Howdy guys,
A friend and I are about to start burning chips for my combo. I have a LSRacingchips.com chip in there so I could get it up and running a year and a half ago and done a few retunes with him. However, I am now going to have two different chips...one for economy and one for performance or at least we hope.

Anyhow, what are the main things to look for when tuning for the stealthram on a 383 with a 730 ecm? I'm hoping to have timing around 38 or higher if it will take it(we will be street tuning it) and fine tune the AFR. Also, if I add a higher stall converter later from stock, will it effect the tune? Any help in what to look for would be greatly appreciated!

Thanks!

 

First, two questions

Why TWO chips? ONE chip should be able to contain the instructions for peak power and peak fuel mileage. The only difference is how hard you tromp down on the pedal. As long as you are at peak efficiency, you get the most power, the most power at that throttle position often gives you the least amount of throttle used. Less throttle to go the same speed means better mileage. Lean cruise helps here as well.

Second, why the fixation on 38* of timing. Modern Fast Burn style heads pull peak HP with as little as 28-32* of timing. Often times they will accept 6-8* of timing after the power starts decreasing before showing signs of detonation.

 

No fixation...that's what most run on the stealthrams from what I see on stealthram.com site. On my chip from LSracing...I'm supposed to have 34 degrees. I'm tuning for power so where it makes the most...that's where it'll be. Well, honestly, I didn't think we could get optimum economy on a performance chip. I baby it in the city but I do like to have fun with it on occasions so if you have any advice...I'm listening b/c I'm new to this tuning thing.

 

Ok....going up with this for some tuning advice. I got the Ostrich instead and I love that thing. Just plug it in and adjust the tune. Ok, now for the tuning. My initial timing is at 23* with a max of 31.99*. I'll do some playing with that later but my first priority was the idle. It always idled about 700 out of gear. I have it now idling at 625 rpms. The AFR reading through a wide band is around the 14.5 marker with it fluctuating from 14.0 and 15.0. In gear, it runs richer with it being around 14.1 and fluctuating from 13.6 to 14.4. How do I make the difference of the varying numbers more consistant. I've moved the min and max plus INT values closer to 128 but I am +/- ~15 on each side of 128. So, min of 100 and max of 150. Should I move these to 128/128 for the INT values or max/min values.

Also, WOT tuning, I've been reading that PE and VE has an affect but which one do you change first....PE then use VE to smooth it out and get your final number. Right now at WOT, its like a /\/\/\/\/ from 12:1 to 13:1 I do believe. I need to do more logging with the wideband and ALDL but wanted to get the Idle right, move to part throttle, and the WOT.

Any help you can lend I would appreciate, I have the LSRacingchip file saved in case I mess up too bad. The EGR, VATS, and AIR are disabled but I don't have them or need them. Thanks for the time!

 

I am not as familiar with the 7730 as I am with the TBI ECMs/PCMs and the LT1 PCMs, but there should be a proportional gain setting of some form. When properly adjusted, this will eliminate the rollercoaster a/f ratio swing at idle and at cruise. The tighter you bring the proportional gains, the closer to open loop that it becomes.

 

There's tuning stickies up top.
Read those first then ask more pointed questions or for clarification on things you don't understand.

AFA the WOT swing, either your PE table is setup that way or your VE table is doing that.
Look at your VE table in graph form and see what the 90 & 100 kpa columns are doing.
I'm not sure if your BLM would cause that, but it might.
Try setting your min/max blm & int to 128 and do a WOT run.
If the swing is still there....

 

I have read all the stickies up top and they went back and forth whether to set the INT from 128/128 or the max/min to 128 but I will set both sets to 128.

Also, on the CCP(charcoal canister purge) Trax. did it in Datamaster. Well, I don't know the code he was using and I am using tunerpro RT and I don't have the CCP hooked up so apparently my HWY mode ain't working. Do you know what I have to do in TunerPro to make it work?

Sorry for the newbie questions, just getting a better idea before I go into part throttle and WOT.

 

CCP cell 4 stickie for one.

I don't recall, and I haven't looked into the hwy mode fix in a while.
One way around this would be to have a look at the Super AUJP stickies.

Reading the stickies and researching things will eventually lead to some understanding. Then you start over with the reading and a few more blanks will be filled in. And so on and so forth till you have a decent idea of what's going on.

I don't mean to be a pain, but the blm and int are used for different reasons.
Reading until you understand what they are is critical.
Then you will understand why you lock one and not the other or lock both.

