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Re: What timing are you running on your 512? [Re: mopar dave] #2679261
07/19/19 11:02 PM
07/19/19 11:02 PM
Joined: Mar 2009
Posts: 2,457
Sydney,Australia
tex013 Offline
top fuel
tex013  Offline
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Joined: Mar 2009
Posts: 2,457
Sydney,Australia
Originally Posted by mopar dave
Yeah, I agree cab. My right foot is part of the problem, but I return from a short cruise with a big smile every time. Torque is cool. My cruise AFR is 13.5 on average. Think I can clean that up with IFR and T-slot jets.


A lot will depend on fuel and carb type .
My 505 runs 13.2-13.5 @ cruise . It will hunt lean at 13.7 .
T slot changes only seem to be required on 4500 carbs .
As others have said before give the motor what it needs , dont chase the mythical number .
With my 29" street tyre , 4.1 gear and 6000 stall i cruise @ 3250 = 63mph thereabouts . Mostly our highway limits are 61mph (100kph) occassionally 65(110kph)
I get 8-9ish mpg daily 10-12ish highway . At 3500 (110kph) it all goes to #ell .
You want economy buy a Hyundai 😂

Tex


New best ET 10.259@129.65 .
New best MPH 130.32
Finally fitted a solid cam,
stepped it up a bit more
3690lbs through the mufflers
New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm
Power by Tex's Automotive
Re: What timing are you running on your 512? [Re: tex013] #2679418
07/20/19 12:45 PM
07/20/19 12:45 PM
Joined: Jul 2007
Posts: 1,682
Philadelphia
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radar Offline
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Philadelphia
Two things- first unless I missed something nobody mentioned welding up the slots in a stock distributor plate to limit the advance. Second- here is the timing chart for my sniper/hyperspark 512 timing. If you’re not used to kpa instead of inches of vacum look it up it’s an easy conversion. My motor is super happy with this table downloaded to the ecu. It is a holley table that I copied from the free ‘v4’ efi software download and pasted into the sniper program. We tweaked it a little on the dyno but just plugging it in made the torque curve look like a plateau instead of bumpy steps. You might think it doesn’t apply to you but there is a ton of good info here and values that you can target with a mechanical setup.

532CA8E9-03DD-4E12-B8BB-E505533ED08D.jpeg
Re: What timing are you running on your 512? [Re: radar] #2679455
07/20/19 02:32 PM
07/20/19 02:32 PM
Joined: Aug 2003
Posts: 8,779
Mt.Gilead, Ohio
OhioMopar Offline OP
master
OhioMopar  Offline OP
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Posts: 8,779
Mt.Gilead, Ohio
I think he was talking about the transfer slots in a 4500 flange carb. But I could be wrong.


1969 Dart GTS 340
1969 Super Bee X9 N-96
1969 Coronet R/T X9 N-96
2015 Dodge Dart GT
2019 Ram 2500 Big Horn.
Looking for the original block for my Bee. The last 4 are 7449
Re: What timing are you running on your 512? [Re: OhioMopar] #2679610
07/21/19 12:04 AM
07/21/19 12:04 AM
Joined: Jul 2007
Posts: 1,682
Philadelphia
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radar Offline
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Philadelphia
Well your 512 timing thread did take a left turn into fuel milage and cruise circuit tuning but I was not talking about fuel. (Although I never heard of changing the transfer slot- why would you do that when you can just alter the mix going to it with the ifle feed restriction and air bleeds?)

I was talking about taking a stock distributor and welding/brazing the slots in it shorter so that you can run less mechanical advance as in 24 at idle and 34 at wot. Combined with spring & vac pot selection and limiting you can dial it in pretty decent. If your motor wants a lot of initial you’ll still need a retard box to start it or a starter button separate from the ignition switch (get it spinning then light it off) to avoid kickback or slow hot starts. The hyperspark does all that for you but there are cheap ways to DIY that just take some more work.

Re: What timing are you running on your 512? [Re: radar] #2679621
07/21/19 01:15 AM
07/21/19 01:15 AM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
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Joined: Aug 2003
Posts: 43,007
Bend,OR USA
A lot of the older drag race Holley carbs, especially the first gen Dominator, where flat pig rich in the transfer circuit so leaning that circuit down insured keeping the spark plugs a lot cleaner when driving back to the pits up scope


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: What timing are you running on your 512? [Re: OhioMopar] #2679656
07/21/19 08:43 AM
07/21/19 08:43 AM
Joined: Jan 2007
Posts: 8,027
Mt Morris Michigan
mopar dave Offline
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Posts: 8,027
Mt Morris Michigan
What's worked best with my 511 so far is 36* read from the plug. No track time yet. Cruise 13.5 AFR,s with a 1150 Dominator.

Re: What timing are you running on your 512? [Re: radar] #2679660
07/21/19 08:51 AM
07/21/19 08:51 AM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline
Taking time off to work on my car
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Posts: 15,439
Val-haul-ass... eventually
Originally Posted by radar
Well your 512 timing thread did take a left turn into fuel milage and cruise circuit tuning but I was not talking about fuel. (Although I never heard of changing the transfer slot- why would you do that when you can just alter the mix going to it with the ifle feed restriction and air bleeds?)

Adding a restrictor to the transition slot passage gives you another tuning parameter. You can have the IAB and IFR right, but the sweet spot for the transition from the idle circuit to the main circuit is rich. I don't know about 4500s, but the 4150s I have with open transition slot passages are close to .120". Bringing that down to about .080" helps lean out that point so the transition is cleaner.

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