3

 

ahem

 

ok this is starting to turn into the meme of phone manufacturers adding more and more camera lenses

 

Either OEM, or single center as that would require the least amount of material so it would be lightest weight / most functional.

 

The 2nd is too similar to a CTR, and the 3rd is too similar to the previous gen Civic Si.

 

7 for me please.

 

Here is an up close sound clip of the exhaust.
Idling and light revving. It is louder than I expected.

 

#3 but with a big ol Tomei

 

Stock, y’all got the itch to upgrade, ha, I have doubts it will add much benefit.

 

Catbacks don’t really ever add power I just want additional sound

 

Downpipe + stock exhaust seems to be the play more recently. Just a bit more sound but a decent power boost. OEM look

 

agreed just preordered island racewerks catless down pipe and mid pipe gonna connect it to stock exhaust with no tune and run mini cats/simulators to defeat check engine light. I want just that smidge more sound and the nice power gain from the down pipe without killing my warranty.

 

there’s a valve for the center exit..

 

I look forward to unplugging that in the open position so it's louder all the time, lol.

 

^^^

 

^^^

 

Oooh so I was messaging rob at RK Titanium and they WILL be doing a system for the GRC. I had their system on my Supra and LOVED it! This will be so good to see.

 

I'm rather fond of RK titanium... Just have a "few" of his pieces on my Evo...

 

Withe the way the muffler is setup, guaranteed gains for spool, power and lighter weight with an aftermarket setup. Problem will be, to gain it, there's really no room for a muffler. A car running this much boost (25 psi), will gain plenty of power from opening up the exhaust. For every psi into the engine, there is almost double that coming out. Since the valve doesn't open until 3k rpm, iirc, you are losing spool. A down pipe should help, but I don't know the specs of it stock. A 260+ whp car needs a minimum of 2.5" through to be ok performance and 3" for maximum. Running a 3sgte at different power levels, you could gain 20 whp with 3" exhaust because stock bottle necked down to 2" in places. Straighter is better too. Imo, I'll probably do double 3" straight pipes out the back and hopefully get to 400+ whp

 

Don't think the stock turbo will do 400+whp without E85. Think the record is like 380ish.

 

@04lexusis3005speed

This car has a GPF (gasoline particulate filter).

That is going to be the big bottleneck.

 

I think that's only the GR Yaris because of European regulations...

 

I'd definitely like to see the entire length of the exhaust for confirmation. However, every single one of these cars I've seen pics of dirty (after drive events, or the Canadian press cars that got driven for longer periods of time, or that guy who signed up who's neighbor has been driving that white one). The exhaust tips are 100% spotless. No soot buildup whatsoever.


EGR is making a comeback, and GPFs are getting installed on vehicles more and more in the US market these days.

 

Tempted to stay oem and just add a down pipe since the exhaust setup kinda grew on me, but if I do anything it’d be a dual outer setup. Hopefully still around oem-ish look/sound wise to open it up and drop some lbs

 

I design exhausts for my current car and after 2 years just threw the OEM exhaust back on it to test a different product. OEM is kinda nice, haha.

 

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.
.

 

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.

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.

 

Just add the 90 bend on it and face it down to the ground. Just throwing ideas out there.

 

I'd want to take the exit as close to where the stock tips are as possible. Mainly to avoid carbon monoxide working its way into the cabin if sitting/idling.

 

Exhaust setup from someone on the Facebook page. 3" midpipe (non-catted) and 3" Catback with a Greddy.

Video of the sound at this link: Toyota GR Corolla Owners | Not a huge fan of the single exit look, except maybe for the track, but 2JRacing built a 3" midpipe (non-catted) and 3" Catback with a Greddy

 

Exhaust setup from someone on the Facebook page. 3" midpipe (non-catted) and 3" Catback with a Greddy.
View attachment 6402
View attachment 6403
View attachment 6404

Video of the sound at this link: Toyota GR Corolla Owners | Not a huge fan of the single exit look, except maybe for the track, but 2JRacing built a 3" midpipe (non-catted) and 3" Catback with a Greddy

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).

 

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...
🤦

 

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.

 

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.

Measuring Exhaust Back Pressure | Tri Star Engines & Transmissions

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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.

 

I'd love it if an aftermarket exhaust would let this thing take a hitch for a bike carrier rack.

 

Ive been looking at all the pics and looks like if they dont do center exit, then should be able to use a hitch from regular corolla hatch. But not 100% sure if the rear end is exactly the same.

 

Have any of the manufacturers displaying their exhaust from the Tokyo auto show put any videos out of it being on?