RPI GT exhaust GB thread.

[RPIpower]

Originally Posted by krnnerdboy

how is the tone at WOT compared to the muffler delete?

check the videos on youtube.

[laidback]

See you guys tomorrow

Originally Posted by RPIpower

Nah, we'll raffle off your massage services. lol

Muffler delete = rasp at WOT
= Lose of HP/TQ

RPI GT= deep sounding
= HP/TQ gain

Originally Posted by krnnerdboy

how is the tone at WOT compared to the muffler delete?

[Beedub]

Z4M + top down + rpi gtr pipes = one fat smile!!

Really enjoying the exhaust, the noise has defo mellowed out and is now imo perfect still very loud but so fitting for this car imo. My ///m now sounds as good as it looks! my best purchase to date on par with my CSLs for grin factor, i dont know how many of these are left but if anyones considering one, snap it up now before its too late!! when the weather pics up ill post up some pics. cheers again rpi, its a pleasure to give my hardearned to a company that treats its customers as you have treated me.

cheers

[Evoking]

Do any of you notice any drone? 3rd gear from 1700-2300 press the gas good and tell us if there is any drone...

[Beedub]

evoking their is a short rev range where their is what i would call drone, but when my stock exhaust was in a certain rev range it also had this drone at a certain rev range but of course it was just quieter. At motorway speeds it falls out of this range and you can cruise comfortably, but get on it and jesus its noisey, like i said i never thought the s54 could sound so exotic, gorgeous noise and a very well researched product.

here a poor pic with my genuine CSLs refurbed to gunmetal

[Evoking]

I asked because my flowmaster mufflers also sound incredible. Of course the drone rpm range is there but much better than when I had muffler delete setup. The only reason I would change from this setup would be a 0 drone kit! That, to me represents masterful design - not to take anything away from RPI.

I suppose if I were going to pay $350 installed all over again for my setup there is a slim chance I would consider paying $900 for the RPI. Course then I would have to switch from the worlds greatest looking tips to the weirdest!

[RPIpower]

Originally Posted by Evoking

Do any of you notice any drone? 3rd gear from 1700-2300 press the gas good and tell us if there is any drone...

You really shouldnt be stepping down on that gas at those rpm ranges in 3rd gear. You'll be putting unecessary load on the engine.

Originally Posted by Evoking

I asked because my flowmaster mufflers also sound incredible. Of course the drone rpm range is there but much better than when I had muffler delete setup. The only reason I would change from this setup would be a 0 drone kit! That, to me represents masterful design - not to take anything away from RPI.

I suppose if I were going to pay $350 installed all over again for my setup there is a slim chance I would consider paying $900 for the RPI. Course then I would have to switch from the worlds greatest looking tips to the weirdest!

The flowmaster mufflers use chambering to break up the exhaust pulses. This allows for little to no drone but great sound when on WOT. The problem is that these suck for performance, esp on the BMWs. I wouldnt be surprised if it dropped 10-15whp. There isnt much science to exhaust design. Allow enough volume at the right velocity and you will get power. The problem comes to noise and drone. The stock muffler is chambered heavily, thus making it quiet. Take that away and you "could" get power if designed right, but then, youll have to worry about the sound. Some companies say their exhaust sounds great but doesnt drone........and also make hp, but I have yet to see one prove it.

[Evoking]

1st I heard that the open exhaust supposedly looses power because of TOO LITTLE restriction. Now its being said that the Flowmasters haveTOO MUCH restriction and is loosing power!

I never dyno'd either but I can say that the open exhaust seems to have gotten faster after a bit of "breakin" - perhaps this was the computer adjusting. At least this is what I could tell from seat of pants as well as against my Jag XJR. I also understand that if I did an ESS tune for the open exhaust it would defeinitly become a plus rather than a con.

I plan on dyno'ing it now and benchmarking against other stock cars. I recognize I don't have a baseline of my own but if it runs neck and neck or better than average its a win no? If I have in fact lost 10hp then I'll be going with RPI or back to my open setup with ESS!

[Rustycat]

Just to add a comment. I've had the RPI exhaust installed for a couple of days. I am driving a Coupe, which I suspect makes a difference in cockpit noise. Yes, the exhaust is loud. It is nicely toned with a sweet baritone song that sings out to the World that it is a force of nature and dares others to challenge. I mentioned that I'm driving a Coupe because I've not seen others comment on the cockpit harmonics that can be set up between 3 and 4.5k rpms. Frankly, the sonic vibrations, and this is dependent not only on rpm range, but load/ acceleration, can be painful to my poor ears. Yes, this exhaust stands center stage and sings out for the World to witness, but, this is also translated to some serious repercussions in the driver’s seat. So, don't expect to be isolated from the event you have authored, i.e., you are fully involved. When you blip or double blip the throttle you hear it, just as easily as you would hear a musical instrument trilling--and it is a wonderful feedback that you will never experience with the stock exhaust. As you back down the rpms slowing to a stop the exhaust burbles and coos like a sex kitten (how’s that for a 60's playboy throwback?) that has just awakened from a night of wanton abandon. When shifting you really don't need to look at the tach, just use your ears, the exhaust will tell you where you are in the RPM range. So, loud and demanding, sexy and in your face listen to me stuff that throws a tantrum that makes you wish you were in another room at times. But, man, I like it, but I'll have to depair my Bluetooth, because there is no way anyone will ever hear me when I'm using the cell phone and accelerating.
Lew

