SIMON HOLTBY

What do you guys using ARAPset your base ignition timing to?
I'm using either 95 or 110 octane fuel .
Thanks

Simon

Matt87GTA

I have mine at 8* with the corresponding correct figure in the bin as well. I really haven't played much with timing aside from pulling timing out of some part throttle stuff to remove some knock I was seeing.... I get 0 knock counts as it sits right now and I know there is much work to be done (and power to be found) in my timing tables, so don't just blindly follow me .... I just didn't get around to really tweaking the crap out of the timing settings before winter set in.... I was busy getting the BLMs palateable..... Plus, the stock ARAP settings are so freakin aggressive, I figured that would be one of the last things I would work on after I got it to record 0 knock.....

Laterzzzz,
Matt

Matt87GTA

Oh yeah, I usually run 93.5 octane (a station close to home has it...) but have had no problems running it on 92 or 91 octane either....

SIMON HOLTBY

i have mine set at about 8* but am going to try higher. Knocking usually appears when the TC locks up in high gear so I'll try increasing the speed it locks. The engine is so much more responsive with more advance its just avoiding the knocks and potential damage.
Thanks

Simon

MikeT 88IROC350

I am also running the ARAP based code, with the base timing at 8deg. I could repeat what Matt said, but I won't. I was getting some knock counts during heavy throttle last summer, thus took some timing out of the advance curve. I would hold back on the base advance of the dist. Don't think it buys you much. The expert engine guys could explain better. 6-8deg is the best setting for our cars. I think the power is in the advance curve. Just make sure your PROM setting matches what the mechanical advance really is.
Just my 2cents.

lock

Mike, Would that be the "Initial Spark Advance" setting in Tunercat? Im messing with the ARAP myself and my timing is WAY high, Diacom shows it reaching 45 or so while driving.

GregWestphal

iTrader: (1)

I'm not Mike, but I'll reply anyways. Yes, base timing is also known as the initial spark advance. The ARAP bin has timing up to 48 degrees, so seeing 45 would be "normal" although 48 is a little excessive. I have mine maxed out at 44 degrees in the mid-to-high-rpm/low-load areas of the s.a. table.

Grumpy

No need to reinvent the wheel, by the time your done you'll be back at 8*.

Funny how easy the buttometer is to fool.
A car shouldn't *feel* fast, it should just pin you to the seat.
Tire spin from a standstill with an auto means you missed the tune. There is alot to tuning, and some of it seems backwards. Tuning EFI is somewhat different from carbs. With EFI you can work the limits of the tires (if you have enough tire), and go for no spin, and that is what gives you max accleration (OK well may 2-3% slippage), but still nothing approaching smoke.

Now using something like launch assist wtihout slicks is just to pysch the other guy out <g>.

SIMON HOLTBY

I've tried higher advance than 8* and have settled on 10* for my car. I can maybe get away with slightly more advance due to 110 octane fuel.
It was mentioned to set this base value in the prom. I wonder what effect this has. I know there is a value for maximum total advance so it will add base value to that in the ignition table and maybe give less maximum available advance ie at high revs low load. Or will it retard all the ignition throughout the rev/load tables?
I sometimes think that my car runs better some days. It kind of feels like it has more ignition advance and is more responsive. But there again it always seems to go better when I have washed and waxed it!
Something else I'm looking into is the EGR valve I'm sure sometimes it sticks open causing a rough idle and code 34. If I put a pipe on it and blow down it, I think this makes it close.
I monitor a forum with guys using propane and they have been getting spectacular gains in fuel economy by disabeling EGR . Strange I thought it would be the other way around. I might give it ago. Setting the enable temperature to some unreachable value should do it. I have read warnings that this causes overheating but most cars in the UK seem to manage without it.

Cheers

Simon

Grumpy

You base timing should reflect what your initial timing is, if your just changing it, without changing the initial your just adding a bias to the numbers.
If you running more then 8* remember that on the odd hot day when the starter motor is slow to crank, and the car doesn't want to start.
There are some roads so well traveled that it's pointless to try and think you're being original, 8* initial and set the base timing to agree with it. Then work on your tables.
Remember there is more then the main spark table to contend with when you make universal changes.