ft86 speed factory uel catted on 2017+ ??

[BRZ FTW]

anyone have dyno results for this?

[jflogerzi]

It's going to be the same as any other twin... IMO stay stock unless you want to go catless.

[ShansBRZ]

I have one on my 17. No dyno results but the header and oft stage 2 has made a big difference.

[Joveen]

Originally Posted by jflogerzi

It's going to be the same as any other twin... IMO stay stock unless you want to go catless.

Why catless?

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[churchx]

Because catted aftermarket headers have mostly cons, and supposed pro cannot be relied upon.

They obviously cost more then catless due having cat, yet even while being more expensive provide way less performance gains, and while they may have been designed to eliminate cat readiness related CELs with stock tune, they don't eliminate it 100% for sure, just making it less frequent/longer to appear, like some O2 sensor spacers. Need to find space/clearance for cat also may cut from design efficiency. By emission related legislation, even while they are also catted, they are still "altering emissions related equipment" and thus they just like catless are not legal. And where emission MOT tests are performed only by sniffing tests, not via OBD, many pass them even with catless header, if one leaves stock 2ndary cat.

Hence more popular choice between running stock header and change just catback and/or intake for better sound .. OR going all way for catless header (most still leave 2nd cat in cars instead of going fully catless) for performance. Not something inbetween that will cost more yet will net less and still won't be completely legal choice.

[ShansBRZ]

The difference in hp and torque between catted and non catted is about 4 hp and the same in torque. There’s a thread on the page here that shows that in a dyno sheet. The reason to go with the an aftermarket header and tune is to get rid of the torque dip in the lower rpms. I feel better running one with a cat in it. My opinion and that’s all it’s worth.
http://www.ft86club.com/forums/showthread.php?t=31555

[churchx]

Gains from header depend a lot from ecu tune. After all, if there is less restriction and better scavenging in catless version, one can & should dial different timings, and net more from catless one.

Can you be more specific which header you have and which results you refer? I wonder if that's not the case of running/testing both headers with same tune (eg. stock, or generic OTS tune), instead of proper tailored to specifics of header. In some header designs (eg. Ace's) gains from not well customized tune to it might be as little as 5whp, while with proper tune it may become top performer with gains few times that. As without ecu tune catless will throw cat readiness CEL soon, but catted also can throw such, imho it makes little sense to not getting ecu tuned, even if it's more for extra performance gain, not just for disabling cat readiness checks. And if one spends for ecu tuning, why not getting right tune for most gains.

[MCTeeJ]

Originally Posted by churchx

Because catted aftermarket headers have mostly cons, and supposed pro cannot be relied upon.

They obviously cost more then catless due having cat, yet even while being more expensive provide way less performance gains, and while they may have been designed to eliminate cat readiness related CELs with stock tune, they don't eliminate it 100% for sure, just making it less frequent/longer to appear, like some O2 sensor spacers. Need to find space/clearance for cat also may cut from design efficiency. By emission related legislation, even while they are also catted, they are still "altering emissions related equipment" and thus they just like catless are not legal. And where emission MOT tests are performed only by sniffing tests, not via OBD, many pass them even with catless header, if one leaves stock 2ndary cat.

Hence more popular choice between running stock header and change just catback and/or intake for better sound .. OR going all way for catless header (most still leave 2nd cat in cars instead of going fully catless) for performance. Not something inbetween that will cost more yet will net less and still won't be completely legal choice.

This guy summed it up well.....Also, I wouldn't rely on just dyno results unless its a trusted third party. A lot of vendors like to cheese their numbers a bit as a selling point.