[jonanator]

^I love the exhaust the MOST when it is between the 3000-4500rpm range. It sounds sooo exotic that I often just keep my foot on the gas just enough to stay in that rev range. I think the exhaust is loud, no doubt about that, but I have used my bluetooth many, many times since installing the exhaust with no issues. I even ask the person on the other end of the line if they can hear me over the exhaust and they have no issues.

[trsbmw]

Originally Posted by RPIpower

You really shouldnt be stepping down on that gas at those rpm ranges in 3rd gear. You'll be putting unecessary load on the engine.



The flowmaster mufflers use chambering to break up the exhaust pulses. This allows for little to no drone but great sound when on WOT. The problem is that these suck for performance, esp on the BMWs. I wouldnt be surprised if it dropped 10-15whp. There isnt much science to exhaust design. Allow enough volume at the right velocity and you will get power. The problem comes to noise and drone. The stock muffler is chambered heavily, thus making it quiet. Take that away and you "could" get power if designed right, but then, youll have to worry about the sound. Some companies say their exhaust sounds great but doesnt drone........and also make hp, but I have yet to see one prove it.

Perhaps I am just ignorant, but could you explain how stepping on the gas in 3rd gear at 2k-3k rpm would put 'unnecessary load on the engine' ??

[Beedub]

Originally Posted by trsbmw

Perhaps I am just ignorant, but could you explain how stepping on the gas in 3rd gear at 2k-3k rpm would put 'unnecessary load on the engine' ??

because using 3rd gear at 1700rpm as stated will labour the engine and drive train, labouring the engine causes undue stress and vibrations put other components under huge stress.

[Evoking]

Doesn't have to be 3rd gear... The drone range is 1700-2400. Do this in any gear. Is the sound borderline embarrasing if you have a business person or date in the car. Is the tone so deep you wonder if stuff will begin rattling etc?

You pass this range in multiple gears all through out the day. The price paid for a great sounding exhaust when you "want it" is a bit of drone when you're tending to something else!

[Nate2046]

Originally Posted by Beedub

because using 3rd gear at 1700rpm as stated will labour the engine and drive train, labouring the engine causes undue stress and vibrations put other components under huge stress.

Old wives tale. If it were true your idle would be set above that point.

[polar]

Originally Posted by Evoking

Doesn't have to be 3rd gear... The drone range is 1700-2400. Do this in any gear. Is the sound borderline embarrasing if you have a business person or date in the car. Is the tone so deep you wonder if stuff will begin rattling etc?

You pass this range in multiple gears all through out the day. The price paid for a great sounding exhaust when you "want it" is a bit of drone when you're tending to something else!

Thanks for your posts Evoking and Rustycat! This is spot on how I've experienced it in my coupe.
I've been trying to kill the low-rpm drone and sonic vibrations by disassemble/assemble the pipes a couple of times now! -Thinking I've got a leak in the flange-connection or something.
I've been reading about "there's no drone" and "it's quiet when cruising" and so on... I was starting to get quite frustrated.
So thanks again E and R for saving my weekend! I was planning another tour in the garage... now I know it's "normal"... hmmm...where did I put my hearing protection?!?

[Rustycat]

Yeah, I'd rather not have to carry hearing protection, so, I'm going to try some rigid insulation in the inside of the trunk. I have some 2" Johns Mansville stored up in the the shop that has excellent audio dampening qualities, I'll experiment with it and see if it makes a difference.
Lew

[trsbmw]

Originally Posted by Beedub

because using 3rd gear at 1700rpm as stated will labour the engine and drive train, labouring the engine causes undue stress and vibrations put other components under huge stress.

Sorry, but that does not explain anything. Can you explain what "labouring the engine" means? I have never heard of that before. (Again, excuse me if I am being ignorant)

If it causes undue strees, wouldnt it be multiplied when it actually produces peak torque? (which I believe is at about 4500 rpm for the S54) Applied torque is applied torque, and I would imagine that the entire car is engineered to reliably tolerate the range of forces that the engine could produce throughout the entire RPM range...

[polar]

...but, there's always a but... when driving home from work, taking an extra long lap through the centre of my hometown, gliding around on 4k+ rpm in 2:nd gear, making spine-chilling sounds, echoing between buildings, peoples 2 blocks ahead of me turn heads wondering wtf is that? -the batmobile, a jetplane? ...-me like! and in those moments I don't need any hearing protection, -they do!

