Z4M - SuperSprint X-pipe, Powerloops and Eventuri (dynos and data logging)

MBan · 10-22-2021, 10:43 PM

Hi all,

After living with the car for a while with Supersprint V1 stepped headers, S-pipe with HJS cats and a Severn tune, I started considering trying to deepen the exhaust note and enhance the intake sound.

I liked the sound clips I had heard of the Supersprint Powerloops and I figured I may as well get the X-pipe at the same time. I honestly wasn’t expecting to keep the X-pipe on because I had heard it increases rasp, which I’m not a fan of, but I wanted to have the option to ‘tune’ the exhaust sound through combining different sections. Supersprint sells two variations of the X-pipe: one with a slip joint for joining straight to the Powerloop mufflers (which also have a slip joint) and one with a flange for joining to the standard rear mufflers. So, I ordered the X-pipe with flanges at both ends, the Powerloop mufflers and the adaptor that adds a flange to the mufflers. I also replaced all the exhaust hangers and hardware.

X-pipe with flanges at both ends – P/N 789833
Powerloop mufflers – P/N 789836 (L), 789806 (R)
Flange adaptor for rear mufflers – P/N 044933

I also ordered an Eventuri intake. The Gruppe M was an option too, but I had seen some dynos online that appeared to indicate that the Eventuri may add a few hp. I wasn’t keen on the red scoop for the Eventuri, so I painted it black (not shown in the picture below).

MBan · 10-22-2021, 10:44 PM

Even I could have installed the Eventuri, but to satisfy my curiosity regarding it adding power, I asked my workshop to fit it and the exhaust and run it up on the dyno after fitting the intake and then again after fitting the exhaust. Unfortunately, they did baseline runs and then a set of runs with everything installed, so I will never know how much each part contributed to the gains.

MBan · 10-22-2021, 10:46 PM

There looks to be a gain from one or more of these parts (approximately 3%). The shop didn’t add my stock run from a while ago to the printout but below are Excel charts I’ve been using to compare various dyno runs. All up, the car is now making about 12% more peak power than stock. Peak torque (vs stock) is only about 3% up, but the gains at rpm below where the peak occurs are between 6 and 10% and the gains from just over 5,000 rpm to red line are between 10 and 20%.

MBan · 10-22-2021, 10:47 PM

Driving the car back home I had some reservations about the exhaust. It was a bit boomy, droned and rasped. At idle it sounded good and above 5,000rpm it sounded great but in between not so much. However, over a few heat cycles and couple of hundred km, the boominess toned down and the rasp decreased a lot. The drone was still substantial from 1,800 to 2,200 rpm, so I started driving around that rpm range. A few months later I had the stock X-pipe swapped back in and on balance this is the best setup for me. I do miss the complex sound the SS X-pipe added. It was a metallic, guttural ‘zing’, overlaid by the Eventuri. When the exhaust shop was re-fitting the stock X-pipe they noticed that the fastener for one of the slip joints between the header and section 1 had snapped off. They commented that the weld for the fastener looks pretty weak. They fitted a regular exhaust clamp (which looks average) as there wasn’t a good way to fix the existing fitting. A bit disappointing all ‘round. This wasn’t the shop that installed the headers by the way.

While I had all the SS exhaust parts fitted, I logged some third gear runs. The gains were more significant than the 6hp gain on the dyno would indicate (**based on what may be a totally flawed method of calculating distance traveled from rpm change over time**). After 10 second full throttle acceleration in third gear from 2,000 rpm, the car traveled 3m further in comparison to before fitting the Eventuri and SS X-pipe and Powerloop mufflers. For reference, headers, cat’d section 1 and a tune resulted in the car traveling 7m further than stock under the same conditions.

Next up for the car is a full suspension refresh and (probably) KW V3s.

wdb · 10-23-2021, 11:51 AM

Great information, thanks for putting this together and sharing!

3002 tii · 10-24-2021, 10:41 PM

Nice write up. I ended up going Euro headers, high flow cat, stock X and SS Powerloops. The only thing keeping me from going aftermarket X was drone as well. Really curious how much the intake alone adds to top end. After hearing so many horror stories with replica csl manifolds, told myself most I’d do is Eventuri or Gruppe M.

