Nitrous Oxide - Closed Loop Tune... Wet OR Dry Nitrous?

im completely new to nitrous and i have a LQ4 in my 65 Chevelle...

the engine had 29k miles on it when it was pulled out of a silverado 2500 by a engine builder/tuner in reno, nv

i was planning on going with a turbo to get more power. but since i dont need all the power all the time(being my daily driver), ive been strongly considering going the nitrous route.

the engine has a Closed Loop Tune(Version of "Speed Density" i am told?)

This is how the tuner described it:
Closed Loop Tuning
This is the fuel injection system that I prefer for aftermarket projects. It utilizes every sensor except the MAF. The O2 sensors adjust fuel below 80% throttle. Above 80% throttle (Power Enrichment) fuel is calculated from a table using the TPS, MAP, RPM, etc. This system DOES adjust with altitude via the MAP (Manifold Absolute Pressure) sensor. The MAP sensor is also used as a BARO (Barometric) Sensor. As you gain or loose altitude the ECM will “shift” the fuel calculations.

what would be the best and safest nitrous to go with, a WET or DRY shot?

what i have:
LQ4(Stock Internally/Externally)
Modified Harness
Closed Loop Tune(91 Octane)
Stock Manifolds
Stock 4L80E Transmission
No Cats
Single Walbro 255

also what kind of a nitrous shot could i run occasionally(1 night every other week[or less] in the summer) without a new tune?

if i was to get a tune and a methanol injection kit what could i bump the nitrous to?

sorry for the long post

thanks everyone.

anyone...

whos your tuner in reno?

BD Turnkey(Bryan) had it bench tuned when I got my engine.

Id go wet. Sd tune basically u dont have an maf. You can adjust for fuel if u need a little more or less, you should get ur computer re tuned for nitrous. But im no expert especially sd tuned cars.

Nitrous Outlet Wet Plate Kit

DONE

Nitrous Outlet Wet Plate Kit

DONE

thank you

advice on shot limit without upgrading my tune/adding a maf?

"must have" safety systems/switches that need to be added to the kit?

im completely new to nitrous and i have a LQ4 in my 65 Chevelle...

the engine had 29k miles on it when it was pulled out of a silverado 2500 by a engine builder/tuner in reno, nv

i was planning on going with a turbo to get more power. but since i dont need all the power all the time(being my daily driver), ive been strongly considering going the nitrous route.

the engine has a Closed Loop Tune(Version of "Speed Density" i am told?)

This is how the tuner described it:


what would be the best and safest nitrous to go with, a WET or DRY shot?

what i have:
LQ4(Stock Internally/Externally)
Modified Harness
Closed Loop Tune(91 Octane)
Stock Manifolds
Stock 4L80E Transmission
No Cats
Single Walbro 255

also what kind of a nitrous shot could i run occasionally(1 night every other week[or less] in the summer) without a new tune?

if i was to get a tune and a methanol injection kit what could i bump the nitrous to?

sorry for the long post

thanks everyone.

Think of it this way...
Doesnt matter if its an open loop or a closed loop tune, because at WOT, its always open loop

Speed Density Means that the PCM does not use the MAF to calculate Density to figure out fueling..its strictly relying on the VE table which has to be set properly.
either way... the MAF or the VE have to be tuned correctly for your car to have the correct fueling..

The car doesnt go into open loop at 80% throttle, it goes by a table, which varies by rpm, but you will find that it comes on as early as 50% on some vehicles
the system does not adjust for altitude via the MAP... yes, it will read 100kpa at 14000ft or at sea level, but it has no idea about density of the air...in Speed Density, it assumes you are staying at a similar altitude, it never corrects for it...fuel trims will adjust for part throttle, bit WOT has no idea and its Just following the #'s in the tables
With a MAF, it measures the actual Density by heating some wires up, and it measures how much current it has to put back in when air blows across it and cools them down. with a MAF system, it can adjust for altitude because the density of the air changes with altitude.
once you tune with a MAF, you will not want to go back to Speed Density on a stock GM PCM

you could always go to an Aftermarket ECU that has better temperature correction and Barometric pressure correction and utilizes a true full time closed loop compensation no matter what throttle position you are at..meaning it never goes into open loop...


Wet or Dry...
well..Wet will in general be the simplest to do, and you can tune it yourself without having to go into the tables in the PCM
you get a nitrous solenoid and Jets and a Fuel Solenoid and Jets..check the plugs and use a wideband, and you can adjust fueling as necessary with the Jets.

you can do Dry Just as easy, but you either need to know a good tuner who you can always have available to retune as necessary, or you need to know how to tune it yourself..
the nitrous side is still the same..but the fueling side has to be done thru the Injectors..

both methods will require you to pull some timing..so you will need a tune of some sort before you can start to spray....
but there are a handful of timing controllers you can also buy and it you wouldnt have to touch the timing that way...

as far as methanol goes....
yes, you can run more timing...
but truthfully, you need to know what you are doing first...and you really need to know what you are doing....

you can easily do a 200 shot without methanol

start on a smaller shot of nitrous and work your way up...
you can easily do a 200 shot without methanol
if you want to go bigger, you need to know that your engine parts can handle it..
and since you say the motor has stock internals... I would stick to a 150 shot at the most...200 if you are feeling lucky as that is the typical start of the breaking point on that motor....guys are doing more on stock internals...but its borrowed time..and you will be replacing a motor sooner than later with a 200+ shot

Since you are not doing your own pcm tuning I would keep it simple and put a wet system on it. Then dial it in accordingly.

Like Scott said either wet or dry will work. I personaly will not run a dry with the factory pcm. Just my preference.
Dave

thank you

advice on shot limit without upgrading my tune/adding a maf?

"must have" safety systems/switches that need to be added to the kit?

Colder plugs, non projected tip
Adequate fuel pump
wideband is nice
Pull appropriate amount of timing
Bottle heater
Pressure Gauge
Window switch

Start with 100 shot and work up to 150

Colder plugs, non projected tip
Adequate fuel pump
wideband is nice
Pull appropriate amount of timing
Bottle heater
Pressure Gauge
Window switch

Start with 100 shot and work up to 150


add a Fuel pressure safety switch to that list
if you are looking at a gauge, you are looking at the wrong things
let a switch shut off the nitrous for you in the event of a fuel pressure issue

I meant nitrous pressure gauge...

Fuel pressure switches are a pain in the ass. I've had nothing but trouble with them and a lot of others have too.

But if you want to use one, more power to you. It's a good idea, but doesnt work worth a shit.

If a fuel pressure safety switch doesn't work right, you either are buying a cheap one, or you.have it set up wrong, or you don't understand your fuel system or its pressure drop when at WOT