EO2K

iTrader: (37)

It did! I ran it N/A on my car for a while, as did Gesso before he gutted his car. It was loud but only when you had your foot hard down. I never got a chance to run it with the turbo.

The Magnaflow 12589 is the one everyone recommends, its center/offset. I belive this is the 12589



The offset/offset and different finish options can be found here: MagnaFlow Exhaust Products - For Trucks, Suv's, American Muscle, Diesel, & Sport Compact Vehicles

These two threads have some good info about the great big magnaflow:

https://www.miataturbo.net/diy-turbo...op-muff-67263/

https://www.miataturbo.net/diy-turbo...install-76891/

codrus

OK, that looks pretty much straight through. Kind of an odd way of doing it, but I guess it works. I'll need to get under the car with a tape measure and see what looks like it's going to fit.

The local CSP/DP autocrossers are all in love with the Burns Stainless mufflers, so I briefly pondered something like this:

SM-300-625-17-2S

Downside is that it's really freaking expensive and apparently the reason that it's so light is because it's thin, which makes it somewhat fragile, so I think that's probably not a good choice.

On a slightly different topic, I decided to try to hook up the thermocouple to the MS3 so I could datalog EGTs. No EGT circuit on my MSLabs basic, so I picked up an AD595AQ from Mouser, put it on a piece of perfboard with a 2:1 voltage divider, and tried to hook it up to the thermocouple. It works, but only on its own. It appears that the 595 requires grounding one side of the thermocouple, while the AutoMeter gauge requires that it NOT be grounded. Worse, the AutoMeter is a pretty low impedance, and TK says that will probably mess up the signal such that the 595 can't read it properly. Argh! Apparently AutoMeter never went to kindergarten and didn't learn to share. :(

So I either need to install a second thermocouple for the MS3 or replace the AutoMeter gauge with one that plays nice with others. Either that or I guess it's theoretically possible to build a circuit that takes the output of the 595 and pretends to be a thermocouple that the AutoMeter gauge can read.

--Ian

18psi

iTrader: (76)

wow 517 for a muffler

EO2K

iTrader: (37)

Yeah, I stopped looking at the Burns website very early in my exhaust odyssey. It's slightly outside my budget tolerance

Who are these local CSP/DP autocrossers? I think NorCalUFO shut down? I've not been out to Marina in a while.

codrus

Yeah, UFO shut down a year ago. These guys ran more frequently with SCCA and AAS, though.

CSP has no minimum weight, just a list of allowed mods. Since exhaust is free, a muffler that weighs 3-4 pounds less means a car that weighs 3-4 pounds less, and apparently building a winning CSP car requires finding a hundred or so ways of doing that.

--Ian

EO2K

iTrader: (37)

That's interesting, NorCalUFO cashed my last membership check. My car is way too heavy to be competitive, but it might be fun

sixshooter

iTrader: (12)

Check this site out: auberins.com, Temperature control solutions for home and industry

codrus

As I understand it, the autox program shut down in the middle of last year, but the actual club windup was supposed to happen in December. Peggy was going to do a final accounting and refund any excess membership dues at that point, but I haven't seen any mention of it. I know that they've been pretty busy with a lot of personal life crises lately, so I suspect that's why.

I used to autox with UFO a lot and intended to switch to another club (probably AAS) after they went away. There's a lot of concern about the ongoing viability of both the Marina and Oakland sites, though. What with that and rebuilding the car after the throttle body incident, I haven't been to an autox in a year.

--Ian

EO2K

iTrader: (37)

Yeah, I'm super not worried. I'm not the kind to get wrapped around the axle about such things. It was fun while it lasted. They are welcome to keep the $ as far as I'm concerned.

The Marina site has always been iffy, they never seemed like they were super receptive to UFO. I remember a couple years ago they kept dropping UFO dates in favor of the CHP and even other clubs. I know BMW, Porsche, Lotus and Corvette clubs still run out there because I see the setups from time to time.

