performance exhaust system advice??

[admanthebadman]

I'm looking to change the standard exhaust on my m roadster for a performance system with a much 'meatier' sound, but don't want a cheap poorly made system from a bunch of kids a RSR. Anyone done this already or can give me any advice on where to go?

Cheers
Adam 8)

[r80ter]

I'm looking to change the standard exhaust on my m roadster for a performance system with a much 'meatier' sound, but don't want a cheap poorly made system from a bunch of kids a RSR. Anyone done this already or can give me any advice on where to go?

Cheers
Adam 8)

Eisenmann dude. I have 76mm ones on mine and it sounds awesome!!!!

[exdos]

I am presently working on a relatively simple modification of the OEM exhausts, that will hopefully give tunabilty for both performance and sound.

I'm sure that a simple replacement of the exhaust tips will increase the noise if that's all you're after, because although the tips are 65mm external diameter, the actual internal bore is actually 35mm only.

A local performance exhaust specialist would be able to do such a mod for you relatively cheaply.

[maahny]

Supersprint for performance and sound or Eisenmann for louder sound as you can spec sound levels. I can supply both of them and they are available through the XS Performance forum.

[pies]

Hmmm, so the choice is more power from Supersprint or an awesome sound from the Eisenmann's?? :?:

Tricky one that. :?

When you say the Eisenmann's are louder, do they just give a more of a bass rumble that upsets the neighbours at 6am or is it more of a hard edged shriek when you're pushing on? :shock:

I've read that the 73mm Eisenmann's are the way to go, but if the Supersprint ones also give more power as well as the noise then surely that's the best compromise :?:

Oh dear, only one week in and i can tell i'm going to spend a fortune on this car :D

[Ivo]

my Eisenmann (custom 76 mm, hard chromed tips) sound like this;

http://www.digitalediensten.nl/mzc/MOV00014.mov

http://www.digitalediensten.nl/mzc/MOV00015.mov

bit dirty in the clips, but nice and shiny when washed :wink:

(only up to 4 k rpm)

[pies]

Cheers Ivo - sounds good.

ok, have to admit to being a bit confused about Eisenmanns.

according to eisenmann.co.uk the choice of tip is 73mm or 80mm.

r80ter and Ivo mention 76mm tips.

XS performance has 70mm or 83mm available!

Plus on zroadster.net i've read that there's different sound levels from +0db to +12db :shock:

can someone make sense of all this? :?:

[maahny]

These are the figures from the Supersprint website. Unfortunately a lot of posts have been deleted but R.Hellenbrand who posts on here and works for Mac Motoren tested these out and got similar power gains as claimed by Supersprint. If IIRC their tests showed Eisenmann losing 1 or 2 BHP!

OEM
Claimed data:
Horsepower 321 Hp at 7400 rev/min
Torque 350 Nm at 3250 rev/min
Actual data:
Horsepower 299.2 Hp at 6760 rev/min
Torque 330 Nm at 3910 rev/min
Supersprint:
- No Kat 786002
- Rear exhaust Ri. + Le. 786066 + 786086
Actual data: Horsepower 312.8 Hp at 6670 rev/min
Torque 348 Nm at 4690 rev/min

Supersprint:
- Rear exhaust Ri. + Le. 786066 + 786086
Actual data: Horsepower 310.0 Hp at 6680 rev/min
Torque 338.5 Nm at 5830 rev/min

[maahny]

Pies

The Eisenmanns come in 3 different sound levels Factory Sport, Road Sport or Race. The sound is specified when the exhaust is ordered from Eisenmann. We can get the 76mm ones too. Just haven't put them on the website.

[admanthebadman]

Thanks for the advice. Ivo is that a full system youv got or is it just the rear boxes?? Also would getting a full system likely to fail an mot??

Peace
Adam

[Ivo]

Thanks for the advice. Ivo is that a full system youv got or is it just the rear boxes?? Also would getting a full system likely to fail an mot??

Peace
Adam

I have the rear boxes only, mainly for the looks & sound. Performance is sufficient already, methinks :oops:

As I'm living in Holland, MOT is not my issue :wink:

I chose the 76 mm, as 73 looks TO standard and 80/83 will melt the bumper (or you have to cut out). Also the bigger ones have a sort of maze/grille inside the tips :cry: . Make sure you ask for the hard-chromed tips, otherwise they'll end up bleuish after some time :idea:

[pies]

Thanks Ivo for the explanation. :)

maahny, how much are the 76mm hard chrome ones that Ivo's talking about? :?:

[M5Pilot]

The Eisenmann's from memory need to be welded on.

The Supersprints fit directly to the standard setup and are a beautiful fit.

