timing on 29 °

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by danny, Aug 3, 2007.

  1. danny

    danny compet elimin

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    What's the max timing to shoot for on a 526 ci KB with BAE fuel heads/psi blower/44 mag/ 9000 rpm on engine and no six shooter or fuel timers just the basic setup.
    We are @ 29 ° advance but seen pro mods set up to 36 °? Thanks danny
     
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  2. blwnaway

    blwnaway Member

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    I have never seen an alcohol car at 36 degrees. A Veney headed engine up to 31 and a BAE headed engine up to 27 is as far as I have seen them go, is this a single mag or dual?
     
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  3. Rapid Randy AA/FA

    Rapid Randy AA/FA Comp Eliminator

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    Danny,

    How big are the chambers in those heads?

    Rapid
     
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  4. eli

    eli Banned

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    If your running 170 cc heads, you can run up to 36 deg. I asked BAE this question for the fat head set up, and the answer was two mags 25 deg. one mag 30 deg. e-mail him he's there to help you if you got his stuff. I'm sure he wont lie to you like every one dose, it makes that motor come to life you will have to richen it up a bit.;)
     
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  5. lugnut

    lugnut Member

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    We Never Tried To Run Our Timing That High ,29 Was About Our Max.if You Do I Would Think Your Compression Is Going To Need To Be On The Lower Side,my Guess No Higher Than 10.8
     
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  6. 23T Hemmee

    23T Hemmee Member

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    Danny,
    Lugnut hit on the main issue and that is the need to know how much compression you've got along with the amount of boost the PSI is putting out. I've run as much as 37 degrees in a fast index drag boat years ago, with a 11:1 1/2" crank combo with a 10-71 at 38% over, 170cc heads. I'm running 30 degrees in a Veney head 541 in my altered and still feeling it out. If you're running 29 degrees now and not burning plugs or other neccessary parts, might bump timing up 2 degrees at a time instead of making any other drastic changes and see where your plug readings take you. No two engines are the same, sounds like you've got a baseline, take small steps, a lot better to burn plugs than valves and pistons.
     
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  7. danny

    danny compet elimin

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    We have 180 cc BAE proto heads with single sparkplug and a 44 mag, compress is 10.8 and blower boost is between 47 and 52 psi.
    We use the n° 10 ngk parklugs gapped @ .014
    Our 60 ft times are still above 1 sec and we need to do something because we only have one chance, there's only one race left for this year.
    We wanted to go to 32 ° advance ans see how the engine responds to it.
    Our exh temps are between 940 and 1170 ° and we are still working on it but time is runnig out.
    We want to have a high 5 sec :D run this year because the rest is runnig in the high 5's to 5.7 sec and if we are not going to be faster we will be kicked out every firts round,no fun:mad:.
    It's our first year in the european championship and we still have a lot to lurn and need to run guy's that are in it for more then 10 years.
    On the 15 aug we are going to germany and try to run more advance and see if it works out and this way we don't need to wait and do it @ the races.We have no track in belgium to test the car out we have to do it @ the races:(. Grtz danny
     
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  8. 23T Hemmee

    23T Hemmee Member

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    Danny,

    My engine combination is pretty old school so I'm almost afraid to recommend too much as I'm running a lot less boost with a Supermag III so what works for me may not for you. There are a lot of guys on here with a lot more experience with the hotter ignitions and hi dollar blowers than me but I believe you could go 32 degrees safely, but keep a real close eye on the plugs. I know its not much fun taking small steps when you're having to do it in competition but its a lot better than scooping chips out of your oil pain. BTW is that .014 plug gap a US or Metric measurement? If US, that seems awfully tight.
     
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  9. TAFC 5 81

    TAFC 5 81 Member

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    Let me ask a dumb question. Is this 27-29 degree timing due to a more potent mag? Because 25-30 years ago 36-40 degrees (Vertex or Super Mag II) was common then.
     
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  10. lugnut

    lugnut Member

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    We Ran Exact Same Same Stuff, And Could Consistently Run Low 5.90's Occasionally 80's.i Dont Really Think You Need To Run Your Timing That High To Achieve What Your Looking For.whats Your Leave Rpm's,boost At Leave Rpm's & Your Temp Average At Leave Rpm's. Are You Staging Shallow To Get A Running Start At Lights.also We Have Had Problems Running Good 60' If We Had Any Cylinders Out At Leave Rpm's.
     