[Rustycat]

There absolutely no disagreement amongst any posters that the sound is more than wonderful--when listened to whilst on the outside of the car. Certainly one of the finest
exhaust notes I've ever heard. For me, the issue is taming the assault on my ears while sitting in das cockpit. It seems logical to start with some sound deadening efforts in the
trunk and see how that effects the sound levels at different RPMs and load.
Lew

[Rustycat]

Here's an answer that I have lazily cut and pasted, that reflects my thinking re labouring the engine at low speeds and too tall a gear. Perhaps the S54 isn't as susceptible as less sophisticated engines, but, for me at least, this explains why I was always taught not to lug an engine.
Lew
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Any downfalls going 20 MPH in 5th gear (manual car) in comparison to 2nd gear 60 mph (high rpm, more gas)?
2 years ago
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by WMC Jr Member since:
September 25, 2007
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Best Answer - Chosen by Voters
When your going 20 MPH in 5th gear your engine will be under severe load at a low RPM. First, at a low RPM the engine oil pressure would be too low to lubricate the main bearings in the engine, while under a heavy load. Second, the combustion chamber will become extremely hot, if done for too long of a period could cause severe engine damage.
Doing 60 in 2nd gear is also hard on the engine. At high RPM the crank, pistons, wrist pins, cams, bearings cylinder walls, everything will be put through a large amount of stress wearing out at a much faster rate. Oil pressures will be much higher. High oil pressure can cause pitting in all of the engine bearings (The reason race car engines are rebuilt so often). As far as gas mileage- it will be terrible for both. At 20 in fifth gear, you'd have to be fairly heavy on the accelerator and that would use a lot of fuel. Especially since efficiency is terrible at these RPMs. 2nd gear doin' 60, that also uses up a lot more fuel. Both scenarios are bad for engines and mileage. Hope this is what your looking for.
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2 years ago
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[polar]

Yes, the inside sound level must be tamed! Lets do some research and post the result asap!

[RPIpower]

Originally Posted by Rustycat

Just to add a comment. I've had the RPI exhaust installed for a couple of days. I am driving a Coupe, which I suspect makes a difference in cockpit noise. Yes, the exhaust is loud. It is nicely toned with a sweet baritone song that sings out to the World that it is a force of nature and dares others to challenge. I mentioned that I'm driving a Coupe because I've not seen others comment on the cockpit harmonics that can be set up between 3 and 4.5k rpms. Frankly, the sonic vibrations, and this is dependent not only on rpm range, but load/ acceleration, can be painful to my poor ears. Yes, this exhaust stands center stage and sings out for the World to witness, but, this is also translated to some serious repercussions in the driver’s seat. So, don't expect to be isolated from the event you have authored, i.e., you are fully involved. When you blip or double blip the throttle you hear it, just as easily as you would hear a musical instrument trilling--and it is a wonderful feedback that you will never experience with the stock exhaust. As you back down the rpms slowing to a stop the exhaust burbles and coos like a sex kitten (how’s that for a 60's playboy throwback?) that has just awakened from a night of wanton abandon. When shifting you really don't need to look at the tach, just use your ears, the exhaust will tell you where you are in the RPM range. So, loud and demanding, sexy and in your face listen to me stuff that throws a tantrum that makes you wish you were in another room at times. But, man, I like it, but I'll have to depair my Bluetooth, because there is no way anyone will ever hear me when I'm using the cell phone and accelerating.
Lew

Some of you have great descriptions and can write womens novels. I have to admit, I got a little excited reading your post. lol

Originally Posted by Evoking

1st I heard that the open exhaust supposedly looses power because of TOO LITTLE restriction. Now its being said that the Flowmasters haveTOO MUCH restriction and is loosing power!

I never dyno'd either but I can say that the open exhaust seems to have gotten faster after a bit of "breakin" - perhaps this was the computer adjusting. At least this is what I could tell from seat of pants as well as against my Jag XJR. I also understand that if I did an ESS tune for the open exhaust it would defeinitly become a plus rather than a con.

I plan on dyno'ing it now and benchmarking against other stock cars. I recognize I don't have a baseline of my own but if it runs neck and neck or better than average its a win no? If I have in fact lost 10hp then I'll be going with RPI or back to my open setup with ESS!

Its not a matter of "open" exhaust. Exhaust design comes down to volume and velocity. Try googling or doing some research of exhaust gas velocity. The chambering of your muffler is hurting the performance. When going with a straight thru design, you need to consider the tubing bend, diameter, resonator and its perforation diameter. This is why it took us so LONG to make this exhaust. All of that can effect the performance and sound. I think we started playing with this exhaust 1-2 years ago? Seems like ages ago.