dynedta

iTrader: (4)

i had just got my car back from ls1speed after a complete dyno tune and i plugged my predator in to monitor kr fuels trims and etc, and i notice my ltft's are postive +10 part throttle and +7.81 at wot, mods in the sig with the exception of the supercharger. any ideas? (i will be calling ls1speed to see what they think)

thanks
Gary

Billiumss

iTrader: (11)

I'm guessing they didn't drive the car around town to properly get the 'Part Throttle' tuning right. Nothing like doing a half azz tuning job and charging you top dollar...

Your Ltrims should be -2 to -10 when normally driving and they should always lock at 0 when you go WOT. By them locking at 0, your computer doesn't think you are lean and just uses the PE & VE table for your fueling.

Ask them if they bumped up MAP 105 on the VE table by 10%

I'm not a pro, but I have tuned a few dozen cars now and I have had a few good "teachers" (pros) to help me out when needed...

Bill

dynedta

iTrader: (4)

thanks bill i should just bring the car down to you, i'll call them when they open and see for sure.

thanks
Gary

Billiumss

iTrader: (11)

Is this the Gary from Lima?

PM me!

Bill

99SSragtop

What if your Ltrims are slightly + and then at WOT your Ltrims go to 0 ?

WS6 GreeN

If they lock at 0 at WOT, then its my understanding that you went into a fuel trim cell that was negative right before you hit WOT.

Billiumss

iTrader: (11)

Yep, you are correct, I have seen this before. Always better to get them on the negative side though.

99SSragtop

ok

qqwqeqwrqwqtq

Nothing like assuming you know what you're talking about.

The car came in with some issues. It makes about 2-3lbs of boost, has exhaust leaks, spark plugs were falling out, etc.

I fixed as many issues as I could within the time I had to work on it. I was told the car was coming back to get straightened out, along with fuel system upgrades.

Point is, you can't perfectly tune a car that has issues.

-Jim

NoGo

iTrader: (2)

That and some slightly positive LTerms are no big deal at all. Drive the thing around in winter and watch watch what your Lterms do.

People get too hung up on LTerms. Sure, they may drive the a/f ratio at WOT around a bit, but hook up a wideband to the car and watch how much your a/f ratio changes between gears (the different gearing loads the engine differently and moves the a/f around)

LTerms less than +10 shouldn't effect much.

Billiumss

iTrader: (11)

Actually, I somewhat do, I have talked to Gary in the past. By chance did you drive the car or just do a dyno tune? Gary informed me that his dyno tune was without the supercharger hooked up. I know what you mean by exhaust leaks, especially if they are by the head.

I was going to tune a 98 Z28 a few days ago and after driving around some, I asked if he had an exhaust leak and he said yep. His Ltrims would go from -4 from driving around to +20 when you let off the gas on decel. We decided to stop there and he is going to go over everything again. I'm guessing the headers aren't mating up with the head properly.

You are right Jim, when the car has issues, it sucks to tune, it's like your fighting a loosing battle.... Sorry I was so harsh........

dynedta

iTrader: (4)

yes im also sorry for the confusion, i talked to mike and got everything worked out, as for the tune without the charger the charger is on the car but the internal belt is broken, its not ls1speed fault, but more fault of the shop i had just installed the motor, my apologies to jim @ls1speed who worked with what he had, the car will be making another trip up for more work.

apologies again
Gary