offroadnutz

Hello all...I am trying to find a 2.5" cat back system for my 1988 4runner 3.0. The largest I can find is 2.25". Does anyone know where I can get the 2.5"? Im trying to avoid going to a muffler shop...

fdp101452

I don't know why you want the 2.5 but I guess you know what you are looking for and why. I just bought an intermediate pipe off of ebay, bought a noise making muffler locally and used a turn down in front of the rear axle. Welded it up and its been on there for years. Its loud but I gave up sneaking up on people a long time ago.

offroadnutz

Judging from the lack of response, looks like I will be taking a trip to the muffler shop. Lol

MaK92-4RnR

What're you trying to achieve? Performance? Sound? Throw away some money that's burning a hole in your pocket?

Robert m

iTrader: (2)

That's all that's going to happen, no matter what.

MaK92-4RnR

Yep.

That's why i'd suggest going with

1) a muffler of your choice

2) have it welded in.

3) make sure the tailpipe is out of the way of everything (rocks, brush & spare tire)

4) Make sure you have a tailpipe if you plan on driving the truck with the rear window down, or you'll gas yourself out.

offroadnutz

So if I need, or want, a 2.5" cat back system, and buy one, then how is that that throwing money away? Im getting exactly what I need or want.
Thanks for your worthless comment....

offroadnutz

With a lot of the cat back systems, depending on the muffler, You can get all the above and weld it in....

Snarky comments aside, im working with a custom fabricated y pipe I got from a friend and a cat back system would likely be a simple install.

Not a lot of useful help from anyone here.....

old87yota

What the folks above are hinting at is a 2.5 inch exhaust will not really gain you anything in terms of power or performance. These engines are simply not large enough to benefit much from that large exhaust. The vast majority either go with the stock exhaust size or go up to 2.25. That is why you don't see much information on your question. You can do what ever you want with your truck.

MaK92-4RnR

What i'm trying to say is, i've been down this road. Years ago I installed DT LT headers, no cat, 2.25" exhaust and a borla muffler on a 3vze and the only thing that i got from it was a cool sounding truck. I blew the headgasket. repaired it and sold the truck.

With my 88, it too is a 3vze but at some point in it's life, a previous owner installed a pro flow muffler and dumped it at the rear axle. I didn't like this because I like to drive with the windows down here in California and fumes were coming back in. I had a magnaflow muffler lying around in the garage and i decided to install that with a new tailpipe that routed the exhaust out to the driver side so that I wouldn't gas myself out with the rear window down.

I wouldn't overthink it. Just find something you like sound wise and put that sucker in. There's not much to gain via exhaust on a 22r(e) or 3vze.

Robert m

iTrader: (2)

You're welcome and good luck with alllllllll that horse power your 2.5" exhaust is going to free up.

Did you ever stop to think that maybe you couldnt find a bolt on kit online because no one makes one because it's not needed? That maybe 2.25" is the max that's required?

Unless you are running forced induction of some kind (and alot of it), your engine doesnt move enough air to need a 2.5" exhaust. You would think that if it was a good idea, someone would have produced a kit by now in the 30ish years these trucks have been around.

offroadnutz

I find it interesting that your saying Im wanting to do this for performance. I never said that and that is not the reason. That reason is only an afterthought.

It seems you are ASSuming to much....

Thanks again for another worthless comment.

offroadnutz

You are assuming im doing this for performance and thats not the case. So Ill give you some background info. A friend gave me a custom y pipe he made that eliminated the crossover pipe but the main pipe is 2.5". Therefore I was looking for a 2.5" cat back system just to continue this to the rear.
I was simply wanting to eliminate the crossover to prolong my head gaskets and to have a cooler engine bay. Was also going to wrap the y pipe.

scope103

You might want to keep in mind that your exhaust is "tuned" https://en.wikipedia.org/wiki/Tuned_exhaust , so just slapping on a giant exhaust pipe will wipe out all that effort and probably result in reduced performance at all rpm ranges. I don't doubt that it is possible to create an exhaust system with adequate scavenging using 2.5" pipe, but I'm certainly not smart enough to design one.

offroadnutz

Scope
You bring up a valid point. It is one I considered but only in passing. I probably should consider it more..
Used to have a 71 vega that I used to street race that had cutouts to run open headers. At the track it ran quicker times when going through the full exhaust.....

