Request: resonated straightpipe

[Lakitu]

Originally Posted by Timmy_Jones

All things equal, a catted setup will be quieter than a catless. The Berk setup probably has a hi-flow cat, thinner material and may be a bit wider? So yes, it would absolutely be louder than stock.

I see. I mean, I'm ok with loud, just not eardrum-destroying rasp. So, basically I have 2 remaining pieces (fp/op) to add to my exhaust system to complete a 2.5" setup of all aftermarket parts.

I have CAI, a catless header, and a resonated CBE. I'm trying to see how much more dampening minimum I can get away with to avoid increasing rasp and drone, and without decreasing the volume I have. So basically:

1. decrease rasp if possible or keep it the same, but do not want increase
2. increase volume or keep it the same, but do not want decrease
3. keep minimum drone

I know changing the frontpipe from stock will only be an increase in x no matter what since stock was designed to be quiet, but I want to offset any increase in rasp/drone.

The JDL catted fp (without the resonator) with the op is what I had settled on. I'm not sure if its high-flow. But its in my cart right friggin' now and ready to lock & load!!

In my mind this works out to achieve all 3 things on my checklist. But I'm not 100% certain.

[mav1178]

Originally Posted by Lakitu

Wait.. Some months ago people here said catted is quieter than no cat, and in my mind that made sense since the sound has to travel through a material, and I based my entire setup and everything off of that. But it's incorrect?

Originally Posted by Timmy_Jones

All things equal, a catted setup will be quieter than a catless. The Berk setup probably has a hi-flow cat, thinner material and may be a bit wider? So yes, it would absolutely be louder than stock.

The reason why Berk is louder than stock is not because of any material differences, it's because 1) the resonator is gone, and 2) the HFC is a smaller volume than the factory catalytic converter. The larger size factory catalytic converter functions as a resonator, most people overlook this when swapping out to aftermarket headers or front pipes when asking about sound.

Aftermarket HFC are smaller because 9 out of 10 makers of catalytic converters make it smaller for "more flow" and also because it's less material cost.

You can't hear it if you use a stock exhaust, but I measured 3.7db louder than stock Berk FP vs stock, everything else is stock.

[ame="https://www.youtube.com/watch?v=J2LGLH7K1Cs"]Berk HFC front pipe Scion FRS Subaru BRZ exhaust sound clip - YouTube[/ame]

Stock everything as tested on this day was 83.7db

Originally Posted by Lakitu

The first one doesn't sound that bad to me. The 2nd has a split second of ear-piercing rasp. Do not want.

You can only hear it outside the car. Inside you can't hear it.

[ame="https://www.youtube.com/watch?v=jDf0bUg-bpQ"]Circuit of the Americas - 29 April 2016 3:00.78 in my Subaru BRZ - YouTube[/ame]

This is the only clip I have of the catless setup in the car, unfortunately there's too much wind noise due to the placement of the camera.

Originally Posted by Horrid_Funk

I'm not following. A high flow cat is louder than a stock cat, sure. Are there uncatted front pipes that have a db increase of less than 4db? I don't think I've looked at the db increases for front pipes (if there even are many recorded), honestly curious.

The only video I did not record before was Fujitsubo front pipe w/ stock everything...the db meter read the same between stock and Fujitsubo FP though.

Here's video of a Blitz exhaust with stock front pipe vs Fujitsubo front pipe.

Fujitsubo front pipe 103.3db:
[ame="https://www.youtube.com/watch?v=a7BECUlOtxE"]Blitz Nur-Spec F-Ti + Fujitsubo front pipe Scion FRS Subaru BRZ exhaust sound clip - YouTube[/ame]

Stock front pipe 103.4db:
[ame="https://www.youtube.com/watch?v=n8ny7Y0R4J8"]Blitz Nur-Spec F-Ti Scion FRS Subaru BRZ exhaust sound clip - YouTube[/ame]

[Lakitu]

So what happens if you go from stock frontpipe to a non-high-flow resonated+catted frontpipe? Would you say its pointless since you're buying exactly the same part again? Or would there be any difference?

[SuperTom]

Originally Posted by Lakitu

So what happens if you go from stock frontpipe to a non-high-flow resonated+catted frontpipe? Would you say its pointless since you're buying exactly the same part again? Or would there be any difference?

Not sure if that exists since almost all aftermarket catted front pipes are going to use high flow cats. JDL ultra quiet front pipe is should be the best for flow and quiet.


I have the HKS Dual resonated front-pipe which is great for sound and flow. However not having a cat is getting to me with the smell in the interior. It looks like I will be switching to the Invidia catted front pipe(60mm). I would go with JDL UQFP but 2.5" piping is too large for my setup to throw in the middle. I currently have Gruppe-S UEL and OP (60mm), HKS DRFP (60mm), HKP Legamax Premium CB (60mm).


If anyone knows of a FP that is 60mm, High flow cat and Resonated please let me know I have been searching everywhere??? Most likely will try Invidia Catted FP and see if its not too loud. Otherwise may be splicing the back of my HKS DRFP to the front of the Invidia.

[Lakitu]

Thank you very much. Quick question though, you prefer resonated+catted over just catted? Is it to eliminate some rasp and drone?

[Lakitu]

How does the JDL ultra quiet (dual resonated+catted) compare to stock frontpipe? Same drone/rasp levels but lower volume?

