FAS lower pulley...

View attachment 128385

Likely shortly followed by needing a new engine.
Was this the cause of the new pulley making more boost and having air/fuel being more rich? I just ordered the predator FAS and AFE intake and now kinda shat myself after seeing this. May just stick to the AFE intake this pulley rabbit hole ive been in has been endless. Thanks.
 
Was this the cause of the new pulley making more boost and having air/fuel being more rich? I just ordered the predator FAS and AFE intake and now kinda shat myself after seeing this. May just stick to the AFE intake this pulley rabbit hole ive been in has been endless. Thanks.
Stock cats are good for about 1200 hp. Tune properly and you won’t have issues. Plenty of us pushing 1000hp+ on stock cats without issue.
 
Stock cats are good for about 1200 hp. Tune properly and you won’t have issues. Plenty of us pushing 1000hp+ on stock cats without issue.
Thanks. I meant for running the FAS pulley and AFE intake without actual tuning which i believe many folks are running on here so to not void warranty. I was under the impression the picture of the failed cats from LowPSI were due to the FAS pulley lol.
 
Thanks. I meant for running the FAS pulley and AFE intake without actual tuning which i believe many folks are running on here so to not void warranty. I was under the impression the picture of the failed cats from LowPSI were due to the FAS pulley lol.
Low PSI? When i had my FAS lower the AFR went down to protect cats because of increased PSI and heat.
 
For some reason i thought those cats were cooked due to the pulley. All good.

Getting the FAS pulley and AFE Force 2 put in. Went with the Force 2 as a package deal with the pulley on 797.
 
For some reason i thought those cats were cooked due to the pulley. All good.

Getting the FAS pulley and AFE Force 2 put in. Went with the Force 2 as a package deal with the pulley on 797.
We bundled our top two parts to try and make it easy! Appreciate you using us.
 
Stock cats are good for about 1200 hp. Tune properly and you won’t have issues. Plenty of us pushing 1000hp+ on stock cats without issue.
How does cat over temp work with the stock tune vs dusterhoff’s tunes?
 
I should have added clarification. That cooked cat is from an S550 mustang not a trx. The first thing people do when adding boost to coyote mustangs and not running an EPA compliant tune (ie a whipple tune that retains the cat protection) is ditch the cats. I'm not aware of any cats that can reliably handle boost and a good tune without being a meltdown risk.

If you're going aftermarket tune without emissions compliance why retain the cats? Unnecessary risk. Manufacturers have to neuter the hell out of tunes to keep the cats happy and in tact.

For the TRX something like the FAS pulley should have little to no impact on the cats as you're retaining the factory tune and theoretically operating within the performance envelope that it allows.
 
The early Hellcats were subject to a recall over this. They had to replace the cats and reflash a lower COT threshold, I believe 1700*. People who had it done were not happy. It made the cars quite a bit slower. Running pig rich like that can easily cost 80-100hp on this platform according to Satera, and it’s certainly possible a pulley like this winds up costing you more HP than it gains in some conditions.

Anyway, I guess you can’t really blame Stellantis for the conservative tuning. Emissions compliance is no joke, cats are expensive and they have to warranty them longer than anything else.
 
The early Hellcats were subject to a recall over this. They had to replace the cats and reflash a lower COT threshold, I believe 1700*. People who had it done were not happy. It made the cars quite a bit slower. Running pig rich like that can easily cost 80-100hp on this platform according to Satera, and it’s certainly possible a pulley like this winds up costing you more HP than it gains in some conditions.

Anyway, I guess you can’t really blame Stellantis for the conservative tuning. Emissions compliance is no joke, cats are expensive and they have to warranty them longer than anything else.
To me sounds like getting headers without cats is best rout lol. I need to find some videos of that setup with stock exhaust, i bet it would be annoying as hell as a DD.
 
I should have added clarification. That cooked cat is from an S550 mustang not a trx. The first thing people do when adding boost to coyote mustangs and not running an EPA compliant tune (ie a whipple tune that retains the cat protection) is ditch the cats. I'm not aware of any cats that can reliably handle boost and a good tune without being a meltdown risk.

If you're going aftermarket tune without emissions compliance why retain the cats? Unnecessary risk. Manufacturers have to neuter the hell out of tunes to keep the cats happy and in tact.

For the TRX something like the FAS pulley should have little to no impact on the cats as you're retaining the factory tune and theoretically operating within the performance envelope that it allows.
Depends where you live. In AZ as long as you don’t have a CEL then you can pass emissions. Which means your tune can get you through the emissions process. However, they still have the right to visually inspect. On a lifted truck where that is easy you might get an overzealous inspector that actually looks if it smells like fuel when you pull in.

Again, our stock cats are actually pretty awesome. On prior GM LS platform vehicles I was always putting in test pipes in the first round of mods. For the TRX I have kept the cats so I don’t have to worry about the fuel smell, not worry about emissions and they provide some sound deadening while cruising. Somewhere between 1000-1100hp and cats are fine.
 
To me sounds like getting headers without cats is best rout lol. I need to find some videos of that setup with stock exhaust, i bet it would be annoying as hell as a DD.

I have long tubes without cats tied into stock exhaust. Sounds mean but I wouldn’t want to drive it daily
 
Last edited:
Back
Top