As for Oakland, I never ran up there at all. It might be fun to go watch and catch an event from time to time but I know I'm not going to be anything like competitive.

codrus

Yeah, the membership dues were like $15, so I really don't care.

The thing about Marina is that there are lot of people involved and they don't all agree on what they want. It brings in money for local businesses and a big portion of the rental fee goes to local charities, so there's a fair bit of support for it amongst the city council and with the Mayor, I think. Then there's the FAA and other parties. It's kind of a mess.

Oakland is a vastly inferior site to Marina, IMHO. It's smaller, and it's deteriorating asphalt rather than really nice military-airbase-spec concrete. It's popular with SFR SCCA because that club is really centered around San Francisco, so Oakland is much closer than Marina.

Back ont he Miata topic, it turns out that Amazon sells TurboSmart springs, so I ordered a 3 psi inner spring and a 10psi outer spring, to go with my two 7 psi springs (one middle, one outer). Since I actually get somewhere around 5.5 with the 7 psi spring, I'm hoping that either 7+3 or 10 will give me around 8.

--Ian

HHammerly

iTrader: (3)

FYI if you are thinking about the 3" offset magnaflow, mine at 4000k mi is already rattling at 3k rpm, sound like a broken internal baffle 😕

codrus

I was thinking of that one -- that sucks. Any idea if it's a one-off, or do they frequently do that?

--Ian

HHammerly

iTrader: (3)

This is my first experience with this mufler, i will call magnaflow to see what they say, and wull cut it open to fix it if they do not replace it under warranty.

EO2K

iTrader: (37)

The ones we have been recommending are all straight through design ones, no baffles. HH, do you still happen to have the PN on the one you bought? Thats got to be a really frustrating rattle.

If you cut it open definitely post pics and PN

18psi

iTrader: (76)

did you get a "turbo" muffler or something?

cause I don't think any of the ones we all normally use have baffles

all are straight through, and while they do "break in" and get slightly louder over time, I've yet to see one completely fall apart and rattle

HHammerly

iTrader: (3)

The mufler part number is MAG 13219 universal XL performance, center inlet offset outlet.
I really wanted a quiet setup so i chose a baffled muffler and used a vibrant resonator that was installed where the cat would be, but the system still drons at 3700 rpm and it gets old on the hwy and now it rattles at 3k pretty bad.

18psi

iTrader: (76)

yup, found your problem

HHammerly

iTrader: (3)

So how loud are the straight trough ones? Talked to magnaflow today and they tell me that it is not a common moroblem unless the engine makes more power than what they are rated for and i am way under that ( i bet they tell everybody that) they will replace it under warranty, just dont want to make the same mistake two times...

codrus

Noise level for exhaust systems all really depends on your personal tolerance. I have a fairly high tolerance for it, but then I rarely drive my Miata for more than 45 minutes at a time (that's what the Audi is for), and I can't hear it all that well with the top down anyway. The FM 3" exhaust is loud enough that I can (barely) hear my car idling when it's in the garage and I'm in the house, OTOH my house is in California and was built in 1964, so there's zero insulation in the walls.

I'm pretty sure the FM 3" system passes 91 db at Laguna, although the last few years I've only gone there with Miatas @ MRLS, and the Mazda connection gets us 102 db days, so I'm not sure. I will say this, my car is vastly quieter than almost every other car in the "A" group there.

So it looks like I need to go do a bunch of reading up on the Magnaflow options, it seems like there are several. First I need to actually measure the backpressure of the FM muffler, though, and determine if that really is the limiting factor of if it's the cat. Anyone know of a cat that flows even better than the one FM uses? I run a cat delete pipe when it's on the track, but it needs a cat for the street.

My new EWG springs showed up! I bought 'em from Amazon.



--Ian

18psi

iTrader: (76)

I honestly don't think the straight through ones are any louder. At least not in any way that would make it more annoying.

Ian, looks like fm finally switched to metalic cats? If so that one should not be too restrictive, though catless will obviously be better (flow). Other than the cat, that 90* inside the muffler is probably the most restrictive part