Can I fix this myself??? w/ sct handheld

[b_dike]

Alll right here's the run down. Bought an 04 cobra in April. All mods and tune done by previous owner. Mods are in my sig.

Finally made it to the dyno (House of Boost) in Lenaxa, KS for those of you in the KC area.

Found out that there is 24* of timing on a 93oct tune(all I have is 91oct in my area)

And at WOT my afr is 12.5(some have questioned the accuracy of tailpipe sniffers, maybe closer to 12.2?)

So my question for you guys is can I fix this myself with the SCT handheld that came with the car. Seems pretty straight forward to me, but some people say it's too complicated and I shouldn't mess with it.

So far I've adjusted the spark between 4k-8krpm's to -3(assuming the value of 0 is 24*, -3 should be 21*?)

And my WOT A/F I set to 2.0 richer. (how much is 2.0???)

Does this seem right? Or should I just leave it all alone and wait till I can get her dyno tuned?

 

[SVTDice]

What is your current WOT A/F At?

 

[b_dike]

12.5 is what it was durning the dyno. I have no way of reading my afr myself, so I don't know. Unless it can be data logged?

 

[01yellercobra]

You can get a wideband installed in your car to check the changes you make to A/F. If you want to just make small changes you're doing fine. If you want a complete retune you'll have to take it in or buy something like Sniper or Pro Racer Package.

 

[b_dike]

So It doesn't look like i've done any thing that would hurt my car right?

And still haven't been able to get an answer to how much 2.0 is. Any ideas? The WOT A/F adjustment goes by increments of 2 all the way to 14.

Thanks guys, guess my next step would be to get a wideband hooked up that will probably tell me how much fuel 2.0 is. btw how difficult is that to do???

 

[01yellercobra]

I think the 2.0 is 2%. So it'll be adding 2% of fuel to the 12.5. It's not an exact science though. I've never dealt with the options.

Hooking up a wideband isn't hard. Just running wires and having a bung welded on your exhaust.

 

[b_dike]

I think the 2.0 is 2%. So it'll be adding 2% of fuel to the 12.5. It's not an exact science though. I've never dealt with the options.

Hooking up a wideband isn't hard. Just running wires and having a bung welded on your exhaust.

I would not have thought of that. Were did you find that info? It makes perfect sense for the # to represent a %. You have no idea how many times I've asked that question, and you are the first to give an answer. :beer:

Thanks a bunch, now how can I plug 2% into an equation to possibly approximate an afr. Knowing this isn't anywhere near an exact science, surely there must be someway to approximate what a 2% gain in fuel would do to my WOT afr. For once I feel like I'm actually making progress here. lol :banana:

 

[01yellercobra]

When making changes to the MAF transfer it's done in percentages. Removing or adding a certain percent of fuel at a given point.

I'd think something simple like 12.5x2%=.25. So adding 2% would put you at 12.25 A/F. But it's going to change since 12.25x2%=.245. So it's not going to change the same amount each time you add fuel.

 

[b_dike]

When making changes to the MAF transfer it's done in percentages. Removing or adding a certain percent of fuel at a given point.

I'd think something simple like 12.5x2%=.25. So adding 2% would put you at 12.25 A/F. But it's going to change since 12.25x2%=.245. So it's not going to change the same amount each time you add fuel.

Thanks man I see what your saying. So 4% should get me where I need to be if 12.5x4% =.480 and 12.5 - .480=12.02, and factor in the fact that tailpipe sniffers usually read a little lean.(.2 to .3) than I should be in the high 11's.

Like you said before, I know this is not exact or anything but at least it's safe. At least until I can have her dyno tuned professionally.

Thanks for the knowledge :beer: