Hemi guru's
#1777943
03/12/15 05:05 PM
03/12/15 05:05 PM
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Joined: Sep 2006
Posts: 1,132 Home of the Bluegrass
MoparJunkie
OP
super stock
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OP
super stock
Joined: Sep 2006
Posts: 1,132
Home of the Bluegrass
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I am trying to get a good baseline distributor curve and timing setup for my 472 which has: 2/4 street hemi intake Eddy 600's MP aluminum heads(the latest greatest ones) 10.5 compression comp cam 248@.050 duration 582/563 lift on 108 LSA and centerline. Running 2 1/8 TTI's through full 3" exhaust. What are the suggestions for timing curves and total...ie intiial, mechanical and when all in??? TIA
"It takes a Mopar to catch a Mopar” 1971 Roadrunner FJ6 Sassy Grass 505"RB, 18 spline 4 speed, and Dana 60 with 3.54 2022 Hellcat Charger Widebody Redeye Jailbreak: Hellraisin with 8 speed auto
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Re: Hemi guru's
[Re: MoparJunkie]
#1777945
03/12/15 06:54 PM
03/12/15 06:54 PM
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Joined: Aug 2003
Posts: 43,230 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,230
Bend,OR USA
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The best total timing(max advance) will be determined by the fuel type and quality,fuel jetting, AFR tune up, altitude and spark plug heat range The higher the altitude them more timing you can use, the hottor the plug the easier it is to get the motor to detoanate, same thing on the air fuel ratio and gasoline quality What altitude are you driving the car at the most? What type(E10,E15, non ethanol) and octane gasoline are you using and what brand and heat range spark plug are you using?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Hemi guru's
[Re: Cab_Burge]
#1777946
03/12/15 07:31 PM
03/12/15 07:31 PM
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Joined: Sep 2006
Posts: 1,132 Home of the Bluegrass
MoparJunkie
OP
super stock
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OP
super stock
Joined: Sep 2006
Posts: 1,132
Home of the Bluegrass
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Obviously I have to start somewhere, and that's why this post was written. I am at about 1000 ft elevation in central Ky. I am gonna start with autolite AR53's. So, that being said... any suggestions for a baseline? I'm leaning on 32 total, but was wondering about a good start for initial then I know how much mechanical. The hydraulic FT cam grind makes power from 2500-6500. So, again my question for good start suggestions of all in by???? Most gas is E10 here...
"It takes a Mopar to catch a Mopar” 1971 Roadrunner FJ6 Sassy Grass 505"RB, 18 spline 4 speed, and Dana 60 with 3.54 2022 Hellcat Charger Widebody Redeye Jailbreak: Hellraisin with 8 speed auto
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Re: Hemi guru's
[Re: mickm]
#1777947
03/12/15 07:54 PM
03/12/15 07:54 PM
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Joined: Jan 2010
Posts: 311 Kingsville, Md
grncpe
enthusiast
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enthusiast
Joined: Jan 2010
Posts: 311
Kingsville, Md
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Quote:
18-20 initial, all in by 2500 at most, 32 total.
start there. in general hemi's like less total, but some combinations do like more.
This
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Re: Hemi guru's
[Re: MoparJunkie]
#1777950
03/12/15 09:32 PM
03/12/15 09:32 PM
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Joined: Mar 2010
Posts: 984 Tennessee
Hemi ragtop
super stock
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super stock
Joined: Mar 2010
Posts: 984
Tennessee
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Since you asked, and I have a VERY similar combo and car weight and since I have been "through it" with the timing, let me share with you what I found. First, with the exception of our trans, (I have a 727/Gear Vendor w/3,000 converter), our cars are very much the same. In my experience, you don't have a CLUE where your timing is until you verify it YOURSELF! First thing, where is top dead center on #1. Think about it, did your balancer, timing chain cover come off the assembly line together? If they did are they accurate? Mine came from a hodge podge of parts. My "professional" engine builder said that when we dynoed the engine it made more power @ 32 degrees vs. 34 degrees. 635HP@ 5,900 rpm. WRONG! When I put it in the car and started driving it,it didn't "feel" right so I checked the true TDC with a piston stop that I made from an old plug. I am embarrassed to tell you how many degrees it was off! Lesson one, don't ASSUME ANYTHING!. So first thing is, KNOW where TDC #1 REALLY is! Step #2, your engine will TELL you how much initial timing it wants, with a warm engine, use a vacuum gauge on a MANIFOLD port. Increase timing until the gauge is "topped out". Then adjust idle circuit until gauge it at highest point. THEN check initial timing @ idle. Then slowly with no load, increase rpms until you see the total timing and at what rpm. If it is over 35, you will have to limit the curve. I won't go into that as I am already "long" on this post and I don't know what kind of distributor you have. I had to take mine apart, weld shut the advance slots, check, pull, grind weld slowly, and check again etc. A long process but, when I was done, I found my engine liked 35 TRUE degrees total and 20 degrees at 1,000 rpm idle. After driving it "before" and "after", I am SHURE that I am making at least what the dyno showed!
