Tune Question - 2003 Cobra

[SC Heaven]

Hoping this is the appropriate place to put this. I have a 2003 Cobra with the following engine modifications.

- JLT Gen2 True Cold Air
- Accufab SBTB and Plenum
- JBA O/R H-Pipe

The car is currently tuned with a canned tune off of an older Diablosport handheld tuner. The tuner has 3 different options for 91 Octane (highest avail. where I live).

1) Custom tune
2) 91 Octane Performance Tune
3) 91 Octane Pulley Tune

As of now I plan on getting the car on the rollers for a proper tune next spring. Unfortunately some unforseen house repairs ate into my play budget and put off work on the car. So as a holdover I am running tune #2 (91 Performance Tune), which research shows should be good for stock to lightly modded cars.

However, the other night I did a WOT pull in 2nd gear down an empty back road. I had friends in another car behind me who came up afterwards saying the car didn't smell right during the pull. My friends are car guys so they understand the car is de-catted and what that should smell like, so naturally I am a bit concerned.

The car has been in its current configuration going on 8 months now and has had 0 issues or drive ability problems. But the 'funny smell' comment has me concerned. The car doesn't smell off to me when idling or driving around, but I obviously can't smell it when I am making a pull, so it's hard to judge for myself.

So my question is, am I pushing too much air with my current mods for the tune? I have debated putting on the pulley tune but am worried about over fueling, although I would rather be running too rich than too lean. I do not have an A/F gauge and like I mentioned, it has not yet been on the rollers, so I do not know what my A/F numbers look like.

So do I leave it as is and just avoid WOT pulls until I have it properly dyno tuned or do I experiment with the Pulley Tune? I also have a smaller upper pulley that was going to go on the car when it got dyno tuned, but funds have stopped that as well as I don't want to install the new upper without an Aux Idler setup.

Also, I am in Denver (5280 ft) so I have a hard time believing the car is running out of fuel.


Sorry for the long read. Thanks in advance for any insight / advice. :coolman:

 

[01yellercobra]

Get a wideband. Cheap insurance for a FI vehicle.

 

[04sleeper]

Any time you change the intake or MAF position, the tune will be off. With the JLT and no tune provisions, you are asking for your motor to blow up!

Do NOT go WOT until you can have the car properly tuned.

 

[SC Heaven]

Any time you change the intake or MAF position, the tune will be off. With the JLT and no tune provisions, you are asking for your motor to blow up!

Do NOT go WOT until you can have the car properly tuned.

Well its not 'untuned' as such. Just on a canned tune. And the tune was applied after all the hardware was installed. So the car should know about the new MAF readings. I guess I was more worried about insufficient fueling than anything. She probably won't be out too many more times before the end of the year, but I will take it easy just in case.

Thanks for the input. :beer:

 

[04sleeper]

Well its not 'untuned' as such. Just on a canned tune. And the tune was applied after all the hardware was installed. So the car should know about the new MAF readings. I guess I was more worried about insufficient fueling than anything. She probably won't be out too many more times before the end of the year, but I will take it easy just in case.

Thanks for the input. :beer:

No, you do not understand. The car MUST be tuned for the MAF. It will not just "Know" that you have a Gen2 JLT. The MAF will be WAY off.

Canned tunes are only based off the stock MAF and Stock Intake. If you change any part of the equation, it will not be correct. The MAF HAS to be retuned for the new intake. No canned tune will be correct.

 

[SC Heaven]

No, you do not understand. The car MUST be tuned for the MAF. It will not just "Know" that you have a Gen2 JLT. The MAF will be WAY off.

Canned tunes are only based off the stock MAF and Stock Intake. If you change any part of the equation, it will not be correct. The MAF HAS to be retuned for the new intake. No canned tune will be correct.

Good to know. I have never messed with tuning before, so this is all good information. Luckily I drive this car like an old lady 98% of the time, so I am not too worried about any serious damage having been done. But knowing this I will definitely keep her out of boost until she is properly tuned.

Thanks.

 

[04sleeper]

As long as you stay out of boost until you get it tuned you should not hurt the motor. The fuel trims will be way off until you get it tuned properly though. Even down low they will be way off.

 

[cj428mach]

Well its not 'untuned' as such. Just on a canned tune. And the tune was applied after all the hardware was installed. So the car should know about the new MAF readings. I guess I was more worried about insufficient fueling than anything. She probably won't be out too many more times before the end of the year, but I will take it easy just in case.

Thanks for the input. :beer:

Changing from a stock intake elbow with a upr cold air kit, to a JLT true cold air kit sent my car 10% richer. As Kevin said the intake systems on these cars have to be tuned, it really sucks if you don't have the tools to do it yourself.

 

[SC Heaven]

Changing from a stock intake elbow with a upr cold air kit, to a JLT true cold air kit sent my car 10% richer. As Kevin said the intake systems on these cars have to be tuned, it really sucks if you don't have the tools to do it yourself.

I know for sure she is running pretty rich at idle, not sure about the rest of the range. Luckily, with the exception of maybe one or two very short pulls, the car has been very babied. But after a local poker run this weekend she will probably be in for the year and I will get her on the rollers first thing in the spring. Hopefully I haven't hurt anything, but no bad noises from the motor, so not too worried.

Really appreciate the input guys. :beer:

 

[evolve]

Kevin (04sleeper) knows his stuff! Good info here.