Speedy

After tons of reading on this site and discussion in this thread:

https://www.yotatech.com/forums/show...4#post50423964

I've decided to go with a Magnaflow 18" muffler single in single out.

In my searching I noticed a lot of folks saying they felt like they were losing some low end torque after going to a high flow muffler such as the Magnaflow. I've been mulling over my exhaust for a couple of days and came up with an idea. What if I ran 2.25" pipe to the magnaflow, then 2" out? Would that give the best of both worlds by retaining some back pressure for torque but still giving more flow when I give it some go pedal at higher RPMs.

I called Magnaflow and spoke to one of their techs and he concurred that on a 207 cubic inch NA motor (3.4L V6) that would work the best on a vehicle like the 4Runner.

Can anyone back up my theory here in practice? I didn't find a single person that went this route in all my reading the past 2 weeks.

Based on what you guys think I'm either going to re-use the stock pipe and have the exit relocated to exit the rear of the vehicle just beside the hitch, or have new 2" pipe put in after the muffler and have it exit the rear of the vehicle just beside the hitch. I'm going to use this tip:

Sleeper

I just replaced my 22" Magnaflow with a 14" due to some warranty issues. I had 2.5" exhaust tubing but went back to the stock 2.25" and dropped is right after the axle. It sounds awesome and I got my low end back. I would wait for others to chime in but thought that you never want to reduce the tubing size as you move further back in the system. That's why the ehaust manifold tubing size is less than the rest of the system. If anything, you could continue the smaller tubing until the outlet of the muffler. Good Luck

midiwall

This is a repeat of what he told you, but for the sake of conversation and passing along information sources, there's a chart on Magnaflow's website:

http://www.magnaflow.com/wideopen/performdata.asp
(the bottom one)

The stock 3.4L is 183hp at the crank, so that puts you on the 2nd line. (single: 2 1/4" -2 1/2", dual 2" - 2 1/4"). The stock pipe on our trucks is 2.25", and from personal experience, I would NOT suggest going to 2.5" while the engine is NA.

I see your reasoning for wanting to shrink the tail, but the added flow of a free-flow muffler (and cat) will not be enough to cause you to need to drop to 2" at the tail. I think you'll be fine and happy with 2.25" front to back.

Speedy

Thanks guys. Keep the opinions coming. I'm gonna get this done in the next 10 days.

alexe

your not loosing torque because of a lack of backpressure. when you increase the size of the pipe you decrease velocity and the scavenging affect.

if you put a large pipe with a restrictive muffler it would make things worse. i would run a smaller pipe with a larger muffler.

that being said i have run a 3" exhaust on a 2.4L 4 cylinder before and didnt notice much power drop. personally, i would go with 2.25" piping and a slighty larger muffler, say 2.5"

it is also best to make the piping as straight as possible, minimize the amount of bends.

Speedy

So that's two votes for 2.25" pipe.

Elton

i have a 18'' one with a 3'' tip on the factory exhaust and man it sounds badass and has plenty of power i did not notice a lost with the new muffler for sound clips click my mods page 2

Elton

heres a old pic of my tip you get the idea

Speedy

Sounds nice going up the road. Some say it drones some say it doesn't. What do you think on the droning in the cab?

MTL_4runner

Make it 3 for 2.25" pipe. I did it out both ways on the Magnaflow scale and in terms of HP you're about the middle of the scale between the levels but if you go by cubic inches, then you're near the top (3.4L = 200+ CI's). I find that the higher revving motors (like the 3.4L) prefer to have more pipe restriction vs a big torque monster inline 4 or 6 cyl motor. Given that I'd stick to the lower side and be a bit conservative by using the 2.25" pipe.

Elton

well it drones a fair bit but i dont care

Speedy

Thanks. After doing the ISR mod with the deck plate it drones, so I guess one will cancel the other haha.

I've always been an exhaust nut and love the sound of a good exhaust system on a V6. I'll go with the 2.25" pipe since everyone here has suggested that.

Now the final question, which muffler? 5"x8" or 4"x9"?

Magnaflow 12256

or

Magnaflow 11256

Elton

here you go same one i have http://www.hottexhaust.com/detail.asp?PRODUCT_ID=11255

Speedy

That one is only 2.25" diameter in and out. It'll take 2.5" in and out to go over the stock pipe. The two I listed above are the two that are 2.5" in and out offset.

Elton

i know that but the muffler shop only had to expand it a little bit and it fit perfect

Speedy

Were they able to mount it flat or did they have to rotate the muffler to an angle? I've seen pictures of them installed both ways.

Elton

its mounted flat

Speedy

Update 2/16/07

I'm going to an exhaust shop tomorrow to get an estimate and information. They quoted me $30 to just weld in the new muffler, but climbing around under the truck last night I had a thought...

I wondered if they could build me a bolt on cat back. That would allow me to bolt my stock setup back on should I ever decide to sell the truck, or at least offer the stock exhaust with the truck when it sold that could be bolted back on should a new owner choose.

This would also allow me to ease some of the bends the stock exhaust has in it especially around the rear axle. I could get the exhaust shop to adjust the location of the muffler so that the bend coming out of it wouldn't have to be so sharp to clear the rear axle, yet still keep the muffler at a location to minimize droning.

The guy said they could do it no problem, but only if they have a flange that'll fit the stock flange at the cat.

more to come.....