Highest Supercharged Mileage

[TexasTruck]

It's been said when you get a code, pull over, turn the truck off, and call "AAA".

I got to thinking about the different CAT substrates like ceramic. I think the factory CATs have a ceramic monolith. I wonder how a sudden rise in temperature like from a WOT launch effects the ceramic material. It just seems like the high heat cycles will eventually cause it to fail. Versus say a gradual temperature rise or even aggressive, just not BAM! I watch the CAT temp PIDs, I'm not even sure they're accurate, but they hover around 900/1200 degrees normally. When I accelerate quicker (from 0 to 3.5K RPM), the temp hits 1600 pretty quick. A gradual acceleration to 3.5K still hits 1600, but not as quick like WOT.

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[2whiny]

It's been said when you get a code, pull over, turn the truck off, and call "AAA".

I got to thinking about the different CAT substrates like ceramic. I think the factory CATs have a ceramic monolith. I wonder how a sudden rise in temperature like from a WOT launch effects the ceramic material. It just seems like the high heat cycles will eventually cause it to fail. Versus say a gradual temperature rise or even aggressive, just not BAM! I watch the CAT temp PIDs, I'm not even sure they're accurate, but they hover around 900/1200 degrees normally. When I accelerate quicker (from 0 to 3.5K RPM), the temp hits 1600 pretty quick. A gradual acceleration to 3.5K still hits 1600, but not as quick like WOT.

This is spot on what I notice on the Banks iDash.

 

[staying_tuned]

Is it possible they opted for a cheaper build approach on the cats? I was running stock cats on two F/I coyote mustangs, the last was a 2015 and I had zero issues and beat the snot out of them and nobody ever talked about cats other than purely from a flow limitation standpoint on turbo applications.

 

[Davidwnuc]

I still think that with forced induction where you boost horsepower by 75%, you also boost exhaust gases by 75% as well. I don’t believe that the stock exhaust system has capacity to handle 75% increase in flow. They just don’t design that kind of excess capacity in exhaust systems. It may work for short periods, but extended periods have got to cause problems.

I believe that the proper answer is to increase the flow capacity of the exhaust system. As an old hot rodder, I can’t imagine expecting to produce 700 horsepower reliably with a single exhaust.

Agreed that more horsepower means more exhaust flow. They have created these kits using the stock exhaust systems. So the vehicles will make that power with the stock exhaust and they will probably make more power when exhaust systems are allowed to flow more.
I am seeing, via internet search, just as many cat failures on 2021+ trucks that are completely stock as I am modified trucks. I don’t know if the cat materials/design has changed but something is different to be causing more failures. I don’t think it is just trying to push more flow. We have been doing that for a while via boost or other mods.

 

[Davidwnuc]

This is spot on what I notice on the Banks iDash.

I am seeing the exact same thing.

 

[TexasTruck]

Is it possible they opted for a cheaper build approach on the cats?

It could be, but how do we know. I like to think that they wouldn't cheap out on critical warrantee type components. A window motor is one thing I suppose, but who knows.....

I saw this posted by the Mustang guys and thought it was good information. Just watch out for the click bait if you visit it......

What you should know about your CATs

 

[Davidwnuc]

Is it possible they opted for a cheaper build approach on the cats? I was running stock cats on two F/I coyote mustangs, the last was a 2015 and I had zero issues and beat the snot out of them and nobody ever talked about cats other than purely from a flow limitation standpoint on turbo applications.

I believe you are correct. I had a Roush supercharged 2014 F150 that put down ~550 whp which would be close to 700 crank hp and never had issues with cats. It was tuned…so maybe the tune saved the cats. or maybe the cats were on the verge of failure and i just didn’t know it.

 

[TexasTruck]

What about intake fowling or long term effects from it? Like from the PCV / CCV systems. Not just the entrained oil but also the gases that effect the air/fuel ratio. I like to think the fuel maps consider it though. The systems rely on vacuum which is available at idle or deceleration. What about during acceleration when there is no vacuum and crank case pressures increase. The driver side PCV attaches to the filtered air intake. I wonder if there is any vacuum (Venturi effect) on that port to help draw out the crank case gases when the throttle body opens....... any way just wondering what other contributing factors might effect supercharged mileage....

