My setup: 1994 Z automatic, small cam and bolt-ons. I have NGK tr6's but they are gapped to .50. I read the reference chart and I should gap them down to .35-.38. I just installed the mallory 685, and it's set to go on at 3300, off at 5600. I'm not sure if the high speed retard is actually working, I may have wired it wrong, but the rest of the ignition is functioning. The reason I think it is wired wrong is that with the full 15 degrees of retard I still see spark knock in datamaster. I am thinkin about putting the h/s retard directly to positive to see if I have it wired wrong. I have it tapped into the relay so that it only sees power when the solenoids are activated. That should be a surefire way to see if I have it setup wrong.

My fuel pressure is 41 flowing @ wot, bottle pressure hovers between 900 and 950. Today I went out and tried various retards, and still saw up to 9 degrees of spark knock, so I let off right away. No audible detonation though?!! I feel like the retard!! I have a 41 nitrous and 23 fuel jet in. Would my jetting be far off enough to cause this? Should I try different fuel or nitrous jets? Would just the gap on the plug be causing this, even with the timing retarded (assuming its wired correctly) The knock retard occurs as soon as the system is engaged at the given rpm. Is the knock retard false maybe? If I go to pull the plugs after running, do I have to shut the car down RIGHT after spraying, or can I go a little distance, shut it off and then check them? Any suggestions would be appreciated, I'm ready to drive it off a cliff!

 

here i how i know that i had my retard wired in correctly. start the car up, let it idle for a minute or so. then set the mallory retard back to 15 degrees, and flip ur toggle to turn ur nitrous on.
right there u should notice ur car idling like crap, not smooth anymore. that would be a start
GL

 

I don't have my system wired like that. I stole power from the relay, so that when I'm in the window, the arming switch, fpss, and wot switch are all triggering the solenoids the relay sends power to the mallory to start retard.

Isn't it a bad idea to wire that to your arming switch? Aren't you pulling timing across the entire rpm range when you do it like that (when your outside of the window and off the bottle). I thought the idea was to only pull the timing when the car was spraying so as to not lose performance before the bottle kicks in. Does the window also control when the retard starts and stops? If it does than wiring it to the arming switch would be fine I suppose.

 

well i dont plan on having the nitrous armed when i am just cruising around. so i dont see y flipping the toggle a few seconds b4 spraying is gonna do any damage or hurt performance.
well GL, we wired ours up completly differently and this was my first time ever doing it. so i hope someone else chimes in

 

I have mine wired up in a similiar way. The mallory box only pulls spark when the nitrous is spraying in my set-up. I just ordered my cable to hook my laptop up to so i dont know as of now im getting any spark knock while spraying. Try gapping the plugs down and see if that helps any. (Mine are at .35) My kit sprays strong so im not thinking about much if any spark knock from it.

 

I have mine setup to retard like that, but I think I might be grabbing power from the wrong pole on the relay. A NOTICEABLE lack of performance should occur if I jack the retard all the way to 15 degrees, right? 15 degrees seems like a ton of timing to pull, and the car should run like a dog with that much retard. Instead, when I change the timing, no noticeable change between no retard and 15 degrees. That means it's wired wrong, correct? I would think the change in performance would be obvious.

 

yeah it is very obvious. no way u cant notice with that much, i can even notice with 5 off.

 

I wired in an LED (flashing) to let me know when voltage was being supplied to the yellow trigger wire on the Hyfire. You can do this with a relay that supplies voltage to the LED when all points are grounded through the Mallory. This way I know for certain when timing is being pulled or at least when the Mallory has gotten the word to pull it.

The trouble with these setups is there are so many ways to accomplish the same thing that one man's poison is another man's quiche.

Are you certain you are getting good fuel flow through the nozzle; have you tested this to make sure?

 

The LED is a great idea, thanks for that. I am pretty sure most of my problem is caused by me. I had my plugs gapped stock, instead of .35-.38, and I dont' think my mallory was wired correctly so it would retard the timing. I'll give these things a shot in the next couple days (weather permitting) and hope that it helps. The car seems to pull strong on the spray, but there is a slight hesitation initially when the system activates, and datamaster shows knock retard which worries me a lot since I'm not on forged internals.

