Im thinking about getting a flowmaster kit on my 1998 4Runner. I heard on the other day and all I can say is wow. I never expected a 3.4L V6 to sound so good, even with a kit. My question is how much horsepower will it give me? and will it help gas mileage?

i would only expect a net change of +7 hp at most out of a muffler-alone change.

As for gas mileagle, its hard to say but typical muffler swaps in alot of other vehicles I track have seen something like +1 or so.

Okay, so I checked Flowmaster's and Magnaflow's website, but they both dont have a exhaust kit for a 4runner...help?

Nate,

first off where are you in E. TN?

Neither Magnaflow or flowmaster is going to have a prefabed kit for a 3rd gen. If you are looking for one that is prefabed, try talking to some of the 3rd gen guys. IF you are willing to just weld in a new muffler, then your best bet would be the one of the ones listed above.

What Casper said... Unless you go w/ a "cat-back" exhaust system, you're going to just have to find a muffler w/ the correct ID/OD (inside/outside) diameter pipe & have it welded up. Any competent muffler shop can do this w/ no problem.

FWIW, I just had a Dynomax "SuperTurbo" muffler installed on our 2000 4R. Supposedly one of the quieter turbo mufflers on the market (very little drone), & claims to outflow the equivalent Flowmaster model. Barely noticeable at idle, but has a nice healthy growl as you move up in the RPM range. Gives the 3.4L much needed tone, IMO.

Re: seat of the pants, hard to tell but it does seem to rev a tad quicker. I forgot to reset the PCM after we had it done, so maybe the computer hasn't yet learned to take advantage of the reduction in backpressure. For <$150 (incl. cost of the muffler), a worthwhile mod IMHO.

Her4Runner