Jerry SuperDork
April 6, 2015 5:46 a.m.

Last thing I want to do is the exhaust. It's just too quiet. (I think the other MR2's exhaust and the Abarth have spoiled me now.)

A few people on MR2.com recommended this one: SV3Power cat back system

"SC-style cat-back muffler bolts directly to OEM or SV3Power Supercharged style catalytic converter or test pipe.

Muffler is a Dynomax Super Turbo. Tone is restrained at low RPM and drone-free at cruise, with an authoritative growl when the throttle is opened and a little snarl on the overrun.

SC Cat-Back Exhaust System features include: - 100% bolt-in fit w/ full OEM compatibility - Heavy 14-gauge aluminized tubing: 2.50" OD inlet, 2.25" OD outlet - Proprietary laser-cut 3/8" thick steel flanges - Inlet flange grooved for OEM-style crush (donut) gasket - Stainless tubular hangers fits car's existing rubber mounts - Muffler brace in OEM location for maximum rigidity - OEM-grade gaskets and quality M10x1.25 hardware included - Excellent replacement for stock vehicles - Easily supports typical performance modifications - Optional dual polished stainless tips

Tailpipes exit at the right side of the car in the same location as the stock muffler. Muffler is shown with optional dual polished stainless tips."

-------I figured I'd also replace the 27 year old cat while I was under there.

"Direct bolt-in replacement cat for supercharged AW11 MR2. Fits OEM Toyota and SV3Power SC-style downpipes and mufflers. Our cats are built on 2.5" Magnaflow blanks. Standard is ceramic-core 53006. Options are spun metallic 59956 for greater flow and durability, or 332305 (2.25") California spec"

-------$120 seemed reasonable. Then I saw the test pipe option:

"Test pipe bolts in place of catalytic converter in Supercharged AW11 MR2. Fits the car's original downpipe and muffler; any aftermarket muffler that is a true bolt-on for the Supercharged MkI MR2 should work with this test pipe.

If a catalytic converter is not required in your area, or if you are building a race car for which a catalytic converter is not required, an SV3Power test pipe is the perfect way to replace your existing (or missing) catalytic converter.

SC-style Test Pipe features include: - 100% bolt-in fit w/ full OEM compatibility - Heavy 14-gauge aluminized tubing (2.5" OD) - Proprietary laser-cut 3/8" thick steel flanges - Outlet flange grooved for OEM-style crush (donut) gasket - OEM-grade gaskets and quality M10x1.25 hardware included"

--------Only $59.

If you were redoing the exhaust on a 27yr old weekend toy, what would you do?

alfadriver UltimaDork
April 6, 2015 6:53 a.m.

Is there any way you can hear something before you install it?

For whatever reason, the Italians are REALLY good at exhaust sound tuning. And that info doesn't seem to translate that well to others. Some companies do post sounds- Kieth put up sounds of their recent NB set up that I'm interested in.

Jerry SuperDork
April 6, 2015 7:09 a.m.

In reply to alfadriver:

They have a video clip that shows what it sounds like... Pretty sweet. Youtube

trucke HalfDork
April 6, 2015 7:11 a.m.

I've run DynoMax Turbo mufflers on my FX16 (4age) and they always sounded pretty good. When they get older, they start to sound a little tinny at higher rpm.

alfadriver UltimaDork
April 6, 2015 7:21 a.m.

In reply to Jerry:

IMHO, if you like it, and it's stainless, get it.

I don't bother much with non stainless stuff anymore- had it rot out of my honda more times than I can remember.

Jerry SuperDork
April 6, 2015 8:01 a.m.

In reply to alfadriver:

Thanks, pretty sure I am. The question was actually should I go test pipe, or a new catalytic converter?

HappyAndy UltraDork
April 6, 2015 8:22 a.m.

My. 02¢ On the subject of catalytic converters. If you are going to be driving in a lot then please put a catalytic converter on it, I don't like air pollution and neither do most people. OTOH, If it's primarily a track toy or weekend warrior I would delete the catalytic converter.

alfadriver UltimaDork
April 6, 2015 8:29 a.m.
Jerry wrote: In reply to alfadriver: Thanks, pretty sure I am. The question was actually should I go test pipe, or a new catalytic converter?

I would.

Besides the environmental argument, I also find I get headaches driving my old car for more than 30 min. Which kind of sucks, because it's a great car. But it seems as if I've become pretty sensitive to exhaust.... Ironic considering what I do for a living- maybe it's mental.

On a car of your vintage, it's not doing a lot, but it is better than nothing.

Tyler H SuperDork
April 6, 2015 8:37 a.m.

For $120, the cat is a no-brainer. No need to pollute, and a step up in performance from a 30 year old OEM cat.

Jerry SuperDork
April 6, 2015 9:05 a.m.
alfadriver wrote:
Jerry wrote: In reply to alfadriver: Thanks, pretty sure I am. The question was actually should I go test pipe, or a new catalytic converter?

I would.

Besides the environmental argument, I also find I get headaches driving my old car for more than 30 min.

