Exhaust for the M3

After the original OEM fitted back box on my E30 M3 finally decided that it didn't like having baffles attached anymore, I have had to look at replacing the exhaust...

I had considered buying an OEM one from a dealer as the one on the car is original...Being as my car is a Feb 87 build, it has lasted 22.5 yrs, albeit with a few repairs to the back box...
However, I wanted to delete the (no longer properly functioning) Cats and was going to buy a Supersprint system comprising a mild steel road centre section (with silencer) and a SS racing rear box...Unfortunately Supersprint have just put up their UK prices by 30% or more making the total cost of that system over £750 without fitting!!

I also considered a Miltek system, but the poor reliability reports put me off.

I have had a quote from TopGear Racing in Aylesbury for £680 inc VAT and fitting for a custom made Powerflow system in T304 grade stainless steel throughout and a lifetime warranty.
The system comes made to my spec with x-pipe, centre and rear silencer a choice of tailpipes (although I will choose a standard twin round straight variety to look as OEM as possible) and a guarantee that the noise will be within 98db at 1m 45deg and 4500rpm.

Has anyone got any comments on the quality (or performance) of these systems before I splash out?

As I understand it, powerflow systems are custom made at the premises that you attend. So quality will, in part, be determined by the skill of the guy putting it together.

Having said that I have experience of two different powerflow systems, one for each of the two M3s I have owned. One did not have the x-pipe. The other had a separate x pipe that I think was taken from the original system. The powerflow system pipes slid over that and were clamped to it with U-bolt thingies.

The size the centre box was vastly different on the two systems.

All welds seemed to be well done and sound levels were fine. 

If it was what you really wanted you can still get a full supersprint system for less than £600 inc VAT (but plus delivery) from motorsportworld.co.uk

Thanks for the info Uwe...
Evolve checked fro me and said the mild steel centre section and the SS rear box from Supersprint did match up...so I guess something somewhere was incorrect...I believe that you know more than they do...

In any case, although I can still get a mild steel Supersprint fro a little less than £600, it still will need fitting...That would mean another few hours work or the cost of doing that on top of the system price...
Furthermore, it isn't SS with a lifetime warranty...

The Powerflow system is, as you say, custom built to the specifications I give...
TopGear racing come recommended for workmanship, even though they aren't the closest Powerflow dealer to me at all...
They know I want to retain the x-pipe and want standard looking rear pipes and that I want to acheive trackday noiselevels...

Tim from TopGear says that is all no problem and the price includes everything including the fitting...
I've already ruled out the Miltek and the options were:
1. Supersprint
1a. Supersprint front section and OEM Evo sport rear box
2. OEM
3. OEM centre and Eisenmann rear
4. Custom built (by me) front and Eisenmann rear
5. Custom built (by me) throughout
6. Powerflow
7. Longlife

Supersprint have ruled themselves out through price...and now also perhaps due to fitment.
OEM is expensive, but does maintain originality without any worry over power issues.
The Supersprint/Evo sport combo was recommneded, but is mild steel throughout and isn't substantially cheaper than a complete OEM system.
I really considered custom building the system myself as I have always done my race car ones with quite a lot of success...However, it does involve a lot of work and trial and error fabrication and I don't really have the time at the moment...
Eisenmann have also increased in price substantially recently...

That left Powerflow and Longlife...they are both custom designed and built and the price includes fitting and a lifetime warranty...
From what I can find written, Powerflow seem to be the better of the two (and are over £100 cheaper quoted, too) and TopGear Racing are highly recommended and are Powerflow dealers...

The main trouble is, whilst there are plenty of reports of Powerflow on other cars, I haven't found any E30 M3 owners with a Powerflow system to ask what they think...

UweM3 wrote: mate has just dens me this http://www.automac.co.uk:80/product/E30%20M3%20RGM%20back%20 box

PS would not go with Longlife. I know two E30 M3's running them. Both sold now but the both had centre boxes replaced annualy with loose baffles.
And I found it a bit droning sound on cruise and juuuust quite enough for track days.

Can you not re-use the OEM centre section? I removed my cats and replaced them with pipe and ran a Eisenmann back box. Mu centre section was riddled with welds but NEVER broke in the 4-5 years I used it. Just have a small long silencer welded instead of the cats and a Eisenmann backbox (or the one from above link)

Edit:
have a look at ZERO exhausts. He make a nice header and a fiend had a whole twin system done for £600. Can't say about longevity, but craftmanship was second to none!

Edited by UweM3

Right...

I decided to have the Powerflow system made in the end...More positive than negative comments, and most about the workmanship...Top Gear Racing in Aylesbury came recommended so I went there...

Had the job done in about 5 hours yesterday.
First impressions:
The quality of the workmanship is truly superb...The welds look good enough and strong enough to last as long as the car...
The parts seem to be decent quality too...
They made and fitted an x-pipe as I requested it and the only re-used bit was the flange to join to the OEM Manifold...

The system is then dual pipe to a largish centre box then dual pipe again to a dual single box at the rear...tailpipes look pretty standard in size, shape and position...
I'm very impressed with the hangers the fitter constucted to utilise the OEM rubbers...They look stronger and better than the OEM ones, too...
The rear boxes are welded together for strength and it is hard to see from the back that there are two boxes in place of the single OEM one...

It is a bit louder than the OEM system...but then it is new and it is SS

At idle it is about the same in volume, but a little more resonant...
At low revs under load it can be a bit boomy, but isn't untolerable...At higher revs it sounds lovely and is quite possibly no louder than the OEM system....

Time will tell on the quality, but it looks and sounds good a day in...

I'll get a db meter on it at the weekend and see how it compares...

Have to say the Top Gear Racing staff were really helpful, competent and nice blokes to boot...

I'll get some pictures later on today, hopefully...Stupidly enough, I forgot to take my camera with me to the fitting centre!!

hmmm, why the single cherry bomb style end box??



Edited by UweM3

UweM3 wrote: hmmm, why the single cherry bomb style end box??

This was for the main reason that they said it would be quieter than the single large box...The larger size box would have been a very tight fit in the space, too...

I'm happy with it to be honest...I was a bit sceptical, but they promised a free-of-charge swap to a single large box if I wasn't happy with their recommended solution...

Also tested it on my own db meter...

At 45 deg. 1m and 5000rpm max level is 98db...so spot on...but it was measured in front of my garage, so it may be slightly lower than that in a clear area...

After driving it for a while, I think there is a *slight* loss of low-down torque, but an increase in top-end power and it seems to rev a bit more freely and easily....
Just an impression, as yet...I'll get round to dyno-ing it soon...