Hello new to exhaust mods. I would like to keep my headers stock. Looking to purchase a Perrin 2.5" resonated CBE. My question is will installing a high flow catted front pipe help increase the loudness while preventing rasp. Also will this effect my emissions during inspections or give me any CEL?

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Anyone have the torque specs for the O2 sensors??

After looking far and wide nobody has posted a definite torque spec for our O2 sensors. So after much looking here is my find. I came to this conclusion by searching o2 sensors for our cars. Then I found NGK's line of oxygen sensors. They listed the o2 sensor as fitting our car and a few other subaru's including a saab LOLOL. but The torque spec for the subaru impreza is 22.1 . So spark plugs are to be torque according to the spark plug itself not car specific is my understanding. So if this plug is an oem replacement then it should be 22.1 on that ej making it 22.1 on our FA..... life is hard

Torque = 22.1 ft-lb. Apply anti-seize SS-30 by JET-LUBE

DO NOT get the anti-seize on the tip.

As per the first post in this thread, you will get little or no power gaind from a Cat back.


Perrin catback 2.5 resonated will sound nice with rest of exhaust stock and wont be too loud.


If you swap out the stock front pipe for a metallic high flow cat front pipe, expect a considerable increase in volume and likely some rasp and drone. Its probably not going to be too bad with stock header, you might gain a little power


but if you ever change out the header for catless, then that setup with high flow front pipe and perrin cbe will be quite loud and raspy.


Putting the stock front pipe in will tame it down a lot with catless header.


If you keep stock header you wont throw a CEL.


Im not sure how strict smog tests, visual inspections are but you should pass with stock header and hi-flow cat, except California I suppose.

Thanks steve99. Are there any suggestions on what type of front pipe I can use to increase volume without creating any rasp or drone?

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Resonated. Think of it like the rest of your exhaust. The size of the resonator (or muffler) will determine the sound.

Small resonator = more noise
Big resonator = less noise

The piping diameter makes a difference as well. The bigger the pipe, the more noise it will produce & vice versa.

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Thanks alxtheoreo. So a small resonator will increase the noise. What will reduce drone and rasp or is it impossible to increase volume without drone and rasp. Would I still be looking at a catted front pipe or going with a catless? Thanks again guys. Complete noob at this.

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Personally, I would look for a catless & resonated front pipe if I want to swap it out. There's very few on the market. HKS has a double resonated front pipe that's 60mm in diameter. Invidia has a single reaonated front pipe that's 63.5 (or 65) mm in diameter.

Don't believe the words that a high flow cat will eliminate drone & rasp. It'll just produce the same sounds as a straight pipe but at different engine loads.

The other option is to keep the stock piece. It's very good at keeping bad noises at bay.

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Catted or Double resonated are pretty good imo.

Could I just go with the perrin unresonated cbe for more noise and then use a catted or resonated front pipe to remove the rasp and drone? Do I have the right idea?

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Cats and mufflers help with volume most, but help with rasp some.
Resonators help with rasp most, but help with volume some.

You'd do okay, I recommend doing one part at a time, and using the next part to adjust further.

IMO a resonated Perrin CBE, and high flow catted front pipe sounds great. If you go with a catless header it's going to get louder too, which is when you may want to add another resonator to the midpipe to help where it can.

One piece at at time if you actually care about getting the right volume and sound quality is my recommendation.

I have a catless EL header and MXP SP catback, and don't intend to add any more exhaust components, as I'd like to keep it quiet. If I choose to swap out the front pipe, it'll be a high flow catted, resonated FP like the JDL ultra quiet.

Thanks for your advice. I watched a few videos online. Sounds to me that the 3" resonated is a lot louder than the 2.5 I think I might go this route. May add a catted front pipe to help regulate any rasp or drone. What do you think? I don't want to change my headers for emission purposes.

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I know emissions is different state to state. Most of the tunes with headers takes care of the codes. If they have to appear stock, you can knock the cat out of your stock header, run an OFT stage 2 EL tune, and get 95% of the performance of an aftermarket header, without the cost, or appearance of an aftermarket header.

I think you should get the Perrin 2.5" resonated exhaust. If you want a little more rasp, get a resonated FP OR get ballsy with a header. Changing the front pipe is technically emissions as well, no different from the header as it has a cat in it.

like the other guy said khs and jdl do quiet front pipe but they are expensive. and they may not be much louder than stock one.

its all a bit suck it and see with exhausts as their are son amny combinations

Added info now that opensource tuning and OFT now have flex fuel and map switching capability on some roms.

Any new info to add for this thread for the 2017+?

have not seen a 2017 here yet.


they already have better air filter


The ecu has different programming and appears to run full time closed loop fuel control and does not run rich at high rpm load (from what I've seen on usa model ecu logs)


Header is changed and intake manifold changed.


Due to stock header being better and fuelling control being better you may not see as much gains from header and tunes as you did on earlier models.


but its early days.

Thanks for your hard work steve. I recently switched to e85 and relied on your info. Very happy.

