Tuning Questions
#441667
08/17/09 11:03 PM
08/17/09 11:03 PM
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Joined: Jan 2003
Posts: 2,072 Cambridge, Ontario, Canada
CUDAJAS
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,072
Cambridge, Ontario, Canada
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So here is my combo:
74 Cuda, 360 727 (stock converter), 3.23 gears, 27.5 in tall tires. The engine is a around 9 - 1 compression. Torker II intake, Torker plus cam (@.050 Int dur. 222 , Ex dur. 234 Lift Int .447 Ex .450 Intake Centre line 107 Ex centerline 116) 750 Holly vac seconday carb.
My initial timing is set to 14 degrees, car starts runs and idles ok (rumbles away at at 750 rpm with no problem). No detonation that I can here under aceleration.
The timing will advance all the way to 55 degrees as you rev it up (not sure if that is it, or at what RPM it stops advancing.)
The car does not bog at all from a dead stop when you mash the go pedel. However, the car will not spin the tires from a dead stop, and it does not accelerate the way I would like / think it should.
So my question is, how do I fix it / make it better?
I am open to hearing all options. Lets start with tuning options, and go from there.
Thanks,
Jason
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Re: Tuning Questions
[Re: CUDAJAS]
#441669
08/18/09 12:41 AM
08/18/09 12:41 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I'd get a baseline, A compression test to see what your cyl pressure is. What total timing is w vac adv disconnected and at what rpm it maxes out at. What springs are in the dist. What do your plugs look like and how much vacuum at idle.
live every 24 hour block of time like it's your last day on earth
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Re: Tuning Questions
[Re: CUDAJAS]
#441671
08/18/09 06:33 AM
08/18/09 06:33 AM
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Joined: Jan 2003
Posts: 5,444 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,444
Indiana
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As previously mentioned, try bumping the initial timing to 18 degrees. Then with the engine at running temp (after a short drive), leave the car in D and apply the emergency brake. Then hook your vacuum gage up to the intake (manifold vacuum)and write down your baseline vacuum reading. Then start with one of the metering screws and turn it in 1/8 turn and watch the gage for 20 seconds or so. If the reading produced more vacuum, then go to the next metering screw and turn that one the same amount and the same direction. If the vacuum got worse, then turn the screw back to where it was and then another 1/8 turn in the opposite direction. Do this with both metering screws (back and forth) a few times and then take note of the vacuum reading. Then readjust your in gear rpms to where you want them and take note again of the reading. You will want to accomplish the in gear idle rpm desired along with the highest in gear vacuum reading along with the steadiest vacuum reading while in gear. Note: Before this test, make sure both (or all four) metering screws are currently set at the same amount of turns outward. It helps me to make a mark at the 12:00 position on the metering screws once I know that they are all at the same position. Then after I am done tuning, I can reference all of the metering screws to see how far they had to be turned.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Questions
[Re: RapidRobert]
#441672
08/19/09 12:01 AM
08/19/09 12:01 AM
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Joined: Jan 2003
Posts: 2,072 Cambridge, Ontario, Canada
CUDAJAS
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,072
Cambridge, Ontario, Canada
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Quote:
I'd get a baseline, A compression test to see what your cyl pressure is. What total timing is w vac adv disconnected and at what rpm it maxes out at. What springs are in the dist. What do your plugs look like and how much vacuum at idle.
Good suggestion, I guess it can not hurt to do a compression test.
I have changed out the heavier dist spring, (that is what the kit suggested). Shoudl I have changed both?
I will do a base line on the carb as suggested.
I have spent some time adjusting the carb, and belive it is pretty close. But i will certinly go through all the suggestions and see what happens.
Jas
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