I just brought the Formula in to the shop for some little stuff and at the same time I was going to have the timing adjusted for better performance. I was told to advance the timing 8 degrees and that would be good. When i told this to the shop guy he took it as I wanted the timing AT 8 Degrees. My question is: What should it be set at for the best performance? What should the timing be after it is adjusted to the best position. I am very confused about this timing stuff. Thank you.

 

id only set it to two degrees ahead of whats called for stock and go from there in two degree increments. Without a dyno, any gains youll thought you obtained will be strictly subjective.

 

So what is the stock timing, because the shop is setting it at 8 degrees?

 

Stock timing for a TBI is 0 degrees. TBI engines in general seem to work a lot better with advance timing. How far you can go depends on the condition of your engine and the fuel octane you use.

My car as an example, will go as high as 6 degrees advance only. no matter what octane (up to 94) it will ping during shifts with timing higher than that. actually at 87 octane I can't run 6 degrees even as it will ping there too. Start at 2 as previously stated and work it up till you hit your limit. I used this method and did WOT shifts to hear pinging. I have no hood insulation on mine so when I heard pinging during the shifts it was pretty loud. Sorta like popcorn popping from the engine compartment. I am running 6 right now.

 

on a stock lo3 it is 0*

i am running mine at 6* right now.

 

The timing is when the spark plug ignites the fuel.

Setting the timing at 0* Before Top Dead Center (BTDC) means the spark will ignite the fuel right as the piston is at it's highest point in the cylinder, or the top. The #1 cylinder is used as the baseline when setting the timing, then the remaining cylinders follow suit.

If you advance the timing 2* (which is 2* of crankshaft rotation), the spark plug ignites the fuel BEFORE the piston reaches the top (BTDC). This may seem odd, but one thing people often confuse is how takes place. It is NOT an explosion. It's just a quick burn. Because the fuel is being burned, it can only burn so fast.

The piston travels faster than the speed of the burning fuel. In an attempt to get maximum power, the spark is timed to burn as soon as possible (BDTC) so the most force from the burn is applied to the piston. However, once the spark starts to ignite the fuel TOO soon, the flame will actually fight the piston as it is STILL coming up. That's BAD for power, and the engine.

You'll hear it on an engine without a knock sensor. It'll sound like a diesel. But on an engine with a knock sensor, the engine will hear it WAY before you, then the ECM will back off the advance until the knock stops.

So... to sum it up... the main goal is to set the timing as far advanced (BTDC) as possible before it starts to fight the piston. The only real way of finding out how much you can advance it is to try it.

Side note... Changing to a higher octane gas is usually needed to prevent the knock. The odd thing is.... you're advancing the timing so the spark starts igniting the fuel BTDC (or sooner), right? Well did you know higher octane gas BURNS SLOWER??? Kind of seems to defeat the purpose of advancing the timing, doesn't it?

That's one reason you'll hear a lot of engine builders say to only use the highest octane that doesn't cause problems. It can actually cause a loss in power because of the slower burn rate. So only use what is needed. If it doesn't knock with 89 octane, don't think that 91 or 92 is going to give you more power. It won't.

 

I run mine at 4* advanced, I didn't know about the slow fuel burn thing. For the longest time I was using 94, then I can't remember why but I went to 93 and the motor seemed to run and perform better. I guess now I know why. I guess next time I'm at the pump I'll try some 89 and see what happens. Maybe a half tank to get a feel for it.

 

to advance the timing what do i do... wich way do i turn the distributor? do i need a timing light? how can i tell how many * i have the timeing to?

 

i advanced my timing 6* (from 0 to 6) and picked up a solid tenth in the quarter mile. I wish i could dyno tune my car like on horsepower tv, but i guess i can only dream.

 

Yes you need a timing light. One with the dial on the back is the best to use. It allows you to easily see where your timing is at any RPM. But it's not absolutely needed.

All you do is loosen the dist hold down, point the light at the timing pointer just behind/below the water pump, turn the dist. counter-clockwise to advance the timing, clockwise to "un-advance" the timing. (A lot of people say retard the timing, but IMHO it isn't retarded unless is ATDC).

You can use a light without the dial on the back. You just have to know which mark on the pointer is lined up with the notch on the balancer. If the pointer isn't legible you'll have to find a picture of one like it. You can find one in a Haynes or Chilton repair book.

