Quietest, Cleanest Stage 2 Pipes?

wyatth · 01-01-2020, 04:42 AM

I lust for the midrange torque of a stage 2 setup, but do not want to change the volume/sound of my exhaust setup nor deal with exhaust smell. What’s the quietest, cleanest approach? I would consider a HFC/resonated midpipe (Challenge Sport, Evolve) or TPs + OEM, or anything else. But reviews for every setup indicate noise and smell increases by at least some people. I cannot find a GESi or HJS equipped midpipe for this platform which is disappointing. Am I dreaming? I’ve done my research and am coming up short, damn near considering a SC.

Cheers,

wfdeacon88 · 01-01-2020, 07:42 AM

Test pipes are probably your best bet.. Retaining secondaries keeps a vast majority of the smell down. I barely notice a difference. If you pair TPs with an unmodified OEM exhaust, the noise increase isn't that much. I have rogue resonated test pipes, but with a Corsa, and it's not that loud most of the time.

If you went with a supercharger, you'd have to go catless or at least test pipes/X-pipe with HFC. So that won't prevent you from any smell increases.

TedA · 01-01-2020, 07:51 AM

I have been looking for one of the following 2 set-ups , but haven’t been able to verify the sound levels:
1. Stock primary cats + quad resonated x-pipe + MPE
2. HF (200 CEL) primary cats + stock x-pipe + MPE

Thoughts? (From anyone that has one of those set ups)

wyatth · 01-01-2020, 08:18 AM

I have Eisenmann Sport now and the sound (tone, volume) is perfect for me. If I didn’t have it, then TPs with an OEM muffler would be a good setup. But I can’t see parting with my muffler now.

It’s surprising that the OE secondaries are so efficient since they don’t give up much more power when removed or replaced with single HFCs.

Coming from the E46M world, the Supersprint HJS midpipe was the gold standard. Killed rasp, odorless, and left no power on the table. There just doesn’t seem to be something equivalent for these cars.

While HFCs are recommended for SC setups, they aren’t necessary and many run OEM midpipes with them. Who knows how long they’d last, but I don’t track so extreme heat isn’t a big concern.

wfdeacon88 · 01-01-2020, 09:25 AM

Quote:

Originally Posted by wyatth

I have Eisenmann Sport now and the sound (tone, volume) is perfect for me. If I didn’t have it, then TPs with an OEM muffler would be a good setup. But I can’t see parting with my muffler now.

It’s surprising that the OE secondaries are so efficient since they don’t give up much more power when removed or replaced with single HFCs.

Coming from the E46M world, the Supersprint HJS midpipe was the gold standard. Killed rasp, odorless, and left no power on the table. There just doesn’t seem to be something equivalent for these cars.

While HFCs are recommended for SC setups, they aren’t necessary and many run OEM midpipes with them. Who knows how long they’d last, but I don’t track so extreme heat isn’t a big concern.

I think it's also the position of the OEM secondaries, being further back. I've heard of horror stories of aftermarket X-pipes with HFC in the same place as the Primary OE cats (up front) and in a few cases they melted or clogged and grenaded the engine. I know you have an exhaust already, but TPs plus Corsa is damn near perfect for not being obnoxious but having an incredible, balanced tone. There's a video on YouTube of this setup and it's hard to beat considering the cost is low, stock secondaries and resonators in place. I have resonated test pipes which probably helps also.

EricSMG · 01-01-2020, 10:50 AM

Good post Wyatt. Doesn't the Evolve pipe use HJS or similar cats? That seems to be the highest quality offering today for a catted x pipe. I bet that pipe has a very exotic sound compared to TPs.

However, something that most overlook is the dramatically different midrange torque curve shape afforded by the BW x pipe with its forward mounted x. MotoIQ or someone did some independent dynos and backed up BWs dynos, showing a total elimination of the 4-6k torque dip that every other setup, including stock, seems to have.

That BW torque curve is what we want, but that pipe is catless and there is no other forward mounted x option today to my knowledge. I think there used be another option. I also think Shadow has a BW pipe that he added cats to.

SAMM3Y · 01-01-2020, 11:24 AM

Any cats on a supercharger setup and you're leaving power on the table.

I've tried 5 different x pipes including an evolve style, straight supersprint, a non catted resonated setup and now I'm on an akra. The akra has been my favorite followed by a custom one that had the hfc's in the primary position and quad resonators.