I took some pics of Khooni's car while it was having its 3.64 diff fitted and the Supersprints look very nice.

Eisenmann are IMHO more about styling and getting a certain noise with no performance gains at all.

Bexley's tested an Eisenmann exhaust out on a 3.2 EVo M3 and there was no difference in power.

I'd definately say go Supersprint if you like the tailpipe design.

[pies]

Anyone know if the supersprint upswept 'DTM' pipes fit with no mods to the rear bumper?
:?:

[AJL]

Anyone know if the supersprint upswept 'DTM' pipes fit with no mods to the rear bumper?
:?:

Yep! no mods required

Fitted my Hamann ones yesterday :D

[AJL]

Here is a quick pic of the DTM pipes not a very good one mind!


http://img.photobucket.com/albums/v507/AJL007/DSC00105.jpg

[pies]

Well, i'm halfway to having a Supersprint DTM exhaust on my car :cry:

Demon Tweeks were having a clearout on ebay and i picked up the right-hand box for £35!! Bargain i thought.....

was going to buy the other half at normal retail and, hey presto, a nearly half price Supersprint exhaust would be mine....

Now i've found out that Supersprint have discontinued these so i can't get the left hand side! :oops:

Anybody think of a company that might have them in stock? :?:
I've tried a few places but the message keeps coming back that's its discotinued and unavailable.

D'oh.

[dalecan]

Prospeed exhaust all the way. Lifetime guarantee, stainless steel all for £450. A few people on here with various aftermarket exhausts have commented on how good mine sounds. Nice rumble on tickover.

[AJL]

Well, i'm halfway to having a Supersprint DTM exhaust on my car :cry:

Demon Tweeks were having a clearout on ebay and i picked up the right-hand box for £35!! Bargain i thought.....

was going to buy the other half at normal retail and, hey presto, a nearly half price Supersprint exhaust would be mine....

Now i've found out that Supersprint have discontinued these so i can't get the left hand side! :oops:

Anybody think of a company that might have them in stock? :?:
I've tried a few places but the message keeps coming back that's its discotinued and unavailable.

D'oh.

I saw that one on ebay!

Can you not try speaking to supersprint direct or something maybe they have a few left somewhere?

[exdos]

This morning I cut open an OEM rear silencer.

I think that it is possible to make the OEM silencers tunable for both performance and sound. I will report back when I've finished my mod and trialled it. The mod will be the most cost-effective way of achieving the result you're after.

[pies]

Spoke to Supersprint's UK distributor and they've asked the factory....no chance of getting the other half of the DTM exhaust anywhere! :cry:

Oh well, anybody want a spare right-hand SS DTM exhaust?

[THE ANIMAL]

Get a straight rear silencer from supersprint and get a specialist to cut the ends of and weld on some new dtm tail pipes job done.

[nemesis]

I bought the Hartge full system some years ago, cost about £2300 from birds and has been awesome I love it and think it looks and sounds great

[ever88]

has anyone 100% simply tried just removing the cats on a standard system and felt the benefit or better still seen the benefit on a rolling road before and after.

cats look very restrictive when you look through them but engines are designed to have some back pressure from exhaust system.

anyone got any sensible opinions here.

[exdos]

ever88,

Read this thread: http://www.z3mcoupe.com/forum2/viewtopic.php?t=4638

The car sounds like a CSL and certainly feels a lot more responsive.

[Lee]

No welding required for eissenmanns :!: probably the best sounding exhaust for the z3mc but only proven gains is supersprint

[ever88]

hi and thanks for your input on the exhaust mod.

still uncertain I'm afraid!

I would give you 10 out of 10 for industrious effort but without wishing to sound like a smart ass when I don't have the answer myself I teach high level physics but the result I'm looking for is only ever best when you measure before and after.

comparing fuel consumption is not accurate I'm afraid.

making your mods to the rear exhausts defiantly 100% improves the flow through them I have no question of that as you can logically see the route the standard exhaust gasses have to take but if the back pressure on the system is lower then the charge filling on inlet is able to sneak down exhaust during valve overlap so this may account for deterioration in fuel consumption.

This may or may not be significant. again it has to do with how the engine naturally breathes
the worst case scenario would be that it does and you loose low down grunt because your not burning this fuel but reap the rewards higher in the rev range when flow of gasses is large anyhow and your flow through becomes more important.

Motor bikes are the worst for this. they are very vulnerable to incorrect exhaust system setups give how short they have to travel. getting the harmonics is problem here.

Another point someone also mention was that the cats restrict the flow anyhow so the gains of improving things further down the system would not improve things a great deal. You can test this principle using a simple water hose. turn it on with a length layed down and stand on the pipe near to the tap to reduce flow. standing on it further down doesn't reduce the flow much at all.

