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Author Topic: Timing, Whats yours?  (Read 158 times)

MrC.

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Timing, Whats yours?
« on: October 20, 2017, 12:05:13 PM »

The base timing is 4 degrees BTDC on the 454, but from a towing/performance stand point, how much advance have you ran with good results?

I advanced mine to 12 degrees BTDC last night, with the tan wire disconnected, then re checked after setting it at 12, with the tan wire hooked back up, at idle it read 22 degress BTDC.
I have had great luck with SBC's set at as much as 32 to 34 advanced BTDC, but this is my first big block.
I haven't had a chance to drive the 454 yet to see if it pings.

My engine is stock.
I will be adding exhaust soon, probably 2.5 single, no cat and a flowmaster muffler.

MrC.
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RPF207

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Re: Timing, Whats yours?
« Reply #1 on: October 20, 2017, 04:10:04 PM »

Never messed too much with timing on engines that didn't have big modifications but I do know that unfortunately you can't get much extra out of a tbi or vortec engine without spending a bunch of money to the point where you could've just installed an LS, built carbed engine, or a diesel. What I do know is when you start pushing the tbi and iron vortecs to make up for lack of performance you need to keep an eye on your trans, the old 4 speeds will start to get hot. Tbi and vortecs don't have the air flow potential.
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1999 chevy HD 4x4 135.5" 6.5 nv4500 bw4470 Dana 70 HP 10 lug front

Due to recent budget cuts the light at the end of the tunnel has been turned off

someotherguy

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Re: Timing, Whats yours?
« Reply #2 on: October 21, 2017, 02:04:03 PM »

The TBI 454's are not HP monsters but plenty of torque.  I'd strongly suggest going over everything first under stock parameters and be sure engine is in top state of tune.  Especially look at fuel pressure, including under load, which will require you to get an inline tee for your pressure gauge and an extension hose so you can hang the gauge under your wiper arm to see it in action under load.  If it's not at least 10-11 psi that's an area to address.

Once you start getting into playing with the timing you will want a scanner that can read live data and would be helpful if it does graphing too. Watch for knock counts and knock retard. Doesn't do you any good to add extra timing if it knocks enough to cause it to pull all that timing back out, and it can knock enough to do that without you ever actually hearing it - have proven this myself on a TBI small block.

Richard
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06 Silverado ISS / 06 Silverado SS / 06 300C SRT8

MrC.

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  • Posts: 28
Re: Timing, Whats yours?
« Reply #3 on: October 27, 2017, 08:14:49 PM »

Thats good info. I have had and played with tbi motors before. And you are right there not hot rods.
As for timing. 12 BTDC was to much. But 6 was noticeable.  More things to come.

Mrc.
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ED-NY

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Re: Timing, Whats yours?
« Reply #4 on: October 28, 2017, 08:21:34 AM »

Not sure what ECM you are using but if it's the 1227747 it can be modified to install a 27SF512 eprom so you can tune (or disable) to your needs. Did a couple a while back and can flash a chip for you if you know parameters (fuel/timing) you want on it.  I have been disabling stuff likes VATS, EGR, EVAP etc for TPI conversions.

Here is a thread discussing the process:

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?172-7747-Flash-Chip-Conversion-(27SF512)&highlight=1227747
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