Personally I prefer xpipes with slip flange type connectors like Supersprint/Akra over the 2 bolt style like challenge. The slip type allows adjustability which can be important when pairing handmade different manufacturer exhaust components. The 2 bolt doesn't and looks cheesy and clunky and have gaskets which are potential leak points.

Just my .02

EricSMG · 01-01-2020, 12:37 PM

Ooohh..... the Akra pipe looks nice!^^

That wasn't on my radar for some reason - I think I thought you had to run their entire system but apparently not so. It's a little more expensive than the Evolve pipe but it probably much lighter AND has a front cross-over pipe.

Interesting. Probably not a popular pipe since spendy but looks very premium. Wonder what the torque curve looks like - if no tangible difference over TPs/Evolve pipe then hard to justify the price.

Edit - looks like you DO need their muffler/slip on for this pipe to work. But then I see threads of people using non-Akra X pipes with Akra muffler/slip ons so I'm confused.

ItsGary · 01-01-2020, 02:16 PM

My current setup is Test Pipes + unmodified OEM muffler.

I've been told its still loud from behind but that's only when you get on it. Otherwise its quiet.

wyatth · 01-01-2020, 05:29 PM

Yeah, anything but top shelf cats in the primary position would worry me after SYTShadow’s experience, even though his car is pushed as hard as anybody’s.

Evolve uses a cat made in Australia but I’m not sure what the details are (other than being 200 cell). They said their midpipe sounds more exotic/smoother than TPs but is a little louder (makes sense given the size of OE secondaries). Some reports of smell, but mostly upon cold start. Still my favorite Xpipe, I think. The vibrant cats on the Challenge/RKP Sport pipe are just too small and weak to get my interest, though the pipes sound great.

The Akra pipe is cool but actually a funny design and is best when coupled with an Akra specific tune. Otherwise I think it’s a torque loser.

I’m really tempted to buy the BW catless X pipe and a pair of GESi cats (which they even sell and equip on their header/track midpipe, wtf!) but I don’t want to be a guinea pig on fitment (scraping and pipe clearance and all that). Could become an expensive “oops.” But in theory that setup would be the bee’s knees. They didn’t respond about whether this could be done.

I basically want these combined and made to fit the OEM headers.

https://www.bimmerworld.com/Exhaust/...rs-E9X-M3.html

https://www.bimmerworld.com/Exhaust/...d-Version.html

BlackM3Comp · 01-01-2020, 07:18 PM

I’ve also been disappointed in the x-pipe options. I have an MPE and would like to open up the exhaust more, but stay emissions compliant and not be obnoxiously loud.

wyatth · 01-01-2020, 08:05 PM

Hard to stay emissions compliant while doing anything to the midpipe, depending on where you are.
I think the MPE sounds best and great when left alone. The tone just doesn’t work for me with any change to the factory midpipe.

wyatth · 01-01-2020, 08:44 PM

Also, Supersprint does have an HJS/resonated setup but it’s sold in Section 1/2 pieces like the E46 and adds up to stupid expensive (like €3K!). If I knew how it sounded I may consider it, but for now it’d be another expensive experiment (though it’d fit at least). Curious what the resonator is like on the inside given it’s unusual shape.
The front pipes are also sold as a pair for €700 and one could add GESi cats themselves to save a little overall.

https://www.supersprint.com/ww-en/su...mw-e92-m3.aspx

EricSMG · 01-01-2020, 10:09 PM

Wyatt - we're on exactly the same page RE the BW setup. It's strange that they include cats for their long tube header X pipe variant but NOT for the factory headers. Bizarre.

Good find on the SS - about the same price as the Akra (but the fitment is questionable with non-Akra slip ons).

Essentially, we have:

- SS @ $3k
- Evolve @ 2.2k
- Akra @ $3k (fitment unclear to me)

None of them have a forward X (except Akra does have forward H) and everything else w/cats seems too cheap to be reliable, no?