[Lakitu]

So basically if I go for JDL frontpipe, I am going from:

1 cat, 2 resonators, 1 muffler

to

1 high-flow cat, 1 resonator, 1 muffler

So we would classify this as louder and more raspy than what I have now. If that's correct, then fml.

[Trueweltall]

Originally Posted by SuperTom

I have the HKS Dual resonated front-pipe which is great for sound and flow. However not having a cat is getting to me with the smell in the interior.

I don't have cats and the only time I notice the smell is if the wind is blowing it back into my windows, maybe you have an exhaust leak.

[SuperTom]

Originally Posted by Trueweltall

I don't have cats and the only time I notice the smell is if the wind is blowing it back into my windows, maybe you have an exhaust leak.

yes that is what I mean. I don't smell it in the winter but in the summer at a red light with the windows down its terrible. And chicks don't like it

[SuperTom]

Originally Posted by Lakitu

Thank you very much. Quick question though, you prefer resonated+catted over just catted? Is it to eliminate some rasp and drone?

I have Dual resonators on my front pipe.

I want 1 cat 1 resonator on my front pipe.

Like stock fp but a free flowing cat and 60mm piping all the way through.

JDL makes this but its 2.5" piping ~63mm. I'm looking for 60mm to keep velocity moving fast which is very important. Most people on the forums throw different sizes on their exhaust without doing research. 2.5" is a bit big on these cars without FI. 2.36" (60mm) is really the sweet spot for NA on this car

read this http://www.gomog.com/allmorgan/exhaustbackpressure.html

[Timmy_Jones]

Originally Posted by SuperTom

I have Dual resonators on my front pipe.

I want 1 cat 1 resonator on my front pipe.

Like stock fp but a free flowing cat and 60mm piping all the way through.

JDL makes this but its 2.5" piping ~63mm. I'm looking for 60mm to keep velocity moving fast which is very important. Most people on the forums throw different sizes on their exhaust without doing research. 2.5" is a bit big on these cars without FI. 2.36" (60mm) is really the sweet spot for NA on this car

read this http://www.gomog.com/allmorgan/exhaustbackpressure.html

Please stop spreading misinformation. Please do some research on why a stock car made more power with a 3" v 2.5" exhaust. Perrin, a reputable vendor did some great research here which was backed by dyno runs.

Please research before making assumptions and trying to inform other people with a poorly written and non-applicable article.

Now, if you want decent (not optimal) performance while keeping volume levels at a lesser level than a larger exhaust you can make a case here.

[SuperTom]

Originally Posted by Timmy_Jones

Please stop spreading misinformation. Please do some research on why a stock car made more power with a 3" v 2.5" exhaust. Perrin, a reputable vendor did some great research here which was backed by dyno runs.

Please research before making assumptions and trying to inform other people with a poorly written and non-applicable article.

Now, if you want decent (not optimal) performance while keeping volume levels at a lesser level than a larger exhaust you can make a case here.

The assumption is that 90% of the board is street driven. Yes a larger exhaust will gain more peak hp but most aren't flooring it 24/7 in high RPM range.

My post was more about exhaust component matching. So if you did an ACE header that ends in 2.5"/63mm then you would go 2.5 the rest of the way.

Most of people on here use the less expensive Tomei/ Gruppe-S headers which end in 60mm. So jumping up to a 2.5" after that there will be some velocity loss..

Ive done 2.5" on other 2.0L and you can definitely feel that loss down low on street driving.

[Timmy_Jones]

Originally Posted by SuperTom

The assumption is that 90% of the board is street driven. Yes a larger exhaust will gain more peak hp but most aren't flooring it 24/7 in high RPM range.

My post was more about exhaust component matching. So if you did an ACE header that ends in 2.5"/63mm then you would go 2.5 the rest of the way.

Most of people on here use the less expensive Tomei/ Gruppe-S headers which end in 60mm. So jumping up to a 2.5" after that there will be some velocity loss..

Ive done 2.5" on other 2.0L and you can definitely feel that loss down low on street driving.

Again, you continue to spread false information. Please do some research before posting here. Your post is completely about spreading things that are not true, you are compiling information from other people who didn't do research and dyno and calling it your own experience. I tend to rely on actual dyno runs.

Since you are having trouble with this, let me help: https://www.perrin.com/blog/post/3-0...d-stage-3-tune

Those are ACTUAL results. Please study the graphs closely and notice the gains from Stock to 2.5" and then even further gains from 2.5" to 3". If you have questions about the graphs, I would be happy to assist interpreting the data.

[SuperTom]

Originally Posted by Timmy_Jones

Again, you continue to spread false information. Please do some research before posting here. Your post is completely about spreading things that are not true, you are compiling information from other people who didn't do research and dyno and calling it your own experience. I tend to rely on actual dyno runs.

Since you are having trouble with this, let me help: https://www.perrin.com/blog/post/3-0...d-stage-3-tune

Those are ACTUAL results. Please study the graphs closely and notice the gains from Stock to 2.5" and then even further gains from 2.5" to 3". If you have questions about the graphs, I would be happy to assist interpreting the data.

your right, I'm wrong. That article was made in 2013 I can't figure out why everyone on forums hasn't put a 3" on their car since then. I would imagine ridiculous sound on a street. My own experience is driving plenty of cars on street and track not just dyno runs from a company trying to sell their parts