Some questions about tuning

[g3t_t0rk]

Hey guys. I have a '05 Vert and I had a couple questions... I spent yesterday at a shop where my buddy with an SRT4 was getting his pile tuned and I learned a few things. For boosted cars, the ideal air fuel ratio is low 11 to 1 and for a N/A car, it's 13 to 1. That being said, I took that account to my own car. Stock gen 3 with Mopar catless exhaust. Since adding the exhaust, I've noticed my car has ran much, MUCH more rich which makes me wonder how much power have I lost? Spark plugs and wires are still the factory ones from 2005 but I only have 30k miles. Do they need replacing?

Here's my dyno sheet BEFORE the catless exhaust. AFR shows 12 to 1 which is too rich?

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To summarize...
-The ideal AFR for boost = 11 to 1 and ideal AFR for N/A = 13 - 1, correct?
-Do my spark plugs and wires that were made in '05 need replacing only after 30k miles?
-Is having a catless exhaust making my car run more rich?
-Which SCT tuner should I get? SCT Xcaliber or SCT Pro Racer Custom?

Thanks in advance for any insight!

 

[prpaster]

11.8 is what most tuners shoot for with SRT-4s as I have one of these as well.

If anything you want to be richer , as if you go lean and then you go boom but if your too rich you are losing power. Do you have a wideband AFR gauge? How do you know you are richer now ? and if you aren't running cats on a stock tune shouldn't you be throwing a CEL ?

 

[g3t_t0rk]

Dyno shop owner was telling me that 13 to 1 would be ideal. I am throwing a CEL but that's because my o2 sensor was damaged a bit from me scraping . When I had cats out and I ziptied the o2 sensors to the frame, I didn't have a CEL. I just feel like it's too rich because it seems to be a lot slower and I've been throwing a lot more flames lately

 

[ViperGeorge]

Funny, on my 06 Paxton car it got leaner with the Corsa installed. I was told to expect this and it did in fact happen. I had it dyno'd at a reputable (or so I thought) shop in MA after exhaust installation and they said it was fine at 12.2:1. They were wrong. Motor went bang. Had it replaced and retuned to a more acceptable 11.x:1

 

[prpaster]

If it seems slowing I bet the computer is pulling timing to compensate from being too lean just a thought

 

[DholiRaja209]

I have an 04 with K$n and Mopar Race exhaust and my AFR is at 12.6 with 33degrees of timing and put down 497rwhp and 530rwtq. I remember before the tune the car felt slow and sure enough I was losing power. With catless exhaust the car was running 10.6 AFR which is way too rich and 26 degrees of timing and put down 435rwhp . In your case 12.1 isn't rich it's considered safe. You can probably pick up a few more hp by going to 12.8-13.1 but to keep it safe my tuner set mine at 12.6 from 2K RPM on. Its been 2 years and I haven't had any issues with my motor

 

[g3t_t0rk]

I have an 04 with K$n and Mopar Race exhaust and my AFR is at 12.6 with 33degrees of timing and put down 497rwhp and 530rwtq. I remember before the tune the car felt slow and sure enough I was losing power. With catless exhaust the car was running 10.6 AFR which is way too rich and 26 degrees of timing and put down 435rwhp . In your case 12.1 isn't rich it's considered safe. You can probably pick up a few more hp by going to 12.8-13.1 but to keep it safe my tuner set mine at 12.6 from 2K RPM on. Its been 2 years and I haven't had any issues with my motor

That dyno was before my exhaust... Now I really think I'm running rich!

 

[DholiRaja209]

Yes going catless will make you run rich if the car isn't tuned.

 

[g3t_t0rk]

Just ordered a SCT tuner

 

[g3t_t0rk]

So I uploaded a tune and I don't feel too much of a difference... Any one else feel a major difference after uploading their SCT tune?

 

[Viper X]

[QUOTE Spark plugs and wires are still the factory ones from 2005 but I only have 30k miles. Do they need replacing?


Short answer on the plugs, yes, replace them. I replace mine every year as they do wear if you run the car hard, and most of us do.....and they are cheap and easy to replace.

Dan