SAMM3Y · 01-01-2020, 10:18 PM

Supersprint will require modification too, I still have the section you're talking about as well as the straight x pipe for SS. I've often thought about butchering it myself to work with the akra rear and add a couple of resonators for a quieter catless light weight system. The akra x pipe runs a little longer than the stock one for mating up with anything other than an akra rear. Most the weight savings in the akra are in the rear section anyway, so I'd recommend doing the whole system if you're gonna do it. They come up for sale used now and then, check eBay as well as the forums. Expect to pay $3kish plus depending on condition for a used system if you don't wanna shell out stupid $ for a new one.

wyatth · 01-01-2020, 10:18 PM

^ Exactly!
I wonder if a US distributor of Supersprint could work on that pricing (and it was in Euros!). Turner lists it all for $3270. But actually I’m not sure about fitment, looks like the connectors are for installing the SS mufflers to an OEM midpipe. Turner says the SS Section 2 will not fit a non SS muffler. And of course the HJS section 1 canny but cut/clamped to the back half of the OEM Xpipe.

https://www.turnermotorsport.com/p-1...th-resonators/

Also BTW I’m glad to see you back in an E9X from the F80.

Note: to fit Akra midpipes to another muffler, you’d need RKP adapters, which can be hard to find.

Good video showing the effect of test pipes with my Eisenmann Sport:

EricSMG · 01-01-2020, 10:44 PM

I'm not back yet, just lurking. Still have the black M4 in sig. I really like the E9XM... just needs a bit more punch, otherwise perfect M car.

The ESS VT2 595 (great midrange, killer top end) is hard to ignore at $7300 when we're talking about $3k just for an X pipe.... plus a tune. Sheesh... half way there. And so then logic takes over and says that anything more than TPs/Tune is pointless... may as well just go blower. I mean, it's not the money so much as the value.

Ugh, this hobby is annoying sometimes

wyatth · 01-01-2020, 11:16 PM

That’s exactly where I’m at. Love the sound as it is now, but just needs a little more punch. I think power wise I’d actually be content with stage 2 since I’m not looking for so much more. But at these price points, the VT2-595 is awfully tempting (or maybe the G1 when more details come out). I loved the Dinan S3 blower on my E46 but said this one would stay NA for cost/simplicity. But yeah. I also said I wouldn’t mod it much at all. LOL

Ugh.

EricSMG · 01-01-2020, 11:22 PM

4K-7k would be all you'd need 99% of the time and that thing would be so fun. The top end would only be when you had the room to let it go but not needed to have fun.

wyatth · 01-01-2020, 11:30 PM

Exactly, we still speak the same language after all these years.

This car doesn’t need that top end boost, but it sure would be fun when you could get into it. But that 4-7K midrange is so flat and juicy.

I actually like the curve of the G1 a little more (second plot). I’ll try to keep this from becoming another SC thread, though that temptation says something.

EricSMG · 01-01-2020, 11:40 PM

Haha, yep, we are who we are. The G1 is a little fatter it seems. More thrilling shape than the S55 even though the output is much less (midrange). The curves above continuously climb which surely feels amazing on the road.

wyatth · 01-02-2020, 05:27 AM

S55 is certainly a beast of a powerplant but tbh it’s delivery does nothing for me. I like the NA delivery and ~8500 crescendo so much more (not to mention the sound). The G1 graph is about as sexy as it gets IMO. For the same reason the Harrop SC doesn’t interest me as much, even though it too would be faster in 99% of situations. I don’t want to really change the torque curve, just lift and flatten it a bit (and if it increases slightly like the G1, that’s just divine).

The Challenge Street pipe goes in and out of interest to me. On one hand, the only 2 dynos I’ve seen have shown modest gains throughout the range (10lb-ft) and in theory it should change the volume/tone/smell the least since it retains the fat primaries and a pair of resonators. I’d be okay with that, if it’s true. And the primaries should be better than the secondaries at cutting down volume and rasp, so I’d think it’d be quieter/cleaner than a test pipe setup. Yet the anecdotal and physics talk around them is that they shouldn’t/don’t add any measurable gains and instead add quiet a bit of volume and rasp. So, beats me!

01-01-2020, 04:42 AM	#1
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	Quietest, Cleanest Stage 2 Pipes? I lust for the midrange torque of a stage 2 setup, but do not want to change the volume/sound of my exhaust setup nor deal with exhaust smell. What’s the quietest, cleanest approach? I would consider a HFC/resonated midpipe (Challenge Sport, Evolve) or TPs + OEM, or anything else. But reviews for every setup indicate noise and smell increases by at least some people. I cannot find a GESi or HJS equipped midpipe for this platform which is disappointing. Am I dreaming? I’ve done my research and am coming up short, damn near considering a SC. Cheers, Last edited by wyatth; 01-01-2020 at 04:49 AM..
	Appreciate 1 //steve\\1074.00 Tweet Quote

