bmwe21.net forums

For 2.3 or 2.5 the flow volume of the O.E. tubing diameter was large enough. As you increase tubing diameter and drop all back pressure you also loose bottom end torque. In order to reduce sound you need some back pressure. Although I dont think the factory was correct by crushing the tubing as it passed over the cross member.

A common mistake is to increase tubing size and actually loose power.

When they did my exhaust they used a bore size similar to OE but did away with the centre resonator section and just fitted to free flowing silencer boxes. In normal day to day driving the exhaust note isn't that different to standard but once the revs rise past 3000 rpm it sounds much nicer but not so loud as to be annoying.

i am quite worried about the effect my systm is having on my engine
i dont think its doing it any favours and its that loud my dads refused to acompany me to wezep in august til i change it back to oe

typically if the tubing is too large, the exhaust simply flow through the center of the pipe ond out as well as the exhaust sound.
Some brands on other vehicles will reduce cost by delete the center resonator. This is a mistake since the resonator baffles much of the sound before it reaches the rear mufflers.

Mine sounds great with the resonator. Certainly not loud anyway. I guess it depends on the silencers used and their tailpipes?

I should have pricing today for each component. Unfortunately the RHD header jig is no where to be found. It looks like what will be avaiable is LHD headers, center seronator, and the L&R rear mufflers with single tips.

O.K. I finally got pricing for each component. The quote is for 60mm single chrome plated tail tips. the headers will be 100% 304 stainless steel. the remainding compontents will be aluminized steel, with stainless internal resonated tubes, and chromed stainless tips.
Headers 780 504 $1238.41
Resonator 780 501 $556.92
Right muffler 780 503 $381.05
Left muffler 780 502 $381.05

these prices are wholesale, to the forum members since this is a one time custom production run for this classic vehicle.
We will need to sell 10 sets to begien production.










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£1 764

Hmm, thickness of the pipe used if its only 304?

If you are doing the rest of the exhaust in mild steel, might be an idea to look at making mild steel headers too as an option. Usually end up with problems with stainless rusting when you mix stainless and mild steel together.

1641 Euro

The header tube wall thickness is 1.5MM. 304 is very common for headers. if its a turbo application we use a higher grade, due to the excess heat. The 304 as an upgrade is because the original as you see in the photo was mild, and no one wants the maintenance issues of mild steel. There should be not issues joining stainless with mild, since we are bolting them together at the bottom flanges. Temps are very cool at that point. We do this combination on many vehicles without any issues.

thats way too much squid!! dont think people are gonna run with their underwear to their ankles on this one!!, its waaaaaaaaaaaay cheaper building a custom exhaust system at the exhaust center!


J

--ALPINA-- wrote:thats way too much squid!! dont think people are gonna run with their underwear to their ankles on this one!!, its waaaaaaaaaaaay cheaper building a custom exhaust system at the exhaust center!


J

+1

Not to discourage anyone from selecting a custom exhaust shop. But I've seen good custom jobs, and then I've seen absolute nightmares. And typically you don't find out what you're getting until the job is done. What we are offering is a system that is a direct fit, designed for all O.E. Hangers. and direct bolt on. Predetermined sound quality. Most likely we still have all the T.U.V. certification. And a system that will have replacable components, with O.E. parts. The purpose of doing this special run is to give the forum members, an exhaust that would qualify for a restoration project of a e21 323i. Supersprint has been an O.E. Supplier to Hartge, and very likely made this system for them.
Whats nice is since the system is to O.E. points, you can purchase individual components and they will inter fit with what was original.