You said the led flashes when all points are grounded......I thought the h/s retard wire was wired to positive to activate, correct me if I'm wrong.

 

With 41.5 fuel pressure(on my old set-up) and a 41 nitrous jet, I had to run a 27-28 fuel jet to get away from detonation(this was proven on the dyno)......every engine is slightly different...and for me the generic jet calculators and their recomendations were always WAY lean......for example: Even with a "higher" 43.5 fuel pressure, NOS recomends a 40 nitrous jet with a 28 fuel jet for their 75 shot......many guys would consider this a VERY rich setting, but On the dyno I've seen It to be very close to just right on some engines.........my point is that I would always start rich, you can always lean it out while on a wideband and while reading the plugs..good luck

 

The flashing LED is a component feature. You can buy leds that flash when energized. The anode must be connected to positive. They are about twice the price of regular LEDs.

The h/s retard receives a 12 volt signal to activate, so you are correct. The LED has voltage the same time the h/s retard gets it. The Mallory provides the ground when the rpm window is achieved. The relay circuit for the timing retard and LED that I mentioned is activated when the WOT circuit comes alive. That is how I wired my system to only retard timing when all three conditions (armed, rpm and wot) are met. The LED lights the same time the voltage signal is present.

wishing you the best.

 

listen to that ^^^^ guy, he was of great help to me.
thanks again glen

 

I think I got the detonation under control. My mallory's retard was functioning correctly. I replaced my ngk tr6's that I had gapped stock to autolite 103's gapped @ .35 (because they were readily available), went down to a 40 nitrous jet and up to a 24 fuel jet, and ended up pulling 3 degrees of timing and set the window at 3100 to 5800. I think it is closer than it was before, (also, the tr6's read LEAN) and there is no hesitation on the initial hit of the system. It doesn't seem to pull very hard with this combination, but I will be able to see what it's doing a little better when I get it on a wideband. I parked the car right after the run. I'm going to go through and read the plugs tomorrow after the car is good and cool. I assume it makes no difference how long it sits after I run it on the bottle, so long as I read them before I fire it up again.

My only question that remains, now when I get completely off the throttle after a nitrous/wot blast there is a little bit of crackling/backfiring, nothing too loud or aggressive, but it's there. The entire run through the gears is fine, it's only after it's all over and I'm slowing down. Is this anything significant?

Thanks for all the help so far!!!

 

I personally like the Autolite 103's gapped at 35-37 better than any of the NGK plugs I've ran, they seem to read more even and they seem to last alot longer also......(like you did)after your fullthrottle nitrous pass, shut the car right off and check the plugs with no additional driving to affect the plug readings(yea, you can wait till it cools)........does the crackling/backfiring your talking about "also" happen after letting off the throttle from a full NON-nitrous pass, or just slowing down after a Bottle pass?.........see what you come up with with reading the plugs, it "could" be too lean still, it's hard to say.......and if you bring your jetting up from there (which Im sure you will )here are some safe starting points that worked great on mine on the dyno 51/34 = 100est RWHP......and 65/38= 125 est RWHP.....this was with 43.5 fuel pressure....with your 41 PSI go one higher on the fuel jettings...........Joe

 

Only mild backfiring after a bottle pass and throttle lift. Does this nescessarily indicate a lean condition? I can't wait to pull the plugs tomorrow, the weather crapped out on me today or I probably would have done it after the car cooled.

Just curious, but this jetting I am messing around with right now is around 70-75 shot I guess, from the calculators.....Is this rwhp? It doesn't feel like it hits very hard, of course I have never rode in a properly tuned nitrous equipped car before either..... I would think adding 75 rwhp would be a real kick in the pants. You mentioned I would probably mess with the higher jettings, and I probably will....and I wish I would have built this motor with better internals, but at the time I couldn't get the money and it was a daily driver.

How do you think a 75/100/125 shot would change my et? I've ran a best of 13.25 @ 104 on MT ET Streets/2k stall/3.73's N/A. I'm considering a higher stall when money permits, because my best 60' is 1.85 with some suspension work and sticky tires. The car almost bogs out of the hole.

I really appreciate all the answers and suggestions, pretty quick answers too!