X-pipe section in exhaust

[ktteoh]

folks, have anyone experienced replacing the central exhaust box (resonator?) by a x-pipe section?

what's the sound like and is the power/torque curve change
as a result?

[Jeff N.]

I've been on this board since day one more or less. Very little experimentation with custom exhausts. TC535 was doing a bit a long time ago. Can't ever recall dyno numbers being posted for any exhaust changes.

[genphreak]

I've been on this board since day one more or less. Very little experimentation with custom exhausts. TC535 was doing a bit a long time ago. Can't ever recall dyno numbers being posted for any exhaust changes.I don't want to be a wet rag but you know BMW have done this thinking already. The science of exahust design is not simple; it involves careful study of lengths, pressures, velocity, noise and heat as well as performance and efficiency. They came up with a custom setup and it was so good they used the same thing on almost all e34s. They did not nobble the exhaust like other manufacturers have been known to do, in order to meet emissions regulations. They had the luxury of a state of the art ECU to play with.

If a x-section or other add-in was going to help performance, the M5 would have had it- if not our cars too. As it is, we're lucky these cars have a decent exhaust from factory.

If it wasn't so damn good, you can be sure there would be hundreds of people touting improved setups for a car as popular as these wiht owners as thrift with their cash and with 'needs' to improve them over the next one. As it is such companies are just supplying market demand for replacements, shinier or noisier add-ons... and very few of them are even dyno tested- probably for good reason too...
Sorry to be a downer but its the truth.

[F4Phantom]

Agree, I went to get a "sports" exhaust on my e30 for a bit more power as at the time all the jap cars were getting them. I only made 1 call and was told much as above, and also that BMW's mostly loose power when you change the exhaust. You got to believe that when the guy wants to sell more product not turn customers away like he did me.

[rob101]

tis true however the X-pipe supposedly increased midrange. but that is SUPPOSEDLY
bmw knows how to make exhausts and engines. i for one have to replace some parts of my exhaust. and there is no way in hell that anyone is putting a custom "I AM A TRADIE WHO DOESN'T UNDERSTAND FLUID MECHANICS" exhaust system on my car.

[genphreak]

tis true however the X-pipe supposedly increased midrange. but that is SUPPOSEDLY
bmw knows how to make exhausts and engines. i for one have to replace some parts of my exhaust. and there is no way in hell that anyone is putting a custom "I AM A TRADIE WHO DOESN'T UNDERSTAND FLUID MECHANICS" exhaust system on my car.but maaaaaaaaaaaaaaate
it will FLOW better!

Aren't you gonna get a FREE FLOW system?

You must have rocks in your head as well as baffles in your exhaust... :D How do we get a cheap stock system supplied in Oz budd?

I hear the Remus distrib is in Brisbane though. I got a quote of $900 or less here (trade) for the rear muffler and resonator. 525 is very very similar :)

They claim in advertising to be stainless but I can't get that confirmed to be the case on e34 setups...

[rob101]

where? where are they?
i was thinking remus
anyway i have to ascertain where the leak is first. it maybe in the front pipe :(

[TC535i]

Mine was just for sound, and altho I have a dyno for that, it also had a Mark D chip... nothing specific to just changing the exhaust. I removed the muffler btw, not the resonator.

I can try to record the sound, but I'm not sure my camera will pick it up, and the car's not very happy with high RPM's right now... I'll see what I can get you guys this weekend tho.

[535ise]

Over here in the UK the E30 M3 and E34 M5 up to '92 didn't have kats fitted as standard, the non-kat M3 and M5 both had an X-pipe so i guess it's beneficial to power and/or torque otherwise BMW wouldn't have fitted it ??

Some E30 M3 owners report a loss of torque when they fit an aftermarket exhaust like Scorpion that doesn't have an X-pipe, they like the Super Sprint exhausts because it has an X-pipe.

My M30 powered E30 uses an E30 M3 Scorpion exhaust so i want to try an X-pipe partly for the chance of more torque/power and i also have an WB02 sensor that only see's the gas's from 3 cylinders at the moment but will be able to see a mix of gas's from all 6 cylinders with an X-pipe.

Another benefit of an X-pipe so i've read is it makes an exhaust slighty less noisey which would be handy because mines a bit to loud.

I know exhaust pulse tuning is complicated business and by fitting an X-pipe things will change from how the M30 was originally set up but my M30 is already going to be differant to standard because of my ported head/schrick cam/M3 exhaust/stand alone ECU. I am going put the X-pipe in roughly the same place as the M3/5 exhaust.

It might be a waste of time but it's not going to cost a fortune to try and the exhaust is already off the car.

Unfortunately i won't be able to check for any extra power even with the old butt dyno because my car is off the road due to fitting an Alpina B10 bottom end so i couldn't atribute any extra power just to the X-pipe. Plus the map's will need tweaking.

[Jeff N.]

BTW, I'm almost 99% sure that on the stock 535 cat system, there is a X-pipe right ahead of the cat. Where the O2 sensor plugs in (this is how it sniffs both sides).

Look closely the next time you have it off and you'll see what I'm talking about. Hidden a bit behind the heat shield...