Billiumss

iTrader: (11)

Ever since I did all the mods to my car, Heads, Cam, Exhaust, Injectors, etc, my L trims has been around +15 - 20.

Please tell me if I'm wrong, since I added new 30lb SVO injectors and adjusted for them in LS1 Edit, when you rescale the IFR, it's not totally 100% correct is it?

Is this why you have to scale the IFR table to bring your Ltrims back in line?

Do you rescale the whole table or only part of it?

Does 5% equal a 5% change in the Ltrims? I've been told by a tuner that 5% change in the IFR table is more like a 10% change, any truth to that?

By changing the IFR table to bring your Ltrims to slightly negative, don't you have to retune you WOT since you tricked the computer thinking you have slightly smaller injectors?

By changeing the IFR table, will this take effect immediately when you car warms up, or does it still have to "learn" to get your Ltrims in line?

If you put your car on the dyno with wideband O2, shouldn't you read a tad more on the rich side, say 11.5 - 1?

I've been doing alot of reading lately about adjusting your part throttle, but it's so hard to go through all the threads and read everything, I start to get confused on what really should work.

LS1 Tech should have a sticky post on certain tuning tricks that are known to work for say a head and cam swap. I know all parts and cars are different, but having a tried and trued starting point helps a lot...

Thanks in advance guys...

Bill

Billiumss

iTrader: (11)

^^^

HumpinSS

iTrader: (1)

Bear with me I am new to this also and trying to learn as much as possible. So I will tell you what I know and hopefully can get the information to you as acurately as possible

Did you key in the new injector offsets. There are formulas floating around here that calculates it for use in edit.

Yes I have read over and over again that the IFR table is used to make BIG changes to get LTRIMs back in line. VE table is used to make smaller more minute changes

I am pretty sure you can approach it this way also changing the cells that are running positve but since you are running positve throughtout the RPM range it will prolly be best to scale the whole table.

This I am not to sure about but I would suspect it would kinda be a 1 to 1 thing since you are in essence adding that much more percentage in fuel

When tuning your LTRIMs you are making sure when you go WOT the computer doesnt start dumping unneccesary amounts of fuel into the mixture. Your LTRIMS at WOT should read 0 providing you have negative LTRIMS before going WOT. Actually the computer uses LTRIMS to acheive the targeted A/f ratio if this is off the computer will compensate by adding or subtracting. So I dont think it tricks the computer into thinking anything it just adds more fuel so the computer has to do less work keeping the car at 14.7:1

It will prolly take some time for the computer to learn and make fine adjustments once you get them negative

No because the target/commanded is 14.7:1 and you are adding more fuel just like the computer is doing to make sure you target/commanded goal is reached. So as long as you dont go too NEGATIVE you should still read 14.7:1 on the wideband. This also can be represented by your o2 becasue they are pretty acurate for part throttle/closed loop operation. WOT is another story and will need a wideband to make sure everything is OK.

Also check out http://www.ls1tuning.com/forums/prof...r&ruid=196 some good information here also.


PS have yuo turned of COT (catylitic overtemp protection). This also will hurt you once you get the car tuned to be slightly lean.