How is everyone pulling timing for Nitrous when its in use?

 

 

Is this documented somewhere? I have read a lot about people getting a tune done. Is it possible to switch between tunes?

 

I use an LNC2000... that way I keep my NA tune and it just pulls timing when on the spray....

 

 

J&S Interceptor. I didn't pull any timing. Ran up to a 275 shot (2 kits) on 93 pump gas in my Cobra on top of 18 psi from twin 57mm turbos all at 56 degrees of timing. The thing flat out works. Soon installing in my ZO6 for a 100-175 shot on pump gas. J&S is far superior to the factory detonation control via the PCM and knock sensors.

 

 

Been in the GM world for over a decade. Just decided it's time to ditch the factory garbage so I can run some spray. Factory GM spark retard logic is just that...retarded.

 

56 degrees of timing?!?!?

 

YESSIR! On spray AND boost AND pump gas. NO RETARD AT ALL!

EDIT: That's how the J&S works. It allows the tuner to "see" ACTUAL knock in the cylinder. But it doesn't globally retard timing like the GM (or Ford in my previous example) logic does. It pulls timing ONLY to the cylinder pinging and slowly (by slowly, I mean 2 deg per every 720 deg rotation of the crankshaft until the next detected ping) returns timing to normal. If it was a "freak" ping then it's full timing restored and business as usual. If it hears another "ping," it retards and maintains 1 deg of timing below the "ping" threshold and holds there for a time variable...approx. 3 seconds IIRC, then the cycle starts all over again. The reason this is a big deal is because in lamens terms, a tuner can tune ANY combination right up to the ragged edge of detonation and provide a 10/20 deg safety net (adjustable by switch). In more basic terms, you can get the MAXIMUM SAFE power out of any combo. NEVER hurt your motor. Pretty sweet if you have 15-20K in a motor. No tuner would've put 56* in my Cobra on a hunch or guess. We played in the 28-32* range for years before the J&S. I would retard 4* while spraying, yadda yadda. The J&S SHOWED us that we were nowhere close to pinging. So we went up 5* a pull (while street tuning) until we reached 58*!!! At 58* we finally saw knock in multiple cylinders (on boost only). Backed it down to 56* and left it for YEARS! While spraying such a huge shot, I never saw anything but trace knock on the initial hit. All this due to the J&S. Worth EVERY PENNY! Think about it this way...the FIRST time it activates, it just paid for itself by saving your engine.

 

untill it forgets to wake up one day?

anyway, what did you do to the engine that it needs that much timing? i had a prv engine that needed 32° at 1.6 bars, but 56°?

 

 

That's a risk with EVERY piece of aftermarket gear. But 6 years on the car, it never failed me once. It was lower-ish CR at 9.28:1 and it's a 4V motor with advanced intake cams. Not that it really explains WHY my motor could take so much timing...but the point is, we would've never found the knock threshold without the J&S.

 

Just because it CAN take that much timing doesn't mean it's making any extra power WITH that timing.

I use an IAT tricker and modified the tune for it. I have it set to show a negative temperature so that the computer actually adds a little fuel instead of having it show a hot temperature and the computer pull fuel..

 

Until you dyno it...and it picked up 84 ft lbs over it's 32* timing setting.

 

This sounds like an interesting route to take. Doesn't the nitrous kit increase fuel pressure to push more fuel through the injectors with a wet kit? Will it be too rich?

What does your setup look like ot trick the IAT?

 

EFILive Custom OS 5 has the option to pull/add fuel and pull timing using a spare PCM pin.

 

 

Is there a good detailed post on how to do the IAT trick?

 

https://ls1tech.com/forums/nitrous-o...-hptuners.html

https://ls1tech.com/forums/nitrous-o...icker-mod.html