COS5 N20 Settings??

[427]

ok guys heres a little information, a while ago now, i actually rang Paul from EFILive to up the multiplier tables to 3.0 as they were only 1.3 years ago, and i couldnt get enough fuel to flow whilst on NOS.

As a good guide, this is how ive tuned many NOS cars including my own, If running a dry shot, and using big injectors, run car at approx 12.8AFR Naturally Aspirated, Arm the NOS system, with NOS bottle turned OFF, depending on NOS shot eg 200hp aim for 10.4 AFR, making sure timing retard is working correctly, run car in closed loope for approx 5 minutes, to clean spark plugs after a extreamly rich mixture.

Heat bottles to 1180psi using an accurate pressure guage, and carry out test on dyno with NOS Bottles turned on. I personally find with a 10.2 to 10.4 AFR with a 200hp NOS shot, AFR will rise to approx 11.8-11.9AFR with the NOS bottles turned on. Just remember this is a guide only. Make sure you have 2 degrees retard for every 50hp of NOS at a minimum.

Just remember this is a guide on what i find, others may find different. Depending on fuel system and Injectors used.

Damm -

why the big bottle pressure

You dont feel once it hits 10.2-10.3 afr the plugs are shot?

[5.7ute]

Damm -

why the big bottle pressure

You dont feel once it hits 10.2-10.3 afr the plugs are shot?

Following Brad's (VYSSLS1) advice a year or so ago when I set up my dry shot it only took a small tweak to get the AFR where I wanted it when spraying. Mind you I only run a 150 shot at 1050psi bottle pressure.
Having the AFR run at around 10.2 for a pass had no adverse effects on the plugs which had cleaned themselves up by the time I returned to the pits.

[VYSSLS1]

Why run the bottle pressure that high?

is simply, your tuning a NOS kit, in a workshop on a dyno, without a bottle heater your pressure will probably sit around 800-850psi, they can even drop down to 700psi on a 18 degree night.

Now what happens when you have the car at a drag strip, the vehicle is parked in the pits, with direct sunlight on the vehicle, and ambient temp at approx 30degrees C, have a look at the bottle pressure, and it will be at approx 1050-1100 psi.

If i run my ute on a 30 degree day, my bottles constantly sit at 1200psi, as they are exposed to the temperatures.

1200psi isnt a big deal, as they say when filling the bottles you can go to 1200 psi, so obviously there isnt a big deal about running them at 1200 psi.

The bottles could probably take 1800 psi, before anything would go wrong, but i wouldnt go higher than 1200 psi, before id be worried.

As for spark plugs, if youve put a new set in anyway, a couple runs running a extreamly rich mixture NA isnt going to hurt the plugs, one cylinder temperatures reach a certain point, which is found in closed loope operation, the spark plugs actually clean themselves.

If youve done 10 or so runs trying to set your AFR where you want them, well then id say change the plugs, as youve probably killed the plugs by then.

If we were to run a extreamly rich mixture with methanol, yes methanol does coat the plugs, and no we dont have closed loope, so the spark plugs are normally stuffed after running at a extreamly rich mixture.

When i use to tune my older commodore with a 375hp NOS shot, i aimed for a AFR of 10.0-10.2 when the gas was turned on running a 200hp shot, when the extra 175hp shot was turned on this mixture used to go to 11.4-11.5. And to protect a standard bottom end i use to run the vehicle at 11.0 AFR at approx 6000rpm.