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  11. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    timing

    danny,

    there is a lot of knobs you can turn to hop a blown alky car up, and of all of them, timing can tear up a lot of parts in a hurry.

    if you want the car to leave harder, i would recommend a low gear leanout as described in the psi manual. it's very simple to install. you need to get a normally open valve and a jet holder (see www.rbssuperchargers.com for equipment) and plumb it into your system. hook the normally open valve to the button you make the 1-2 shift with, so that it closes that leanout when you shift into second gear. start out with a 45 to 50 jet and hang on.

    while i would be very, very careful putting more timing to it than 29 degrees, in a psi application, i would creep up on it in half degree incriments, and no more. half a degree will make a difference. when you start getting too much timing, you're robbing hp due to the detonation. even if you just have a little too much timing and not hurting parts, i still think you're robbing hp.

    it's the same way with fuel. it's much easier and way cheaper to creep up on the tuneup from the conservative side down. when you take what so and so said and start out way too lean or way too much timing, it's much more expensive to work your way up to safe than down.

    also, egt's should not be your primary measure of how lean your motor is. there's 3 ways to measure....plugs, bearings, then egt's. the plug and bearing won't lie to you. the egt will. there are a number of different reasons that will make an egt lie to you. if it's too rich or way low on timing, the fuel will fire in the pipe making it read warmer than it is. if you search 'reading spark plugs' on this site, mike canter has a good article about it. also, check both the width at the bottom of your bearing and the end to end clearance. a hard bearing won't move as much at the bottom of the bearing, but will show when it's getting beat on by 'shrinking' it's end to end clearance. a hemi rod journal is 2.500. i typically don't like to run a bearing that gets below this number. you can bend it out slightly with your hand, but that metal has some memory to it. when it loses it's clamping strength by getting too small, it's going to be more prone to spin.

    hope that helps, let me know if i can help any more. email me at will.hanna@insidetopalcohol.com if you like.
     
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  12. eli

    eli Banned

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    Oh Danny boy,some of them them pipes are not gettin the heat, I would work on getting the egt's even first, then worry about the timming. give the hot cyl some fuel, take it away from the cold ones. ( port nozzels). Here is a chart that i made up for the % of change for jets and nozzels, just calculate how much you want to change each cyl.take note that the smaller the jet/nozzel, in size the bigger the change in % ;) happy tuneing. P/S if your running 29* i dought if your fireing out the ex pipe so your egt's should be right, when you don't have enough timming the mag fires outside the cyl head and into the ex pipe where the egt pick up is, and you get a false reading on the egt's
    Jet Size & area
    50 =.001963
    51 =.002042=3.87% more than # 50 jet
    52 =.002123=3.82% " " # 51 jet
    53 =.002206=3.77% " " # 52 jet
    54 =.002290=3.67% " " # 53 jet
    55 =.002375=3.58% " " # 54 jet
    56 =.002463=3.58% " " # 55 jet
    57 =.002551=3.45% " " # 56 jet
    58 =.002642=3.45% " " # 57 jet
    59 =.002733=3.33% " " # 58 jet
    60 =.002827=3.33% more than # 59 jet
    61 =.002922=3.26% " " # 60 jet
    62 =.003019=3.22% " " # 61 jet
    63 =.003117=3.15% " " # 62 jet
    64 =.003216=3.08% " " # 63 jet
    65 =.003318=3.08% " " # 64 jet
    66 =.003421=3.02% " " # 65 Jet
    67 =.003525=2.96% " " # 66 jet
    68 =.003631=2.92% " " # 67 jet
    69 =.003739=2.89% " " # 68 jet
    70 =.003848=2.84% more than # 69 jet
    71 =.003959=2.81% " " # 70 jet
    72 =.004071=2.76% " " # 71 jet
    73 =.004185=2.73% " " # 72 jet
    74 =.004300=2.68% " " # 73 jet
    75 =.004417=2.65% " " # 74 jet
    76 =.004656=2.58% " " # 76 jet
    78 =.004778=2.56% " " # 77 jet
    79 =.004901=2.51% " " # 78 jet
    80 =.005026=2.49% more than # 79 jet
    81 =.005152=2.45% " " # 80 jet
    82 =.005281=2.45% " " # 81 jet
    83 =.005410=2.39% " " # 82 jet
    84 =.005541=2.37% " " # 83 jet
    85 =.005674=2.35% " " # 84 jet
    86 =.005808=2.31% " " # 85 jet
    87 =.005944=2.29% " " # 86 jet
    88 =.006082=2.27% " " # 87 jet
    89 =.006221=2.24% " " # 88 jet
    90 =.006361=2.21% more than # 89 jet
    91 =.006503=2.19% " " # 90 jet
    92 =.006647=2.17% " " # 91 jet
    93 =.006792=2.14% " " # 92 jet
    94 =.006939=2.12% " " # 93 jet
    95 =.007088=2.11% " " # 94 jet
    96 =.007238=2.08% " " # 95 jet
    97 =.007389=2.05% " " # 96 jet
    98 =.007542=2.03% " " # 97 jet
    99 =.007697=2.02% " " # 98 jet
    100=.007853=1.99% more than # 99 jet
    101=.008011=1,98% " " # 100 jet
    102=.008171=1.96% " " # 101 jet
    103=.008332=1.94% " " # 102 jet
    104=.008494=1.91% " " # 103 jet
    105=.008659=1.91% " " # 104 jet
    106=.008824=1.87% " " # 105 jet
    107=.008992=1.87% " " # 106 jet
    108=.009160=1,84% " " # 107 jet
    109=.009331=1.84% " " # 108 jet
    110=.009503=1.81% more than # 109 jet
    111=.009676=1.79% " " # 110 jet
    112=.009852=1.79% " " # 111 jet
    113=.001002=1.68% " " # 112 jet
    114=.001020=1.77% " " # 113 jet
    115=.001038=1.74% " " # 114 jet
    Exampal 100 jet to 99 jet, divide area 7697 into 7853=98.01 subtract that # from 100.answer, 1.99%
     
