Rapid Exhaust - Marriage Savers

[The91kwbeast]

An exhaust fabricated at a exhaust shop, using quality resonators and mufflers is what you need

The centre resonators that come standard, and the resonators that 99% of aftermarket exhausts use are cheap rubbish without any internal volume or real though in the actual design

It is the same with the mufflers used

Large bodied resonators and mufflers is what is required

I'm running 1 7/8 4:1 headers to the Sureflo 3.5" single on my blown VX SS with 3.46 rear, the center muffler and rear resonator both have large bodies, there is no drone at any RPM, and both me and the Mrs do alot of hwy miles where drone would be unacceptable

With the windows up and cruising at 100 - 110kph you wouldn't know the engine was running until you mashed the loud pedal

This pic isn't mine, but the exhaust is typical to mine, the muffler is in the middle (basically the biggest that fits) with the big (huge) resonator at the rear
View attachment 240455

Disclaimer: my exhaust shakes the house when it starts up in the garage, but sitting inside it is nice and quite with only a slighty shake from the cam

It would seem so. I'm booked in to head back to Rapid again and add more hotdogs on my marriage savers - will report back.

Again it's a very poor reflection on the industry (excluding Rapid Exhaust who have actually tried here!) to not bother to understand the car/engine better. It's really lazy stuff.

Like seriously - my 2nd/wife's car is a Kia Cerato GT (turbo). Resonator delete costs $150 - sounds great like an AMG A45 and is noise & emissions compliant, and drone free (dual clutch auto probably helps). People spend thousands on their Commodore for a full exhaust, and achieve none of those.

I've also come to the conclusion that:

1. Many off the shelf brands, and the tuners that sell them, create products for the sole objective of max power figures. Many are selling 100 or 200 cpi cats in their off the shelf systems to generate the quoted power figures - which would instant fail emissions test.
a) Even worse are the idiots who go MAFless - instant fail again
2. Next is they are selling products to achieve a certain sound, which are almost always too loud and fail the noise test - in addition to having drone issues on automatics.
3. Combination of the above two points means instant fail on rego next renewal, unless you have a dodgy mate that will pass the car. Then when you go to sell it - the next bloke can't get it registered either!

I just simply couldn't fathom paying $3.5k+ for a full exhaust (oh - which then needs to be tuned with the cats change, so full cost more like $4.5k) only to be defected (noise + emissions) and take it all off again. WTF is the point (unless you're just taking it to race/drags every few weeks).

Industry is full of lazy crooks mate looking to make a quick buck on labour and parts.

 

[RevNev]

Darren said he could add a hotdog in the Centre section of the marriage savers.

Ask Darren to make a set of fibreglass packed straight through mufflers with the cannister size of the stock one's and fix it properly. The drone issue is that everyone in the aftermarket goes too small in the rear mufflers. It's always best to use the biggest rear mufflers that'll fit under the car and adjust noise level at the midpipe.

 

[The91kwbeast]

Ask Darren to make a set of fibreglass packed straight through mufflers with the cannister size of the stock one's and fix it properly. The drone issue is that everyone in the aftermarket goes too small in the rear mufflers. It's always best to use the biggest rear mufflers that'll fit under the car and adjust noise level at the midpipe.

Dunno about this either. I currently have the HSV bi modals on (vacuum not hooked up), fully open they drone 1600-1900rpm and that product is exactly what you are describing - a largeish straight through rear muffler.

I've zip tied the valve about 80% shut and it's much more quiet - but there is stillll some remaining drone.

I've assembled a few posts from my research but it seems the only way to fix is installing a H pipe behind the centre brace (just behind hotdogs). I will enquire about this.

 

[RevNev]

Dunno about this either. I currently have the HSV bi modals on (vacuum not hooked up), fully open they drone 1600-1900rpm and that product is exactly what you are describing - a largeish straight through rear muffler.

The loud side of a bimodal is virtually straight pipe through the cannister with minimal muffling capacity. Bimodal open is more a rear muffler bypass that's why they can drone. The electric bimodals in Series 2 are programmed to close at the drone points, they also drone when left permanently open.

Here's a bimodal internals

 

[RevNev]

I've also come to the conclusion that:

1. Many off the shelf brands, and the tuners that sell them, create products for the sole objective of max power figures. Many are selling 100 or 200 cpi cats in their off the shelf systems to generate the quoted power figures - which would instant fail emissions test.
a) Even worse are the idiots who go MAFless - instant fail again
2. Next is they are selling products to achieve a certain sound, which are almost always too loud and fail the noise test - in addition to having drone issues on automatics.
3. Combination of the above two points means instant fail on rego next renewal, unless you have a dodgy mate that will pass the car. Then when you go to sell it - the next bloke can't get it registered either!