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Re: Hemi guru's
[Re: Hemi ragtop]
#1777951
03/12/15 09:50 PM
03/12/15 09:50 PM
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Joined: Mar 2010
Posts: 984 Tennessee
Hemi ragtop
super stock
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super stock
Joined: Mar 2010
Posts: 984
Tennessee
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Post note: How fast should the curve be? In other words, at what rpm should your timing be "all in"? You have a 4 speed. A clutch loads the engine totally different than a converter. Then your driving style. Do you tend to "lug" the engine to keep from shifting so much? Mine liked to be "all in" at 2,500rpm, but yours may need to be higher. Listen carefully, check plugs for shiny spots, DO NOT DETONATE THE ENGINE! Then the most argued point, do you or don't you run vacuum advance? I do, my engine has 45+ degrees WITH vacuum advance with no load, trust me, it LOVES IT at part throttle "tip in". By the way, I am not a "guru" just a basement built "hot rod".
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Re: Hemi guru's
[Re: RUNCHARGER]
#1777952
03/12/15 10:24 PM
03/12/15 10:24 PM
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Joined: Sep 2006
Posts: 1,132 Home of the Bluegrass
MoparJunkie
OP
super stock
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OP
super stock
Joined: Sep 2006
Posts: 1,132
Home of the Bluegrass
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Sheldon, I need to get with you on jet selection and springs. As I saw your post about your setup.
Last edited by gg70rtUcode; 03/12/15 10:30 PM.
"It takes a Mopar to catch a Mopar” 1971 Roadrunner FJ6 Sassy Grass 505"RB, 18 spline 4 speed, and Dana 60 with 3.54 2022 Hellcat Charger Widebody Redeye Jailbreak: Hellraisin with 8 speed auto
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Re: Hemi guru's
[Re: RUNCHARGER]
#1777956
03/13/15 12:25 AM
03/13/15 12:25 AM
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Joined: Sep 2006
Posts: 1,132 Home of the Bluegrass
MoparJunkie
OP
super stock
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OP
super stock
Joined: Sep 2006
Posts: 1,132
Home of the Bluegrass
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Thanks Sheldon. You da man!
"It takes a Mopar to catch a Mopar” 1971 Roadrunner FJ6 Sassy Grass 505"RB, 18 spline 4 speed, and Dana 60 with 3.54 2022 Hellcat Charger Widebody Redeye Jailbreak: Hellraisin with 8 speed auto
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Re: Hemi guru's
[Re: 71birdJ68]
#1777959
03/15/15 01:37 PM
03/15/15 01:37 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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What steps will help you avoid a woman pulling out or making a left turn in front of you, in order of results (best first)? 1. Mars light 2. 150 db horn 3. brights on 4. be 20 feet high, 30 feet wide, and on fire
I have an intermittent flashing headlight on my Harley Fat boy, and I can tell you that many, many drivers look at me, don't see me, and start to pull out. Then the flash catches them and the nose sags as they brake. Personally, I'd put a 10mm warning shot through their windshield but that simply trades being dead for a different problem.
Wait! Exception: anyone who causes an accident by texting should be burnt alive in her car.
Boffin Emeritus
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Re: Hemi guru's
[Re: MoparJunkie]
#1777961
03/16/15 09:06 AM
03/16/15 09:06 AM
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Joined: Mar 2006
Posts: 9,910 Eighty Four, PA
B G Racing
master
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
I am trying to get a good baseline distributor curve and timing setup for my 472 which has: 2/4 street hemi intake Eddy 600's MP aluminum heads(the latest greatest ones) 10.5 compression comp cam [Email]248@.050[/Email] duration 582/563 lift on 108 LSA and centerline. Running 2 1/8 TTI's through full 3" exhaust. What are the suggestions for timing curves and total...ie intiial, mechanical and when all in??? TIA
This combo should not exceed 35* and you want the full advance as soon as possible.
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