I am going to upgrade my exhaust system and I am wondering if I will notice a big difference if I change the pipe size to 2.25". I am planning on getting a catback system with a Magnaflow muffler. Will a free-flowing cat make a big difference?

 

i have a freeflowing catco cat on my truck never knew what it was like stock..im sure it helps out... i have 2.25" piping on mine.... my trucks a 4x2 85 22r

 

Has anyone ever driven a truck with a 2" exhaust and compared it to a 2.25"?

 

Anyone ever done anything like that?

 

the 2.25 is fine

 

I have the 2.25 on mine with a magnaflow cat and proflo muffler and running back out into 2.25. its sweet. you will like it better. more flow and rumble.


errrr edit....uh I didnt look to see what kinda rig you were working with until after i posted. 22r and huge exh will kill you imo. 225 may be to big but i have never had a 22r. I have the v6. So I hope you find the info you really need. surprised more members have not replied to help you out.

 

my friend had a stock 84 22r and his truck was a lot slower than mine.. his also 4x2 std cab shortbed... eh had smaller tires too....

 

Slower with smaller tires? What other mods do you have besides the exhaust system that would make your truck faster? I am assuming that you have a carbureted truck.

 

yup my trucks got a carb.... i have an intake mod done as well.... its really just a bigger filter but it does help out a good amount... my trucks a 4x2, and they are from what i have heard a lot quicker then the 4x4.... his tires were 30x9.5s and my tires were 31x10.5s i have 3.08 gears with a 5 speed stick though.. he had a 5 speed but i didnt know what gears he had in his truck...

 

http://www.explorerforum.com/data/sh...y.php?cat=3367 is the gallery housing my intake pics....

 

Check in with members deathrunner and crazydiamond. I believe they both have 2.5" exhausts and differing opinions on the results. Depends on what you want to do. My understanding is that too big (ie the 2.5") kills low end torque but is good in the upper speed ranges. Therefore good on hwy but not so good for slow wheeling. I've also gotten the impression that 2.25" gives a reasonable bump in power and helps low end torque a bit. There are plenty of threads about this if you do a search with opinions ranging from "huge increase in performance" to "didn't do much". The only real agreement I've seen is that they all "sound cool". I'm interested in ths mod as well but fortunately it is low on the priority list so I have time to learn more about it. Good luck.

Mike

 

I usually keep my RPMs down, so I will probably just stay with 2", but I was thinking about doing that intake mod. Does it lower gas mileage at all?

 

This site has some pretty good info on sizing exhaust:
http://www.torquetechexh.com/whichsize.htm

The short form is this graphic:


2.25" would be too large for the 22r.

 

Thanks for the chart. 2" almost seems to large. I just measured my tailpipe and it appears to be 1.75" in diameter. If I upgrade to 2" from the cat back, do I need to do something to the collector in front of the cat to make a difference?

 

I recently put on a 2.25" catback exhaust on my truck and I didnt noticed a decrease in low end at all. Really the only thing it did was give it a kick around 3500rpms and up. You will be fine running 2.25" tubing.

 

Thanks for the information. If I upgrade the pipe diameter, will I need to do something with the collector in front of the cat to see a difference?

 

2.5 in exhaust works great..

 

You should see a big improvement in power with the new cat and 2.25 exhaust, It made a big difference on my 86 4runner, adding a header made even more power. You might want to do the air filter mod also. My 4runner is a 22RE but I did the mod on my 90 two wheel drive truck and it made a big difference when I step on it. The only difference in milage is the fact that I always have my foot in it since it's more fun to drive now...

 

Supernerd never got an answer to his question, and I'd like to know too. If I go with a 2.25" catback exhaust, I'm assuming that "catback" is meaning that the diameter of the cat is 2.25" too. In other words, the increase in tubing size happens right before the cat... Correct? So, as supernerd asked, does anything have to be done to the collector or downpipe in front of the cat? What benefits, if any, would come from increasing the size of the downpipe?

 

Run the 2.25" exhaust pipe. I have a 2.25" exhaust, high-flow cat and a Dynomax "Super Turbo" muffler on mine. I've noticed no decrease in TQ with the 2.25" compared to the stock pipe. In fact, the low-end TQ increased with the 2.25" exhaust. However, I wouldn't go to a 2.5" pipe, you may lose some TQ with that. The 2.25" will be fine.

I also have the tri-Y Thorley header as well. Highly recommended with the 2.25" exhaust! It'd be like a whole new truck with the header and exhaust. Trust me! You'll really notice the difference going up freeway on-ramps and moderate to steep hills. A poor mans dyno if you will.

I never liked steep hills or freeway on-ramps with the stock exhaust and manifold. With the header and exhaust, the truck loves these inclines now. It just keeps on pulling and pulling until I get near redline.