LT4 hot cam manifold vacuum question
#12
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Joined: Nov 2004
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From: On A Dirt Floor
Forgot to add: I use RPm Airgap's and Holley's with no chokes. Factory 8 base timing make these a *****. Just by going up 4 degrees let's turn into a near stocker.
Foreworn: you'll mellow out the idle....which I like....stealthy.
Foreworn: you'll mellow out the idle....which I like....stealthy.
#13
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Joined: Apr 2010
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From: Daniels, WV
Should I maybe find a v8-20 module so I can set the base at 12*. For some reason I have it in my head that 18* at base (v6-14 module) is going to fight the starter. My compression is also 10:1 and I don't want it to detonate at low rpm. Just seems that 12* base would be better than 18*. But I may be wrong.
#14
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Joined: Mar 2008
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From: Vancouver BC
Should I maybe find a v8-20 module so I can set the base at 12*. For some reason I have it in my head that 18* at base (v6-14 module) is going to fight the starter. My compression is also 10:1 and I don't want it to detonate at low rpm. Just seems that 12* base would be better than 18*. But I may be wrong.

I promise you won't have any problems cranking. Get the V6 module! Lots of guys are running 30+ degrees locked out. Don't worry about it. You want at least 18-20 degrees initial.
#15
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Joined: Mar 2008
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From: Vancouver BC
Another thing that someone more familiar with the TB-IV's might be able to confirm is whether or not it has a set timing for cranking. Other modules only have 10 or 15 degrees while cranking and then ramp in the rest once it gets past 400rpm when it knows the engine is running. Anyone know if the TB has this feature? Either way you'll be fine, just thought I'd throw that out there.
#16
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From: Daniels, WV
Found a v6 module, hoping the guy will get back to me with a price tomorrow so I can get it shipped and on the way. Hopefully this will help the hard start issue. I also like the fact I will only have to rev to 2500 rpm to check full advance. I keep hearing 32* max on vortec heads. How do they run at 30* and how do they run at 34* versus 32*?
#17
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#19
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From: Daniels, WV
Got a v6-14 module that works. Damn thing starts with ease. Never in my life would I have imagined it to make that big of a difference. Only question now is the fact that when the total advance is at 32* the base is at like 21-22. Does this seem normal for this module? Other than that I have no complaints thus far, I'm gonna run it at the lake tomorrow and start prop testing. Do i need to worry about detonation while cruising now since the timing comes all in at 2500 rpm? Should I run 30 or 32 total advance?


