What ignition system for Lt1 on nitrous

Well nitrous will be going on soon and i dont want to send out my computer to have timing pulled for nitrous i just want to get a ignition system to adjust it when im using it and then going back to my Madz28 tune when im not on nitrous basically have the best of both worlds. On my 93 Z i pulled timing buy using the chip and the car ran horribly slow on motor. Ive heard you can get an ignition system not sure but a mallory 685 and just pull timing out according to how much nitrous your running and then set it back again. Either way whats the best ignition to have when running nitrous, so far ive done all the basics meaning spark plugs for nitrous, i changed my plug wires and coil now im looking for a good ignition system, any help would be appreciated and thanks in advance.

Mallory 685 ign. box here. Flip the nitrous switch on and your good to go.

Ive heard some ignition boxes will not work with some coils, i have a MSD coil on as we speak would it be ok to use the Mallory 685 ignition box with it?

I don't think it would be an issue, alot of people, including myself, use the MSD coil harness to hook up the Mallory box to the stock coil.

Please don't post the same question on multiple forums.

sure no problem, sorry about that.

I have the Mallory 685 box and an MSD coil. No issues and works great.

I have the Mallory 685 box and an MSD coil. No issues and works great.

Same with my set-up.

Will be using a mallory 685.

Will be using a mallory 685.

What were you running to get 13.5? I'm bone stock running 13.5's with 100 shot zex and a cold air intake. 97 LT1 Rebuilt to stock specs but with moly rings, teflon seals, stainless valves no mods to the engine. Just wondered what to compare to. w/0 the nos I'm doin 14.8's :(

Corrected for altitude, temperature and humidty, and with a 2.0-sec or better 60-ft time, a stock LT1 should be running low 14's. With a 100-shot and traction, you should be knocking on the 12's.

hmmm, I'm getting 14.8's stock (CAI) with 2.2-2.4 short times. Wonder why im only getting 14.8's. Maybe a few extra pounds? could that make that much of a difference? I do have a sub box and amp in the back. And the old owner (I bought the car when it was two years old) put a trailer hitch on it cause he used to have a wave runner. What could that be together? 75lbs maybe? I changed to 18" wheels also, 8.5 frnts and 10.5 rears (Ruff Racing) Or maybe Jasper just didn't build the engine right or something. I have a Jasper crate and its based on the stock specs. Its only got about 18,000k on the new engine. IDK. I also bypassed the air temperature sensor with a resistor, my air intake temp always reads 35 deg. lol. I wonder if because I have a Jasper engine if maybe it needs to have more timing or something tuned different then stock? I did call Jasper and ask them and the girl that had to put me on hold every time i asked a question :( told me that the stock flash is what this particular engine recommended.
Maybe I need to change my name to slomaro :/

At Palmdale LACR when it was open, i think elevation is 2700-2900 and horrible track i ran a 2.4 60ft and 14.2 ET at 103 Mph in my 93Z 6speed with all the bolt ons, no nitrous. They say that track is about half a second slow if you were to be running at sea level and better conditions. I went to a different track ofcourse thats closed as well at 106 Degree heat, failed clutch after my 3rd run i got 13.6 at 105mph, no nitrous there either and cant remember my 60ft at that track.

I ran the 13.5 with intake, exhuast, and a 3.73 gear, and dr's.

Stock i ran 14.10's and 14.20's. @99 mph. 60fts on the 13.5 was 2.04, and on the 14.10's 2.21.

hmmm, I'm getting 14.8's stock (CAI) with 2.2-2.4 short times. Wonder why im only getting 14.8'sj


Post up a complete timeslip. Going from a 2.4 to a 2.0 60' can improve your ET by more than 1/2 second. That 14.8 with a 2.4 60' could be a 14.2 with a 2.0.


Maybe a few extra pounds? could that make that much of a difference? I do have a sub box and amp in the back. And the old owner (I bought the car when it was two years old) put a trailer hitch on it cause he used to have a wave runner. What could that be together? 75lbs maybe? I changed to 18" wheels also, 8.5 frnts and 10.5 rears (Ruff Racing)


Weight can also be a factor - from your sub boxes and trailer hitch to your larger wheels.

What size tires are you running? Taller than stock will cut gearing and potentially slow down acceleration.

All factors combined, you are leaving a lot on the table NA. I agree with what Fred said - you should be running close to 14-flat NA and knocking on 12s with a 100 shot.

To the OP... on my nitrous'd '96 Firebird, I used an MSD digital 6 for nitrous rev limit and timing retard. Worked flawlessly back in the day, but there may be better pieces out there today.

I pulled 2 deg for every 50 hp and ran a step colder on the plugs.

I am still running a digital 6....it is the box I would suggest.

THe 685 is a nice piece if you are wanting an all inclusive box....I am wanting to run a seperate nitrous controller so the internal window switch is of no use to me. THe Digital 6 is also a smaller box.

Run w/o nos 60' 2.253, 330' 6.319, 1/8 9.614@74.87, 1000' 12.437, 1/4 14.810@94.93
Run 1 w/nos 60' 2.301, 330' 6.155, 1/8 9.159@82.64, 1000' 11.721, 1/4 13.906@103.29
Run 2 w/nos 60' 2.227, 330' 6.090, 1/8 9.097@82.80, 1000' 11.649, 1/4 13.809@104.38
Run 3 w/nos 60' 2.217, 330' 5.943, 1/8 8.894@84.01, 1000' 11.418, 1/4 13.563@105.06

I checked tire sizes going through this process knowing in my head I wanted to stay as close to stock diameter as possible, the stock tire (245/50/16) has a overall dia. of 25.64
My new tires, Front 235/40/18 (9.25 width) oa dia 25.40 and the rear, 275/35/18 (10.82 width) oa dia is 25.57. So they are slightly smaller.

I do notice i'm having a little bit of a shifting issue while on the nos, but that doesnt really explain the 14.81 stock time, although if your saying the 2.25 60' were a 2.0 then maybe I might be at 14.2 then I would be around normal.

I ordered a b&m shift plus yesterday, hopefully that helps but I think I may need to do something with the trans.

Thanks for all your input.

I really didn't intend on hijacking this thread :(
Sorry bout that karpetcm.

[QUOTE=SpeedZ28;5586586]Run w/o nos 60' 2.253, 330' 6.319, 1/8 9.614@74.87, 1000' 12.437, 1/4 14.810@94.93
Run 1 w/nos 60' 2.301, 330' 6.155, 1/8 9.159@82.64, 1000' 11.721, 1/4 13.906@103.29
Run 2 w/nos 60' 2.227, 330' 6.090, 1/8 9.097@82.80, 1000' 11.649, 1/4 13.809@104.38
Run 3 w/nos 60' 2.217, 330' 5.943, 1/8 8.894@84.01, 1000' 11.418, 1/4 13.563@105.06


You need some drag radials. Bad.

Has anyone mentioned the digital 6 yet?:D

Yeah those 60s are horrible man...not real sure how yours is setup...maybe hit it a little further out (once you hook). May just need some more seat time...that alone can pick a car up without changing anything.