01-01-2020, 07:42 AM	#2
wfdeacon88 Major 1105 Rep 1,389 Posts Drives: E90 M3 Join Date: Sep 2018 Location: Triad, NC iTrader: (0)	Test pipes are probably your best bet.. Retaining secondaries keeps a vast majority of the smell down. I barely notice a difference. If you pair TPs with an unmodified OEM exhaust, the noise increase isn't that much. I have rogue resonated test pipes, but with a Corsa, and it's not that loud most of the time. If you went with a supercharger, you'd have to go catless or at least test pipes/X-pipe with HFC. So that won't prevent you from any smell increases.
	Appreciate 0 Quote

01-01-2020, 07:51 AM	#3
TedA Private First Class 48 Rep 177 Posts Drives: 2012 E92 M3 ZCP Mineral White Join Date: May 2014 Location: Upstate NY iTrader: (0)	I have been looking for one of the following 2 set-ups , but haven’t been able to verify the sound levels: 1. Stock primary cats + quad resonated x-pipe + MPE 2. HF (200 CEL) primary cats + stock x-pipe + MPE Thoughts? (From anyone that has one of those set ups)
	Appreciate 0 Quote

01-01-2020, 08:18 AM	#4
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	I have Eisenmann Sport now and the sound (tone, volume) is perfect for me. If I didn’t have it, then TPs with an OEM muffler would be a good setup. But I can’t see parting with my muffler now. It’s surprising that the OE secondaries are so efficient since they don’t give up much more power when removed or replaced with single HFCs. Coming from the E46M world, the Supersprint HJS midpipe was the gold standard. Killed rasp, odorless, and left no power on the table. There just doesn’t seem to be something equivalent for these cars. While HFCs are recommended for SC setups, they aren’t necessary and many run OEM midpipes with them. Who knows how long they’d last, but I don’t track so extreme heat isn’t a big concern.
	Appreciate 0 Quote

01-01-2020, 10:50 AM	#6
EricSMG Captain 576 Rep 829 Posts Drives: E46 M3 Join Date: Mar 2016 Location: San Diego iTrader: (0)	Good post Wyatt. Doesn't the Evolve pipe use HJS or similar cats? That seems to be the highest quality offering today for a catted x pipe. I bet that pipe has a very exotic sound compared to TPs. However, something that most overlook is the dramatically different midrange torque curve shape afforded by the BW x pipe with its forward mounted x. MotoIQ or someone did some independent dynos and backed up BWs dynos, showing a total elimination of the 4-6k torque dip that every other setup, including stock, seems to have. That BW torque curve is what we want, but that pipe is catless and there is no other forward mounted x option today to my knowledge. I think there used be another option. I also think Shadow has a BW pipe that he added cats to. __________________ Current - 2022 540XI M Sport, BSM/Black Sold - many M3s and an M4
	Appreciate 0 Quote

01-01-2020, 11:24 AM	#7
SAMM3Y Colonel 3085 Rep 2,747 Posts Drives: 2008 m3 Join Date: Feb 2018 Location: NorCal iTrader: (2)	Any cats on a supercharger setup and you're leaving power on the table. I've tried 5 different x pipes including an evolve style, straight supersprint, a non catted resonated setup and now I'm on an akra. The akra has been my favorite followed by a custom one that had the hfc's in the primary position and quad resonators. Personally I prefer xpipes with slip flange type connectors like Supersprint/Akra over the 2 bolt style like challenge. The slip type allows adjustability which can be important when pairing handmade different manufacturer exhaust components. The 2 bolt doesn't and looks cheesy and clunky and have gaskets which are potential leak points. Just my .02 __________________ 9ers
	Appreciate 1 E92M3GT101.00 Quote

01-01-2020, 12:37 PM	#8
EricSMG Captain 576 Rep 829 Posts Drives: E46 M3 Join Date: Mar 2016 Location: San Diego iTrader: (0)	Ooohh..... the Akra pipe looks nice!^^ That wasn't on my radar for some reason - I think I thought you had to run their entire system but apparently not so. It's a little more expensive than the Evolve pipe but it probably much lighter AND has a front cross-over pipe. Interesting. Probably not a popular pipe since spendy but looks very premium. Wonder what the torque *curve* looks like - if no tangible difference over TPs/Evolve pipe then hard to justify the price. Edit - looks like you DO need their muffler/slip on for this pipe to work. But then I see threads of people using non-Akra X pipes with Akra muffler/slip ons so I'm confused. __________________ Current - 2022 540XI M Sport, BSM/Black Sold - many M3s and an M4 Last edited by EricSMG; 01-01-2020 at 12:49 PM..
	Appreciate 0 Quote

