My downpipe is hooped and I have several holes in my exhaust. The time has come for replacement. I am thinking of the flowmaster downpipe kit, and the largest exhaust pipe I can get bent locally is 3". I will gut the cat and get a see through muffler, but would I be better off with a larger diameter system? If the largest downpipe you can fit is 3" does a 3-1/2" or 4" pipe make any difference?
Existing Downpipe and exhaust appear to be stock, the truck has 308,000 km.(30,000km on new engine and transmission) Truck is daily driver but do occasionally haul my forklift on my tandem trailer..(10,000-11,000lbs short hauls less than 60 miles)

I just ordered the ssdieselsupply.com 4in exhaust. I don't have it yet but the price is very good. I have a crossover pipe to install as well. I will post on it when I finish the install.

Only benifit of 4" is MORE NOISE as far as i've heard so far. I'm actually contemplating a muffler to quiet it down a little (just contemplating though)

I had a 3" system installed all the way through, no cat, straight through muffler and couldn't be happier with it. I have heard that anything after 3" doesn't make much difference other than noise as stated by CanadianRigger.

I just installed the SS Diesel 4" system. Sounds great, helped my mileage, egt, and power a bunch. It's a tight fit like a shoehorn and the hangars are useless for my truck.

If I were to do it again, I would get a JK 3.5" system.

3" is not going to be much better than 2.75" stock.

You need to go at least to 3.5" if you plan on doing more mods.

I went 4".

I run a 3" straight pipe and it's light years from stock.

QM doesn't yours stop right under the cab or is that another truck?

I think Pinnical is running a Special on their 3 inch down pipe to 4 inch for either $290 or $300. I have their old 3inch and has been a great set up.

QM

Imagine what 3.5" or 4" will do for ya...

Can 3.5" go straight from the downpipe to the muffler or do you have to bend to go over the torsion bar cross member???

Carey

"torsion bar cross member"?

I'm guessing that you have to bend the 3" at the torsion bar crossmember. My stock pipe was crimped in half at the cross member. It had a 6" long flat spot with a heat shield attached to it there. It measured about 1 3/4 x 3 where it was flattened. It shouldn't cost much if you install the flowmaster downpipe and take it to a local shop to have 3" bent up and installed.

I reccommend the Stainless steel $275 kit from ebay I'm very happy with the power and the sound. 3" downpipe for about 18" then up sizes to 3.5" for about 30" then into 4" muffler and 4" rest of the way out with quality hangers that mate up to factory hangers pretty well.

Only benifit of 4" is MORE NOISE as far as i've heard so far. I'm actually contemplating a muffler to quiet it down a little (just contemplating though)CanadianRigger, when the time comes, if you decide a muffler. Check out MagnaFlow.(Wide Open)Their mufflers have no chambers,baffles and louvers.

I have a 3.5" downpipe into a 4" pipe through 4" Magnaflow. IMO, just go with the largest one you can find. Why not? Plus, you will never have to worry about it when you do mods. The 3.5-4 is tight, but it works and sounds great too. Quick and easy for enormous results.

Dkubek,
How did you manage to get a 3.5" down pipe onto a 3 inch diameter exhaust port from the turbo? Where did you get it? I have a JK's exhaust system which is 3" down pipe and 3.5" on back. Friend of mine has a 4" exhaust system on his 97 and and there is no exceptional power gain. The deeper growl is the only difference.

Ordered a 4" system from the auction site yesterday. Thanks for all the replies.