timing on 29 °

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

 

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?

 

Danny,

How big are the chambers in those heads?

Rapid

 

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.

 

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

 

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.

 

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 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.
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

 

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.

 

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.

 

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.

 

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%

 

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

 

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

 

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.

 

Nope, 14th. to 16 th.

 

Gean is right....14-16

 

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.
thanks you all for the input and i will let you know how things worked out when we are back from germany next week