350 tbi timing

[Overland Suburban]

Hey guys and gals I know I'm suppose to set the timing at zero and the computer adjusts the advance until the knock sensor tells it to stop. My question is if I bump my timing 2 or 3 degrees and run 92 octane fuel so the knock sensor allows it to advance will the 350 tbi see any benifit??? Ive personally seen as much as 3 mpg benefit on non computerized engines. I have read that this does work on a TBI setup but can't believe everything you read on the internet.

Thanks

 

[RoryH19]

I have 1 or just under.
Never tried 2 or 3.

I like to run 87 in one car I own.

 

[bucket]

The computer can only advance the timing so far and the stock setting is absurdly cautious.

If the engine is in fairly good health and runs properly, a TBI 305/350 likes anything in the 8-12° btdc range and will usually do it on 87 octane without knocking. Hot weather and high loads may make 10° the max without changing the fuel.

 

[Overland Suburban]

The computer can only advance the timing so far and the stock setting is absurdly cautious.

If the engine is in fairly good health and runs properly, a TBI 305/350 likes anything in the 8-12° btdc range and will usually do it on 87 octane without knocking. Hot weather and high loads may make 10° the max without changing the fuel.

Thanks Bucket! Would I have to reprogram my computer or can I just bump my distributor up a bit?

 

[Rusty Nail]

One must locate the tan wire with black line out of the firewall and unplug it to set timing.
I run mine at 10° .

 

[RoryH19]

The computer can only advance the timing so far and the stock setting is absurdly cautious.

If the engine is in fairly good health and runs properly, a TBI 305/350 likes anything in the 8-12° btdc range and will usually do it on 87 octane without knocking. Hot weather and high loads may make 10° the max without changing the fuel.

Good to know. I've never tried that much timing. I'll move to 8 and test for a few days.

 

[Itali83]

I’ve always put a few degrees into my Tbi motors too. I usually set it 5degrees with absolutely no issues.

Ben

 

[Overland Suburban]

I’ve always put a few degrees into my Tbi motors too. I usually set it 5degrees with absolutely no issues.

Ben

Thanks Ben that's what I was looking for. Do you have to run higher than 87 octane when you do that?

 

[Rusty Nail]

ahh. 10° with 87 octane*, NP.

 

[Jerry phillion]

I've run my 350 tbi with 2 degrees adv and it ran better. I sold
My truck since then, but I would try 8-10 degrees. You can
Always set it back if need be.

 

[Overland Suburban]

Thanks for all the advice! It sounds like I should just set it to zero and mark my distributor location! Than I will fill up with premium grade and make timing bumps and test drives. When it pulls the best I will lock it down and run it right there. Looks like some have realized gains and maybe some haven't.

I've seen as much as a 7mph gain in the 1/8 mile and went from 17 mpg to 22 mpg with a 91 ford truck with a 302. In fact I've netted noticeable results with every distributor engine I've tried this with. I've just never tried it before with a computer controlled distributor like the TBI, the reason for my questions in hopes of maybe finding unknown tips or tricks.

Thanks for all the advice and feel free to chime in still if you see something that you feel got looked over

 

[bucket]

If you are willing to run higher octane fuel, just set it to 12-14 btdc and forget about it. Your engine will like it.

 

[Itali83]

I only ran 87 octane just because I’m cheap but 5 degrees is still very safe with cheap gas

 

[1987 GMC Jimmy]

Remember to reset the computer after any timing adjustment by disconnecting the battery for thirty seconds.

 

[F-64]

So many variables! At 3mpg increase you save about $6 per 1000 miles if you fill up at the shell.
What are you after? Performance or efficiency?

Also, make sure your knock sensor is working. Dangerous knock is not necessarily loud enough to be heard.