MBan · 10-25-2021, 04:29 AM

Quote:

Originally Posted by 3002 tii

Nice write up. I ended up going Euro headers, high flow cat, stock X and SS Powerloops. The only thing keeping me from going aftermarket X was drone as well. Really curious how much the intake alone adds to top end. After hearing so many horror stories with replica csl manifolds, told myself most I’d do is Eventuri or Gruppe M.

I think your exhaust setup is one of the best for our cars and leaves audio bandwidth for the intake.

My car is in storage at the moment (garage failure…) but when I get it out I’ll do a bit more data logging. That will delete the SS x-pipe from the equation but still won’t be able to isolate the gains from the intake from the Powerloops and no dyno either.

I have read about eggman’s problems with the Evolve intake. Have there been others? I haven’t ruled out a CSL intake yet but it would be Karbonius at a minimum and preferably OE.

maupineda · 10-25-2021, 12:01 PM

I have the Karb box and it has hold well, but I can see it not lasting forever. They even advised to send it for a refresh and sealing of bungs, etc.

I am even considering an eventuri as a back up plan if needed.

Consider that some functions are lost with the CSL intake approach, such as cruise control and ability to run VANOS test with ISTA+

MBan · 10-25-2021, 04:48 PM

Quote:

Originally Posted by maupineda

I have the Karb box and it has hold well, but I can see it not lasting forever. They even advised to send it for a refresh and sealing of bungs, etc.

I am even considering an eventuri as a back up plan if needed.

Consider that some functions are lost with the CSL intake approach, such as cruise control and ability to run VANOS test with ISTA+

Thanks, maupineda - those are a couple of limitations of the CSL-style airbox that I wasn't aware of. Every time I start to swing back towards a CSL intake, reality hits again.

MBan · 10-25-2021, 05:42 PM

Oh, one thing I would add about the final Excel ‘dyno’ graph is that it plots the most recent run against the very first run, raw. Each time I made modifications I did a new baseline run, which was essentially a re-run from the previous modifications. I noticed that the baseline run generally didn’t line up perfectly with the run from the previous dyno session, so it’s not going to be accurate to make direct comparisons and probably a bit risky to calculate gains from that comparison. If I add the per cent gains at each stage (each with a new baseline) the gains are actually larger, particularly through the lower revs. I may try to plot that next weekend.

