CrazyRS

iTrader: (1)

This is for the nitrous gurus out there in the dry camp. I don't have much experience with dry systems, and I've been pondering some issues related to relying on the computer to increase fuel via the MAF sensor. So here goes...

Issue #1: Density difference between air and nitrous oxide.

When the MAF senses the increased total air density from nitrous injection, won't the computer add fuel based on tables that were designed for a normal air fuel mixture? (I think air is 20% oxygen by volume, and I would imagine the oxygen charge in the cylinder is a great deal higher with nitrous!)

Issue #2: Charge temperature. (related to above)

Most of you, I would assume know how an MAF sensor works, so I won't go into it, but won't the extreme temperature difference (-125 degrees f vs. ambient air temp) act as a multiplier on the already increased total density of the nitrous oxide? This is of course the cool aspect of nitrous , but in terms of computer fuel control, how does it react? Again, I would assume it will adjust fuel based on a table for air?

If the computer is adjusting for changes in normal air density, then wouldn't it be fair to say that the fuel enrichment will not be enough to compensate for the total amount of oxygen that will break away from the N20 molecules at combustion temperature?


I have since found MAF sensors that are calibrated for nitrous injection, and I am guessing it is because of the above.

So, is it really wise to trust the LS1 ECU and stock MAF? It seems like a safer bet to run a dedicated nitrous program that is calibrated for your system? I know that there are plenty of you running dry systems with great success, so I'm very interested in your thoughts and knowledge. Thanks guys.

KCJeff

iTrader: (1)

I'm the furthest thing from a nitrous guru. Just lucky to have some friends who fit the bill. When shopping for a dry system, I didn't want to rely entirely on the MAF sensor for fueling. The Harris dry plate attaches between the throttle body and the intake. The Interface harness plugs directly into the MAF. Lots of adjustments on the Interface for pulling timing, fueling, etc. Tune on a dyno with a wideband o2 sensor to watch & adjust air/fuel ratio. The only fueling problems I've heard are when people max out injector duty (mostly 1998 C5's and on those that are spraying more than a 150 shot).

Hopefully you will receive responses from some of the resident experts. (Beer? Joey?).

CrazyRS

iTrader: (1)

Thanks man. I would definitely love to hear from Robert and camp.

JoeyGC5

iTrader: (24)

Think of it this way. A calibrated sensor is one that has gone through a set routine with the control module and has been calibrated to said set routine. Now buying an after market MAF is nice and all, but you still have to calibrate it to your pcm. No diffeent than what GM did when you bought your car. To me it's the tomato - Tomato arguement. The stock MAF's work fine with dry nitrous kits in accordance with fueling and timing adjustments. Wether these adjustmentsare made via interfaces, pcm calibrations/tuning, or external timing ticker/IAT devices.

CrazyRS

iTrader: (1)

Sure. I would imagine that they work fine, as many people are having success with them. I am simply questioning the accuracy of adjustments. I have just been confused by the die hard dry system lovers. I dig it too, but I am questioning how it is more or less simple or effective than a wet system? It seems that an advanced system needs proper tuning and adjustment either way you go. I am interested in this info because it seems important in the process of choosing wet vs. dry (already an existing thread...I know)...I'd love some more thoughts. Thanks Joey.

JoeyGC5

iTrader: (24)

Honestly I prefer Wet systems for simplicity factor. But the Dry offers the escape from any fuel in the intake puddling issues. Then again your depending so much on the computer to make the most accurate fuel corrections in a dry system.No clear cut way to go.

Alt

iTrader: (6)

You're also depending on your computer to give you the correct fuel w/o nitrous as well. If you can't trust it to do that then you shouldn't have a fuel injected car. Thats my 2 cents. The computer takes care of fueling without nitrous, so pushing the nitrous through the correct area so the computer can fuel it correctly seems like a no brainer to me.

Robert56

iTrader: (2)

Never heard of dedicated nitrous MAFs, or nitrous recalibrations? Your stock tables work fine for dry hits, so no need to do anything in that dept. Many 300 plus dry hits have been jammed down the throat in front of the stock MAF tables. As long as you have the right size injectors and had them rescaled, the sky is the limit as the injector tables are relative to the MAF freq table and MAF freq will increase as you add more nitrous IE; reads a colder mix. actually with the advent of the Interface and dry plate kits, along with the mech adjustablility of the new NX dry kit, they are much, much simpler than a wet hit, imo, and much safer.
Robert