Will a highflow cat change the flow cat change the tone of my exhaust.
Is it safe to run a high flow cat with dp,catback,and intake?

 

Yes, it is perfectly safe. Will help prevent boost creep. More than likely, it will make it a little quieter

Trev

 

Im currently runing a stock cat
the upgrade will make my car quieter?

 

Nothing will be quieter than the stock cat it is the most restrictive.

For a dp, catback, intakes and highflow I would get a PFC and a tune.

 

Mazda should have just made the Fd with a PFC.... most fd owners have one it seems....

 

It will be significantly louder. I have seen high flow cats make more noise than a midpipe with a magnaflow muffler welded in.

 

I noticed a slightly louder tone after installing a bonez high flow.

 

 

The stock cat is a better muffler than most mufflers. If you really want stealthy quiet and ok performance then weld the outside of your stock cat at the flanges and grind the inside welds off flush. Run a stainless steel downpipe and the RB catback with it.

 

I installed the bonez HF cat and it got louder but a deeper tone so the sound note improved. keep your boost at 10 psi and you will not need a pfc for now but if you have the money go for it. it will only improve the car and give you a higher level of safety for the motor.

Jeff

 

Just save up until you can get a magnaflow res midpipe, pfc, and a tune.

 

Not trying to thread jack but how hard is it to pass emmissions with a high flow cat?

 

I have the bonez DP and HF cat and I love it man, a lot of my friends say it sounds really aggressive (or as they like to put it pissed off sounding). For the passing emissions part...no one has said anything to me so I just leave it at that.

 

I passed emissions here in Spain with Bonez hi-flow cat and air pump running, and I can assure you here they are very restrictive with emissions... No problem.

And about the extra noise, I have noticed no difference between stock cat and hi-flow one, in fact... But maybe that's cos I'm running a loudly Greddy ti catback

 

I have a high flow cat welded into a 3" midpipe for emissions and I have a borla muffler welded into a 3.5" midpipe that use the rest of the time.

The cat in the 3" pipe is louder by a ways. The muffled midpipe is much more mellow sounding. It is hard to describe but you can feel the exhaust noise with the cat a lot more because of the frequency of the noise. With the cat installed it shakes my front door when I pull into the carport. My muffled midpipe doesn't do that.

Anyway in my case the cat is louder and it is noticeably louder, despite being 0.5" smaller diameter and more restrictive than my midpipe.

 

as long as you control boost to 10psi or less via boost controller you will be fine. Like mentioned the car will get a little louder and deeper tone but trust me its good....nothing obnoxious and is more than ok to drive around town with

 

I know this thread is old, but I disagree with this. Those mods don't necesarily call for a PFC. A decent BC maybe, but the stock ECU does just fine with those mods.

 

I just did an FD last week with those mods, and injector duty cycle was 99% on the PFC after doing the exhaust work...

I did two more last month that had 86/89% injectorty duty cycle with the PFC...

I would definitely get a PFC, and do the rest of your maintenance( fuel filter etc).

 

Knowing your experience...respectfully, running what PSI and at what RPM? I ran my car for over five years with those mods with absolutely no issues. DP, Bonez Hi-flo and opened intake, efini 'Y' with a manual BC. The only other mod I had was a re-located IAT. This past fall I finally added a PFC but never exceeded about 78% on the commander, even with the cooler fall ambient temps.

 

^ did you have any catback though?

 

^Yes. Greddy SP

 

im going with a 3 inch downpipe and a hiflow cat(basically a straightthrough pipe going through a muffled casing).....i have the 99 spec JDM engine. will i face boost creep? and should i get a FPR to compensate for the extra boost incase of the creep? cant really afford a boost controller at the moment

 

If it was me I would do the PFC before all those other mods, but that is just me. I think the stock ECU is garbage and responsible for a whole lot of the FDs problems/failures. I got mine brand new with commander for around $800 and it was probably the best money I ever spent on the car. When I had the twins it instantly made the car smoother.

Elliot...
What AFR was that last FD at? I would think with just those mods that is a little high of duty cycle. It is either running crazy rich or something else is causing it.

 

It will be considerably louder than the stock cat. I passed emissions with mine.

 

I totally agree.

That last one was at a 11.5afr @ 10psi. We did a fuel filter at the same time too. However we're going to go through the rest of the fuel system. I was shocked seeing how much fuel we had to add.