What is "no cats"?
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Which Ride?
- Thread starter ChuckMK23
- Start date
Catalytic converter
ABMD
Bullets don't fly without Supply
Correct, stock downpipe and exhaust included 2 catalytic converters. Eliminating them, while not environmentally friendly, removes a lot of restrictions for the exhaust.
How much is a lot depends on the car. I remember an old Chilton manual from the late 1970s that had several torque and horsepower figures for otherwise identical cars and drivetrains, with and without catalytic converters (depending on the market the new car would end up). The difference was about 5%. For a modern 220hp Saab turbo, even one that's been hopped up to about 300hp, the difference with and without the cats ought to be a similar percentage (turbo Saabs generally had excellent exhaust systems to begin with). 15 "free" horsepower is still nothing sneeze at and of course the surest answer would be to see before and after dynamometer runs.
It's pretty amazing what the Swedes did with that old Triumph engine
and I remember when the 16 valve head was something really special back in the 1980s.
It can be very expensive too, depending on the mood of the police officer you drive by. I always thought an electric or handbrake lever cutout was a nifty workaround. "Officer, you're free to look under there...there's a normal exhaust and cat. You must have heard someone else."
Yep- with a truly pipe-only exhaust, with no muffler or resonator baffles and no catalytic converter matrix to take the edge off the sound, it makes a pretty distinct crackle when you open up the throttle past a certain point. There's a shockwave in each exhaust port every time the valve opens, like a little sonic boom in there, and the pipe is like a big trumpet to carry the sound out the back of the car. It's loud as #$%@ and it's also fun, like can't-stop-laughing-fun because it does things like set off car alarms and generally raise hell.
If you have a badly designed exhaust system then a standing wave will form inside at various rpm bands, starting at around 2000 for a pipe that spans the distance from the engine and back bumper of an average car. Think of it like an organ pipe from hell. The best description I have for the sound of this effect is it's a lot like a fifty caliber. Now that is some kind of fun (that is if you think being an asshole on wheels is fun).
Move to Tennessee…. They don’t care and it’s awesome…. Except for some of these piece of shit pickups that are loud and sound like shit…. Some even roll coal!
ABMD
Bullets don't fly without Supply
How much is a lot depends on the car. I remember an old Chilton manual from the late 1970s that had several torque and horsepower figures for otherwise identical cars and drivetrains, with and without catalytic converters (depending on the market the new car would end up). The difference was about 5%. For a modern 220hp Saab turbo, even one that's been hopped up to about 300hp, the difference with and without the cats ought to be a similar percentage (turbo Saabs generally had excellent exhaust systems to begin with). 15 "free" horsepower is still nothing sneeze at and of course the surest answer would be to see before and after dynamometer runs.
It's pretty amazing what the Swedes did with that old Triumph engine
It also helps to reduce EGT (exhaust gas temperatures) especially for a turbocharged engine. Same reason lot of Saab guys keep the stock compressor side of the turbo, but seek out the old 9000aero turbine/exhaust side. On that particular engine, the exhaust housing is 20% larger allowing better flow out of the cylinder-head and keeping head temp lower. Once you exceed 300-400hp, you are getting into forged internals (thanks to more heat) and custom turbo manifolds and ported heads all to keep temps manageable, or get an e85 tune then find a station that carries it.
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ABMD
Bullets don't fly without Supply
Standby, I removed the cats, but left the mufflers/silencers. I wanted a quick adult car, not some riced out Swedish import. Also, with the added 1-1.5" suspension drop, the guys at the emission center couldn't tell what was going on under the car. (MD you have emissions testing every 2 years, they just casually throw a mirror under the car and are supposed to check).
And yes, the stock Viggen exhaust is quit good, but it can always be improved upon. A good tuner will take all your upgrades into account when tuning your ECU, for my stage 3 it was a requirement to have certain things done, one of which was the 3" downpipe.
The more I talk about it makes me wish I never sold it. I do keep in touch with the new owner. He has an all original RX7 that he bought brand new (so jealous!), another 2001 Saab Viggen (red) and if memory serves me correctly a Porsche 944 Turbo.
If it's Swedish, wouldn't that involve more lutefisk than rice anyway? Or perhaps some meatballs?
Why do you hate the polar bears?
I tend to hold on to cars for a long time, have only had four not including my wife's automatic V6 Mustang that she brought to the relationship that we traded in on the third car below.
-First up is my ensign-mobile, Mitsubishi Eclipse GT bought new prior to even getting my commission and still going str....well, still going. Extensive suspension work and many mods over the last 2 decades.
-Next up is a 2012 Jeep JK that I had to order form the factory to get the manual (Thankfully the wife know how to drive manuals). Only just recently lifted it with some bigger tires.
-Third was a 2012 Mercedes E350 coupe. Really liked this car but we ended up getting the four door below with a new addition to the family. Almost ended up with a BMW 6-series and would have kept that car and made it work with a car seat, but hindsight is 20/20.
-Last is a 2015 Volvo S60 R-Design. This is the last model that Volvo made with a 6 cylinder engine and comes with a Polestar tune making it comparable to a Mustang GT in terms of speed. Have a host of mods in the works to take it into the 400-ish hp range pretty easily.
-First up is my ensign-mobile, Mitsubishi Eclipse GT bought new prior to even getting my commission and still going str....well, still going. Extensive suspension work and many mods over the last 2 decades.
-Next up is a 2012 Jeep JK that I had to order form the factory to get the manual (Thankfully the wife know how to drive manuals). Only just recently lifted it with some bigger tires.
-Third was a 2012 Mercedes E350 coupe. Really liked this car but we ended up getting the four door below with a new addition to the family. Almost ended up with a BMW 6-series and would have kept that car and made it work with a car seat, but hindsight is 20/20.
-Last is a 2015 Volvo S60 R-Design. This is the last model that Volvo made with a 6 cylinder engine and comes with a Polestar tune making it comparable to a Mustang GT in terms of speed. Have a host of mods in the works to take it into the 400-ish hp range pretty easily.
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ABMD
Bullets don't fly without Supply
lol, I like Polar Bears, but I like speed/acceleration more.
I’ve heard of people doing burnouts in their garages. Maybe give that the old college try?