The reality is, compliance isn't the component true enthusiasts are seeking, it's individuality, wow factor and horsepower. Compliance is all about minimising attention from the cops. Most true enthusiasts cars are non compliant, too low, too loud, wheels and tyres too big, tint too dark, engines and exhausts that'll fail emission testing etc!

 

[The91kwbeast]

The reality is, compliance isn't the component true enthusiasts are seeking, it's individuality, wow factor and horsepower. Compliance is all about minimising attention from the cops. Most true enthusiasts cars are non compliant, too low, too loud, wheels and tyres too big, tint too dark, engines and exhausts that'll fail emission testing etc!

Lol! Not a good reflection on car enthusiasts if so. It's funny as again you can have all those mods and be legal but there is more money to be made by tuning shops and performance part shops clearly by selling all sorts of crap that instant defects your car.

Can you also imagine being in an accidental and having insurance refuse payout from one or some of your mods... That would keep me up at night worrying!

 

[The91kwbeast]

The loud side of a bimodal is virtually straight pipe through the cannister with minimal muffling capacity. Bimodal open is more a rear muffler bypass that's why they can drone. The electric bimodals in Series 2 are programmed to close at the drone points, they also drone when left permanently open.

Here's a bimodal internals

View attachment 240528

That's pretty interesting thanks. So basically unless it's fully shut (I can only zip tie about 70% shut currently) it's gonna drone.

This also supports my theory that Holden/HSV gave up trying to design a good muffler and just put a band aid via the bi modals on.

Presumably the E1 HSVs that did not have bi modals wouldn't have that issue, but are probably not very loud either?

 

[RevNev]

Lol! Not a good reflection on car enthusiasts if so. It's funny as again you can have all those mods and be legal but there is more money to be made by tuning shops and performance part shops clearly by selling all sorts of crap that instant defects your car.

Can you also imagine being in an accidental and having insurance refuse payout from one or some of your mods... That would keep me up at night worrying!

True car enthusiasts in my 46 years of experience are addicts no different than drug addicts aren't overly concerned with the legality or compliance of the substance they're taking either. In SA for example, you can't have a VF Commodore at the desired ride height, they're too low and will fail a rego inspection. You can't have darker tint than 35 on the front windows where desirable tint starts at 20 and preferably 15's good!. My ute would probably pass a rego inspection for the engine and exhaust but technically doesn't comply with an HSV 340 set up on a MY17 compliance vehicle. HSV 340 compliance ended November 2016. Very difficult in fact to have the desired mods and maintain compliance.

 

[Skylarking]

This also supports my theory that Holden/HSV gave up trying to design a good muffler and just put a band aid via the bi modals on.

Bi modal exhaust systems are controlled by software and with software anything goes… It wouldn’t surprise me if the electronics can determine when test procedures are occurring and thus noise remains within legislated limits but are way over in spirited driving just as the customer likes. And don’t forget some engineering effort as put into the exhaust system the patented hole in the muffler exit pipe (Ballie tip)…

Bi-modal exhausts may ultimately be found to be of a similar cheat to VW who fell neck deep into the poo by using logic to determine test procedures may be occurring and thus ensured pollution stayed within legislated limits while at other times power was the main game…

So, maybe it’s not so much a band aid solution but maybe more a case of complex engineering brought to you by unconscionable management

As is, I often wonder how AMG can be legal as their cars have a ferociously loud bark on gear changes during WOT take offs but are nice and quiet at other times… sort of goes against the intent of noise laws

 

[RevNev]

As is, I often wonder how AMG can be legal as their cars have a ferociously loud bark on gear changes during WOT take offs but are nice and quiet at other times… sort of goes against the intent of noise laws

BMW M cars with bimodal exhausts are ridiculously loud with the valves open. In Sports+ mode, the valves are permanently open on most and drone like crazy. My wife has an X3 M40i SUV, a 3 litre 6 cylinder turbo and I remember on start up in the show room when collecting the car, it sounded like the exhaust had fallen off the turbo. These are stupidly loud on initial start up to the extent that you'd wake the neighbours starting it up in the middle of the night. Although they're quiet with the valves closed, it's a wonder how they comply when a flick of a switch unleashes a noise level that certainly wouldn't meet noise compliance.