Building a Tune

[Dirmaid]

I recently got a new Sniper Special Forces tuner (which is rediculously epic) and I'm trying to build a 93 octane race tune. I don't care about gas mileage, jut safe power gains. Before you ask, yes I can modify the spark advance and global fuel, the afr, everything like that.

I'm running the 4.0l SOHC with the 5r55e tranny, 03 engine with 50k miles. I'd wait to retune it at the track so no worries about getting the truck there on this tune.

Any suggestions on how to squeeze the most of of this engine tune wise?

 

[Bird]

Get a wideband insalled and then start datalogging : A/F, Spark, Knock retard, rpm, IAT, load. For best WOT power, you want no knock retard and 13.0 A/F ratio throughout your WOT powerband. Before you even start any additional tuning, you want to address any knock retard you may already have whether it's from a lean cylinder, too much timing, etc. As these things are factory tuned for 87 octane, you 'should' be able to globally add 4 degrees of timing and then tweak from there. The old rule of thumb is to add timing till you see a speed dropoff in the 1/4 mile, but the timing under the whole curve is now more tunable and there's gain's to be had in tweaking that. If you're getting knock retard in a certain range of RPM, you can tweak the timing / fuel in that range to fix it.

Bird

 

[Dirmaid]

alright, ill hook my laptop to the truck and make a coupke runs soon. it has a 93 octane tune already that just needs the fine tuning that you were talking about, i just wasnt sure what all i need to look at. thanks for the re[ply and ill let yoy know what all i find in my data logs

 

[Hahnsb2]

Without a wideband you really aren't going to get far.

 

[Bird]

Without a wideband you really aren't going to get far.

EXACTLY RIGHT - without a wideband, you're just guessing at things and taking chances on messing something up


Bird

 

[Dirmaid]

i can monitor the O2 output from my tuner, so could i just replace the stock o2 with a wideband 02 and not get the entire standalone kit, or will the ecu not return the right data and i need the meter and everything?

 

[Bird]

ECU won't give you the right output - need to mount the wideband sensor in th ey-pipe and get a meter. Also, if your logger has the capabiliites to bring in an outside input, you'll be able to read the wideband through it's interface.

Bird

 

[06RangerXLT]

X like 6 on the wideband. but unless you have a turbo or supercharger or some heavy engine mods, you shouldnt expect more then 25 HP gains.

 

[disciplerocks]

Just harp on everyone else's post, you NEED a wideband. Bird has some good info to get you started up there. I'd also look into your tranny shift points. Too bad you didn't get the Commando version and had full control over your fuel maps and everything. But the Special Forces really is more than enough for an N/A application.

 

[Dirmaid]

do yall have any suggestions on a particular wideband kit? I'm looking for that sweet spot: good but not the best, inexpensive but not cheap

 

[Hahnsb2]

Aem uego.

 

[Dirmaid]

I was actually looking at those earlier, so now I'll definitely look into that. As of right now, the software has a 93 octane tune built for daily driving so I'll drive it like that until I get the wideband to do the performance tune. I definitely want to run all of the 87 out of the tank before I even attempt to load the performance tune just in case, so now is just a good of time as any right?

 

[disciplerocks]

AEM and Innovative Engineering are the best 2.

And if ya really want to pep it up and take advantage of a tune, mill your heads about 0.040".

 

[Dirmaid]

I was thinking about doing some head work sometime this coming winter if I run out of things to do, but my partner-in-mods is going to college quite a ride away so that project may have to wait till the summer

On a side note, what's the fastest 4.0 SOHC that was N/A that you have seen? These seem like pretty stout motors, so i'm just kind of curious as to what kind of power people have gotten out of them

 

[Dirmaid]

Dead thread redemption!

I've finally gotten a hold of a wide band and.. holy carp I'm lean!
Idling and light cruising I'm seeing around 14.6-14.9 (my tuning guys say this is a "perfect cruising" AFR)
Part throttle is 15.2-15.6
WOT is averaging 15.5

It's amazing I haven't blown this engine up ages ago!

What's weird is around the time that my converter locks up at 45 mph it dips down to 12-13 for about 10 seconds then climbs back to 14.7.

Giving it a light rev test the truck reacts about right (goes lean, then rich, then settles into idle) so I'm thinking it's about time to add a bit of fuel on my tune. I'm thinking if I'm running this lean either there is an air leak somewhere or there is a problem with the MAF. Any other ideas guys?