I have an 89 RS with a 305 tbi auto. What base timing will be optimum for performance and drivability. Stock its suppossed to be 0 deg. It's now at 4 deg. just wonering how far advanced is safe????

 

i have mine set up at 20 btdc ...i really think that its a bunch of bull that the timing should be at 0 degrees ... before i started playing with the timing it looked like it was factory set at 16 degrees btdc. i
have no idea why there would be a zero degrees setting..if you think about it zero means it should ignite at top dead center which theoretically you need some really low octane gas to burn that quick (or try putting nitromethane in it..hehheheee)...well..i dont know i could be wrong..but my car is pretty fast set at 20 degrees initial advance.

 

just so I make sure I understand. Your timing is set at 20 deg. with the bypass wire unhooked or with it hooked up. because if you set it to zero deg. ,when the bypass is hooked back up it seems to idle at about 6 deg btc.

 

I may be wrong but I think stock is 6 btd, is this righ

 

nope, stock is 0*

 

OK stock is 0 deg. , but whats best for performance and still has good drivability???

 

i would go 6* advance if its all stock. btw i have an 89rs too and i run 4*.

 

i liked 4 better than 6, but mines not all stock. if its BONE stock, 6* was the best for me.

 

It's safe to advance it as far as you can as long as you don't get engine knock, but I don't think more than 6* advanced is going to give you any difference. The trick getting your base timing to work well when the computer starts to control it.
I run 4* with noticeable improvement and I use 93 octane...but I also have a aftermarket chip.

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92 Camaro RS, LO3, 5-spd, T-tops

Performance:
K&N Open Air Filter, Edelbrock performer TBI intake, Fastchip Prom, Timing +4 degrees, Centerforce clutch, Xact 8mm wires, SLP 1 3/4" Headers (coated), Flowmaster Catback Exhaust, Z28 Grille w/aftmkt fog lamps, MacEwen white-face guages
Electronics:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-846 Amps powering 2 12" Pro Red subs, 2 Pioneer 6x9 and 2 MTX 4x6 speakers.
NEXT UP: TBI mods, 3.42 gears w/Torsen posi

 

I've tried 6* and now it's at 4* base timing,and yes it is bone stock. your right 6* does perform better I just wanted to make sure it won't hurt the engine by knocking..

 

I've tried 6* and now it's at 4* base timing,and yes it is bone stock. your right 6* does perform better I just wanted to make sure it won't hurt the engine by knocking..

 

Where does your timing go when you plug in the EST. Mine goes all the way off the scale like maybe 20*


Thanks
Brian

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1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

www.geocities.com/feltsb

 

If it's at 0* the timing is between 6-8* w/EST hooked up, but I haven't cheched it when it's advanced. It does have more power at 4-6* but I don't want to hurt the engine, so it's at 4* right now...But doesn't the knock sensor snse when there is a knock and retart the timing. I want to try 6-8* deg ,but don't want any detonation..What are some of you other stock LO3's running?

 

Thats normal. There is 14-20degrees timing in alot of stock proms at idle.

 

I've got mine set at 4* BTDC. I checked the total timing at 4000rpms and it was at 30* in Neutral. I gotta Jet Stage 2 Chip. I was thinking of trying a little more to bring the total up to 34-36*, but I'm afraid that it could do more harm than good.

Yes, colincamaro, the knock sensor does tell the ESC to tell the ECM to retard the timing when knock is present. It will retard the timing as much as needed to get the knock to go away. That in itself will decrease power output. Usually more than needed. Let's say you got your timing set at 4* BTDC and you change it to 6*. If that causes knock, the ECM will retard the timing about 4*-6* (or more) to try and get rid of the knock. You'll never hear it because the knock sensor is so sensative that it can detect a dime hitting it. Then the ECM will return the timing to normal, but the knock will reoccur that split second. Then the whole cycle will start again.

FastBroker recommended that I use an AutoXray, or other diagnostic device that has a Knock Counts reading on it. That will tell you if the knock sensor is detecting anything or not. The only other way I can think of would be 1/4 mile times. But I doubt if I could drive consistent enough to notice a difference that 2 degrees makes.

------------------
92 RS w/t-tops 305 TBI Auto.
170K miles and don't burn a drop o'oil
-K&N Truck filter #1500 w, open ele.
air cleaner
-Dynomax 2 1/2" cat-back
-B&M TransPak
-Jet Stage2 Chip
-180* T-Stat w/ 185* Fan Switch
-JVC CD--Alpine speakers & 4ch. amp
Rockford 2ch. to 2 MTX 12" subs

 

I have an ADS superchip, how much does it advance timing? Would it be safe to advance it 4* with the chip still installed?

 

The amount of advance you see in nuetral at 4000rpms is not the same as WOT.

WOT timing is looked up from a different spot on the timing table. Additionally, there is advance added when you hit WOT mode.

 

So am I supposed to run along side the car while my friend hits WOT? What other way could I check it?

I've always heard & read that the ECM (stock) is supposed to advance the timing no more than 22 deg. at WOT. Well, IMO, adding the chip plus advancing the base timing 4 deg. would make sense that 30 deg total would seem about right. I'm sure that the JET chip would tell the ECM to advance the timing a few degrees more than stock, right? Plus the advance I gave it. If there is another way to test total timing at WOT, please, do tell.

Thanks,
AJ

Edit: BTW, I know that my brakes won't hold without spinning that peg leg rear end. So that won't work.

[This message has been edited by AJ_92RS (edited July 10, 2001).]

 

I generally take the hood off and ride on the drivers side fender. I wouldn't recommend it though. It gets pretty scary about 60mph.

I see what you are saying, but to get WOT spark advance the MAP has to be near 100kpa and the TPS past the WOT threshold (55-70%). You simply can't do this sitting still, the engine needs a load on it.

I bet you could take a reading while running WOT on a chassis dyno.

The JET chip may or may not have any additional advance. Some chips have very little changed from stock.

I wouldn't be too worried about hitting a specific amount of advance. Testing the cars performance and changing the timing to see what performs best is the way.

 

Ok, I feel dumb asking this but, just to reiterate, you guys are suggesting 4*-6* BTDC, or ATDC? With base timing at 0*, I'm not too sure which direction is "advance".

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No guts, no glory.

 

Don't feel dumb. The only dumb question is the one you DON'T ask. That's BTDC. Anything after TDC is retarded.

Well, I was a little ahead of ya on that one. That's why I wrote "in Neutral". I figured that a car with EST needed a load in order to show full advance. I guess I decided to use 4000 as a baseline. Gotta start somewhere, right? I never thought of the TPS dictating what timing the ECM would put out. Doesn't the ECM go into open-loop at WOT?

I'm used to the old days back when distributors used mech. advance. That was the only way to check total timing back then. The only way I know how.

Thanks Brent,

AJ

 

Well, the ECM technically stays in Closed Loop mode at WOT. However, Learn Control turns off, so the O2 is ignored. I can email you a diacom run showing this if you want.