StevieZ

iTrader: (3)

I presently am seeing 30* WOT with little or no knock. It showed a 2 HP gain pretty much across the board compared to 29* but with 29* , I got absolutely no KR and with 30* I get .5* KR sometimes. How much timing is everyone else running?

Jpr5690

iTrader: (13)

im not sure but if your seeing gaqins and no knock then u must be gong in the right direstion (imo) im pritty sure its one of those things where you'll know when its too much by the loss of hp

MyLS1Hauls

iTrader: (2)

If 29 got you no KR, thats what I'd be running, just in case you run into hotter weather and or worse fuel. 2hp is negligible.

WS6 GreeN

I agree with the above.

jaywoo

I don't agree. If you can run 35* with no knock, run 35. Keep going up a little at a time until you run in to some KR, then back it off a bit.

MyLS1Hauls

iTrader: (2)

These motors dont really need anymore timing above about 28-29 degrees due to the efficient combustion chambers. Look at the post Jason 99T/A made about what high timing and poor fuel did to his pistons!

CAT3

iTrader: (9)

Question on this one. Would it be more that he had bad fuel and was detonating w/out knowing it or just as you lead the timing? It seems to me that bad gas, or insufficient supply etc.. and detonation would be a killer even for a car w/ stock timing. I am not flaming, seeking more knowledge. I agree the combustion chambers are superior to older designs, but if you can step the timing up a couple degrees without knock, and det.(safely) than why not?

jaywoo

Yep, detonation did in those pistons. That's why I said advance the timing until you get a little KR, then back it off. Fuel is important also. I always run 93 octane, so it's easy to tune for it. Outside temp can also cause detonation, so you need to factor that in. As long as your A/F is somewshere around 13.0 (what I tune for with my techedge) and I'm not getting any knock, the engine is safe.

BLK02WS6

iTrader: (2)

I would also caution against using too much timing. I did in a set of pistons because of a tune with too much timing.

The thing about detonation from too much timing is that it can be present without hearing it or having any KR show up.

The mail order tune I got had mine way too advanced right in the heart of the daily driving range (too much throughout for that matter, but the worst at 1,800 to 2,200) - I never heard a ping or saw any KR where you tend to watch for it most.

I had a live data scanner instead of a data recorder, so that may have had something to do with it. I may have been saved if I was logging with ATAP vice watching live.

Just my 2 cents - Is 2 HP really worth the thousands it will cost you later?

critter

iTrader: (9)

It is sort of an old wives tail that more lead is better. In fact, you generally want to arrange the engine to minimize the lead it takes. In my experience, max hp is usually a couple degrees back from knock.

StevieZ

iTrader: (3)

I pulled it back to max 29* and may even go back to the stock 98 timing wich is max 28* and is already quite aggressive.

MyLS1Hauls

iTrader: (2)

From the bit of timing tuning I've been doing, there's more to be gained in editing the tuning in the midrange rather than the peak. I've got mine running a max of 29 deg peak, but have the area in front of and after the torque peak bumped up by about 4-5 deg. I've also seen jagged dyno graphs from too high of timing, yet the engine was showing no KR. The timing was pulled back 2 deg and the curve smoothed right out even though the car lost a few peak hp.

TheDogofWar

iTrader: (2)

Just FYI, you'll find that alot of tunners are getting better numbers throughout using a less aggresive spark with large cams.

Pro Stock John

iTrader: (34)

I totally agree with this statement.

Also keep in mind that your car will run leaner on the street and the strip than it will on a Dynojet.

With my 422ci we had 29 degrees but we ramped it back to 25 degrees and it made the same power. If I were you I'd tune that stroker for a 12:1 AF on a Dynojet.