Andrew Parker

Aside form the naysayers and the ease with which to point to the 3VZ-E being underpowered, owning a pair of these only promotes one's desire to make them the best they can be. So in light of that end the 2.5" CAT-Back is right in line with that desired end. One certainly can get LC engineerings CAT back which I think is 2-1/4" in diameter but it is expensive. So, I have purchased a 2.5" Flowmaster FX oval muffler with the miss matched zig/zag entry exit tube positions. It has no baffles in it just a zig zagging perforated tube and a bunch of packing in the 14" long muffler body (<$40). Along with this is a 2.5" diameter SpeedWay bend up (<$35) with 180 and 90 degree bends in it and a length of 2.5" I had from some test pipe project I did. The reason to go with 2.5" diameter pipe is flow and this size makes for a nice single pipe with the DT headers. Just make sure you pitch the O2 sensor adapter and weld the OEM bung to the collector tube were the left and right merge together. I still need some rod to bend up and weld to the FX to recreate the OEM hanger at the muffler location. Then I will fashion an over the axle tail section from the bends and exit behind the DS wheel just as the Bosal CAT back does now. My take is that most if not all of the aftermarket and oem tube sizes were originally designed for the 22R's and economy of scale and mass production stuffed this same exhaust size on the 3VZ-E's. My son and I have a 1990 and 1991 model of the 3.0L 4Runner. Both are 5 speed manuals. His is still running a tired >250K mile power plant with stock exhaust. Mine is rebuilt with some refinements to the internals that I took on during the MLS and ARP equipped rebuild. The DT headers and a 16" long 2.5 inch muffler which replaces the CAT flows into the Bosal which is puny in diameter and looks ridiculous but sounds ok. However, with both rigs running 57-9006 air filter kits the 90 is very smooth off idle from the 1K to 4K RPM transition which eludes to the tuning and torque that the OEM system exhibits. Were as for my own rig the transition has shifted and seems to really come alive more at 2K to 4.5K and am looking forward to seeing how this opened up CAT back does. Hopefully there is a little more going on at the 70 to 90 MPH transition in speed. The reality is that getting the 3VZ-E to breath will forsake some off idle low end grunt but the running at high speed is much better and it pulls well up the hills and gets 16 MPG on average with mixed trips of off-road, highway and surface street running on 31" rubber with OEM gearing. My sons 90 will comfortable cruise the neighborhood at 2K RPM. Where as mine seems to be happier above 2K and purrs at 3K with much better throttle response. For the money spent the reward is the reliability that these second generation Toyotas hold that no other brand can touch.

MaK92-4RnR

I think you're assuming that my response was about performance and it wasn't. In my response(s), I did cover every base which included wasting money.

Now that we have an idea of what you're trying to accomplish, here's my response:

You're starting with some backyard fabricated y-pipe and i'm telling you I did headers, y-pipe, no catalytic converter and a Borla muffler and it still blew the head gasket. It's inevitable. Water temperatures remained normal (185-195 degrees) and under hood temperatures bounced between 200-220 on a cold/hot day. In the grand scheme of things, it wasn't worth doing which goes back to my original base covered of: Wasting money. Save your money towards a 3.4 swap, a new long block or rebuilding the motor.

Next time, let's lead with the correct information on a forum post (mentioning you have a backyard fabricated y-pipe and you're trying to make it work) and you'd probably get a much more informative response. You got offended when Robert M essentially answered your original question with what you described as a "worthless comment" and quite frankly, he was just agreeing with me when i asked what you were trying to achieve since you mentioned a 2.5" exhaust (which we all gave answers to) and in reality, you're trying to reinvent the wheel by getting a custom y-pipe to work.

Here's the answer to all your questions:

https://www.lmperformance.com/560722...SABEgJbx_D_BwE

/threadover.

offroadnutz

Your ASSuming I wanted or needed your input on what I was doing and why I was doing it. I did not. Had that been the case I whould have mentioned that and asked in the original post.
It was a simple question on product availability thinking I might be able to avoid an hour drive to a muffler shop. Your commentary has been quite worthless for me as well. However, perhaps some of the info in this thread can help others with their projects....

And....Im hardly reinventing the wheel as this came off a friends truck that was wrecked. So Im just using an already invented wheel.... His application was slightly different though as he had engine mods which is why scope123's comments were very useful. As well as Andrews.

MaK92-4RnR

I fixed a lot of your punctuation and spelling errors. You wanted me to fix those, right? (Please emphasize the word assuming again. That's my ultimate goal.)
I'll be keeping an eye out for any posts about your "retrofitted y-pipe". I look forward to seeing what you come up with.

offroadnutz

Your argument fails so you turn to petty actions. Thats small. Nice.....