to eliminate a variable. I don't think the 7 will keep up with the mag but it should be within reason once the tune is closer.

.145 main :shock: w/.039 and .046. I'm sure you know not all 110's are created equal :wink: I know you're a world record holder and very knowledgeable but sometimes we all forget the dyno vs acceleration factor when we think about fueling MFI. I'm really curious to see what you find. I would think the alcohol rich condition would like a longer duration spark that the mag would give. I've never had the opportunity to find out. Known good mag would also eliminate bad msd coil or polarity reversal on the 7's crank trigger if you haven't checked that yet.

Let us know.
Heat is energy, energy is horsepower...but you gotta control the heat.
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Re: Blown-inj-alky w/msd 7al ign.?

Post by Blown526 »

Was told msd 7al wasn’t enough to run a blown engine up there in revs, especially with a big blower. But also wanted to know if u can get a msd 7al hopped up to an msd 8? Thx
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Re: Blown-inj-alky w/msd 7al ign.?

Post by Dave Koehler »

Blown526 wrote: Tue Oct 13, 2020 7:52 pm Was told msd 7al wasn’t enough to run a blown engine up there in revs, especially with a big blower. But also wanted to know if u can get a msd 7al hopped up to an msd 8? Thx
No sir. Different animal.
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Re: Blown-inj-alky w/msd 7al ign.?

Post by Dave Koehler »

While I tout mags as best for alky use there are boxes strong enough to handle almost everything.
Everyone should remember when trying to ignite uber high compression or boosted combos that the downfall to boxes is keeping the voltage up at the box.
An alternator is pretty much a must have to ensure success.
Do you want to run an alternator?

Without an alternator.
Will you load check your battery often? Electronic testers work best for tracking battery capacity.
Will your battery have enough grunt to start it on a grumpy day and still have enough left over to launch the car?
Dave Koehler - Koehler Injection
Enderle Fuel Injection - Nitrous Charger - Balancing - Nitrous Master software
http://www.koehlerinjection.com
"Never let a race car know that you are in a hurry."
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Re: Blown-inj-alky w/msd 7al ign.?

Post by rebelyell »

CD box "masseur"
Nelson Crozier at Mooresville NC
http://www.nelsonspecialties.com/
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