10-22-2021, 10:43 PM	#1
MBan First Lieutenant 166 Rep 358 Posts Drives: BMW Z4M Coupe Join Date: Jul 2014 Location: Perth, Western Australia iTrader: (0)	Z4M - SuperSprint X-pipe, Powerloops and Eventuri (dynos and data logging) Hi all, After living with the car for a while with Supersprint V1 stepped headers, S-pipe with HJS cats and a Severn tune, I started considering trying to deepen the exhaust note and enhance the intake sound. I liked the sound clips I had heard of the Supersprint Powerloops and I figured I may as well get the X-pipe at the same time. I honestly wasn’t expecting to keep the X-pipe on because I had heard it increases rasp, which I’m not a fan of, but I wanted to have the option to ‘tune’ the exhaust sound through combining different sections. Supersprint sells two variations of the X-pipe: one with a slip joint for joining straight to the Powerloop mufflers (which also have a slip joint) and one with a flange for joining to the standard rear mufflers. So, I ordered the X-pipe with flanges at both ends, the Powerloop mufflers and the adaptor that adds a flange to the mufflers. I also replaced all the exhaust hangers and hardware. X-pipe with flanges at both ends – P/N 789833 Powerloop mufflers – P/N 789836 (L), 789806 (R) Flange adaptor for rear mufflers – P/N 044933 I also ordered an Eventuri intake. The Gruppe M was an option too, but I had seen some dynos online that appeared to indicate that the Eventuri may add a few hp. I wasn’t keen on the red scoop for the Eventuri, so I painted it black (not shown in the picture below). Attached Images
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10-22-2021, 10:44 PM	#2
MBan First Lieutenant 166 Rep 358 Posts Drives: BMW Z4M Coupe Join Date: Jul 2014 Location: Perth, Western Australia iTrader: (0)	Even I could have installed the Eventuri, but to satisfy my curiosity regarding it adding power, I asked my workshop to fit it and the exhaust and run it up on the dyno after fitting the intake and then again after fitting the exhaust. Unfortunately, they did baseline runs and then a set of runs with everything installed, so I will never know how much each part contributed to the gains. Attached Images
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10-22-2021, 10:46 PM	#3
MBan First Lieutenant 166 Rep 358 Posts Drives: BMW Z4M Coupe Join Date: Jul 2014 Location: Perth, Western Australia iTrader: (0)	There looks to be a gain from one or more of these parts (approximately 3%). The shop didn’t add my stock run from a while ago to the printout but below are Excel charts I’ve been using to compare various dyno runs. All up, the car is now making about 12% more peak power than stock. Peak torque (vs stock) is only about 3% up, but the gains at rpm below where the peak occurs are between 6 and 10% and the gains from just over 5,000 rpm to red line are between 10 and 20%. Attached Images
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10-22-2021, 10:47 PM	#4
MBan First Lieutenant 166 Rep 358 Posts Drives: BMW Z4M Coupe Join Date: Jul 2014 Location: Perth, Western Australia iTrader: (0)	Driving the car back home I had some reservations about the exhaust. It was a bit boomy, droned and rasped. At idle it sounded good and above 5,000rpm it sounded great but in between not so much. However, over a few heat cycles and couple of hundred km, the boominess toned down and the rasp decreased a lot. The drone was still substantial from 1,800 to 2,200 rpm, so I started driving around that rpm range. A few months later I had the stock X-pipe swapped back in and on balance this is the best setup for me. I do miss the complex sound the SS X-pipe added. It was a metallic, guttural ‘zing’, overlaid by the Eventuri. When the exhaust shop was re-fitting the stock X-pipe they noticed that the fastener for one of the slip joints between the header and section 1 had snapped off. They commented that the weld for the fastener looks pretty weak. They fitted a regular exhaust clamp (which looks average) as there wasn’t a good way to fix the existing fitting. A bit disappointing all ‘round. This wasn’t the shop that installed the headers by the way. While I had all the SS exhaust parts fitted, I logged some third gear runs. The gains were more significant than the 6hp gain on the dyno would indicate (based on what may be a totally flawed method of calculating distance traveled from rpm change over time). After 10 second full throttle acceleration in third gear from 2,000 rpm, the car traveled 3m further in comparison to before fitting the Eventuri and SS X-pipe and Powerloop mufflers. For reference, headers, cat’d section 1 and a tune resulted in the car traveling 7m further than stock under the same conditions. Next up for the car is a full suspension refresh and (probably) KW V3s.
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10-23-2021, 11:51 AM	#5
wdb dances with roads 4717 Rep 4,094 Posts Drives: '07 E86, '02 996, '95 Seven Join Date: Jul 2015 Location: the perimeter iTrader: (4)	Great information, thanks for putting this together and sharing!
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10-24-2021, 10:41 PM	#6
3002 tii Lieutenant General 2280 Rep 12,565 Posts Drives: Z4 M, X5, GX460 Join Date: Apr 2008 Location: CT iTrader: (99) Garage List F15 X5 xDrive35i [8.75] E86 Z4 M [10.00] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.50] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [9.20]	Nice write up. I ended up going Euro headers, high flow cat, stock X and SS Powerloops. The only thing keeping me from going aftermarket X was drone as well. Really curious how much the intake alone adds to top end. After hearing so many horror stories with replica csl manifolds, told myself most I’d do is Eventuri or Gruppe M. __________________ Follow for latest mods
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10-25-2021, 12:01 PM	#8
maupineda Captain 456 Rep 973 Posts Drives: E86 Z4MC Join Date: Jul 2012 Location: Detroit, MI iTrader: (3)	I have the Karb box and it has hold well, but I can see it not lasting forever. They even advised to send it for a refresh and sealing of bungs, etc. I am even considering an eventuri as a back up plan if needed. Consider that some functions are lost with the CSL intake approach, such as cruise control and ability to run VANOS test with ISTA+
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10-25-2021, 05:42 PM	#10
MBan First Lieutenant 166 Rep 358 Posts Drives: BMW Z4M Coupe Join Date: Jul 2014 Location: Perth, Western Australia iTrader: (0)	Oh, one thing I would add about the final Excel ‘dyno’ graph is that it plots the most recent run against the very first run, raw. Each time I made modifications I did a new baseline run, which was essentially a re-run from the previous modifications. I noticed that the baseline run generally didn’t line up perfectly with the run from the previous dyno session, so it’s not going to be accurate to make direct comparisons and probably a bit risky to calculate gains from that comparison. If I add the per cent gains at each stage (each with a new baseline) the gains are actually larger, particularly through the lower revs. I may try to plot that next weekend.
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