Bracket Talk
Can you run on 7 cylinders?

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https://drr.infopop.cc/eve/forums/a/tpc/f/80760912/m/4447091296

December 19, 2019, 05:22 PM
Fatboy81
Can you run on 7 cylinders?
I know this sounds crazy but I have a son that is learning to drive. He has ran 10.75 before in his sisters truck but she’s going to want to run also. My car runs 9.60s but I can’t have him running that fast. I was watching Engine Masters the other day and they built a 200mph engine they they planed to set some records with and for one record they planed to disable a cylinder to run in a smaller cubic inch class too. I’m not sure how they planed to do that but it got me thinking. Can I just pull the wire off the number#1 cylinder without hurting anything. I know it will file the plug but I can swap it out later.
December 19, 2019, 05:41 PM
sr4440
Pulling the wire would not be good, the spark is going to go somewhere. I would ground the electrode on the plug instead. That being said, I would lengthen the throttle cable so the blades only open about 30%, if i wanted to train someone to drive.

Joe


Without data, you’re just another guy with an opinion.
December 19, 2019, 05:58 PM
Larry Woodfin
consider a small two-barrel carb or disconnect the secondary on a small four-barrel

I think running with a dead cylinder has potential problems like fuel dilution and inconsistency


Larry Woodfin



December 19, 2019, 07:31 PM
RacerVX54
AHH NO...


"Just Shut Up and Race"

Brian Martin
Martin Racing
5.66 @121.55
December 19, 2019, 08:12 PM
Fatboy81
quote:
Originally posted by Larry Woodfin:
consider a small two-barrel carb or disconnect the secondary on a small four-barrel

I think running with a dead cylinder has potential problems like fuel dilution and inconsistency


I ran a two barrel with my little girl when she was learning to race but the car has a 4500 flange carb so I’m limited to what I can put on it. My try to disconnect the back barrels. I hate to do that because the extra vacuum pulls more fuel so you have to drop the jets a good bit
December 19, 2019, 08:16 PM
Brktracer
Disconnect the secondary. Will need to lower shift rpm appropriately. It should slow down about .5


Matt Ward



December 19, 2019, 09:27 PM
Larry Woodfin
Fatboy,

just a suggestion, use a 1/2" thick aluminum plate to adapt a two-barrel to the 4500 flange.

Even have a local water jet cutting shop build it for you.


Larry Woodfin



December 19, 2019, 09:42 PM
chasracer
Put a mechanical throttle stop on it - it's just a piece that mounts off the carb flange and allows you to manually adjust how far the carb can open.

Jegs has them, about $32 - 710-65042 is the part number.

Reducing the timing will take power out of it too.
December 19, 2019, 10:06 PM
Fatboy81
quote:
Originally posted by chasracer:
Put a mechanical throttle stop on it - it's just a piece that mounts off the carb flange and allows you to manually adjust how far the carb can open.

Jegs has them, about $32 - 710-65042 is the part number.

Reducing the timing will take power out of it too.


I never knew they sold these! Thanks guy!
December 20, 2019, 05:35 AM
BJs Wild Ride
I redid a bunch of stuff on my dragster one winter. Ran 5.18 when I parked it, 5.65 when I brought it back out. Couldn’t figure it out so raced it anyway. Did pretty good as it was printing tickets.

After I lost I started checking everything again to find the missing 1/2 second. Turned out I had landed an intake pushrod (#4 I think) on the lifter valley instead of in the lifter. Stud rockers obviously.

I’m not sure how long you could do that before it would hurt a lifter somehow but it made it ~6 passes just fine that day.
December 20, 2019, 05:42 AM
sr4440
quote:
Originally posted by Fatboy81:

I hate to do that because the extra vacuum pulls more fuel so you have to drop the jets a good bit


On the dyno I tune all 4 barrel carbs 2 barrels at a time and have NEVER seen this.

Joe

Edit: I don't tune blow-thru turbocharged 4 barrels on 2 barrels.


Without data, you’re just another guy with an opinion.
December 20, 2019, 06:46 AM
Busted Knuckles
Pull some timing out and limit throttle travel.


Organized people are just too lazy to look for their $h!t.
December 20, 2019, 10:07 AM
FootbrakeJim
Or get an Edelbrock # 8716 adapter, to mount a 4150 style carb on a Dominator intake. Under $70.
I did that, and used an 850, didn't kill as much as I hoped. But a 750 sure will!


Dan "Jim" Moore
Much too young to feel this damn old!!
December 20, 2019, 10:59 AM
gxp7903
tight converter and secondary's discounted will slow it down a lot. that's how I started.
December 20, 2019, 12:42 PM
1leg
On the Bonneville motor they would also have to remove the push rods and rockers on the disabled cylinder.
I recommend limiting the throttle travel, reduce the timing and short shifting. Going to be easier to switch back when you need to.


Meziere Tech.
Make sure your water pump is on whenever you check your coolant level.
December 20, 2019, 03:46 PM
Fatboy81
Gotcha! Thanks for all the help!
December 20, 2019, 09:25 PM
Ron C.
Just run the car in high gear only. Had two grandkids that went from Jr Dragster to blown alcohol dragster. Just used high gear only until they got caught up,.....which didn't really take very long.


Fellow racer and servant of the Lord of Lords
John 14:6
"Creekside Racing Ministry"
MFI system, ProCharger Non-intercooled [6.02 @ 229 or 3.91/660' soft tune and killing power above 6K rpm]
Ron Clevenger
December 21, 2019, 07:01 AM
TPaton
On my camaro, i short shifted from 7k to 5500, and disconnected the secondaries on my 750 holley, and it killed .75 seconds in the 1/4.. we used to run it in. Street 13.00 limit and modified. Worked well
December 21, 2019, 07:24 AM
67 Goat
Do not run any engine on 7 cylinders, it will run terrible, not be consistent, and can possibly do damage.