01-01-2020, 02:16 PM	#9
ItsGary Colonel 1458 Rep 2,336 Posts Drives: 2009 E90 M3 Join Date: Oct 2017 Location: Vancouver iTrader: (0)	My current setup is Test Pipes + unmodified OEM muffler. I've been told its still loud from behind but that's only when you get on it. Otherwise its quiet. __________________ '09 ///M3 Sedan - Jerez Black/Fox Red Ext. '09 335i Coupe - Alpine White/Black - SOLD
	Appreciate 0 Quote

01-01-2020, 05:29 PM	#10
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	Yeah, anything but top shelf cats in the primary position would worry me after SYTShadow’s experience, even though his car is pushed as hard as anybody’s. Evolve uses a cat made in Australia but I’m not sure what the details are (other than being 200 cell). They said their midpipe sounds more exotic/smoother than TPs but is a little louder (makes sense given the size of OE secondaries). Some reports of smell, but mostly upon cold start. Still my favorite Xpipe, I think. The vibrant cats on the Challenge/RKP Sport pipe are just too small and weak to get my interest, though the pipes sound great. The Akra pipe is cool but actually a funny design and is best when coupled with an Akra specific tune. Otherwise I think it’s a torque loser. I’m really tempted to buy the BW catless X pipe and a pair of GESi cats (which they even sell and equip on their header/track midpipe, wtf!) but I don’t want to be a guinea pig on fitment (scraping and pipe clearance and all that). Could become an expensive “oops.” But in theory that setup would be the bee’s knees. They didn’t respond about whether this could be done. I basically want these combined and made to fit the OEM headers. https://www.bimmerworld.com/Exhaust/...rs-E9X-M3.html https://www.bimmerworld.com/Exhaust/...d-Version.html Last edited by wyatth; 01-01-2020 at 09:50 PM..
	Appreciate 0 Quote

01-01-2020, 07:18 PM	#11
BlackM3Comp New Member 8 Rep 19 Posts Drives: 2012 BMW M3 Join Date: Dec 2019 Location: CT iTrader: (0)	I’ve also been disappointed in the x-pipe options. I have an MPE and would like to open up the exhaust more, but stay emissions compliant and not be obnoxiously loud.
	Appreciate 0 Quote

01-01-2020, 08:05 PM	#12
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	Hard to stay emissions compliant while doing anything to the midpipe, depending on where you are. I think the MPE sounds best and great when left alone. The tone just doesn’t work for me with any change to the factory midpipe.
	Appreciate 1 dparm3849.50 Quote

01-01-2020, 08:44 PM	#13
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	Also, Supersprint does have an HJS/resonated setup but it’s sold in Section 1/2 pieces like the E46 and adds up to stupid expensive (like €3K!). If I knew how it sounded I may consider it, but for now it’d be another expensive experiment (though it’d fit at least). Curious what the resonator is like on the inside given it’s unusual shape. The front pipes are also sold as a pair for €700 and one could add GESi cats themselves to save a little overall. https://www.supersprint.com/ww-en/su...mw-e92-m3.aspx
	Appreciate 0 Quote

01-01-2020, 10:09 PM	#14
EricSMG Captain 576 Rep 829 Posts Drives: E46 M3 Join Date: Mar 2016 Location: San Diego iTrader: (0)	Wyatt - we're on exactly the same page RE the BW setup. It's strange that they include cats for their long tube header X pipe variant but NOT for the factory headers. Bizarre. Good find on the SS - about the same price as the Akra (but the fitment is questionable with non-Akra slip ons). Essentially, we have: - SS @ $3k - Evolve @ 2.2k - Akra @ $3k (fitment unclear to me) None of them have a forward X (except Akra does have forward H) and everything else w/cats seems too cheap to be reliable, no? __________________ Current - 2022 540XI M Sport, BSM/Black Sold - many M3s and an M4
	Appreciate 0 Quote

