Will Davesport cat fix midpipe smell?
 

Hey guys I have the AP dual res midpipe and like most midpipes it is smelling terrible and I am wondering if ordering a Davesport cat will fix the smell? I seriously smell like a dirt bike every time I get done driving an gets inside the cabin while driving.
Also, what else can I get from having the Davesport cat?
Does it just bolt right in to my setup?
Will it make my car louder or quieter? (quieter would be better)
I'm stuck between selling the midpipe or ordering this to make it not smell.
I have a TopSpeed Pro-1 catback and an AP dual res midpipe

Sigh

Hi again.

Yes, every un-catted rotary will smell different. Some people love it. You are apparently one that doesn't.

Every cat will "clean up" the smell.

If you aren't paying ~$1,300 or more for the cat (buying new), then it will burn up or blow out under high RPM high load use. A davesport cat can blow out in as short as 1 day of autocrossing. Same with any other cheap cat. The only non-OEM cats that can hold up are the same price or more than the OEM cat. Once the cat fails, then you are back to square 1 with the smell. Unless it clogs, in which case you are doing damage to your engine.

I'm guessing that you didn't realize that removing the cat would mean an increase in exhaust fumes?


If you can live with the smell (I miss it terribly), then ignore the cat options. If you can't live with the smell, go back to the OEM cat. It's the cheapest and most durable of all of the bad options.

Yes it should help with the smell.

No it doesn't just bolt up, it has to be welded into your existing mid pipe.

It will quiet it down.

I suggest getting a catted mid pipe and selling the AP dual res. It shoudl also be notes that aftermarket cat converters don't last long. The only one that probably will is very expensive (HSJ IIRC).

Damn I waited too long to click post :lol:

Well I thought I could handle the smell and I can but I don't know it would be making me smell as well. I'm going on a date Thursday night and I'm going to be showing up smelling like exhaust which isn't good! But okay thanks for that advice, helps a lot.
I don't autocross and it's just a daily driver. Do you think it will withstand my driving if I just daily and baby it? Yes, every now and then I still get on it but nothing crazy

And 9k what are some examples of the catted midpipes?

search.

1 day of autocross is at least 3 runs, at about 1 minute each. Less than half of each run is at full power and high RPM.

So the Davesport on that guy's 8 lasted through about 90 seconds of high RPM full throttle driving.

You know your driving. How many miles of driving will you be able to resist full throttle high RPM for a cumulative total time of less than 90 seconds? It it's like you can just keep "resetting" the damage you do to the internals.

$400 for 90 seconds of full throttle is quite a steep price to pay.

Well said. I'll probably end up putting the stock cat back on selling the midpipe and just buy some suspension. And the rasp you guys told me about is there from the 3k to 4k range and it sounds kind of dumb from inside the car but outside the car it sounds totally different and it is a pretty cool sound. My friend loves it and wants an rx8 now.

I wish there was another way I could take care of the smell because I love the sound!
9k how did you like your HKS single?

I think anyone that saw your original midpipe thread has a free hand to come in here and post: "I told you so".


Any reason you felt that our advice wasn't accurate?

The only reason I didn't listen to it was because my friend has an r3 with the AP pile and said it wasn't raspy and told me a lot of good things about it. He also said his friend had an rx8 like mine and had the AP pipe too so I used their input an just went with it for the price. The rasp doesn't bother me though, it's the smell. I can handle it, but when it's making me smell too, is what I can't take.
And yes I'll even say it, you guys were right and you told me so!

I've had a Magnaflow #59959 ($100 from Summit Racing) metallic-substrate cat welded in for ~8,000 miles now. One autocross and 2 DGRR trips running the piss out of it with no troubles at all. Way way more than 90 sec of WOT. Pulled it out ~1k miles ago to put on a header and the honeycomb looks brand new. No CEL and no stink.

YMMV

Wow thanks! You might've just saved me from selling my midpipe. I wonder if it will fix the rasp of the AP midpipe. I really am wanting the no stink also.

Good to know. First cheap cat report I've seen that wasn't a failure.

What midpipe were you running if you had one on?

I checked out his garage and it says he has a custom 3 inch midpipe from rx7store.
Hmm I wonder if the same concept would work on my AP pipe.
Taking away the rasp and smell

Alright new question:
My midpipe is 3 inches and my exhaust piping 2 and 3/8 inches.
What size cat will I want?
I don't want to lose HP but I do want to take away the smell of the midpipe and take away the rasp of the midpipe OR quiet it down a bit.
On the website, they have 2 inch, 2.25 inch, and 3 inch

OP: I took a used RX7 store straight 3" midpipe (no resonators, no cat), picked up used for $75, then had the 3" 59959 welded in up close to the manifold end, in front of the O2 sensor bung, then bought a BHR resonator/silencer and had that welded in toward the rear. The fact you have a resonator where the cat needs to go will probably complicate the install since I think that front resonator is longer than the 59959, so the installers might have to add some 3" pipe to get it to match. My combo + Greddy SP-2 catback (one of the louder ones) still has drone in that critical 3-4k rpm range, but it's not too bad. (Though the car is "soundproofed" to some degree with Second Skin Damplifier = quieter, plus header = noisier). My midpipe + stock exhaust is quite ok.

Stock manifold + this small cat + rear AP resonator + stock exhaust? Hard to predict since one's dealing with resonances. I'll guess though that the drone will still be there.

I checked my logs this evening, it's been installed now for 9000 miles.

In the pics below, the rear "resonator" is a Morroso spiral flow, which is built too lightly - a BHR is now in its place. The bung welded in in front of the cat is for an EGT gauge.

To be clear, for me,
"rasp" = Civic fart can sound.
"drone" = steady tone or hum.

Even the dead stock system drones, but Mazda shoved the resonant frequency down to under 3k rpm which we seldom cruise at for long.

Thanks for the response and pics. I just ordered that same cat.
But yes the rasp is a civic fart can sound and inside the cabin while driving is what it sounds like but only from 3k to 4k rpm. I hope this fixes the rasp!
And as for the smell? How is yours?
Again, I just have a 3 inch dual res midpipe and a topspeed pro-1 catback.
Didn't know if you were confusing me with having stock exhaust

No smell.

YESSSS!!! thanks alot.

i got a 04 and at idle im suspecting its my cat that rattles and whenever i rev you can see smoke coming out of the exhaust.Also the smell coming out of the exhaust is soo strong. Now i honestly am a rotary noob so i'm wondering what catalytic converter should i get that will last with normal daily driving not aggressive autocross. I have a racing beat catback as well. PLEASE HELP. My bad for the super late forum bump but yes.