 

Here's a pic I took from the Hayne's manual, it's the not the best but you can make it out:

 

Do you turn the distributor while the engine is running?

 

Yes. I've found it best to loosen the hold down bolt most of the way while the motor is off, then with it on loosen it just enough to let your rotate the distributor. You don't have to turn it very much, just about 1/2 inch either way to get the adjustment right.

I'd recomend buying a Hayne's manual for your car. It's a great tool for finding out how to do little adjustments here and there. General repairs, and such.

 

Stupid question.....but what is that "magnetic timing probe hole" in the pic..

 

If I knew I'd probably use it, all of our cars have them, but I have no idea what the hell it does :lala:

 

There's a "scope" that a mechanic (or technician if you want to be politically correct) uses to check everything as far as the ignition system is concerned. It has a magnetic pick-up that it uses to scan the timing with.

"Insert here"

 

hey all, a while back, i installed a custom chip. Then a little later, my tech told me after i ran a trouble shoot on my car that i had a loose ground. Well when i picked it up, he said that being my pal he had placed my car back to zero. Well, my bottom end sucks, is that the reason?




1992 Firebird Convertable
305 TBI w/ open element K&N
Flowmaster Catback w/ 40 series muffler

best e.t. 16.4 @ 86mph
(reaction time- 1.125)

 

"my pal" ??

You do know the acronym for "pal" don't you? "Personal A$$ Licker" :sillylol:

Seriously, did he remember to disconnect the ESC wire? If not, that would cause a loss in low RPM torque, as well as through the rest of the RPM range. You would only notice it in the lower RPMs though, since that's what they butt-dyno feels the most.

I'd take it back to him and tell him that since he did what he did, it's lost some *****. Then WATCH him adjust the timing again. Look to see if he unhooks the ESC wire. It's a brown wire that's on the passenger's side, right near the blower motor. It should be a black connector sticking out of some wire loom.

If he doesn't touch it, point it out to him. Tell him that you read somewhere (don't tell him on the internet or he'll roll his eyes at you) that it needs to be disconnected when setting the base timing.

If he says "No it doesn't." or anything like that, find a new "pal."

 

Actually you should just do it yourself. That's what this website is all about... the "do it yourselfer".

Go spend the money and buy yourself a timing light. I suggest one with the dial control on the back. It's better for a tool to keep. You can use it on other cars without EST to set timing curves, check total timing, etc., and it's only ~$20 more than one without the dial.

The timing tab is mounted to the timing chain cover, right behind the water pump. If it isn't there, then it's either been removed or fell off, or someone's changed the timing chain cover.

Disconnect the coil wire from the distributor.

Once you find the timing tab (if you do), crawl under the car and have a buddy tap the starter to rotate the engine until you see a groove on the balancer that's about 1/8"-3/16" deep. Use white paint or a white crayon to fill in the groove so it's easy to see.

Hook the coil wire back to the distributor, and unhook the ESC connector. It's located near the blower motor on the passenger side firewall. It'll be the brown wire sticking out of a black wire loom. Just seperate the connector and leave it sit.

Hook up the timing light using the inductive pickup to the #1 sparkplug wire. It's the one that's on the driver's side of the engine, closest to the radiator.

Loosen the distributor hold down bolt just enough that it takes a little effort to be able to rotate the distributor either clockwise or counter clockwise.

Start the engine and aim the timing gun straight down between the water pump and the engine block. Look for the groove in the balancer.

A stock LO3 should be set at 0* BTDC. The groove should be lined up to the first "V" on the timing tab (the one closest to the driver's side). If not, rotate the distributor one way or the other until it is. At this point ignore the other "V' grooves.

Turn the engine off and tighten the dist. hold down bolt. Start the car and check the timing again to be sure the dist. didn't move while you were tightening the hold-down bolt. If so, correct it.

Once you're done, turn off the car and hook the ESC wire back together. Take it for a drive and see it that feels better.

When using a timing gun with a dial, only use the first “V” groove on the timing tab. If the timing mark on the balancer doesn’t line up with the “V” groove on the timing tab, rotate the dial on the back of the gun until it does. Whatever number the dial is pointing to is where the advance is set BTDC.

 

From the picture above, mine points to 8* is that advance or retard?
Thanks...

 

ignore it, its not even used unless u have the equipment to use the probe it points wehre it points check ur timing with a light ignore the lil "hole thingy" or the magnetic probe holder whichevre you want to call it.