I am working a a gen 5 5.3 with a decent cam, drop in rods and pistons and a pair of 67’s. It is kind of a budget build. It is my intention to turn the boost up pretty high. I am at 17psi now and 900rwhp. It will be at 25psi in soon and likely 30+ this season.

my goal was to keep the timing on the safe side and “make power with boost” but now that I am into it I really don’t know where that “safe” side is.

i will post a chart of 16deg vs 18deg from 6000 up. It really liked that 2 deg. Does that mean keep it or did I just up the cylinder pressure a ton.

Considering how much it liked that timing I am thinking keep it. Thinking 18deg from 6k up at 15psi. Drop that to 16deg at 20psi, 14deg at 25psi, 12deg at 30. In all cases about 4 deg less through peek tq. Good plan? Bad plan?

 

I see that is kind of hard to read. 57hp right where the line is from just 2 deg. This is at 14psi.

 

Would depend on octane, back pressure, etc. If its efficient and you have good octane, it sounds like you have a good plan.

 

pump e85. Current back pressure is close to a 1/1 but I am sure that will go up. Something else it has a massive air to water intercooler with chilled water. Current iat’s are around 70deg and I do not expect that to go up much.

 

Sounds like a stout setup and ready to crank up.

 

+20hp per degree is in the sweet spot to me, as is roughly -.5 degree/lb. Keep an eye on the plugs and it'll let you know what it wants, its not uncommon to have 1200+whp setups in the 12-13 degree range with the plug looking happy.

 

just to be clear. If you get 20 or more hp per deg you keep the timing in? If less you don’t?

with my current rise in hp/psi I will be around 30psi to get 1200hp and be around 12deg if I stick to my plan. Seems like my peek timing plan is adequately safe. How about timing through peek tq? Keep in mind my shift extension should only drop me to 6200 at the shifts.

thanks both of you for the help. I wasn’t sure if this place was still active.

 

If it doesn't make at least 15whp a degree doesnt make sense to keep it there to me, turning up the boost will usually be a bigger impact. But you can try adding a degree or so when you rev them over 7000 see if it picks up where yours starts to drop off 7000-7500. Main thing is watching the plugs it'll let you know when its happy and when you're reaching too far. I'm careful with the peak torque timing on SBE stuff and also having the peak be too low, but yours is fairly flat 4500-6500 so you may just be slowing down your spool taking out timing under 5000, but maybe a degree or two out at 6200 where it would get loaded down again on the shift then ramp it back in up to 7500.

 

Capizzi would tell you to look at the plugs after a hit, but your plan sounds pretty sound.

 

On my combo, rod and piston 6.0 twin FI billet 66s at 20 lb and 16 degrees put the timing mark right at the bend of the strap on the plug with a 11.3 afr. Looked very happy and safe

 

Are the rules unchanged for reading plugs as in put in a new set, minimize idle/cruise time, make a hit or 1/4 pull, pull over and remove a plug or is there more flex than that these days with the advent of fuel injection?

 

I believe that's requires to dial in your fueling if you don't use a wideband. Should check the plugs regardless for fuelint. I don't subscribe that the method you outlined is required to confirm if timing is too much or if there is too much heat in the threads.

 

Let’s talk about this more.

if your on a dyno and can load it so that the run time matches you track time can you read the plugs there or does it have to be at the track? Do you look at all of them or just a couple? Start with fresh plugs I imagine but after that if they didn’t show too much heat can you put them back in and keep going?

my plugs are a bitch to get too and cost $10 ea. There are a few easy to reach ones.

also what does the heat tell you? If it is too hot the plug might glow and you get detonation? I can see how timing would drastically effect cylinder pressure but not clear on how it heats up the plug.

 

I only tune on the street or track. Even load bearing dynos only go so far to recreate the same load as the street or track.

Depends if you're talking about first tune or changes. First tune you need to check all 8 and find the hottest plug or 2. Then you tune to those plugs.

Heat in the plug is typically looked at from the threads. How many threads that change color depends on the heat in the chamber and the plug heat range. You only want to see heat in the 1st thread or 2. More than that and your plugs are too hot and you risk turning the plug into a glow plug and cause preignition.

There's some good videos and sites showing all kinds of plugs and how/what to look for.

 

See this is where I'm at with the car already having a tune, just needing some tweaking.
I recently picked up a 99 Camaro with a forged LS1, billet S484 that has a WOT dyno tune but needs a little work in the cold start and low speed drive-ability tunes.
Plus I'd like to take advantage of the A2W setup and turn the boost up on pump to see what it can make but am trying to learn what the best process is for doing that.
Been watching lots of videos but nothing really helpful about guidelines for tuning based on timing/boost/fuel/IAT etc.
I'm probably not looking in the right place but everyone seems to be running E85 which is largely unavailable where I live.

 

I'm sure opinions will vary, but I've never so much as lost a head gasket with my tuning. My steps:

Fresh plugs before a tuning session.
Keep timing very conservative but in the expected ballpark. You can't throw crap timing at it or you'll have other issues.
Work on getting your AFR dialed in with the wideband.
Once the AFR is what you want, then start dialing in the timing. I typically keep it conservative a bit still.

Once you feel good, head home and let it cool. Pull the plugs and see whose the hottest on each bank. Make sure fueling looks similar between all cylinders. Check heat range in threads, check porcelain for spots, and ground strap for the timing mark. We can have a whole thread about what to do depending on what you see lol. From this point you now have a baseline to start upping the boost or adding timing and can tune to mph or use a dragy to play with gains. If you make changes I always check the hottest plugs again to confirm it's not on the edge.

 

That's great info!
What would be considered conservative ballpark timing using pump fuel I guess would be my question?
If I was gonna fill the tank with ice water and get the IAT's as low as possible and start adding more boost assuming the AFR's were good what would be a good starting point?
Figure 9.5:1 or 10:1 compression LS1 w/ small dish pistons and CNC ported 243's, pump 92 fuel, IAT temps in the 80-100 degree range. (IAT were at 109' with ambient temp water during 1/4 mile passes in 105' heat, no ice so ice should be much better)

 

$10 plugs in a 5.3? WTF? Basic $2 NGK units handle 1500hp no problem.

 

it is a gen v motor. The plugs are longer. I am not sure what the $2 ngk plug would be for a gen v but people seem to like the brisk rr12s so that is what I run. Typically I just use one set a year so it isn’t a problem.

if I am going to be trying to read plugs and that involves using more plugs I may need to find a cheaper unit.

 

Ahh missed that detail, I've seen so many blown up LT's at the dealer and my friends shop I try to forget they exist

What are you doing for fueling or you add port injection?