If you have the revs above 3000 much of the time as you mention I think your mod would largely improve things but for me I only put foot down occasionally and think I would be put off by poor fuel consumption and reduced low down power if that is it was effected.

I hope I have not bored you with a lesson as I'm much in favor of people whom try things and give it a go. I'm also not saying I'm right and your not. without the figures it's all subjective.

I'm being very diplomatic here as some can get a bit hot under collar when people pass knowledge on. I hope you see me comments as useful for you to continue with your trial and error approach.

hats off.

cheers
Paul Razz

[exdos]

Paul,

You sent me the posting above as a PM and I replied to you in a PM. Having replied to you, I'm now surprised to see that you've posted the PM in this thread, so I'll post my PM reply to you here as well.
__________________________________________________ ___________________

I fully realise that my findings would be far more useful to me (and everyone else) if I had proper figures to show me exactly how both my air-intake mod and exhaust mod affect performance, but as you know, that sort of information costs money each time the car is dynoed, and since I am not attempting to sell anything all my R&D is done empirically.

I regularly meet up with other members off the MC forum and go for a blast in company, and I know from first-hand driving experience that none of my mods have slowed my MC down when driving with other MCs. If I had seen any detriment to my MC's performance with any of my mods, then I woud have reversed the mod in question to restore the OEM condition.

I absolutely understand your point about loss of pressure at low revs, but since the MC is first and foremost a performance car, I think that when the car is being driven in anger (as it should be), one is looking more for mid-range to top-end grunt, well at least I am.

You say that comparing fuel consumption is not an accurate measure of performance change, and I agree in part, but in the absence of other measurable parameters. I'm afraid it's been the best guide that I've had. I'm an avid recorder of my fuel consumption in the MC and although my driving style hasn't changed over the period of doing my mods, my fuel consumption has progresively improved I live in a rural part of the UK and get to drive the MC very spiritedly for approx 90% of its miles, so something must be happening to improve my fuel consumption, and it's not my right foot

You wrote: "if the back pressure on the system is lower then the charge filling on inlet is able to sneak down exhaust during valve overlap so this may account for deterioration in fuel consumption" - Since I'm not finding that my fuel consumption has deteriorated, the opposite in fact, nor do I smell petrol from the exhaust or other signs, then I don't think that I've created a power loss with my exhaust mod.

Before I embarked on my exhaust mod, I obtained a pair of unwanted OEM silencers so that I could use these as donors for experimentation, so that I could revert to my own OEM silencers if I didn't think my mod worked, or found it was detrimental to performance. As it is, I've done two lots of "surgery" on the donor zorsts, taking a day's work for each operation, and I haven't found a need to revert to my original OEM zorsts. I do intend to get my MC on a dyno sometime to get a ball park figure of its output.

The Supersprint exhaust system for the MC is reputed to produce a power gain (backed up with indepenent dyno evidence I believe), even with the OEM cats being retained, so if that is true, then as I see it, converting the "reverse-flow" OEM design to "straight-through" seems logical to expect a slight improvement, although, as always, I stand to be corrected.

At the end of the day, my mod is intended as a cheap alternative to ditching perfectly serviceable OEM silencers and spending £800 on a pair of aftermarket silencers, when I think that a bit of internal "surgery" on the OEM can produce an improvement in both sound and performance. My car sounds like the CSL with this mod. I did consider making and fitting a weighted flap over the inlet pipe inside the silencers (like you sometimes see on tractors and lorries) so that the flap would add some back-pressure at lower revs, but I considered that this would be too much of a hit and miss affair and difficult/impossible to adjust when the silencers were welded back together. Likewise, I have the equipment and the skills to do the experimentation without it costing me much to do, and the desire to try the idea, so I simply couldn't resist having a go.

Personally, I wouldn't want to remove the cats, because I wouldn't want the hassle of refitting them and removing them again for each MOT. I've already removed the silencers off my car 4 times in all, and that's enough for me

[buckieblake]

Hi.

After 6 Months of reading about various exhaust options on this forum (some excellent feedback by the way), I opted for a customer setup instead of a off the shelf make. I lost count how many people recommended C&Cs in Glasgow, went with it.

They were amazing, really professional and knew exactley what I wanted. They pointed out that the standard system has a restriction as it goes under the suspension (pipe squashes a little), kept mine to a 2 1/2" straight through from cats, job done in a day.

From all the cars I have owned and various exhaust systems, noting compares to this one. The car pulls harder lower down the range and all the way through to te red loine (no flat spots now!), sounds and looks amazing.

Total cost, £490 all in, a decent saving over Eisenman or Hamann etc.

Send me a PM if you want more info, it's worth the drive up :-o

Good luck!