 

[Dale B]

What about intake fowling or long term effects from it? Like from the PCV / CCV systems. Not just the entrained oil but also the gases that effect the air/fuel ratio. I like to think the fuel maps consider it though. The systems rely on vacuum which is available at idle or deceleration. What about during acceleration when there is no vacuum and crank case pressures increase. The driver side PCV attaches to the filtered air intake. I wonder if there is any vacuum (Venturi effect) on that port to help draw out the crank case gases when the throttle body opens....... any way just wondering what other contributing factors might effect supercharged mileage....

You brought up a subject that I had puzzled over, vacuum. Thirty years ago when I added cruise control to a turbo charged vehicle, I had to add a vacuum storage canister to the vacuum system to power the control system for cruise. The turbo was not under boost enough to cause problems as long as the storage canister was sized properly.

I assume that a supercharged 5.0 is seldom producing vacuum. Is there a supplemental system to supply vacuum? Maybe very little on an f150 requires vacuum these days, but I would assume that the brake booster still needs vacuum.

 

[Davidwnuc]

You brought up a subject that I had puzzled over, vacuum. Thirty years ago when I added cruise control to a turbo charged vehicle, I had to add a vacuum storage canister to the vacuum system to power the control system for cruise. The turbo was not under boost enough to cause problems as long as the storage canister was sized properly.

I assume that a supercharged 5.0 is seldom producing vacuum. Is there a supplemental system to supply vacuum? Maybe very little on an f150 requires vacuum these days, but I would assume that the brake booster still needs vacuum.

At idle and lite throttle, we are making the same amount of vacuum as a non forced induction engine. I have measured it. Here is an article talking about the boost bypass system that Roush uses. I am sure others do something similar.

https://support.roushperformance.com/s/article/What-is-a-Boost-By-Pass-Valve

We have electric brake boosters now, cruise is controlled electronically, and so is the HVAC system. I can’t think of anything that our trucks would use vacuum for except maybe emissions stuff? I don’t claim to know a lot about our trucks though so i could be missing something.

 

[Dale B]

At idle and lite throttle, we are making the same amount of vacuum as a non forced induction engine. I have measured it. Here is an article talking about the boost bypass system that Roush uses. I am sure others do something similar.

https://support.roushperformance.com/s/article/What-is-a-Boost-By-Pass-Valve

We have electric brake boosters now, cruise is controlled electronically, and so is the HVAC system. I can’t think of anything that our trucks would use vacuum for except maybe emissions stuff? I don’t claim to know a lot about our trucks though so i could be missing something.

Thank you for the information. I have experience with forced induction going back to 1978, but all have been turbos and no new ones in the last two decades. Time has passed me by. I never imagined electric brake boosters, but I guess if the plan is to go all electric it has to go that way. Thanks for the update.

My f150 is in route from Kansas City. When it gets here, it looks like I have a lot to discover.

 

[TexasTruck]

My f150 is in route from Kansas City. When it gets here, it looks like I have a lot to discover.

Hey hey!!! That's exciting! Let us know how it goes, pics too

 

[TexasTruck]

Here is an article talking about the boost bypass system that Roush uses. I am sure others do something similar.

They do, to bleed off boost pressure. Whipple puts theirs in the front right corner of the blower on F-150/Mustangs. Vacuum activates it at idle or cruising speed.

 

[Dale B]

Thank you for the information. I have experience with forced induction going back to 1978, but all have been turbos and no new ones in the last two decades. Time has passed me by. I never imagined electric brake boosters, but I guess if the plan is to go all electric it has to go that way. Thanks for the update.

My f150 is in route from Kansas City. When it gets here, it looks like I have a lot to discover.

I just discovered that the power steering is electric now as well. Wow, I do have a lot to learn. I guess that is why the 200 amp alternator is a must have.

 

[Davidwnuc]

Update posted here


https://www.f150gen14.com/forum/threads/p0430-failed-catalytic-converter-pictures.22728/

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