Mazdaspeed upgrade guide on FM website

[devgru38]

whats the increase in power with the Downpipe/catalytic converter for Mazdaspeed MX-5? as on the website you say  "When combined with our Mazdaspeed exhaust.... We measured a 23 hp and 26 lb-ft increase" reason i ask is i dont want to change the muffler as it'll make the car loud, but i am after a tad more power.

dp alone will also make the car louder.   DP is responsible for most of those gains, I would think the catback is only responsible for 1-5whp at most.

Sorry to revive a month old topic, but can anyone confirm this?  Is it worth doing JUST a dp?

(I'm a college student, $$$ is limited)

[SilverMiataRacer]

DP only as regards to no catback??

Yea, it's worth it.

[devgru38]

DP only as regards to no catback??

Yea, it's worth it.

Haha, my bad, not enough info.

I mean't stock catback, aftermarket (or home-made) DP.  Worth it? Or will the stock catback system just limit it to the point that dp alone isn't worth it?

Anybody actually done aftermarket DP with stock catback?

[SilverMiataRacer]

I already said it's worth it.  Yes, you'll get more with a catback but you'll get an improvement with just the DP.  Biggest improvement is from an intake though.  Do you already have that?  If not start there.

[devgru38]

I already said it's worth it.  Yes, you'll get more with a catback but you'll get an improvement with just the DP.  Biggest improvement is from an intake though.  Do you already have that?  If not start there.

Yep, got the intake.  And sorry, when you said "no catback" I thought you meant like... no catback at all  (Open DP)

How significantly perceivable are the benefits to the DP as compared to the intake (incl mbc->10psi)? (I know it's a different effect, but just curious).

Also, is there much of a difference in exhaust tone?

Thanks!

[bigx5murf]

I'm running an eBay catless dp with stock catback, it was my first mod. Definitely worth it, for the quicker spool and noise alone.  Begi dyno'd just dp, and I think they recorded a 17whp gain.

Like smr said though, intake added more.

[SilverMiataRacer]

Like he said and he is running catless which will make the gain/feel more

[Keith]

We actually developed our downpipe first, before the intake. When you're addressing exhaust parts, you always go to the biggest restriction. In the stock system, that's the stock cat. And it definitely makes a difference. I'm thinking it's in the 20 rwhp range, I forget the exact number. The catback will also help, but only once you've changed the downpipe.

[devgru38]

I'm running an eBay catless dp with stock catback, it was my first mod. Definitely worth it, for the quicker spool and noise alone.  Begi dyno'd just dp, and I think they recorded a 17whp gain.

Like smr said though, intake added more.

Thanks for the info!

Keith: 20rwhp range for the DP alone? Where is all the restriction coming from?  Just the cat?

Would I be correct in assuming:
Stock Cat -> High Flow Cat = ~20hp
High Flow Cat -> No Cat = ~5hp?

[Keith]

You can make up magic numbers for the lack of cat, I have no measured ones. However, if the stock muffler is now more restrictive than the new cat then I wouldn't expect much change until that was sorted.

[emexfive]

whats the increase in power with the Downpipe/catalytic converter for Mazdaspeed MX-5? as on the website you say  "When combined with our Mazdaspeed exhaust.... We measured a 23 hp and 26 lb-ft increase" reason i ask is i dont want to change the muffler as it'll make the car loud, but i am after a tad more power.

The DP nor the cat back will make the car what I'd call loud. To me it makes it sound perfect! Stock the MSM (thus I assume the MX-5 SE) sounds WAY too quiet compared to most naturally aspirated MX-5s to me. I was shocked and dismayed how quiet (and boring sounding) this new "performance" Miata was when I first bought mine. The FM DP and catback just are a bit louder than a stock non turbo MX-5 to my ears. I don't think you'll be attracting cops or anything with the extra volume if that's your worry.

[SJMSM]

I have been running the full FM exhaust for over two months now and can attest to the fact that it isn't loud and hasn't gotten any louder. The complete system is a work of art, polished stainless, and everything fits with no problems. It makes good sense to do the entire exhaust rather than try to mate the new 2 1/2" downpipe to the 2 1/4" OE midpipe.

[gregmiata]

When I bought my MSM last fall it had the stock MP and muffler with the FM DP. The sound was muted but with a nice purr. I added the rest of the FM exhaust over the winter and really like the increased sound too with one exception - there is a pretty loud bass resonance around 1,800 rpm for me now. Get under about 1,500 and above about 2,200 and its gone. Not sure its really heard outside of car but its pretty loud inside. If I could take that away I would be 100% happy with the added sound.

[Graz16]

Hello Keith,

Thanks for supporting a forum where your customers can ask you infinite questions, before, and after they send you money.

I just installed your cross flow radiator and stage two fan assembly on my '04. I had eliminated all other issues, so I had to have a cooling problem. I believe that the P.O. had installed a massive (unknown make) inter cooler that virtually covered the under hood intake. So, I was not getting enough air through the inter cooler, the power steering cooler, the AC condenser to cool off the radiator. I just happened to take a very long way around realizing this.

Anyway... The installation was nearly flawlessly easy. One point I would suggest that you look into though is to add another bracket to the radiator kit. Since the cross flow radiator has a filling cap that extends behind the radiator, I now have "contact" with the inter cooler intake. Sorry... I do not know if it is stock.

This presents a problem. Installation called for some "elbow" grease" to push the IC down pipe back far enough that the flanges that mount it to the frame no longer fit.  I have a picture someplace that I can't upload at the moment. (ASAP) This also made the bottom connection of that pipe to the inter cooler separate.  Presenting the obvious problems. I fixed it by connecting the pipe to the inter cooler, then pushing it below the radiator filling port and tightening all connections that fit. There are still two securing nuts that won't mate with the original bolts on the frame. I will have to make a bracket to connect the upper bolt, and I will have to bend the lower bracket to reach the stud on the frame.

Since all other parts of this installation went very smooth. I am a little surprised that you had not considered this contingency. Since I don't know if I am talking about stock plumbing, I can't tell. And I understand that you can not prepare for all possible installations. But... It seems that a universal adapter could be made and sold with the kit to enable this problem moot. Some instructions on your very precise documentation could also include bending the lower bracket to fasten to the frame.  What do you think?

Oh yeah!   If I spent over $900 on these components, I would think you guys could throw in a couple of FM decals or stickers too!   

[Keith]

I think I need to see what you encountered before we "fix" this problem.

We do usually include stickers, but occasionally we run out.