Timing for 150 shot

[RocketcarX]

So my tuner has my max timing around 31.5-32* on my all motor tune and "100" shot tune at 25* total, since that is basically 7 degrees pulled out of total timing shouldn't I be able to step up to the 150 shot with this timing setting?
The current tune on 100 shows zero knock retard.
What has been everyone's experience with total timing and nitrous on the 3v?

 

[702GT]

On 91 octane my 100 shot was 19 degrees at the top. 91 NA was 27 degrees. My tuner never pushed more timing than was needed. Once gains per degree diminished, he stopped. I think around 3hp per degree was his cutoff. I could run more timing without detonation, but the gains didn't justify it.

Nitrous is an accelerant, it can be somewhat unpredicatable. While it cools the air charge as it flows through the intake, it burns extremely hot once combustion occurs.

On a 100 shot, you can just about run NA timing, but you don't have any safety net. Fuel has to be spot on. 150 should be treated with respect, whatever you run on 100 shot, knock it down a few pegs.

 

[RocketcarX]

On 91 octane my 100 shot was 19 degrees at the top. 91 NA was 27 degrees. My tuner never pushed more timing than was needed. Once gains per degree diminished, he stopped. I think around 3hp per degree was his cutoff. I could run more timing without detonation, but the gains didn't justify it.

Nitrous is an accelerant, it can be somewhat unpredicatable. While it cools the air charge as it flows through the intake, it burns extremely hot once combustion occurs.

On a 100 shot, you can just about run NA timing, but you don't have any safety net. Fuel has to be spot on. 150 should be treated with respect, whatever you run on 100 shot, knock it down a few pegs.

Do you not think the 2* for 50 horsepower applies to the 3v? I'm on 93 octane for what it is worth. When I was tuning myself I ran 28* total N/A, but I figured the well know tuner I am using is more knowledgeable, the car runs great at the 32* total N/A he uses. He mentioned 20* being the set point for a 200 shot. I've let go of that goal for now, and just want to move on to the 150 shot at this point.

 

[702GT]

If there's gains it's good. 93 is much better than west coast 91. On my setup I stopped making gains after 28 degrees, it was maybe a couple hp for a couple degrees, not worth risking detonation. Seen some horror tunes in town. If he knows what he's doing, tuning a 150 shot will be a walk in the park.

 

[RocketcarX]

I was thinking about having my tuner pull the timing back to 20* and going for the 150 shot on my next tune revision.
I have the car dialed in pretty consistently on the 100 shot, being able to adjust the nitrous controller to hold an AFR based on my wideband in real time is helping a lot, that and the separate ramp for the fuel solenoid have really allowed me to flatten out the spikes and valleys on the AFR line in my datalog. Way less of a lean spot on the hit and really getting into target range quick.
The return fuel system fixed the drop to 18-22psi I was seeing on the hit, the lowest it drops now is to 42psi from the 58psi delta I'm using with the new regulator, the recovery time is much faster.
I want to work on a few different things in the nitrous tune and see if making some strategy changes in the nitrous controller helps dial in in even further, pending that I think I'm ready to do the 150 shot. I may be chasing my tail trying to flatten out the AFR on the nitrous to too fine a level, I guess we'll see.
I will also start with a less aggressive ramp on the nitrous activation, I bring it in from 27% at 2650rpm to 100% at 3550rpm with the 100 shot. I was figuring I would reduce the percentage at the low rpm to 18% and raise the starting rpm to 2800 and stretch the ramp to 3800rpm for 100%.

How much do you think traction plays a roll in AFR, meaning the load of a car hooking verses spinning the tires and the rpm moving up faster?

 

[702GT]

I was thinking about having my tuner pull the timing back to 20* and going for the 150 shot on my next tune revision.
I have the car dialed in pretty consistently on the 100 shot, being able to adjust the nitrous controller to hold an AFR based on my wideband in real time is helping a lot, that and the separate ramp for the fuel solenoid have really allowed me to flatten out the spikes and valleys on the AFR line in my datalog. Way less of a lean spot on the hit and really getting into target range quick.
The return fuel system fixed the drop to 18-22psi I was seeing on the hit, the lowest it drops now is to 42psi from the 58psi delta I'm using with the new regulator, the recovery time is much faster.
I want to work on a few different things in the nitrous tune and see if making some strategy changes in the nitrous controller helps dial in in even further, pending that I think I'm ready to do the 150 shot. I may be chasing my tail trying to flatten out the AFR on the nitrous to too fine a level, I guess we'll see.
I will also start with a less aggressive ramp on the nitrous activation, I bring it in from 27% at 2650rpm to 100% at 3550rpm with the 100 shot. I was figuring I would reduce the percentage at the low rpm to 18% and raise the starting rpm to 2800 and stretch the ramp to 3800rpm for 100%.

How much do you think traction plays a roll in AFR, meaning the load of a car hooking verses spinning the tires and the rpm moving up faster?

It's not wheel spin that would hurt the AFR, but the load-up that happens when if it catches traction too hard. Usually you'll break hardware before you have AFR issues (axels, diffs, driveshaft, clutch, tranny, ect.,). If you were free spinning with no load, it'd be an issue if you suddenly hooked with spray in the manifold. But from a drag launch with normal wheel spin, there's enough load it shouldn't be an issue. If you launch and catch no grip and just spin, you're going to have to peddle it anyway, which should be deactivating/reactivating spray as you peddle into traction. But from a drag point of view, if you botch your launch right out if the hole, there's no point in trying to make up for it and punishing your car. You either get a good run or you don't. When I'd botch a launch, I'd baby down the track after. Fast enough to get out if the next runs way, but not gonna throw the car balls to the wall, as if I'll make up that 60' after the 1/8th lol.

On the street, as I said, you should be peddling the throttle to maintain traction, even if that means sacrificing power and your grudge. If having constant traction issues under spray, I would address those issues directly, as you may not have enough tire or weight transfer for the torque, ultimately the road quality will be the deciding factor.

If you were doing nitrous burnouts for show, I'd say you want to definately jet for the rich side (though spraying for burnouts is generally bad form), but it sounds more of a drag traction issue. Your datalogs should tell you if you're getting extreme load spikes, but I'd bet they'll show minor changes in load during traction loss. Had a buddy with minor traction issues with spray on the track, mostly from other cars dripping water from the burnout box onto the line. He'd break loose but it wasn't worth peddling because there was enough traction to get him through 1st and 2nd would hookup pretty quick. If he tried to peddle it would dead hook, and yield a slower E/T than if he just stays in it. All that said, let your datalogs be your guide.