Status update: I've driven a few hundred miles now in roughly the same mixture of highway and city driving.

Before y-pipe: 17.3 mpg
After y-pipe: 19.0 mpg

Take-away:
If you drive in Colorado where the average price per gallon is $2.72, the y-pipe will pay for itself in ~31,000 miles.

If you drive in California where the average price per gallon is $3.60, the y-pipe will pay for itself in ~23,000 miles.

So, if you need additional justification (i.e. spouse-factor), and you plan to keep it long-term, the y-pipe is a good investment. The price of gas is likely to increase, not decrease, so its value improves over time.

I gotta be honest, I feel like an almost 10% increase to mpg is a little surprising, but I was legit driving in the same conditions, sometimes in very strong winds, sometimes stopped on the highway... It's probably a fair representation of realistic gains, but take it with a grain of salt.

@Adoniram question.

when you installed the y-pipe, the two crush gaskets will be inserted at the inlet of the Y. soooo what do we do with the single exit portion of the Y? did you just use the existing gasket?

I spoke with gadget but he said I only needed 2.

what did you do?

thanks for your help! i get my y-pipe this Friday so hopefully install Saturday morning. and the MAF Cal is back-ordered a few weeks

There's a doughnut gasket (that's what I'm calling it anyway) at the other end. I just reused the existing gasket. My vehicle only had about 7000 miles on it, so it was in good shape. I think another one of those was something like $20-30 from Toyota. I couldn't find a parts store that carried it.

thank you for the update! I'm at 10K so I'll assume I'm good too.

Hows the fumes after removing 2 cats? I tend to run my rear window down all the time.

ill let you know when summer hits southern cali lol. its been cold (cali standards) lol.

you dont want to hit up a muffler shop and have them redirect it to the side? that was my next plan before the summer here.

That's an option. The bumper on the SR5 premium/limited editions are actually lower than the normal offerings. A side exit will sit a little lower than the OEM height. Not sure how odd that'll look.

@Adoniram did you put some kind of heat reflecting material on the trans panel? I've been reading there could be heat soak from the y-pipe that crosses over. Gadget said no but I think some members took preventative measures.

i have left over reflect-a-gold tape from DEI and i'm wondering if i can put the tape on it. just peace of mind since the cross tube is right under it.

Because this I started looking at the Doug Thorley Y Pipe which goes down passed the transfer case and back up meet the catback. I was set to get that one but some material says stainless steel and others say aluminumized steel which apparently rusts. So I’m not sure what I’m gonna do

Link to the DT Y pipe please?

Looks like its from here:

https://www.urdusa.com/urd-off-road-...03-4runner-v6/

$500 dollars seems like a lot for a Y-pipe

Originally made for FJ but also for 4R. They’re site says stainless but a lot of reviews says it’s actually aluminumized steel.

2007-2016 Toyota FJ Cruiser / 4Runner 4.0L V6 Performance Mid-pipes

The DT pipe can be had for $350-$375 but i'm not sure how I feel about all the bends. URD pipe seems offly close to the tranny pan which I don't like either. Not sure i'll go with either one.

There is no heat to the trans pan. There is at least 1+" of an air gap between the two with airflow. Whoever thinks this is transferring heat is simply making stuff up with no related experience.

The only reason to wrap the pipe or add additional insulation would be to help keep air velocity up... but it won't make any difference really.

Beat me to it @wfo9 !