Catless and the imfamous CEL

[5.0_Lojos]

Have a bad cat and those worked for me

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[Deleted member 69311]

Have a bad cat and those worked for me

Link? Or the item name?

 

[tosha]

Alright, resonators are on and what a difference it made. Sound is refined no rasp no drone. Highly recommend them

Some videos please

Also, can you deep dive a bit on how cats were removed? Did you with pipes or punch out option?

 

[5.0_Lojos]

Some videos please

Also, can you deep dive a bit on how cats were removed? Did you with pipes or punch out option?

Regretfully no before and after but without a doubt a huge improvement in terms of eliminating rasp and the famous trumpet sound. Resonators are not restrictive at all and does a great job in refining the sounds. It's a win now that my exhaust is free flowing and the sound is refined. Car is def peppier w/out the Gen 2 boosted with also a 2018 intake mani upgrade. Aside from full headers (which given the cost I think the delete 3" all the way) is the way to go.. Most if not all restrictive points have been remedied... so far so good.

 

[Rolls]

This is an interesting subject that I’ve spent a ton of time working through.

At wot it's generally accepted that EVC of 15 works well. It's not very influential to power output. There might be a little bit of power way up top by advancing to 5-10 at 7500 rpm. So, the focus is on the intake cam timing.

Virtually all modern Coyote tunes advance the intake cam to -20 in the lower/mid rpm, which generally traps more charge in the cylinder before dynamic effects come into play at higher rpm. Usually around 5000 rpm is when the dynamics start to matter and that rpm range is when the intake cam is in the middle of retarding.

In setups where intake runner dynamics can affect airflow (NA, centrif, turbo), the intake cam retards a lot, all the way to 15 to as much as 25 IVO.

In PD blown setups, the blower size, speed, and inlet pressure dictate the airflow, so the air dynamic effects in the port can't affect airflow. It becomes a game of efficiency and knock (if on pump gas). In general, advancing the intake cam has less tendency to knock, but retarding it helps reduce pumping losses which improves efficiency. And by efficiency, I mean producing more power from the same airflow. Why it reduces knock by advancing the intake cam is up for discussion, but I think it has to do with purging hot gases from the cylinder during overlap. The Roush stock calibration only advances the intake cams from -20 to -12.5 and they run it much more advance up top than anyone else. Is this due to them wanting to maximize performance on 91 octane? Maybe. Most others such as Whipple and major tuners retard the intake cam to around 0, +/-5. Note that this is still a lot more WOT overlap than stock.

So back to the original question....I had optimized cam timing for 93 octane so it was somewhere between -5 and 0 IVO, and 10-15 EVC. I was hesitant to retard the intake cam much beyond that due to the amount of time I spent arriving at those numbers to begin with. For sure, more retard would have reduced overlap and, thus, blowthrough, but would borderline timing have been reduced as a result? And would the trade-off net more power? I don't know. To be honest, this happened on the dyno and it took me probably a week to analyze the data and figure out what happened...plus the cats are back on the car so I don't think blowthrough is currently an issue.

By the way, blowthrough logic is active on ecoboost and the Roush supercharger kits, but not GT or even GT500.

This is an extremely interesting topic and even more so when you have fully independent intake/exhaust. The biggest interest to me is how oscillations can shift torque curves due to moving angles in transient conditions despite steady state showing something different. Makes transient tuning even more difficult!

 

[5.0_Lojos]

This is an extremely interesting topic and even more so when you have fully independent intake/exhaust. The biggest interest to me is how oscillations can shift torque curves due to moving angles in transient conditions despite steady state showing something different. Makes transient tuning even more difficult!

So what is best bet?

 

[Rolls]

So what is best bet?

Specifically regarding?

Also whilst I develop custom automotive software I want to make it clear by no means i am I a tuner so take any tuning advice with a piece of salt.

 

[JVO21303]

Link? Or the item name?

O2 extensions

 

[5.0_Lojos]

O2 extensions

Zero issues experienced. No CEL light and the car is performing datalog was also sent jic. All was spot on. Thank!

 

[JVO21303]

Zero issues experienced. No CEL light and the car is performing datalog was also sent jic. All was spot on. Thank!

So you used the extensions sorry for the late response

 

[Rolls]

Has anyone tried running 2 cats in parallel on each bank? Surely you can keep the back pressure down, (do some muffling as they act as a fantastic resonator). Pass emissions and everything is hunky dory?

I don't know why no one has something like this for sale? If it works It helps the industry tremendously, you may have to increase the cold start enrichment to get them to heat up fast enough, but I'm sure it's possible and EO passable.

 

[5.0_Lojos]

Wait, 4 cats total?

 

[WildHorse]

Has anyone tried running 2 cats in parallel on each bank?

lots of manufactures , well mainly hi-performance use a pre-cat , and regular cat . I feel there would be no benefit (other as to like you said, sound control) for the Mustang.

 

[Rolls]

Wait, 4 cats total?

Yes. That way you could meet emissions and keep the cats. What does the 700hp raptor exhaust look like? Or the Gt500?

I'm sure you could extrapolate on that.

 

[5.0_Lojos]

lots of manufactures , well mainly hi-performance use a pre-cat , and regular cat . I feel there would be no benefit (other as to like you said, sound control) for the Mustang.

Yes. That way you could meet emissions and keep the cats. What does the 700hp raptor exhaust look like? Or the Gt500?

I'm sure you could extrapolate on that.

Did not know this. Shoot, most if not all are trying to get rid of the 2 kitties let alone have or add an additional 2. interesting.

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