Hi.
Sorry in advance to double post. Hoping for better luck here.

Working on a 3.4 into a 95.
Got the ToyOnlySwaps crossover done two years (?!) ago.
Got all hooked up, with original collector and CAT. Turns out my donor WAS a CA certified.
I thought then the easiest thing to do would be to order a muffler section for a 99 3.4 and attach it. So I did try. Well that was close but not cigar. I will at minimum have to cut the section with the second rear-most O2 sensor and rotate it. And also somehow messed up estimates on length, so I'll have to cut a section out to pull the muffler part forward a ways. Probably 6 inches with calibrated eyeball. Then the plan was to find a shop that could make a custom same-size tail pipe (forgot whom on here mentioned some shop over in Golden) for driver side exit.

But I also have a problem, maybe. I went with the 3.4 exhaust system sort of, becuase the pipe diameter is bigger than the 3.0 that was there. However I noticed that sure, the pipe at the joints is bigger, but where they tacked the flanges on, it then necks down to a smaller pipe. Bigger than the 3.0 but for sure not the same size as the 3.4. Not sure if I can return, was my first thought. Well, second.

Anyone have thoughts on this, or are any of you folks study fluid dynamics in grade school? Have no clue in how much pressure and volume would be effected. Original is 2.5" and this is mostly 2.25" inside.

 

Verrrrrrry roughly, you can thumbnail it at about 100 hp per 1" of exhaust pipe. Here an online calculator, not sure if it does anything much more complicated, it might: http://www.mk5cortinaestate.co.uk/calculator5.php

But a 2.25" exhaust should be good enough for a 190 hp 5VZ. But not with a huge margin, any restrictive mufflers or perhaps crush-bent curves might make it ever so slightly restrictive. But only just barely, not way strangled down.

 

Thanks Jomoka.
If my son still lived in that area, I'd drop by to buy you an adult beverage of your choice.

That helps a lot. I'm pretty sure I will be okay then. I'll just hack this new one up a bit to rotate so the O2 sensor doesn't co-occupy the torsion bar bracket.
I won't be posting pics tho, cuz I don't want you all crying because of the perfection of my welds! Good day to try too, its 'spozed to be mid 60s today. High of minus 6 friday. This much better.

Cheers.

 

Heh, I wouldn't be criticizing any exhaust welds. I've hacked together turbo downpipes with my old cheap MIG. A little grinding, a little heat wrapping, nobody can see anything to say anything!

 

Well saga continues. Remeasured, and the "factory fit replacment" is only 2" ID. It necks down at flanges on either end. Using Jomoka's calc' above, thats good for 164 bhp.
So I don't think Toyota motor would have used 2.25" ID for 3.4L (194 bhp?) when 2.0 would have been just fine. Not with the fanatical cost control and all at their factory.

Going to try to return the part to ebay vendor. Did get the CAT outlet tube hacked up enough to attach. So I can connect O2 and start it. Hopefully.
Did get cruise controller mounted up. And the airbox attached. Missing a connector for the ABS pump. Oh and gas canister vapor hoses. That was 2 years so for sure not 'membrin some stuff.