Front-Pipe Question for FRS
 

Hello,

Got a question regarding Front-Pipes. From my understanding there are 3 options available for the FRS/BRZ/86.

1. Test-Pipe
2. Front-Pipe with High Flow Cat (HFC)
3. Front-Pipe with Resonator

I understand Test-Pipe option is essentially straight pipe. And for most part I understand Front-Pipe w/ High Flow Cat which in it's application should be less restrictive then OEM Cat, but not be as Loud (in Theory) as the Test-Pipe. Since you can make it stupidly loud with some aftermarket UEL's.

What I don't understand is Option #3, that is Front-Pipe with Resonator. A Resonator can't act as a Cat, but it's only function is to Cancel out some sound waves which are deemed annoying, aka Drone.

If anyone is running Front-Pipe w/ Resonator how does it compare to the Test-Pipe or Front-Pipe w/ HFC.

I wan't to slowly start assembling my Exhaust piece by piece this Summer for my 2015 FRS 6AT. And trying to figure out the best route.

Test pipe = straight pipe. Loudest.
Front pipe with high flow cat = still has cat but a tad louder than stock.
Front pipe with resonator = front pipe with no cat but with a muffler basically to lower sound. Louder than front pipe with hfc.

If you want performance, it has been proven for ATs, best performance upgrades are final drive swap or save for turbo. All other mods, you'll still be slower than a MT.

You are going to be talking minimal performance differences between all 3 options, so really it's a case of which one suits your needs best. Most of the HFCs that are available will not pass emissions testing here in the UK, so they aren't as good as the OEM cat by a fair bit.

I have gotten a dyno tune with stock exhaust with a catless frontpipe vs stock, no WHP gain, stinks, is way loud, I was so happy to switch back. I had a resonated catless front pipe. Really not worth it, I also run catless UEL headers and those add enough volume.

I see, the problem I see (at least in my view) is that a Turbo is a rather expensive upgrade. For example let's take Crawford Performance Turbo 100 Kit. It claims to add 100hp on Pump grade fuel.

However that raises question about further improvements that may be needed, like Brakes, Cooling, ect. Nor do I know how the stock FA20 block will handle, I'm not mistaken the stock engine should be good for 340-360 HP.

I have a full exhaust. Tomei UEL/OP invidia FP and invidia r400. I've been running invidia's test pipe for 2 years. With the setup it sounds really good but always like you're going 100%. There is no in-between. Just accelerating from a light at normal speed sounds like you're trying to race everyone. It also had a bit of rasp at around 3500 when actually accelerating hard.

Just a few days ago I switched over to the resonated Invidia FP. It's seriously night and day. The resonator is straight through and small but extremely effective. Now I don't sound like an idiot at every stop light and have to completely relearn how the car sounds since I shift by sound. What little rasp there was is now gone. Under 4500 it's perfectly tame and smooth. Above 4500 it sounds the same as before just more refined and slightly quieter. Don't have any sound clips but may as well tack on the 2 pipes side by side.https://uploads.tapatalk-cdn.com/201...c1f36805f3.jpg

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Well exhaust never add performance, maybe a tiny tiny 0.5hp due to weight savings, but nothing else, outside of noise really. As far as headers goes it seems EL Headers are only headers that actually make power on the FA20 vs UEL's so if I was upgrading I would go EL route.

Canada here, so our regulations aren't as uptight as Euro spec once. But I still don't want to get a ticket for removing a Cat, since in some magical sense it seems to be illegal under Canadian regulations.

You need to look at the area under the curve before you make assumptions :)

Hmm, interesting. I have been always swayed towards HKS Hi-Power Spec-L (Ti Tips).
Kind of considered BERK Technologies Duel-Tip Muffler Delete + BERK High Flow Cat Front-Pipe mixed with either Borla EL or Tomei EL Headers. The only part I was missing is Mid-pipe and Over-pipe.

I'm basing it off some Dyno charts I seen for the Tomei EL and Tomei UEL. My biggest problem is that I have 50% telling me to get EL as it ain't going to mess with Cylinder x and 3 while other 50% say its all BS and that UEL is just fine on the Cylinder x and 3 and I have nothing to worry about regarding additional wear and tear on Cylinders x and 3, (sorry I forgot which other cylinder it was so let's call it x):bonk:

The issue is that cylinders on one side see more heat than the other. So odds and evens.

UEL will fill in more torque in the middle, EL are technically more efficient and will add peak HP. It really comes down to where you want your torque added.

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