Well I'm trying the trial and error method, and I'm stopping to ask a bit of advice (again). I'm trying to adjust the timing of my car. I understand that most of the timing comes from the chip, but I need to get base timing down first. I spent last weekend at Maryland Int'l Raceway doing runs and adjusting timing each time. I set it where the book tells me to for stock applications (6-8* ADV), and the car ran like poop. As I retarded it it slowly got better and better. It's now sitting at about 8* BTDC. But it's still incredibly rich (it burns your eyes), and puffs black smoke every now and again. I'm posting screen shots of my timing table from TunerPro. Maximum Advance Timing is set at 41.84*. "Initial Spark Advance" is set at 8.09*. Based on these facts can anyone make a recommendation on where to set base timing? Or does it really just come down to trial and error? Also, with cast iron Sportsman II heads... anybody have a favorite spark plug to run with them? Any tips on what has worked for someone in the past?

 

Can you give a few more details on your combo? CR:1, pistons, cam and etc.

I see your car is a 85' and i see that your using a MAF table. But what ecm and .bin are you using?

Are you datalogging these runs? Watch some of the logs (if your logging) and see what actual timing is. Remember you have alot of corrections going on there other than you main SA table.

Do you have access to a wideband?

 

Here goes:
Flat Top pistons, approx. 10.5:1 Compression
Comp 477 intake, 480 exhaust lift
224 intake, 230 exhaust duration / 114 Lobe Sep.

I'm using the stock 870 computer w/ the Moates hardware, and TunerPro RT. The .bin is actually copied off a Hypertech chip I had made for the car years ago. But since the cam swap the chip is not useful. I also have access to a stock .bin. The only .ecu file I have is the only one available for my ECU (that I've found), and the only program I have right now to datalog is WinALDL, which as far as I know doesn't tell me timing. I haven't been able to find a working datalog file for TunerPro RT yet. There's a value on WinALDL labeled "SAREF", which I read has something to do with timing, but that stays at 0. Oddly enough my O2 sensor puts out a constant .477v. No access to a wideband (yet, its next on my list of goodies.) Sorry for not being clearer like this earlier, after a while one starts to get frustrated.

 

You are mistaking your terms. When they say to run 6-8 * ADV it means 6-8*BTDC.

You actually started out at 8*ATDC which is what is called retarded.

I have found that the Stealth Ram likes a higher base timming (12-14* BTDC). Change the base timming in your chip to 12, unplug the ESC wire and set the engine timing to 12*BTDC. Plug it back in and try that as a starting point.

 

Base timing is ONLY for getting the engine to start best at all temperatures.

You DON'T need to have it finalized before you go about the other business of tuning.

You DO need to put the base timing value correctly into the chip if you want to "get" the timing that it says in the bin. If you change the base timing, change the base timing in the chip. That's all.

Rich - well, what injectors did you put in there? If you put bigger ones into the older PW vs LV8 MAF computer, just multiply each PW by (OLD FLOWRATE)/(NEW FLOWRATE). So, if you're using 30's when originally 19's, it's multiply by 0.63 (in other words: 63%).

 

Man... I had no idea I was messing that up that bad. Thanks for straightening that all out for me gcpoland. You really saved me a big headache. Thanks again to RednGold for explaining that all to me. Makes a lot of sense now. I've actually got 24 lb/hr injectors right now. With the 406 everyone is telling me to upgrade at least to 32 lb/hr. So I figure I'd take the equation you gave me... bounce it off the stock .bin, and the stock injectors, and hopefully I'll be in like flint for a starting point. The last question I have now is about Spark Plugs... right now I run AC Delco R45TS gapped to .45 with my Sportsman II heads w/ the 72 cc chambers. Are these ideal? Or has someone out there found something better?

 

I wouldn't run 45's with 10.5 CR.
They might be ok until you get your fuel closer.
Then I'd try 43's.

 

Yep - Z69 is right - I used the 43's in my 383 when I had the SPII heads. Like the NGK UR5's too....