Sinister95Z

I am new to the nitrous game and have a few questions regarding my Mallory 685 box. Before I permanetly mount it, I want to get all the settings correct. I have a PCMForLess tune (not tuned for the nitrous), Tr-6 plugs and a Harris Speed Works Wet kit in which I will be spraying a 100 shot. My car is a 95 Camaro Z28. Here are my three questions:

1) What should I set the main rev limiter at? What is the factory limiter set at?

2) Being extra cautious, what should I set my window switch at? Opening RPM and Closing RPM.

3) What is the best way to hook up the timing retard function? How many degrees should I retard the timing with my PCM performance tune?

Any other advice would be appreciated as well.

Ray@NitroDaves

you would have to ask PCMforless what they set the rev limiter at.
Correct me if I am wrong but I think the factory rev limiter is set at 5800.


Is your car an auto or manual...if auto do you want to spray through the shifts.

Open RPM should never be below 3000rpm, that is to ensure you have enough velocity through the intake to prevent puddling.
Close rpm should be 1-300rpm before the rev limiter on a M6 or befoere the shift point if an auto and you do not want to spray through the shift.

Spraying through the shift will net a faster ET but will be harder on the tranny.

For my personal car my window is 3000-6900 w/a 7000rpm rev limiter
My current shift point is 6500 w/a full manual 700r4.
I am spraying from green light to win light.


With the normal installation wiring it will automatically retard the timing when the kit activates. For starters I would pull 2-4 degrees on stock timing as long as you are seeing no knock retard or signs of detonation on the plugs you can add more timing back in....some cars will need no timing pulled for a 100 shot others might need 5+ degrees pulled. Every car is different

Hope this helps...let me know if you have any other questions.




P.S. try to keep a straight face the first time you spray it....I didn't stop smiling for a week :drive:

LT-x7

Looks like ray nailed everything.
I was told the stock limiter was 5886 rpm. I set mine at 6000, and my window from 3000 to 5800.

Sinister95Z

Thanks for the replies. That is what I am looking for...examples of how people with similar set-ups are setting up the 685. I drive a M6 by the way.

Injuneer

In the stock M6 programming for the LT1, the rev limiter for 1st gear is 5,886 rpm, and for all other gears its 5,805 rpm.

Sinister95Z

I'll run what I am thinking about doing by you guys and see what you think. Please critique:

Main RPM limiter: 5800 RPM's
Window Switch Start: 3200 RPM's
Window Switch Finish: 5600 RPM's
Timing retard when Nitrous is active: 4 Degrees

Since I have the PCMforless tuning, I figure this would put me at about 2 degrees retarded. (Counting the advance of the tune)

If I ever disconnect my battery, will the 685 keep my settings stored or will I have to reset them every time?

seawolf06

How do you know how much you're already advanced?

LT-x7

It will keep the settings when you disconnect the battery.
Your settings sound fine to me.

69gto96z

Those are the exact settings I am going to use. I have a MadZ28 tune with a 2 degree advance. I am hoping I spray safely on my stock motor with 125k miles on it.

97formulakid

I run the 685 also and these are all of my settings.

Rev limiter - 6500 (I don't really use it because the Madz tune is set at 6000)

Window on - 3800
Window off - 5800

Timing retard - 3 degrees

I am running TR6's, 125 shot through a Nitrous Works plate kit, and a Madz tune.

nfa

Aint that the truth!!! I had originally planned on trying it out for the first time with a 50 shot, but my friend convinced me to try out the 125 shot first. Cold day, street tires and engaging the nitrous in 2nd gear at 3000 rpm resulted in the back end stepping out and the car shooting across to another lane - scared the crap out of me. Once I got used to it, the instant rush of power was amazing. I love nitrous!

01Z

Me too! I just wish the bottle would either last longer or it didn't cost me $50 and change to fill it.

camzaro28

If the battery is disconnected it will stil have your settings stored.
my window switch is 3200-5600 ( i tried 5700 and hit the rev limiter on the 2-3 shift )
My madz28 tune has the timing advanced 1 deg, so I have the timing 6.5 on the mallory. Total of 5.5 degrees.
Also, I am spraying a 150

Sinister95Z

Thank you for your input. That is the help I was looking for.

97formulakid

camzaro28 - why are you retarding your timing so much. I talked to Madz28 and he said that only 2-3 degrees was necessary for a 150 shot. You might look into that.