I am learning tuning thanks to the help of Nomake Wan, who has brought me along to this point, he helps alot of guys on here and I know I for one, appreciate guys like that. Thanks Dude!

For reference I am working on a 95 6sp lt1. I have eehack & Tunerpro and have successfully taken backup copies of my stock tune and made a few log files. It definitely feels like I need to add some gas to my tune after installing LT headers, x pipe and muffler deletes. I also cut the air lid and deleted A.I.R & EGR. In addition to gaining whatever HP I can on fuel & spark I would also like to modify the Deceleration Fuel Cut Off so that I get more crackle and pop.

What modifications do I need to make to the Deceleration Fuel Cut Off to accomplish this goal?

Also wanted to ask if anyone knows, or are willing to do an email tune for me that I can learn from? I willing to pay a reasonable fee for your/their time.

 

Hi AgentEran,
I can send you my LT4 file that was a mail order tune by PCMFORLESS. I have ARH 1 3/4" headers with cats, 3" exhaust going to 2 3/4" repro mufflers (for drone free cruising).
Lloyd Elliott custom cam (219/221 @.050 541/565 lift) and some porting of the intake, 52mm TB, cold air, and air injection delete. My car never had egr from the factory.
I also tweaked the PCMFORLESS tune with my JET DST tune because I didn't like the higher idle 900 RPM. I also reinstalled the PASS key for some reason PCMFORLESS removed it. And I removed CAGS.
Let me know if you want a copy of the JET file.

 

The JET file will not work; Eran has a '95. They're completely incompatible.

 

Not familiar with tuning that era car, but for a crackle and pop tune all you need is fuel in the exhaust and retarded timing that can light that fuel up. For an LS, you completely disable DFCO (set all the enablers to extremes)and retard the base timing table to about 10*BTDC.
What XDF are you using? I can take a look and give you an idea for parameters and values to change.

 

I am using eex.xdf

am now using eextra.xdf

 

http://fbodytech.com/eex-tunerpro-definition/

https://www.corvetteforum.com/forums...post1603036553 <--EEXtra

 

I would like it if you don't mind. I need to look at the changes as my LT1 is going to be really close to your configuration, with the difference being Trick Flow heads and a LT4 hot cam.

I emailed you my email address.

Your PM box is full and not accepting any PM's.

Thanks

 

First off, I always recommend against pop and crackle tunes because you can easily scorch exhaust valves and drop seats, they sound cool but should only be used in moderation, only run that kind of tune if you do not care about your cats or no longer have them installed, also, expect a drop in city fuel economy if you drive in traffic.
To disable DFCO, set 128A4(DFCO Enable Min-RPM) and 128A5(DFCO Cancel- Low RPM)to a high value, typically 500RPM above your rev limiter will work fine, the first value defines what RPM you want DFCO to be triggered at 0%TPS, and the latter determines what RPM DFCO will be disabled once it is triggered. For an LS that would be sufficient as all enablers must be true, but if you are still having DFCO enable, you can change 128B2(DFCO Enable-Max TPS) to be 100% across the board. This will have you popping any time you lift off the throttle and for the entire duration until the engine returns to idle, if you want to have it do it every time you lift but only for a short duration you can set 128AB(DFCO Enable Delay Timer) to how long you want it to be plus about 1 second, so if you want it to pop for 3 seconds after lifting, set this parameter to 4 seconds. This is where my inexperience shows, I see that the XDF says "Timer to DFCO if CAT protect 0", I am not sure if that means you have to zero out the cat protection tables, or if this decreases/increases the delay until cat protect reaches 0.
You now have excess fuel in the cylinders and exhaust, to light it you will need to retard your timing. To do that, you will want to retard tables 1208A(Main Spark Advance) and 1217D(Extended Spark Advance), I don't have a bin file so I do not know what your base numbers are, and again am unfamiliar with these engines, but I would say do the majority of the retarding in the 25KPA column starting at about 1400RPM and up. Retard in 5* increments until it's close to what you want and then 2* for fine-tuning. You can also retard the 30KPA column and maybe even the 35KPA column, but you have to be careful to not go too far or you will negatively impact your acceleration, for the higher pressure columns, focus around the higher RPMs and leave the area around idle as it is.
Hope that helps and happy tuning!

 

Hi drcook, I emptied my inbox never even noticed it was full.
Send me your email and I will send my JET file to you. I cannot seem to PM you a file attachment as there is no option to do so other than a picture file.
Update: File sent to your email address.

 

Bin file for a 95 manual: http://fbodytech.com/bin/EE_16210071.bin

"Cat Protect 0" just means "Cat Protect Off," AKA "normal operation."

 

That answers that then, so as long as all the flags to disable Cat protect are satisfied, the delay timer will give you your pops for a bit and then switch to normal. Taking a deeper look at things, and anyone with experience with these engines please call me out if I am wrong, you may be able to get away with just changing the 12056(Closed TPS Spark Advance) to retard the timing, but I don't know the criteria required for the ECM to use that table. If it is as simple as TPS=0 and no Cat protect flag etc, then that would be the only table you needed to mess with to get some pops.
Here are some snapshots with what seem like reasonable numbers, but again, no real-world experience with the LTs.
How to disable DFCO:

Notice the maxed out enablers and disabler, this ensures that the ECM never commands DFCO and always commands DFCO disable.


This is basically 15* retarded, for a larger effect that slowly went away you could heavily retard 3600RPM+ and then interpolate down to the base timing, either way, you will want this table and the base timing table to be as close as possible to prevent issues when transitioning between the two.


I set the DFCO enable delay to 4 seconds, on the right you can see the blend table, you would use that to sort out any surging or jerking that could occur from DFCO to normal operation.


And lastly, the base timing table(s), ideally the transitions would be much closer than 5-10* but that will take in-car driving experience to smooth out and get right, in some places you can get away with it, in other it'll leave you with a jerky mess and a bad headache.

 

Thank you for taking the time to explain this at length and with screen grabs, I appreciate it.

 

No problem, keep us updated!

 

Idk what I'm doing wrong but when I change the values in 128A5 & 128A4 and click save the values don't keep and when I reopen them the values are back to 0.00. is it supposed to be that way?

 

By the way, totally unrelated to your crackle tuning, but if you haven't done this already, do it. It made my car way more pleasant to drive in stop-and-go traffic:

http://fbodytech.com/tutorials/fix-l...e-stall-saver/

 

It should not, try restarting your computer and reselecting the XDF, tunerpro can be picky sometimes.

 

Nope. Same deal

 

Do you have difference check enabled by chance?

 

What exactly is difference check? Where do I check?

 

Nevermind that only works if you have a bin loaded to compare the difference in values. PM me the changes you want made and your email, and I'll send you the edited bin and we can give that shot.
Just to be sure, are you sure you are using the right XDF for your bin? Try loading the bin Nomake Wan sent and give that try.