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Exhaust Set Up

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I just think the 3rd tip is weird, and also wouldn't mind a hitch for hauling a bike.

I'm going to see if it might be possible to add a couple 90 degree bends and relocate the 3rd pipe sideways and tapped into one of the outer tailpipes.
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I just think the 3rd tip is weird, and also wouldn't mind a hitch for hauling a bike.

I'm going to see if it might be possible to add a couple 90 degree bends and relocate the 3rd pipe sideways and tapped into one of the outer tailpipes.
Ha! I think that's doable, but would take some legit welding skill for sure. And it'll be tight.

I thought there was a good amount of room between the valve mechanism and the bumper skin but this picture shows better how tight it all is in there. I sketched in where about I think the unmodified Curt hitch structure will sit when installed. There will barely be room to squeeze in a jog to the side and down if deleting the valve.

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I believe closing the valve is really only about controlling sound, power/torque can't suffer in any way opening it up. Anyhow I'll wait to see what aftermarket 2-tip exhausts pop up before making any modifications. I'll probably get the hitch and fit it up right away to at least confirm that.
 

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I just think the 3rd tip is weird, and also wouldn't mind a hitch for hauling a bike.

I'm going to see if it might be possible to add a couple 90 degree bends and relocate the 3rd pipe sideways and tapped into one of the outer tailpipes.
.
View attachment 5683
Some exhaust set ups from the Tokyo Auto Salon 2023
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Looks like the center exhaust will probably be the dominant aftermarket option so far.
 

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Like I said earlier, the bends on that center exhaust are terrible.. it has 2 90° bends which will restrict flow. Fujitsibu did the center exhaust piping really well to prevent any extreme bends in the piping. If I center exit, it will be the Fujitsibu exhaust (hopefully they release a titanium version).
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Ha! I think that's doable, but would take some legit welding skill for sure. And it'll be tight.

I thought there was a good amount of room between the valve mechanism and the bumper skin but this picture shows better how tight it all is in there. I sketched in where about I think the unmodified Curt hitch structure will sit when installed. There will barely be room to squeeze in a jog to the side and down if deleting the valve.

View attachment 5718

I believe closing the valve is really only about controlling sound, power/torque can't suffer in any way opening it up. Anyhow I'll wait to see what aftermarket 2-tip exhausts pop up before making any modifications. I'll probably get the hitch and fit it up right away to at least confirm that.
The receiver part of the hitch is hollow right? Just pipe the center exhaust out of it.
 

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Pic 1: how to properly route a center exit exhaust on the GR Corolla, minimizing bends to improve exhaust flow (courtesy of Fujitsibu)....

Pic 2: how NOT to route a center exit exhaust on the GR Corolla using two 90° bends severely restricting exhaust flow...
🤦
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The receiver part of the hitch is hollow right? Just pipe the center exhaust out of it.
:unsure:

Pic 2: how NOT to route a center exit exhaust on the GR Corolla using two 90° bends severely restricting exhaust flow...
🤦
To be fair, that piping is so huge the exhaust is probably at atmospheric pressure the whole way through those bends, ha
 

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Just an FYI, IIRC, exhaust pressure on turbo cars is higher than intake pressure. This means, on boost, over 25 psi. More than likely, over 30 psi in the exhaust.
Maybe on the input to the turbine, but not on the outlet side.

Pretty sure the pressure in exhaust systems is very low, probably about 1 or 2 psi, and that's only due to restriction from pipes, cat, and muffler.
 

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Maybe on the input to the turbine, but not on the outlet side.

Pretty sure the pressure in exhaust systems is very low, probably about 1 or 2 psi, and that's only due to restriction from pipes, cat, and muffler.
If intake manifold pressure is 10 psi, exhaust manifold pressure is 1.2-1.5x that (12-15 psi). You think that pressure exiting after turbine is 1-2 psi?where did the air go? I mean, if you run an open dump waste gate, lots would exit there, but still would be much higher on boost than 1-2 psi. Assuming internal waste gate, there should be just as much, if not more pressure exiting the turbine. Think, the air in also gets added fuel then ignited, creating MORE gases. That's why exhaust valves are bigger. That said, exhausts are typically larger diameter than intake plumbing. Typically ~2" intake plumbing vs 2.5" exhaust, but there are more restrictions in the exhaust side. That means, there should be similar pressure at least. The more you release that pressure, faster spool, better response and more power. If exhausts saw so little pressure, how would they make 15-20+ whp on most performance cars?
 

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The pressure in the exhaust pipe is created by the restrictions, and by definition the pressure is different if you are measuring before the restriction or after the restriction.

The turbine restricts the exhaust, creating high pressure, which is what drives the turbine to 100,000-ish rpm.

After the exhaust comes out of the turbine, it has a relatively easy path out, and for example if you insert a pressure gauge in, for example, the O2 sensor port, it will measure only 1 or 2 psi.


 

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With these bends in the center exit I now think the most flow efficient and light weight is going to be a single exit drivers (L) side exit.

Doing this would also open up the center for a bike / ski mount set up if that's to your liking.
 
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I'll probably just do a resonator and twin pipes out the back without any muffler at all. I've heard many turbo cars like this and they sound pretty good. Will probably get it custom titanium, unless something really nice comes out. I live in the country with the closest neighbor about 200+ yards away.
 
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