This is a big part of the question. I may not have long hair anymore, but still kinda hippie/green in my thinking, when I can. But being a weekend nice weather toy it was less smog and more "will I get a berkeleying headache and stink like exhaust every time I drive it?"

alfadriver UltimaDork
April 6, 2015 9:28 a.m.

In reply to Jerry:

If that is your honest consideration, I would get it. The car's controller was designed to run with a catalyst- so at least it will actually work without any modification. Make sure you have a good working O2 sensor.

My car, I have to change from mechanical injection to electronic.

April 6, 2015 4:43 p.m.

Test pipe is lighter, freer, cooler (likeless hot), better.

Trackmouse Reader
April 6, 2015 4:49 p.m.

Why are you paying 60$ for a test pipe that MIGHT sound good. Get a chunk of pipe in the diameter you need, twist it on. Fire up the car. If you like it, weld it. If you hate, take it off and club someone with it. Cost? Maybe 5$ if you do the welds.

nokincy
nokincy Reader
April 6, 2015 4:50 p.m.

Get a new cat. You're not gaining anything substantive with a test pipe on your car with an otherwise stock engine. The cat will keep drone down and also make yourself and everyone behind you happier.

Trackmouse Reader
April 6, 2015 5:02 p.m.

The benefit is money. Cat-120$. No cat- 5$. That's a lot of premium fill ups.

Tyler H SuperDork
April 7, 2015 10:41 a.m.

The benefit isn't sitting in traffic and huffing your car's flora...for you and everyone else. I'm no greenie, but these days I feel like for a hundred bucks and no performance hit, going catless on the street is borderline irresponsible.

GameboyRMH MegaDork
April 7, 2015 10:57 a.m.

I'd get the cat unless it's a dedicated track car, or the engine's worn enough that you think oil fumes could ruin the cat.

Petrolburner HalfDork
April 7, 2015 11:29 a.m.

Get a cat. People choking on the fumes around you would think ill of the MR2, you owe it to enthusiasts everywhere to be a good representative.

April 7, 2015 11:42 a.m.

Meow.

SV3Power None
April 20, 2015 11:27 p.m.

Found this thread via Google. Hope you guys don't mind me participating. Jerry, please let me know if I can answer any questions for you.

As far as the cat vs. test pipe question, I prefer a cat for everyday street use. It's required by federal law, helps soften the exhaust note, and makes the exhaust less unpleasant to smell/breathe.

Then again, on a weekend toy, you might not be bothered by the aroma (provided you have a functional o2 sensor) and might prefer a little more noise. Speaking of which, my car (seen/heard in the video you linked to) is...not normal. Here's what the system sounds like on a supercharged AW11:

https://www.youtube.com/watch?v=IkkKiPrPjOw

Trackmouse wrote: Why are you paying 60$ for a test pipe that MIGHT sound good. Get a chunk of pipe in the diameter you need, twist it on. Fire up the car. If you like it, weld it. If you hate, take it off and club someone with it. Cost? Maybe 5$ if you do the welds.

Maybe I can explain why I do things the way I do.

Not everybody has welders and torches handy, so I build parts that can be installed with hand tools in the driveway. I've seen way too many cut-and-weld hack jobs on MR2s, and if anything needs to be replaced, the whole system usually goes in the scrap bin. Bolt-on stuff is far easier to remove or replace.

FWIW, I include two gaskets with a test pipe, and they cost much more than $5 each, to say nothing of the flanges, the hardware, my time to jig and weld it, and the tubing itself. Of course, anything can be done cheaper, if cheapness is the highest priority.

You do get a $10 credit/discount when you buy two items that mate up to each other. Also FWIW.

Kenny_McCormic PowerDork
April 20, 2015 11:44 p.m.

I doubt the magnaflow cat will be detrimental to performance. It shouldn't stink if it's running right without one though, unless you're exceedingly sensitive to such things. If the one on it isn't clogged up (look through it) or rotted out, I'd just leave it. The ones that really sucked power and flowed like crap were the pellet type from the 70s.

Jerry SuperDork
April 21, 2015 5:54 a.m.

In reply to SV3Power:

Thanks for reviving this thread! It's mostly a weekend toy, but I'm thinking I don't want the smell even on a weekend. Not racing, just enjoying, and want a little more oomph and sound. (And I also don't have welder/torch/skill so yes I don't mind paying a reasonable fee for quality work or products.)

chiodos Reader
April 21, 2015 6:38 a.m.

While yall are on the subjects, why do high flow cats smell funnier than no cat at all?

alfadriver UltimaDork
April 21, 2015 6:44 a.m.
chiodos wrote: While yall are on the subjects, why do high flow cats smell funnier than no cat at all?

Funny as in what? Sulpher? If it's that, it would be a result of the washcoat used- OEM's use a little nickel in the mixture to keep H2S production to a min.

If it's not that, can you describe it?

April 21, 2015 6:54 a.m.

I'm also with the cat crowd. Less pollution is great, and quiets the exhaust if you don't want it loud.

In reply to chiodos: It's actually the other way around, no cats may smell funny depending on the age of the engine, etc.

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