Tuning Questions

Dontech · June 11, 2007

I had my truck tuned on a dyno and have a couple of questions on what I saw. Can anyone can explain injector slope, they reduced my injector slope. Also, air/fuel ratio, what is optimum?

Just for those who want to know I have a NBS 5.3 and my stock numbers were 230hp/290ftlb of torque.

After a Preditore tune it was 252hp/295ftlb

After manual tweaking with programer 258/298ftlb

I did not mess with any torque management so that may be why the torque did not change.

Any help undertstanding would be great. Thanks.

svensk · June 11, 2007

Just for those who want to know I have a NBS 5.3 and my stock numbers were 230hp/290ftlb of torque.

That's the stock wheel power from a NBS? Egad...

Dontech · June 11, 2007

Just for those who want to know I have a NBS 5.3 and my stock numbers were 230hp/290ftlb of torque.

That's the stock wheel power from a NBS? Egad...

Yes, those are the stock numbers. No mods. With the other runs I had the Corsa and the program, nothing else.

ridnlow · June 11, 2007

I dont know about the new trucks but most of the 99-07 trucks do not have to worry about injector slope.. We have a vacuum referenced fuel pressure regulator.. Injector slope is mainly in the F-Bodies as they have to accommodate the change in air pressure in the intake from vac to wot.. If you have a vacuum referenced fuel pressure regulator then your IFR table is flat.. If not then you have to slope it..

ridnlow · June 11, 2007

13-14.6 is good AFR for NA and boosted applications you want to keep it around 11.5..

Dontech · June 12, 2007

MY air\fuel is running between 13.16 and 11.74. The lower number at the high end of the tach. After all the little adjustments I did not really see that much improvement over what was in the tuner so I set it all back to the standerd tune. I am kinda of unsure of what adjusting all the other peramaters is doing for my truck and six horse does not seem like that much of a gain to take a chance.

Things that I saw that they did were:

injector slop= -3

wot fuel 2k, 3.8k = -3

4k, 7k = -3

wot spark 1k,1.8k = +8

2k,3.8k = +4

4k, 7k = +2

ridnlow · June 12, 2007

Who did the changes?? i am guessing they uploaded a custom tune in your predator.. dont focus on dyno numbers.. how did the truck feel.. a dyno is simply a tuning tool and you may not get a lot of hp out of changing something but the truck may feel a whole lot better.. spark looks good and looks like they leaned it out a bit.. your AFR is good..

Dontech · June 13, 2007

Who did the changes?? i am guessing they uploaded a custom tune in your predator.. dont focus on dyno numbers.. how did the truck feel.. a dyno is simply a tuning tool and you may not get a lot of hp out of changing something but the truck may feel a whole lot better.. spark looks good and looks like they leaned it out a bit.. your AFR is good..

The performance shop that had the dyno was a predator recomended facility. The tech made the changes to the truck on the dyno, and downloaded it and then saved them as custom tunes.

How does the air/fuel look? what is the target number?

From what you posted before it sounds like injector slope is a waste on my truck. Is that what you think?

The truck did seem to me more responsive but not like "holy ----" faster. I just don't want to kill it.

ridnlow · June 13, 2007

As long as your AFR is in the 12.5-14.6 range you wont kill it.. Are you seeing in Knock Retard?? Like I said I dont know about the newer trucks but my injector settings are flat across the table..

Dontech · June 14, 2007

I don't know how to tell if my injector settings are flat or not. All that I know is he took -3 out. Doing some research I was reading that you should set them when the truck is in close-loop operation. and when you pull slope you should lean the ratio as well.

Make sense?

ridnlow · June 15, 2007

I dont even know why they would mess with injector to start with.. Hell even people who have to worry about injector slope only have to figure it out when they upgrade to bigger injectors.. not really sure what the purpose of taking -3 out is..

Dontech · June 15, 2007

Yea, that's why I put it back to the diablo tune. All in all it was still cool to run the truck on the dyno.

ridnlow · June 15, 2007

Good deal.. you should get hp tuners and start fooling with it yourself... youve got a good starting point with the diablo but you can fine tune from there..

DanMan_S · June 25, 2007

Good deal.. you should get hp tuners and start fooling with it yourself... youve got a good starting point with the diablo but you can fine tune from there..

Does the diablo tuner have a preset tune that it uploads and you can tweak or do you have to do it all yourself? My performance shop was recommending I pick up one and the gains on the Vmax didn't look too shabby.

Dontech · June 26, 2007

Good deal.. you should get hp tuners and start fooling with it yourself... youve got a good starting point with the diablo but you can fine tune from there..

Does the diablo tuner have a preset tune that it uploads and you can tweak or do you have to do it all yourself? My performance shop was recommending I pick up one and the gains on the Vmax didn't look too shabby.

Yes, there are two different tunes in the Diablo SPORT for my truck. There is one marked 87 tune and one marked Performance tune. The 87 is just that, a tune for 87 octane and the other is for 93. You can also tweek each one.