babyfood1217

Time to finally do the exhaust on my truck. '88 4rnr w/ 22re. Currently, everything is stock (engine included), and I will be putting on (to start out with at least), a Magnaflow cat (2.25") and a Flowmaster 40 series (2.25" center in, 2.25" center out.) The remainder of the pipe work I realize will have to be done up as a one-off. I have the means and the know-how to do the welding/fab work, but I'm wondering if anyone could provide any images of their welded up system to give me an idea of what materials I'm going to need.

My big inquiries refer to the following...

-I know I will need to fab an adapter to transition into the 2.25" diameter cat inlet, but I'm not sure where to place that adapter (right next to the cat? forward on the system, near the downpipe?)

-To address the routing over the rear axle, the OE systems are arched (mandrel bent or kink bent.) I know bends are available, as are straight sections, but are you guys just crawling under, measuring stuff and winging it when it comes to fab, or are there dimensions/measurements out there that I could track down to help streamline the process.

I'm hoping to mock up the new system off the truck WITHOUT taking the old off to do it. It's currently my only vehicle, and I can't drive around with no exhaust to go back and forth between exhaust shops or hardware stores to put things together on the fly.

Thanks in advance!

-Chris

peow130

take it to an exhaust shop, if you have this many problems..
it cost me 80 bucks for a new stock-style exhaust from Y-pipe back on my bronco.

warpigg

go to summit racing and get the 80 or 90 doller tail pipe kit and it comes with a lot of different bends, you should also get a straight pipe section too which is around 25 dollers i think.

babyfood1217

Ah ha. That's awesome. Totally missed that when I was perusing for mufflers and cats. The straight I could get locally, for sure. I figured I would also just bend up some 3/8" or 1/2" round bar stock for the hangers and reuse rubber saggy mufflers bumpers as needed. Sweet.

Thanks for the tip!

babyfood1217

ran into a snag when in the planning stages, and haven't had a chance to sort it out until now...

snag: O2 sensor just before the cat...

Still trying to figure out where I should place the adapter for the exhaust pipe size (stock pipe diameter to 2.25"), and when crawling under the truck to look around I was reminded of the sensor. Should the adapter to the larger pipe size go before this O2 sensor? Since I'll be welding up the exhaust on my own, I could put the adapter right next to the O2 sensor, or the closer to the manifold. Planning on just welding on a new bung for the sensor in roughly the same spot. Does NOBODY have any pics? I know people have welded up their own exhausts...

Thoughts?

-Chris

warpigg

i can take pics if you want but mine is a third gen and its alot differnt. thats why i didnt take pics before.

RRogers

Might check out using one of these to make things easier. http://www.summitracing.com/parts/SUM-693322/

babyfood1217

hmmm... different, yes. Perhaps though, you could elaborate on where you place certain items? The O2 sensor (same relative spot as before?) transition piece to adapt from one pipe diameter to the next? It is the transition/adapter that I am most concerned with figuring out. All people are saying is "put it before the cat" and while that's good and all, it seems to me that putting it directly prior to the cat will negate the concept of opening up the exhaust pipe diameter to 2.25" from stock. Wouldn't putting this adapter right after the downpipe make the most sense? 2.25" would then be running from the manifold all the way out through the exhaust tip...

Good idea. I was just going to make a jig or two to hold the pipes in place for the weld. I may be sleeving the pipe before I weld it though, so I might not need these. I'll add it to the possibilities checklist...

warpigg

when i bought my 4runner it came with an aftermarket cat. mine has two o2 sensors on before and one after the cat. i just discounected the pipe after the cat and put on my new exhaust. and yes mainfold back with 2.25" would be more free flowing then just a cat back.