Need help....
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From: Harford Co. Maryland
Need help.... Timing at 40* at idle (40's the limit) and does drop as throttle opens (due to vac. drop)
I tried a lower timing set-up but ran like ****, may need some more carb adjustments ?
32* with 10* vac. advance.
I tried a lower timing set-up but ran like ****, may need some more carb adjustments ?
32* with 10* vac. advance.
I agree, I'd like to see the scale of the map table you plotted, its very important. I dont think you need to limit it to 40*, it will like more at part throttle / high vacuum.
you can start your rpm graph at about 15* at 0 rpm up to a bout 500rpm, then go strait to your 32* at a couple hundred less rpm than your idle speed - i chose 500rpm, as I idled around 900ish, but it doesnt really matter, just get all the timing in at idle speed.
You can actually add a degree after peak torque ,aprox 54-5500(up to 33* from your 32*). your graph has it dropping timing out after peak torque - that is opposite of what my n/a engine wanted on the dyno.
Do you have a wideband O2 yet?
11.2psia at idle? haha. thats a nice rough idleing cam!
you can start your rpm graph at about 15* at 0 rpm up to a bout 500rpm, then go strait to your 32* at a couple hundred less rpm than your idle speed - i chose 500rpm, as I idled around 900ish, but it doesnt really matter, just get all the timing in at idle speed.
You can actually add a degree after peak torque ,aprox 54-5500(up to 33* from your 32*). your graph has it dropping timing out after peak torque - that is opposite of what my n/a engine wanted on the dyno.
Do you have a wideband O2 yet?
11.2psia at idle? haha. thats a nice rough idleing cam!
what psia does it see when at cruise rpm while driving?
since you see 11.2 psia at idle you should move the map dot from 11psia-10* over to the right to about 13psia-10*. I would consider adding 2 * to the map table as well, but experiment to see what it wants
since you see 11.2 psia at idle you should move the map dot from 11psia-10* over to the right to about 13psia-10*. I would consider adding 2 * to the map table as well, but experiment to see what it wants
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with a 4500 converter, you can add timing in all rpms BELOW stahl rpm, this will make it even quicker throttle response, and better part throttle manners, and use less fuel.
here is what I think you should try on the rpm graph:
here is what I think you should try on the rpm graph:
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From: Harford Co. Maryland
Barret...do you use the MAP also ?
Whats your timing limit ?
Still thinking old school and points/HEI set-ups
Don't need to destroy a new motor 
Whats your timing limit ?
Still thinking old school and points/HEI set-ups
Don't need to destroy a new motor Last edited by Doug G; Mar 31, 2013 at 09:09 AM.
yes I did on the first N/A setup, but last seasons cam had NO vacuum, so I didn't bother.
If you figure out what psia your car cruises at I can definitely recommend a map curve for you.
My timing limit was around 50 i think, I dont remember. those curves crashed with my laptop last year.
the map curves are pretty easy, you just need to know what psia it idles at, and what psia it cruises at to make sure its right.
If you figure out what psia your car cruises at I can definitely recommend a map curve for you.
My timing limit was around 50 i think, I dont remember. those curves crashed with my laptop last year.
the map curves are pretty easy, you just need to know what psia it idles at, and what psia it cruises at to make sure its right.
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From: Harford Co. Maryland
Test drive cancelled due to rain
Pulled #1 plug and I think there's way too much timing...heat mark back at threads (maybe 1/16" max from them) These are the stock AC Delcos 41-11 ? that come in a '04 Silverado...So I guess I should look into some NGK BR?? plugs.
Pulled #1 plug and I think there's way too much timing...heat mark back at threads (maybe 1/16" max from them) These are the stock AC Delcos 41-11 ? that come in a '04 Silverado...So I guess I should look into some NGK BR?? plugs.
Oh yeah I should have mensioned use about a br7ef plug.
There shouldnt be any heat mark unless you had the engine under load for at least an 1/8 mile pull
Did you make a tdc mark on the balancer and verify that the MSD is providing acurate timing? Also, make sure you have the correct map sensor selected
There shouldnt be any heat mark unless you had the engine under load for at least an 1/8 mile pull
Did you make a tdc mark on the balancer and verify that the MSD is providing acurate timing? Also, make sure you have the correct map sensor selected
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From: Harford Co. Maryland
This is a pretty interesting curve. I may run it on mine for a pass and let you know what difference it makes. Why go down to 32 and not flatline 33 all the way through? Going to high at the end will scrub off MPH, but 33 is definitely not to high.
If you are to use this for yourself, consider your stahl speed and make sure you dont have the aggressive low rpm timing still in it when the converter is coming in.