Hello I couldn't find anything on this, so please​ excuse me if it's a double. I have 13 FR-S with and agency power catback. I love the way it sounds and is great quality no issues what so ever. Just wondering has anyone with this set deleted there CATS, of so what's the sound like? I'm concidering it until I have the money to buy a new header and down pipe. Any vids would be fantastic. Thanks the car is stock ATM other than the catback.

I am having a hard time finding an answer to this. I hope someone can help me out.

If I add an "high flow catted front pipe", will this get rid of the catless header smell? I won't lose any gain/mess up anything with catless header/stage 2 right?

I'm sure it varies, but my experience is that it won't always, at least not entirely. Cold start is the worst, it's just harder to get the cat up to operating temperature relative to one in the header.

C

I have a JRSC c38 and I just installed a flexfuel kit (still on 91oct) and 700cc injectors today. Is it safe to start the car without a re-tune just to let it idle and check for fuel leaks?

Got a question that ik is stupid. BUT how plausible is it to slap on a supercharger as my first mod and then getting a big break kit, tires+wheels, suspension, flex fuel, etc later.

I know its not advisable but with a low psi tune would it be safe to run a stock FRS with a supercharger kit?

I really want the fastest results for my build to maintain a low overall cost. See ik if i upgrade everything previously mentioned before forced induction i will be craving that power. That 30ish hp from e85 wont be enough to satisfy my craving. So why not get the supercharger first and make it the perfectly balanced car later on when i have time to save instead of making myself wait and spend a lot of money before forced induction?

Please advise, any help would be appreciated.

There is no reason you can't go that route but you'll find yourself annoyed pretty quickly that you can't make use of the power without potentially killing yourself. That said, I actually think there is some merit in this approach in that you get the power level you want first, then build the rest of the car around that. You will waste less money this way.

That said, the car is still fun on sticky tires and aggressive brakes with the stock power level and you aren't forging any new ground so there are plenty of resources available to tell you exactly what you'll need to support the power before hand. If nothing else, get yourself stickier tires and upgraded brake pads to reduce the chance that you'll kill yourself.

I have a 2017. I got my hands on a Nameless header, 3" outlet. I'm deciding between the nameless over/front pipe combo (3" to 2.5"), or JDL ultra quiet 3" with grimmspeed 3"/2.5" adapter.

Ecutek seems expensive; I might be better off OFT for this, even on a 17?

I was wondering if you had an opinion or warning here?

For intake all I have is a new tube with sound delete; I'm willing to buy the grimmspeed or other if it will help here. Either way, full foil and I'm looking for where I can get an oil pan heat shield (like the one you can get with the gruppe-s)

Thanks,

-George

OFT guys have some tunes for basic mods for 2017, but the ecu logging for 2017 roms not working correctly so its difficult to work out exactly how the tune is running at present.

Ecutek will be more expensive but if you want to mod tune it will be better as logging will work correctly

Hey Steve, thanks for this thread. Most useful thread of all for me, it's been the basic guide I have used for all my mods and I love my car all the more because of it.

I skipped most of this other than oft, catback, e85 and got bored. Was tempted to do headers but with gains total waste of money. Now thinking turbo with money already saved though... Now im thinking why not ls1 swap. It never stops :(.

Shoulda got header instead of the catback. You went about things a little bassakwards.

Snorkel removal may not be good idea
 

Snorkel removal may not be good idea - see below

https://www.pointmeby.com/2016/09/15...z-frs-gt86-86/

Thanks. Never hurts to repeat it.

hmm. If an OFT tune with a catless stock header eliminates the cel, do I need to reinstall the O2's in the header?

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You need the O2s for your ECU to know the AFR

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2017 86, knocked out cat in OEM header.

90° mini cat ($40AU fleabay jobbie) on rear O2 sensor, no codes after 200 km of hwy and general thrashing.

Gains, losses, don't know for sure, seems better in the midrange....seems to rev much more freely.......it is better than with the cat, how much??????? F knows.

Has header back X Force exhaust, OEM overpipe.

Cold start is obnoxious loud.

Settles down on idle.

Sounds great at full noise.

Tune will fix cold start.

Should have time for a tune in a month or two.

Until then I'm an annoying prick in the mornings.

Being possibly an idiot, can anyone tell me if running a jdl catted header with the OFT e85 tune will cause any problems? I want to run this setup as I'm not worried about going full flex fuel cuz I have like 5 e85 stations by my house and I want to keep the catted header to keep noise level down. I keep looking and dont see any definitive answers or I've missed it somewhere.

will be fine

the newer oft V4 tunes the stage 2 tune is for catted header and stage 2 plus for catless.

oft E85 tune works with ethanol contents from about 60-90%, unfortunatly some "E85" in USA can be as low as 50% that would cause issues

Thanks for the info. So if the e85 in my area is of low quality I should avoid running the e85 tune with a catted header? I'm in SoCal so I wonder if the e85 out here is crap with all the hate on cars we get out here.

yes you probably need to test it you can buy low cost test kits on ebay


if its below 60% ethanol you will need to mod tune or just not use E85 tune




something like this


https://www.ebay.com.au/itm/REV-X-Su...MKj:rk:15:pf:0

Beautiful thanks for the info!