In this case, you are locking both so as to prevent them from adjusting fuel while you do a wot run. This way you know only the table values are being used to calc the fuel. In the 128/128 post you are subscribing to, the int was left unlocked so you could see which way you needed to adjust the VE tables while in CL and not in PE. The int is locked to 128 in the following circumstances by the aujp code - this may not be all the times.
DFCO
PE
OL
Hwy MD

 

The first thing to do when tuning your car is gathering info.. Yes, reading up on what others are doing is grande, BUT, often people fall into the mind trap if *A little is good more is better, and too much is just enough. There is a false preception that the more timing you can run the better. Ain't true, all that gets you is too much timing, too much fuel, and knocking the corners off the pistons, or breaking rings.

So, start with a moderate amount of timing, and work DOWN from there. With some old vintge heads, you might need 38d, but none of the new, or *FAST BURN* heads will need that much timing.

If you were to draw out a piston in a cylinder, and then look at it's position at 38d and 32d, you'd realize just how much wasted energy that much timing generates. You want the peak pressure at 12d after TDC, so using 38d advance means the flame is burning for ~50d of piston movement, vs say 45d. That gives detonation alot of TIME to develope.

Then in order to really see if your going in the right directions, you want to use a G-Tech or some sort of timing devise, since to most people their butt dynos are fooled by too much timing, and fuel, *feel* faster.

 

Thanks grumpy, I have a G-tech and my heads are the AFR 180cc. I see that AFR has almost the same setup as mine but with a carb and they ran 36d of timing max but like you said less could be more and that first post, I was inexperience in tuning and I still am but I wised up and learned a lot so far with the idle so, I haven't messed with the timing yet. Its still at 31.99. Just trying to get the idle/cruise/part throttle right but going at it some more.

 

That definately cleared up what they were trying to do....thanks! But if you do the idle/part throttle tuning first that Trax. said to do, would you want to lock them out at 128 or leave them open to changes? And then once you get those set right, remember them and lock it to 128 so that you can tune for WOT?

 

It depends how far off you are on your initial tables.
If they are very rough then leave the BLM open for changes and adjust your tables using the BLM info as a guide.
Once the tables are close you can lock the BLM and use only the INT to get the fine tuning of the tables done.

If your tables are way off and you lock the BLM and only use the INT, it will just peg to the max and not give you a good indicator of how far to adjust the table. Just a direction of adjustment but no magnitude.

As another helpful thing, (When its time) bring your timing max up to 38-41 and have some additional timing added below your "idle MAP" area for decelleration use. This will help with reducing the engine braking so you don't hit your head on the windshield when you let off the gas.

 

Thanks, the tune is pretty good so far, I read the chip from the guy I got it from when I first built the engine to get it going and I'm just trying to get a better idle, more mpg, chisper throttle response, and more power. Like I said, the A/F ratio is 14.5 usually according to the wideband but it varies from 14.0 to 15.0 in park and 13.6 to 14.4 in gear.

Been reading up on open loop tuning but don't know if I want to do that or not. One thing I have noticed so far is that, lets say I am idling at a stop sign about 14.5 and I go to give it some gas into traffic, no more than 25% throttle, the AFR goes to about 15.0 around with it fluctuating up and down. Is this good or should it richen up when throttle is increased.

 

There are additional values that can be adjusted for the closed loop routines to make the O2 swing at a richer AFR. The stock settings seem to be a bit on the lean side.

As for open loop tuning, you start at the low load and RPM operation and tune those areas. Once these are tuned, you can see trends developing. You guess on what those portions of the tables at higher loads will look like and then start tuning at higher loads and RPMs. At each step, you forcast ahead, and then tune there, progressivly working your way out. You definatly need to tune open loop once youve roughed in using the BLMs. In closed loop, you really dont know how close things are.

 

I think I'm just rough in tuning period......hahahaha....just inexperience. Like I said, the idle is much improved and there was a lag between 1400-1800 at part throttle and that seemed to have gone away now.....b/c it still pulls in that area instead of die/flatten out. I raised the timing 2d in that area and for some reason, it dropped off really quick in timing in those spots. Open loop could be a good idea and bad idea at the same time. I just want to get it close right now with my current 383 b/c I am about to build another one with more compression and bigger cam, so basically, this is my tuning mule.

 

hey i need too get ride of the egr in my ecm. i have eliminated everything under the hood how do i get rid of it in my ecm thank for any help

 

Set your min speed to 255mph, Min MAT temp to 151, and EGR TPS/Duty Cycle to 0.

 

Ok, just went on an in-traffic run with the wide band. At idle, its still richer than Stoch.....idling about 14.3 in gear and park after a good bit of drive. Cruising around steady about 45 mph it holds 14.5(varying from 14.3 to 14.7)....not bad there and it appears once I hit 50 mph it jumps to 15.5-16.0 so maybe hwy mode is working after all b/c 50 is the mph set for when hwy mode engages.