Now that I can weld an exhaust together myself, what do you guys think would be the best setup for my V8? I've been doing some research and there is so much contradictory exhaust info on the web.

Dual w/ x pipe or single w/ y pipe?

I just don't think a dual system will provide much gains over a proper single system, add more weight and cost, and maybe only sound a little different and have cool dual outlets. If you think of exhaust flow as separate gas pulses, a dual 2.5" won't flow more or scavenge better than a single 2.5" system with a good y pipe merge. And if I supercharged or want high rpm gains I could still go single 3".

I've yet to see any dyno graphs showing a difference between the two. I might be able to set up a jig and build these for you guys, and could even dyno test a difference between dual/single but if there isn't a power difference between them, it would just be double the weight and cost of a single system.

How would we setup a dyno test, have two prebuilt systems one with equal length piping to the y and one with equal length piping to the x, and use all the same mufflers. Swap the systems out between dyno runs, disconnect the battery, drive around the street for 10 minutes, then re-dyno it? I could even test equal length vs normal y pipes.

I'll build equal length piping after the headers to either the y or x to increase scavenging potential but with the odd firing order of the V8 it will only help 3/4 of the firing sequence unlike the V6 where it alternates between cylinder banks 100% of the time.


So would it be worth to test any of the following? What would you guys like to see?

equal length vs unequal length
2.25 single/dual
2.5" single/dual
3" single

Keep us posted on our progress!

Maybe baseline dyno run(s) with the current Dirty Deeds exhaust, what's the pipe diameter of that system?

I think its 2.25" but I'll have to check.

Edit: it's 2.5", tailpipe section is 2.4" or 60mm. Y pipe is tiny at 1.9" and it's double-walled so at least 1.5" if not smaller.

I don't know if it will tell me much because I have the rear cats deleted so a somewhat hacked y pipe with non-mandrel bent tubing.

If I could find a stock y pipe to install for testing that would be a more fair comparison, I can get my hands on a free Gibson system from a buddy so we could do a test of an off-the-shelf catback, stock y pipe, and long tube headers.

I really think equal length piping after the headers before the merge into a y or x will be the best system possible so testing the stock y pipe will help prove that. I just don't want to do a million dyno runs, and don't want to install long tube headers only to reinstall stock manifolds in between dyno tests.

Bought some Magnaflow goodies while they were 20% off. For research purposes.

(3) Magnaflow 12646, 6" x 6" Round Body, 2.5" Center/Center, 18" Body Length

(1) Magnaflow 12649, 6" x 6" Round Body, 3" Center/Center, 18" Body Length

From my build thread:

More work done today on the Y pipe, should be able to finish it up tomorrow.
Drilled out the corroded bolts on the cat flanges, if not for that I'd have the entire thing tacked welded together.







Got the Y finished this weekend, though I was worried it might take a few more hours on Monday to button it up.

I'd like to think at least some of my welds show some genius. If I could get perfect tube fitup I could just fusion weld everything (no filler) and move fast to keep the heat down.

I wondered all weekend what initial startup would feel like, it didn't disappoint. A surprisingly higher pitched tone, it sounds a lot different than any 2UZ I've heard, super happy with it. Exhaust vid coming.









Finally got this #*%*! out.

Whipped up a catback yesterday.

Dirty Deeds 5" diameter 20" length vs Magnaflow 6" diameter 18" length.

Sound camparison:

With just the Dirty Deeds catback, no y pipe the sound was deep, and when I added gears interstate travel was a little noisy with the higher RPMS.

With the Dirty Deeds and fabricated Y pipe/gears the sound was higher pitched and interstate drone might have gotten a little more annoying.

With the Magnaflow and fabricated Y pipe/gears the sound is deep like the first setup, but interstate travel is quiet.


So surprisingly the Magnaflow muffler is quieter than the Dirty Deeds. I lifted each system in each arm and the Dirty Deeds system is actually like 5lbs heavier!! I told you guys that thing was stout! I actually prefer the angry 'flat plane crank' sound the Dirty Deeds/ Y pipe combo gave me over the basic deep rumble, I'm not sure how to fabricate a system that sounds like that.

Most badass 4Runner exhaust system? (Excuse the temporary lack of headers)

Bought a 12" disc sander and a fancy cutting jig/clamp for pre-bent elbows which should make fitup and replication a breeze.

Next step is to build a dual system utilizing the two same magnaflow mufflers with a custom fabricated X pipe.

Then create a jig to start selling these.

Nice work!
Just picked up a 05 V8. It has the famous Exhaust manifold leak. I am going to order the DT headers next week and I am in need of exhaust like this. I will take one of the Y pipe & cat back set up! I will PM you tomorrow to discuss this in further detail. Keep up the great work!!

HDHP

Looks Awesome man. Love the Work. Looks Top Notch.

Can you Please post a pic and some more info on that jig/clamp for the pre-bent elbows? I love doing metal fab, and something like that would be very useful for any tubing project, not just exhaust.

Your welding skills are coming along very nicely! I’m still researching multi-process welders myself because my little Lincoln mig just isn’t cutting it anymore. Definitely need a bigger machine, and the ability to TIG. I looked at the one you have, and I’m currently checking out the 2 higher end HF offerings, the Vulcan Omnipro 220, and the Titanium Unlimited 200.

Here's the link.

Elbow Cutting Jig for 2", 2.5", 3" OD & 1D/1.5D CLR - Sequence Mfg by Ticon

I'd totes m'gotes be interested in a y-pipe... Keep on keepin' on!

Oooh X-pipe, can't wait to see what you've got in store. This guy has a x-pipe with "bullet" style mufflers https://www.toyota-4runner.org/3272358-post74.html so it's pretty raspy, your setup should be a little more mellow with those longer Magnaflows.

Man I am Glad I have the V8