New Cat = Big gas milage gains.

4

4RUNNER1

New member
Someone decided to "borrow" my cat and I was left to buy a new one from Toyota. I decided to get a Magnaflow hi-flow cat from auto zone and it only cost $60. Don't remember the part number but its 1/4 of the size of the Toyota cat. I'll post the part number later. I was worried about getting a cat efficiency below threshold code. The code never came. Before replacing the cat I was getting 319 miles per tank. After replacing the cat I'm getting 360 highway miles to a tank. I don't know if this is normal but I'm pretty happy about it.

1997 4Runner Limited
 
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4RUNNER1 said:
Someone decided to "borrow" my cat and I was left to buy a new one from Toyota. I decided to get a Magnaflow hi-flow cat from auto zone and it only cost $60. Don't remember the part number but its 1/4 of the size of the Toyota cat. I'll post the part number later. I was worried about getting a cat efficiency below threshold code. The code never came. Before replacing the cat I was getting 319 miles per tank. After replacing the cat I'm getting 360 highway miles to a tank. I don't know if this is normal but I'm pretty happy about it.

1997 4Runner Limited
Click to expand...

how many miles on your 4runner?
 
That's terrific gas mileage, but I doubt the cat's size has much to do with the mileage increase with the rest of the exhaust stock.

If anything, it means your old one was clogged up over time. Any new fresh cat will do the same thing. Have you thought of also replacing your O2 sensors while down there? Easy swap and worth it (at least in my case).

I, too, noticed a gain with the high flow cat, though it was the last piece of my exhaust puzzle. I already upgraded the size to 2.5 all the way through beforehand. My old cat was a clogged piece of junk.

The only thing I despise about the catalytic converter I got is MagnaFlow's bullsh*t quality. Make sure you sign up for that warranty, you'll likely need it sometime down the line. I paid $300 for mine a little over a year ago (CARB legality, ugh) and the heat shield's welds have already failed. My Magnaflow mufflers have broken, all 3 of them, in the course of one year. I'm not expecting much out of the cat.
 
4RUNNER1 said:
I was worried about getting a cat efficiency below threshold code. The code never came.
Click to expand...

Mine didn't throw a code either...for about 5,000 miles on the new cat. Now I can't get rid of the P0420 code. Glad your mileage went up though. Hopefully you don't get a code issue like me.
 
Limited2K said:
Mine didn't throw a code either...for about 5,000 miles on the new cat. Now I can't get rid of the P0420 code. Glad your mileage went up though. Hopefully you don't get a code issue like me.
Click to expand...

Funny, I've heard that from so many V6 owners. I guess mine must be just different enough with the 4 cylinder.

Sorry dude. Just another testimony to how bad Magnaflow products really are.
 
i know COB will boo me and flame me but i just picked up a brand new magnaflow "hi-flow" 2.5" cat for $50 brand new in the box warranty card unfilled out... i live in Wa so it dosent matter to me that its only a 49 state cat. but i will be doing full header-tip exhaust sometime this fall, gonna go with 2.5 pipe all the way back and then put a 3" tip(last 6-10" or so) im hoping this will give me a little better mpg and some free up some power
 
360 mpg....you either have a 4cyl.....or never drive above 45mph. Best I ever got was 300 on a full tank w? a v6
 
the kid said:
i know COB will boo me and flame me but i just picked up a brand new magnaflow "hi-flow" 2.5" cat for $50 brand new in the box warranty card unfilled out... i live in Wa so it dosent matter to me that its only a 49 state cat. but i will be doing full header-tip exhaust sometime this fall, gonna go with 2.5 pipe all the way back and then put a 3" tip(last 6-10" or so) im hoping this will give me a little better mpg and some free up some power
Click to expand...

I can't really flame you cuz I have one too, but I'm serious about that warranty.
 
Here is the part number.

Magna Flow 94300 Series Universal Catalytic Converters (High-Flow, Oval) Cat 2 1/2 Inch IN/OUT

I have 201,000 Miles 3.4 V6. Everything on the motor was just replaced in the last 10k miles. I do mean everything externally. All highway miles. I drive about 65 -75 mph on the highway. Oil change every 3000k 4 quarts oil, 1 quart Lucas oil stabilizer. Same with transmission. Transmission fluid and one quart Lucas Transmission stabilizer fluid.

And yes. I did get 360 miles on my last tank. Going from east to west. I-90 all the way.

I don't care if a single person believes me or not. I was just passing the info on. I will simply enjoy the mileage :) :zoom:
 
What was the part number for that cat? I'm going to replace my twin CA spec cats with a high flow soon, so I'm doing some research. Did you get it from a local Autozone, or order it online?
 
Best I ever got was 300 on a full tank w? a v6
Click to expand...

Same here.


And I agree that miles per tank is a bad metric. I think the only real way to know for sure is to use an scanguage or an mobile app that takes into account your tire size.
 
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