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    Last edited: Aug 6, 2007
  13. secondwindracing

    secondwindracing top alcohol

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    just called brad anderson and talked to donnie he said with the fuel heads on alcohol to put 40deg. of leed in it and go racing
     
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  14. Dave Germain

    Dave Germain New Member

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    You will see a lot of advice on here from guys with small chamber heads. The small chamber heads don't run much timing. I ran the big chamber WAR heads for years and the car was a total dog with only 29 degrees in it. On the dyno we got as far as 37 degrees and the power was still going up. Just make sure you don't get too wild with the compression and the timing at the same time. Dave Germain
     
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  15. nitro4100

    nitro4100 New Member

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    As far as plug gap I think the alky guys run them at 18 thousands, I may be wrong but I have worked with a couple guys that run them like that.
     
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  16. eli

    eli Banned

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    Nope, 14th. to 16 th. ;)
     
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  17. secondwindracing

    secondwindracing top alcohol

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    Gean is right....14-16
     
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  18. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    numbers

    i'm not claiming to know what the magic number is on timing for the big cc heads. i know people that run veney stuff, and they don't run that much timing. that much timing was the norm when those heads were the latest technology mainly because the mags were so much weaker right then. numbers aside, that wasn't my point.

    the point i was making is can you afford to go from 29 to 37? unless you just hate your motor, i wouldn't recommend that kind of jump. if 37 is too much, you may be talking about how much timing to put in the next motor, not the next run. too much timing will absolutely wreck a motor. maybe 37 is the magic number. i don't know, but i doubt it. even if you go a degree at a time, at least you don't wreck your motor.

    that aside, i still don't think timing is the answer. maybe it could use a few degrees, but that low gear leanout will wake it up. the whole fuel system could be too rich.
     
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  19. Mike Canter

    Mike Canter Top Dragster

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    I called both Venney's and Newberry's shops about two weeks ago to ask them both about timing with a ProMag 44 on a Rootes blown alcohol car that has Venney 170 cc heads. The owner of the car insisted that he was told to run 36* advance on the motor. Both Venney and Newberry shops stated that they would not run that much advance and that I should stay around 28-29*. I passed this data onto the car owner but they made one more run at 36* and kicked out all the rods. I guess the next question is if this was caused by the 36* advance and I can't answer that but I would guess it was or it didn't help

    My guess is that you can probably get away with 36* or more if the mixture is fairly rich but as soon as you start to work the fuel system to a GPM that matches the boost and it leans the motor out it is more likely (most probably) to go into detonation especially after one shifts into 3rd gear. So here lies another question is what combination works best on a Rootes blower car... a rich mixture with more advance or a leaner mixture with less advance. I do know what the ideal AFR is for methenol alcohol is for making horsepower in the final part of the run is and that matches the GPM for the leaner motor with less advance.
     
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  20. danny

    danny compet elimin

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    We stay @ 29 ° and work on the temps first.
    We ordered parts for leaning out the engine a bit like Will says and we hope the parts get here on time
    Thanks Gene for the chart it's a helpful tool ;),but how mutch can you go of the set up with the % ?We always stay right on it but it's not easy to get all the cyl at the same temps.
    Over here we see pro mods guy's running with venney heads/roots blowers and timing set @ 36° ( tuned by Jim Oddy ) and they are going in the 6.2 zone,but alot of them wreck the engines complete and we don't want this
    We are running on a very small budget with no sponsering ( like a lot of guy's but the rest we have to compete against them who have sponsers )and we have to keep everything together.
    Our team is my wife,my son of 21 years doing the cluch / engine /... and my 14 year old son doing together with me the bottom end and they are all doing a real good job;) and we have to work our ass of the hole weekend to keep it running,because nobody over here knows or wants to work on a alcohol funnycar it's to mutch work.:confused:
    thanks you all for the input and i will let you know how things worked out when we are back from germany next week ;)
     
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