01-01-2020, 10:18 PM	#15
SAMM3Y Colonel 3085 Rep 2,747 Posts Drives: 2008 m3 Join Date: Feb 2018 Location: NorCal iTrader: (2)	Supersprint will require modification too, I still have the section you're talking about as well as the straight x pipe for SS. I've often thought about butchering it myself to work with the akra rear and add a couple of resonators for a quieter catless light weight system. The akra x pipe runs a little longer than the stock one for mating up with anything other than an akra rear. Most the weight savings in the akra are in the rear section anyway, so I'd recommend doing the whole system if you're gonna do it. They come up for sale used now and then, check eBay as well as the forums. Expect to pay $3kish plus depending on condition for a used system if you don't wanna shell out stupid $ for a new one. __________________ 9ers
	Appreciate 0 Quote

01-01-2020, 10:44 PM	#17
EricSMG Captain 576 Rep 829 Posts Drives: E46 M3 Join Date: Mar 2016 Location: San Diego iTrader: (0)	I'm not back yet, just lurking. Still have the black M4 in sig. I really like the E9XM... just needs a bit more punch, otherwise perfect M car. The ESS VT2 595 (great midrange, killer top end) is hard to ignore at $7300 when we're talking about $3k just for an X pipe.... plus a tune. Sheesh... half way there. And so then logic takes over and says that anything more than TPs/Tune is pointless... may as well just go blower. I mean, it's not the money so much as the value. Ugh, this hobby is annoying sometimes __________________ Current - 2022 540XI M Sport, BSM/Black Sold - many M3s and an M4
	Appreciate 0 Quote

01-01-2020, 11:16 PM	#18
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	That’s exactly where I’m at. Love the sound as it is now, but just needs a little more punch. I think power wise I’d actually be content with stage 2 since I’m not looking for so much more. But at these price points, the VT2-595 is awfully tempting (or maybe the G1 when more details come out). I loved the Dinan S3 blower on my E46 but said this one would stay NA for cost/simplicity. But yeah. I also said I wouldn’t mod it much at all. LOL Ugh.
	Appreciate 0 Quote

01-01-2020, 11:22 PM	#19
EricSMG Captain 576 Rep 829 Posts Drives: E46 M3 Join Date: Mar 2016 Location: San Diego iTrader: (0)	4K-7k would be all you'd need 99% of the time and that thing would be so fun. The top end would only be when you had the room to let it go but not needed to have fun. __________________ Current - 2022 540XI M Sport, BSM/Black Sold - many M3s and an M4
	Appreciate 0 Quote

01-01-2020, 11:30 PM	#20
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	Exactly, we still speak the same language after all these years. This car doesn’t need that top end boost, but it sure would be fun when you could get into it. But that 4-7K midrange is so flat and juicy. I actually like the curve of the G1 a little more (second plot). I’ll try to keep this from becoming another SC thread, though that temptation says something.
	Appreciate 0 Quote

01-01-2020, 11:40 PM	#21
EricSMG Captain 576 Rep 829 Posts Drives: E46 M3 Join Date: Mar 2016 Location: San Diego iTrader: (0)	Haha, yep, we are who we are. The G1 is a little fatter it seems. More thrilling shape than the S55 even though the output is much less (midrange). The curves above continuously climb which surely feels amazing on the road. __________________ Current - 2022 540XI M Sport, BSM/Black Sold - many M3s and an M4
	Appreciate 0 Quote

01-02-2020, 05:27 AM	#22
wyatth Colonel 3549 Rep 2,824 Posts Drives: E90 ZCP Join Date: Dec 2007 Location: Bay Area iTrader: (0)	S55 is certainly a beast of a powerplant but tbh it’s delivery does nothing for me. I like the NA delivery and ~8500 crescendo so much more (not to mention the sound). The G1 graph is about as sexy as it gets IMO. For the same reason the Harrop SC doesn’t interest me as much, even though it too would be faster in 99% of situations. I don’t want to really change the torque curve, just lift and flatten it a bit (and if it increases slightly like the G1, that’s just divine). The Challenge Street pipe goes in and out of interest to me. On one hand, the only 2 dynos I’ve seen have shown modest gains throughout the range (10lb-ft) and in theory it should change the volume/tone/smell the least since it retains the fat primaries and a pair of resonators. I’d be okay with that, if it’s true. And the primaries should be better than the secondaries at cutting down volume and rasp, so I’d think it’d be quieter/cleaner than a test pipe setup. Yet the anecdotal and physics talk around them is that they shouldn’t/don’t add any measurable gains and instead add quiet a bit of volume and rasp. So, beats me!
	Appreciate 0 Quote