Guys/Gals,

I am trying to tweek my 95' LT-1 (383) setup and need some advise on the following TunerCat tables:

My setup is a CC305 cam, AFR 195 heads, 30# injectors, 58mm TB, mid headers, etc...

The columns I need advise on are:

%Change to Fuel/Air Ratio Vs. RPM at WOT
%Change to Fuel/Air Ratio Vs. Cool. Temp at WOT
MAF Sensor Calibration Tables (1-4)

I am pretty knowledgeable with tuning, however I don't have access to a Wideband O2 and am trying to save the 500+ bucks for a complete dyno tune. What I am looking for is some recc specs for these fields with this Cam and setup as all I have found is a 383 .bin file for the CC306 cam and these settings probably won't work. Any suggestions?

Thanks!!!

 

What you need to do first is set all the constants correctly, which you may have already done. injector engine size blah blah blah.

What i like to do after that is set the car in speed density mode and use ve master and get the blms at a reasonable range, then i switch over and go to maf mode. Some people say a car doesnt use ve tables in maf mode, i'm not giong to argue it works for me.

After you do that start working on the maf tables if its rich lower the grams it sees for that maf frequency, if its lean tell it its getting more grams and it will fatten up. I like to do the range surrounding it so i keep the same general trend, i usually up 2.5-5% depending on what the blm is at that level. The only way to tell what you need is to take a log and keep an eye on what the trims are doing or if you had a wideband you could tap that into the a/c pressure sensor and log it with datamaster.

After i get my long term trims to a level i'm comfortable with i usually use some sort of blm locker so that the wot wont be affected by the trims and they just go to 128.

I usually zero the vs coolant temp tables out. That way if my coolant temp jumps around on the dyno or through the pull i dont end up chasing my tail trying to get the a/f to where it needs to be.

Honestly if you understand how the tables for wot enrichment work, and what does what, rent a dyno with a wideband for a hour or so and take a crack at it. Its not that hard.

 

Just an FYI. Don't just zero out the vs. coolant temp table without doing anything to the vs. rpm table. Both those tables do the same thing. Zeroing out the coolant temp table without adding any other fuel to the other table will just lean the heck out of it. You don't want that. You can adjust one or the other. What i've done is basically set the 56deg C to 92 deg C to all pretty much the same number and only adjust in the rpm table for WOT fuel adjustments. With the 383, you might need to crack your throttle blades open a bit using the throttle stop screw to help out the idle/coming down to idle a bit and then readjust your TPS sensor back to the correct voltage. You may need to elongate the screw hole on the sensor to do that. Also recheck your IAC counts after that. Think you want them in the 20 to 30ish range. Like stated above, make sure your constants are set correctly for your injectors and such. Should probably also cut back the timing a bit until you see what it's doing there too, then add if you don't see any knock retard. If your MAF hasn't been ported or anything, then you should probably start with the stock tables and go from there. I've used VEmaster when i was N/A after getting some good long cruising around scans and it took all my BLM's to just under 128. Didn't need a BLM locker cause it would run at 128 at WOT. Didn't need to go speed density mode to do that either and it worked for me. As for the WOT A/F's, i've found that my regular O2 voltaged ran around 900mv+ when i was around 13.0:1 or richer, but best to tune with a wideband whenever you get your hands on one. Go a range colder on the plugs also and close up the gap a bit too. Being N/A, your not gonna need too much tuning and what you do will be mostly in the A/F and timing arena once you get the inital constants and mechanical adjustments set up where they need to be. Good luck.

Ken R.

 

I suppose I should have said level out the table rather than zero out for coolant vs pe. I leave the extreme areas the car will likely never see at a factory setting or even richer. Also to add the pe vs coolant tables are a really good way to adjust the entire curve up or down by a few %, use the pe vs rpm curve to flatten the curve or take care of problem areas.

Also allow me to explain the speed density deal before using ve master. Its a subject of controversy with lt1 tuning using ve master on maf cars, it seems to work for me every time even in closed loop just as you experienced, i'd rather just avoid pissing and moaning so thats why i said what i said .

My experience with the narrow band o2's has been the same as yours under wot conditions, but i always verify with the lc-1.

 

Thanks for all your help guys, I'll give her a shot, but it looks like I might be a bit out of my element here and might be best to just save up and have her dyno tuned down the road.