Cat and tranny

[CapriceBoy214]

I have a 89 Caprice with fuel injected 350 motor. I want to know if I take off the cat would it get more horsepower? Can a 200-r4 handle the power of a 350?

[silicon212]

Answer to question #1 -

Yes, you will see about a 1-2 hp increase (yes, that's one to two horsepower). However, don't drive it around me or through any air I have to breathe. Plus, if the feds find out, it might wind up costing you $25,000 and a trip to federal court.

Answer to question #2 -

Yes and no. It depends on how the transmission was rebuilt. If it's a stock rebuild, personal experience tells me that it will last 4 good months of normal driving. Then again, I'm hard on transmissions. You might get 8 months out of it.

[PeteA216]

The longevity of a 200-R4 seems to be underestimated. Granted it is not made to handle the power of a 350. A 700-R4 sometimes has trouble backing up a 350 in the long run. But if it was built right, and thoroughly gone through, even with stock specs I can see it lasting around 40-50K problem free assuming it's driven "normally." But since you're looking for more power I'll assume that you're not a gentle driver. In which case Silicon's etimation may be accurate.

[silicon212]

The 2004R that was in my car came out of an '87 Grand National - larger passageways, better valve body, supposed to handle the power. It did an admirable job, too - right until I burned the forward clutch out of it.

The 700R4 should be a post-'85 unit, made for an 8 cyl engine and if it is, it will be fine behind the 350.

[mike561]

I def know you still have the cat on your car silicon, i noticed your really against removing it, nothing wrong with that though. one of the guys in my automotive class took off the cat on his 91 jeep cheroke, and wow did that smell strong!

[silicon212]

Yes, I have very strong feelings about it.

First off, I am pretty far from a tree hugger - in all actuality, my politics are libertarian/conservative.

However, I am also environmentally responsible - not because it affects the earth, but because it affects humanity.

The first generation catalytic converters were pretty restrictive. Removing the catalytic converter on my '75 Grand Am was worth about 25 hp, and that's pretty significant. When I had to put one back on to get through the inspection, I opted for one of the newer tri-cats. That was unrestrictive and I didn't notice a difference with it on or off.

Cats of today are not restrictive, nor have they been for about 20-25 years, but there is this mentality that exists that says "Remove the cat for HUGE GAINS" and that is simply no longer the case. Technology has come a long way.

The point is that the power gain is negligible with removal of a cat from a car unless the original cat is plugged. There's also the fact that I don't want to breathe the exhaust of a car that is running a cylinder down. While still stinky with a cat, it won't make your eyes water.

[Blue Bowtie]

As an example, the 1981 Corvette 350 had a four barrel car which flowed about 725 SCFM and two catalytic converters. It made about 205 HP on a GOOD day. The 2001 Corvette had an engine with 4 cubic inches less displacement, no carburetor, and SIX catalytic converters (two pre-cats, two main cats, and two post-cats), and made about 330 HP on a BAD day.

Perhaps you should reconsider the idea of strapping on a big carburetor and chopping off the cats, and add some instead.

The 2007 Corvette makes 505HP on any day, but only has four cats (I don't know how they ever managed) - And all without hacking on a Holley or Edelbrock carburetor in place of the "tiny" 80mm TB.