crkemppainen

OK, i'm trying to sort out the nitrous system i'm putting together for the '93 i just bought, and i am looking to do some new stuff that i haven't messed with before. i'm an Old-Tech guy, so i'm a little behind when it comes to electronics- and this is blowing me away

Here's the question-

I want to retard the timing in direct relation to the amount of nitrous injected.
The Mallory Hyfire VI digital has a built-in boost-refrenced retard capability that will retard timing as boost rises...all you do is hook up a MAP sensor and plug it into the box.
The Jacobs Electronics Nitrous Mastermind varies the amount of nitrous and fuel injected into the engine by reading the RPM and pulsing the solenoids faster and faster untill they are all the way open at whatever preset RPM.

How would i wire it so that the "pulse" from the nitrous mastermind could be used by the boost retard circut in the Hyfire?

(basiclly- read pulses as frequency, convert to what a MAP sensor puts out)

OR who can i ask that can answer these questions?

crkemppainen

Oh, come on- dosn't anybody even know who i can ask?? i know we got some pros on this board!

Slow Poke

I've been down a similar route as you are trying to do with my 95 coupe. I was using the Accell 300 digital ignition and the Jacobs Mastermind Nitrous Controller in series to control flow and timing. The bottom line is the Jacobs Mastermind is a POS! Don't waste your time with this unit. It is highly inaccurate and that is an understatement to say the least to dial in. The pulse modulation system is controlled by an analog dial which has no true reference point and the timing retard section is nothing more than a resistor pot (0-100k). I scrapped the unit and would not even consider selling or giving it to someone who values their motor. The LT1 edit program solved my problem by allowing me to take out timing thru the PCM. Unfortunately, the 92-93 cars are ECM prom based and LT1 Edit doesn't work on them. I would stick to just using the Mallory timing retard unit and live with the retard across the rpm band. For what its worth, my 95 was mostly stock, no cam or heads, 3.45 with a stock tranny and converter and I dialed out only 4 degrees using a custom built 225 hp wet kit with no detonation problems using 100 unleaded VP gas. The car ran consistant low 11's and high 10's for over 4 years without any parts breakage. Good luck and ditch the Jacobs!

REDC4CORVETTE

I thought I would throw in my 02 worth.
You have a 1992 and can not program your computer.
I know a lot of guys dont like the msd boxes but you eather get a good one or a bad one.
I use and msd box 6al with a dial msd retart so I can retart the timing
The retard box with the retard pins is what msd recomends and I tried it for a while I just did not trust it,so I switched to the dial retard box.
She runs 13.50 off juice and 11.20 with a 125 shot.

crkemppainen

That's a VERY impressive gain from a 125 shot!

and thanks slowpoke for the info on the mastermind- i've not used one before and knowing this, i never will!