Catless and the imfamous CEL

[WildHorse]

Done that enough "back in the day" to know that calibrated Widebands are much more accurate.

and there's much better stand alone widebands out in the wild.
but whatev.. I grow tired of this, you WIN.

Sponsored

 

[engineermike]

Along the subject, my shop custom made the 3" Cat delete for my setup which I see it's customary in the "Cat delete" scene. My question is, should there be any modifications done additionally or a custom H pipe 3" to match? I currently have the Steeda H PIPE which is not 3" does this matter.

A customer at the time of install made a comment about my exhaust from factory headers to catback was a "Bottle Neck" setup?

any insight on this?

Are you still using the stock resonator? If so, it has a 2.25" factory connection at the front and I believe necks down to 2" at the rear for a short section before going back to 2.5".

I've done a lot of work around this and I found that a supercharged coyote really needs dual 3" exhaust to get the backpressure down to recommended levels. I apparently went a step too far, though, when I ran without cats and full dual 3" with all straight-through mufflers.

Decades ago one of the legends (Vizard or Lingenfelter, can't remember which) that 5 psi should be max exhaust pressure, which I found to be true on the dyno with an NA setup. Boosted can tolerate more. A full stock exhaust is 15 psi or more when supercharged. I did get too low, I suspect below 5 psi. This allowed charge blow-through, which in turn fools the O2 sensors into showing lean and that causes it to unnecessarily add fuel and actually run rich (O2 sensors fooling you again). My best recommendation is to keep backpressure between 5 and 10 psi in a blown coyote, but you'd have to install a gauge to check it.

 

[Rolls]

@tosha the “right” way to delete cats (if it were legal) while minimizing other issues would be to turn off FAOSC and use the anti-foulers. Pcmtec gives you access to 10,000 parameters but that’s not one of them. Most big tuners won’t do it either because they value their business and fear jail time.

We purposely disable the ability to blatantly disable cat monitors and mil warning lights in the US market as you can make 1000hp whilst meeting emissions. We want to exist in 10 years time hence the decision.

Personally id try and fit 4 cats, 2 in parallel if possible to reduce the load and back presssure on them.

Might need some tweaks to cold start to get them to light off as fast as stock though.

 

[tosha]

in the US market

What about Canada?

 

[5.0_Lojos]

Are you still using the stock resonator? If so, it has a 2.25" factory connection at the front and I believe necks down to 2" at the rear for a short section before going back to 2.5".

I've done a lot of work around this and I found that a supercharged coyote really needs dual 3" exhaust to get the backpressure down to recommended levels. I apparently went a step too far, though, when I ran without cats and full dual 3" with all straight-through mufflers.

Decades ago one of the legends (Vizard or Lingenfelter, can't remember which) that 5 psi should be max exhaust pressure, which I found to be true on the dyno with an NA setup. Boosted can tolerate more. A full stock exhaust is 15 psi or more when supercharged. I did get too low, I suspect below 5 psi. This allowed charge blow-through, which in turn fools the O2 sensors into showing lean and that causes it to unnecessarily add fuel and actually run rich (O2 sensors fooling you again). My best recommendation is to keep backpressure between 5 and 10 psi in a blown coyote, but you'd have to install a gauge to check it.

No Stock resonator, added the Steeda H. (Today I am adding the 2 vibrant resonators to refine the sound. I understand that has nothing to do with performance ) I'd hate to come this far and ultimately sacrifice the very thing we are all after - (PERFORMANCE) 🫣

 

[K4fxd]

We purposely disable the ability to blatantly disable cat monitors and mil warning lights in the US market as you can make 1000hp whilst meeting emissions. We want to exist in 10 years time hence the decision.

It's really a shame that an unelected rouge agency of the US government can put enough pressure on an overseas company, that they are worried about being put out of business.

What are the people making 2000 + HP supposed to do? Stand alone?

 

[5.0_Lojos]

It's going down guys. Vibrant resonators are in the works.

 

[Rolls]

It's really a shame that an unelected rouge agency of the US government can put enough pressure on an overseas company, that they are worried about being put out of business.

What are the people making 2000 + HP supposed to do? Stand alone?

Do you want us to exist and innovate?

It is a non question.

No offense taken but we have 5 employees not 100+

We cannot create an EPA approval process like our competitors and exist as a profitable business until we grow.

This is the only way forward.

 

[K4fxd]

This is the only way forward.

I'm not faulting you at all. I place the blame squarely on our US government. These agencies are not legally able to create law. Due to the laziness of our congress they can and do get away with it.

When I was a kid lake Erie caught fire. Many days smog was so bad I could not see the valley floor from the ridge.

Today we can eat the fish from that lake and the air is so clear the valley floor is 100% visable. Yet we are told tens of thousands of kids are killed each year because we need to clean up car exhaust another 5% with a draconian cost to our lives.

 

[engineermike]

What are the people making 2000 + HP supposed to do? Stand alone?

In the governments eyes, those people should buy cars like the cobra jet or something really old. Legally I think that’s the only “legit” way.

 

[Grimreaper]

Are you still using the stock resonator? If so, it has a 2.25" factory connection at the front and I believe necks down to 2" at the rear for a short section before going back to 2.5".

I've done a lot of work around this and I found that a supercharged coyote really needs dual 3" exhaust to get the backpressure down to recommended levels. I apparently went a step too far, though, when I ran without cats and full dual 3" with all straight-through mufflers.

Decades ago one of the legends (Vizard or Lingenfelter, can't remember which) that 5 psi should be max exhaust pressure, which I found to be true on the dyno with an NA setup. Boosted can tolerate more. A full stock exhaust is 15 psi or more when supercharged. I did get too low, I suspect below 5 psi. This allowed charge blow-through, which in turn fools the O2 sensors into showing lean and that causes it to unnecessarily add fuel and actually run rich (O2 sensors fooling you again). My best recommendation is to keep backpressure between 5 and 10 psi in a blown coyote, but you'd have to install a gauge to check it.

What ivo/evc did you see this at for blow through if youd share? Boosted usually runs from -20ivo to 0 ivo and 15 evc. Some tunes run near stock ivo retard though into 15ivo north of 6krpm.

Id need to double check I plugged things in correct but gen2 cam producing this at -20/20. Most significant overlap by far.

 

[5.0_Lojos]

It's going down guys. Vibrant resonators are in the works.

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

 

[engineermike]

What ivo/evc did you see this at for blow through if youd share? Boosted usually runs from -20ivo to 0 ivo and 15 evc. Some tunes run near stock ivo retard though into 15ivo north of 6krpm.

Id need to double check I plugged things in correct but gen2 cam producing this at -20/20. Most significant overlap by far.

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.

 

[5.0_Lojos]

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.

Your Brilliant AF!

 

[JVO21303]

I’ve been cat less and the CEL never turned off. I had the spacers too and it didn’t help. I have high flow cats right now and they still haven’t turned off. I think you have to get a tune to turn them off.

Have a bad cat and those worked for me

Sponsored