followtheF

Has anyone been in the market for an RCF magnaflow exhaust, or used one on their ISF?

I've had a local shop contact me about one. I haven't really gotten into the mod game before (afraid of the endless money pit lol) but they were offering to do it for super cheap in exchange for getting to use my car to test it out I guess (still need to call and get all the details).

Just curious what any previous or current F owners have to say about magnaflow exhausts, in terms of noise/performance/etc.

Thanks.

DrRick

the ISS exhaust for the ISF used magnaflow cans. i had that on mine and it was quite loud. but mine was the 'race' exhaust that had 4 smaller mufflers with no resonators (QES) instead of 2 larger cans WITH resonators (DES).

i would expect it to sound similar to this on an RCF....

followtheF

Thanks for the link.

Just talked to the magnaflow guy, and they want to use my car as the prototype for the production exhaust they want to start manufacturing. So I'd have to leave my car with them for a week or two while they sweeten up all the hardware fittings, sounds, etc, but then I'd get to keep their prototype exhaust. Sounds like they're just making one version, at least for now, as opposed to other cars where they've made a "street" and "race" version. This one sounds like it'll be more like the street version - not TOO rowdy, but it'll amplify those bassy-er hums over the mechanical whir.

They'll give me back the stock pipes so I can always go back if I'm not happy. Seems like too good an offer to pass up, I just have to give up my new car for a couple weeks. What do you guys think? If I go with it, I'll let you know what you can expect to hit the streets in a couple months.

DrRick

It'll be interesting to see the gains that an exhaust system can attain. On the ISF, there were so very real restrictions. There don't seem to be as many on the RCF.

Good luck!!!

rjmalm

There is an art to getting the sound level vs RPM smooth and not having peaks (drone) that are too loud. I had the stock resonator removed and replaced the stock mufflers with magnaflows. I had the single pipe replaced with dual pipes from the cats. ($500) Bottom line it was just too loud and could not run it at the local track (AZ Motor Park) and had to add 2 magnaflow resonators back in as well as do some B-Quiet sound adsorb material in the trunk and behind the back seat for road trips. I never did a dyno measurement. See attached plots.

Remember that "Sound studies tell us time and again that a 3dBA increase in sound level is barely noticeable to the human ear. In fact, you have to raise a sound level by 5dBA before most listeners report a noticeable or significant change. Further, it takes a 10dBA increase before the average listener hears “double the sound.” Dont go by the fact that 3db in sound level is 2x change in energy, the key is what is heard or felt by the human ear.

You can measure the sound level with phone apps or sound pressure meters and video it and your tachometer as you change the rpm but use your ears and make notes. Some of my videos are here: https://www.clublexus.com/forums/rc-...und-level.html. If I change my future RC-F exhaust I will consider having a pro solution like Joe Z.

Bye the way
Normal conversation at 3' 60-65dB
Telephone dial tone 80dB
City Traffic (inside car) 85dB
Train whistle at 500', Truck Traffic 90dB
Jackhammer at 50' 95dB
Subway train at 200' 95dB
Level at which sustained exposure may result in hearing loss 90 - 95dB
Hand Drill 98dB
Power mower at 3' 107dB
Snowmobile, Motorcycle 100dB
Power saw at 3' 110dB

followtheF

Thanks for the info, guys.

I agree that the RC-F stock exhaust seemed to already take advantage of a lot of the restrictions that were on the IS-F, so I'm not sure what gains can really be achieved. I'm guessing not very much, and any exhaust system is going to be primarily for sound, or as a part of additional mods (intake/headers/etc.).

Supposedly magnaflow is going to spend a week or two fine tuning the sound/rpm performance, so hopefully there aren't bad peaks. From a few videos I've heard of magnaflow exhausts on other cars, it seems to mostly just up the low frequency sounds, without being overly loud, almost like adding a sub to a stereo system. lol Hard to tell from just videos though without hearing it in person.

I'm not a fan of throwing on an exhaust just to make a car obnoxiously loud. But I know magnaflow makes a quality product, and considering I'd be getting it for free (plus a week or so in a loaner car) it seems hard to go wrong. Decisions, decisions....

4TehNguyen

iTrader: (1)

RCF is at least true dual unlike the ISF, but there are some ugly restrictions still. When the piping passes under the rear LCA the pipes diameter reduce and are pinched

https://www.clublexus.com/forums/rc-...s-weekend.html

oohpapi44

iTrader: (1)

Doesn't seem like you have much to lose as you can always return to stock. I've always used MagnaFlow and been very pleased with the results (sound and performance). Go for it.

rjmalm

Maybe you can have them give you a sound pressure plot (db) vs RPM before and after, interior and exterior. Dyno results before and after would be nice as well.

This could help set a standard and allow people to compare specs of after market exhaust mods.

rjmalm

followtheF,
Another idea if you want to document and compare sound level at different frequencies.
You need a before and after recording of the sound with a good microphone
in the same location for each recording and have about the same change in RPM vs time.
You can use something like PC program FlexMusic to look at the frequency content. Maybe there is
another spectrum analysis tool that you can feed 2 sound files to that would do an even better display but this is all I could come up with with the tools I have installed now. Attached is an example compare with my annotations. I will capture a waveform of my RC-F when I get it and look for a better app.

I created 3 waveforms from DrRick's video and show waveforms with frequency display, 2 waveforms at a time. Attached.
I did make a mistake on the Stock vs ISS image, I tried to maximize volume to see the frequency area better in the Stock vs ISS. So dont compare ISS between the 2 attachments.

followtheF

Cool, thanks. If I'm not able to find the time/tools to do my own audio comparison, I'll definitely ask if they can give pre/post recordings and/or plots


I asked about dyno tests and they said they only do that unless the car has been broken in at least ~10k miles, which mine hasn't yet since I've only had it a few weeks. So no dyno unfortunately, but hopefully they can provide some other data that would be interesting. Maybe once I hit ~10k though I can bring it back with the stock pipes to do a dyno comparison. You know, so they can have that info for marketing purposes or something, no ulterior motives here.


Yeah I'm hoping they can squeeze out some gains, and it sounds like from what you guys have seen there's opportunity to do that.


Yeah I'm pretty much all for it, as long as the wife gives the thumbs up.

DrRick

annnnnnndddd that was my problem. the 'race' exhaust was so loud that my wife hated the car. refused to drive it. so make sure you get resonators....

followtheF

haha yeah I might have to look into resonators, and then again I'll keep the stock exhaust so I'll have that as a backup. Magnaflow said the one they want to build will sound more like their "street" exhaust than their "race" version, so hopefully that'll help? I don't know I guess we'll see!

4TehNguyen

iTrader: (1)

give her a set of earmuffs

DrRick

the race is just for single folks. gotta be. interestlingly...i never saw a dyno for the DES vs QES exhausts. maybe i missed it. but yo....no man with a woman to answer to can have an exhaust without resonators and keep a happy home.

thats for quiet, sessy time. and it has NOTHING to do with the car. hahahhahaha