alright fellas, ive been wanting to get into tuning for a long time but never have.

i am going to get into nitrous this summer and im going to need to pull some timing. SO, i can get a Mallory 685 for about $250, or i could get a 94-95 pcm and get tunercat and start tuning.


what do you guys think.

BTW, i sold my supercharger, so im running the car in the sig, minus the blower and meth, but i just installed 4.10s. so i need to have the speedo recalibrated also....which will cost me 50 bucks plus shipping for madz28 to do......

thanks,
Jeremy

 

Tunercats is a vital thing to have imo for any modded lt1. Just because you can spend the time and look at fine details and take care of any nagging issues that crop up.

However... I would want all the features of an ignition box too. If you're just going to do one, I would get the ignition box. I am not a fan of pulling timing all the time for spray like you would end up with if you tuned it that way so there I would prefer the ignition box and add ons that can be used with it for nitrous.

I guess the other question is how much nitrous. If you just need to pull 2-3 degrees out for a small shot thats a different game than putting 300hp into it.

My answer may change if its not much nitrous at all.

 

with the stock bottom im running, im only going to do 50-100 shot for now....

how difficult is it to change ignition timing with TC? i was thinking i could just pull a couple degrees when i go to the track and spray, then change it back when im DDing.

another quick question....my nephew has a 95 auto. i was thinking of getting the program so that i could tune his car a bit too. how difficult is it to adjust shift points?

thanks,
Jeremy

 

did you switch to obd1, or are you tuning your II?

thanks,
Jeremy

 

Listen to WS6T3RROR.... tune it perfectly in the PCM for NA performance. Then use an external box to pull timing. It makes no sense to have to reprgram your PCM every time you go to the track, then reload the NA program when you leave the track.

The alternative would be an aftermarket ECU that can be programmed for both NA and nitrous... but now you are talking $2,000-5,000. Makes sense for mutli-stage nitrous, or a dry 300-shot, but for what you are tryig to do, a simple box like the MSD-Digital6 will do everything you need. You also want a different type rev limiter on the spray - cut ignition, not fuel like the stock PCM does. The "box" will incorporate all this and more.

 

sweet, thanks for the info.

Jeremy

 

I would not waste my time flashing the pcm twice every time I wanted to go to the track. Any issue with your flash and you will be buying another pcm or getting yours repaired.

Nitrous is a special situation and requires a special eye for detail. You need to add several safety systems before I would consider the system complete. Unfortunately this makes nitrous not so wallet friendly like most seem to want it to be. I will also say that in my experience with nitrous, I much prefer boutique nitrous kits to large brand name systems. The tuneups are often very far off with many of the big name systems. Too rich on nitrous will kill pistons just as quickly as too lean will. You will want to move the pcm rev limiter up to the max in tunercats so you never hit it and cut fuel on nitrous. With a manual trans, I would also seek out one with a two step. Get a fuel pressure safety switch etc.

The same cable and software will program both cars if you do an obd1 conversion on yours with no additional equipment to buy. Adjusting shift points is easy but more of an art than a science. I have posted on it several times and my theories on setting them up.

My car is obd1 converted for many years now and converted a bunch of others.

 

thanks for the info.

i wont be spraying it until ive got all the accessories. thanks for the tips.....

 

This. You do not want to have the stock PCM cutting your fuel if you are going to use nitrous, you'll blow your engine first time you hit a rev or speed limiter. I have the MSD Digital 6 in my car, it's an excellent box for the price and will do almost everything you need for a standard nitrous setup. I have mine ran into the glove box to keep it from being affected by heat/elements in the engine compartment and for easy access in case I need to make any adjustments.

When you do your tune, make sure to set all the RPM limits and speed limits to the maximum in Tunercat (and your re-engage RPM and speed at just 1 or 2 below the cutoffs), then set your Digital 6 with the desired RPM limit.

 

ive heard that the mallory 685 is easier to use, cheaper and has more features....

i just sold a crane hi-6r with the boost retard box from my blower kit. all the descriptions said that it was designed for boosted and NITROUS apps, but i think that it was truly made for boost. but i was wondering if i had sold something that i could have used for N2O......