Dual sync distributor

Bobby Fazio · 03-30-2015, 04:02 PM

Does anyone know what rpm these go to in sequential fire using both crank and cam sensor? My car breaks up right before finish line, and in good air like Charlotte this weekend, even earlier in the run because the rpm wanted to climb. Happens right around 6500rpm, little blips here and there. Everything checks out.

03-30-2015, 04:33 PM

Quote:

Originally Posted by Bobby Fazio

Does anyone know what rpm these go to in sequential fire using both crank and cam sensor? My car breaks up right before finish line, and in good air like Charlotte this weekend, even earlier in the run because the rpm wanted to climb. Happens right around 6500rpm, little blips here and there. Everything checks out.

Sounds like maybe a bit of valve float. IMHO

ss3011 · 03-30-2015, 05:04 PM

What type of ignition, and what rev limiter chip do you have in it ?

magnumv8 · 03-30-2015, 05:38 PM

while I can't say what rpm they are good for I do know that I was told to use a crank trigger and not use the crank signal from my dual sync....
Rich Nedbal of Fastman Efi said it would not be as accurate as the crank trigger.....

D L Rambo....Stk 1300

Bobby Fazio · 03-30-2015, 05:57 PM

Quote:

Originally Posted by ss3011

What type of ignition, and what rev limiter chip do you have in it ?

Crane HI-6 with LX92 coil. That only has one rev limiter and that is set for the starting line launch. The EFI has a high side that I have set at 7500 that I raised to see if that had any impact.

countrypuppy4865 · 03-30-2015, 06:56 PM

Bobby,

When in sequential mode it is not triggered by RPM. It will be active at all times.

Bobby Fazio · 03-30-2015, 08:47 PM

Quote:

Originally Posted by countrypuppy4865

Bobby,

When in sequential mode it is not triggered by RPM. It will be active at all times.

Hey cooter are you talking about the rev limiter?

buzzinhalfdozen · 03-31-2015, 09:08 AM

Bobby, in my opinion the best place to create an ignition signal is at the crank. Using the dist. can induce a fluctuation in the signal due to many factors such as chain or belt whip, plus the gear interface of the cam and dist. gear, compounded if you're also driving the oil pump. looks like you could install a standard crank trigger set up and still use the cam sync input from the dist. for sequential. I wouldn't think the real issue is the actual RPM of the engine but more a result of all the potential lash in the system. Most dist. based cam syncs will vary a degree or two simply due to the lash in the system. Good luck Joe BTW this is all assuming that the dual sync is the actual problem.

Bobby Fazio · 03-31-2015, 11:04 AM

"Crank trigger systems prohibited unless OEM distributorless ignition." Believe me I want to.

buzzinhalfdozen · 03-31-2015, 11:30 AM

Bobby, I've never used one of the dual sync set ups....what type of trigger is being used? Are both sensors the same (Hall effect,or VR type) ? Also your EFI controller does it have datalogging? If so does it indicate unusual engine speeds when the issue arises or a big change in injector pulse width? Or do you have other datalogging (racepak Ect.) that may show an unsteady RPM? I would think that if the crank trigger portion of the unit were acting up it would show up on a datalogger as a drop or spike in engine RPM. Joe

03-30-2015, 04:02 PM	#1
Bobby Fazio VIP Member Join Date: Nov 2009 Location: Egg Harbor Township, NJ Posts: 1,463 Likes: 1,414 Liked 4,354 Times in 497 Posts	Dual sync distributor Does anyone know what rpm these go to in sequential fire using both crank and cam sensor? My car breaks up right before finish line, and in good air like Charlotte this weekend, even earlier in the run because the rpm wanted to climb. Happens right around 6500rpm, little blips here and there. Everything checks out. __________________ '65 Mustang SS/L & L/SA DriverInterviews.com \| App.DragInsights.com

03-30-2015, 05:04 PM	#3
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 903 Likes: 69 Liked 237 Times in 112 Posts	Re: Dual sync distributor What type of ignition, and what rev limiter chip do you have in it ?

03-30-2015, 05:38 PM	#4
magnumv8 Member Join Date: Feb 2009 Location: Coraopolis, Pa. Posts: 172 Likes: 0 Liked 0 Times in 0 Posts	Re: Dual sync distributor while I can't say what rpm they are good for I do know that I was told to use a crank trigger and not use the crank signal from my dual sync.... Rich Nedbal of Fastman Efi said it would not be as accurate as the crank trigger..... D L Rambo....Stk 1300

03-30-2015, 06:56 PM	#6
countrypuppy4865 Senior Member Join Date: Nov 2003 Location: Donaldsonville, LA Posts: 977 Likes: 17 Liked 227 Times in 69 Posts	Re: Dual sync distributor Bobby, When in sequential mode it is not triggered by RPM. It will be active at all times. __________________ Jimmy "Cooter" Hidalgo, Jr. 4865 E/SA '04 GTO 4865 SS/GA '99 Firebird

03-31-2015, 09:08 AM	#8
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Dual sync distributor Bobby, in my opinion the best place to create an ignition signal is at the crank. Using the dist. can induce a fluctuation in the signal due to many factors such as chain or belt whip, plus the gear interface of the cam and dist. gear, compounded if you're also driving the oil pump. looks like you could install a standard crank trigger set up and still use the cam sync input from the dist. for sequential. I wouldn't think the real issue is the actual RPM of the engine but more a result of all the potential lash in the system. Most dist. based cam syncs will vary a degree or two simply due to the lash in the system. Good luck Joe BTW this is all assuming that the dual sync is the actual problem. __________________ Joe Buchanan SS/BX 3117 Last edited by buzzinhalfdozen; 03-31-2015 at 09:22 AM.

03-31-2015, 11:04 AM	#9
Bobby Fazio VIP Member Join Date: Nov 2009 Location: Egg Harbor Township, NJ Posts: 1,463 Likes: 1,414 Liked 4,354 Times in 497 Posts	Re: Dual sync distributor "Crank trigger systems prohibited unless OEM distributorless ignition." Believe me I want to. __________________ '65 Mustang SS/L & L/SA DriverInterviews.com \| App.DragInsights.com Last edited by Bobby Fazio; 03-31-2015 at 11:11 AM.

03-31-2015, 11:30 AM	#10
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Dual sync distributor Bobby, I've never used one of the dual sync set ups....what type of trigger is being used? Are both sensors the same (Hall effect,or VR type) ? Also your EFI controller does it have datalogging? If so does it indicate unusual engine speeds when the issue arises or a big change in injector pulse width? Or do you have other datalogging (racepak Ect.) that may show an unsteady RPM? I would think that if the crank trigger portion of the unit were acting up it would show up on a datalogger as a drop or spike in engine RPM. Joe __________________ Joe Buchanan SS/BX 3117