Questions about M5 exhaust on 525i

[Jon K]

I Have an M50 525i. I need to know the pipe diameter of both a stock M50 525i exhaust system as well as pipe diameter on B&B Triflo M5 exhaust.

Also, how hard will this be to get to fit? We have a welder, but I guess the hardest part wil be stepping my 525i exhaust pipe diameter up to the M5 diameter?

[Jr ///M5]

Jon,

I looked on the ETK and it shows the M50 exhaust being 47mm. It shows the STOCK M5 exhaust to be 60 mm. It also showed a welding sleeve for the M50 and the size of it was 49mm. Local muffler shops may have a concentric reducer that could be made to weld the two together. The question that still needs to be addressed is if the system will physically fit on the 525, the other question is if the larger system will create enough back pressure for engine needs. Hope this helps some.
By the way, how's the sis liking the new BMW?

Jr

[spoolinturbo]

sorry im new but whats the M50? i have an 89 535i...with a 3.5l ...info? haha

[Jon K]

Jon,

I looked on the ETK and it shows the M50 exhaust being 47mm. It shows the STOCK M5 exhaust to be 60 mm. It also showed a welding sleeve for the M50 and the size of it was 49mm. Local muffler shops may have a concentric reducer that could be made to weld the two together. The question that still needs to be addressed is if the system will physically fit on the 525, the other question is if the larger system will create enough back pressure for engine needs. Hope this helps some.
By the way, how's the sis liking the new BMW?

Jr


Hey JR, just picked up the exhaust, it looks the same size (muffler wise) as my stock system did when I had it out, so it should physically fit. There are NO (or very small) resonators on the B&B system, so that won't be a problem either. Sister is loving the E34, trying to get her the mandatory clears and eurostrips etc. Otherwise the car is perfect!

[Kalevera]

Good, if not rudimentary info, to know:

http://www.unixnerd.demon.co.uk/enumber.html

best, whit

[bahnstormer]

hey jon u should have called me, i got to jasons around 7.30

[Jon K]

hey jon u should have called me, i got to jasons around 7.30

I had to roll man, i had to put two turbo kits on, one a VW Corrado (vr6) and the other a GTI (vr6)

[Jon K]

Good, if not rudimentary info, to know:

http://www.unixnerd.demon.co.uk/enumber.html

best, whit


I know most of this info, but how does it play role in what I am trying to do?

[Paul in NZ]

it doesnt jon that was info for spoolin turbo post #3

[pmlmotorsports]

I would call B&B and explain your intent on supercharging you car, if that's your true goal, and see if perhaps with the added exhaust flow you would benefit from the substanially larger diameter tubing. I have heard from several exhaust companies that too large a tubing on an exhaust can cause a loss of performance due to insignificant back-pressure. I am sure B&B can add some vital input on this matter. I personally prefer the Supersprint product or the Eisenmann (did I spell it right?) ....the B&B is just too loud for my personal taste but it's an excellent product and very well constructed. Hope this helps.

[Kalevera]

lol...good question :)

[Jr ///M5]

I Have an M50 525i. I need to know the pipe diameter of both a stock M50 525i exhaust system as well as pipe diameter on B&B Triflo M5 exhaust.

Also, how hard will this be to get to fit? We have a welder, but I guess the hardest part wil be stepping my 525i exhaust pipe diameter up to the M5 diameter?

Lay the old system out on the floor and build a jig. This way you can position the Tri-flow exactly when you're going to weld them together. The hangers will fit right and the exhaust won't hang funny. The jig plus a dimensioned drawing will make the fitment perfect.
Where exactly did you plan on making the connection? Are you leaving the cat in place? Some people on the Yahoo M5 group reported that the B&B Triflo was too loud for their liking, maybe cause of the resonators?

Good luck Jon,
Jr

[Jon K]

Lay the old system out on the floor and build a jig. This way you can position the Tri-flow exactly when you're going to weld them together. The hangers will fit right and the exhaust won't hang funny. The jig plus a dimensioned drawing will make the fitment perfect.
Where exactly did you plan on making the connection? Are you leaving the cat in place? Some people on the Yahoo M5 group reported that the B&B Triflo was too loud for their liking, maybe cause of the resonators?

Good luck Jon,
Jr


I am going to cut off the flanges on my stock resonators, use a reducer (inverted... so an expander essentially) welded on to the stock flanges, then cut the pipe in front of the B&B resonators a little short to make up for the cutting, weld it up, and hopefully bolt her in.

[Jon K]

I would call B&B and explain your intent on supercharging you car, if that's your true goal, and see if perhaps with the added exhaust flow you would benefit from the substanially larger diameter tubing. I have heard from several exhaust companies that too large a tubing on an exhaust can cause a loss of performance due to insignificant back-pressure. I am sure B&B can add some vital input on this matter. I personally prefer the Supersprint product or the Eisenmann (did I spell is right?) ....the B&B is just too loud for my personal taste but it's an excellent product and very well constructed. Hope this helps.


Almost any forced inductoin (i am going to say 99.99%) system will benefit from a larger/more flowing exhaust than stock, aka less backpressure, because as you move more air into the engine it needs somewhere to go.

[bahnstormer]

yeah it'll benefit from a larger than stock one, but i gotta wonder if the triflo
will be enough...

60 millimeters = 2.36220472 inches

so i guess if the triflo is like 2.5?
good lucks =]

i was talking to jason about it and he said it'd set off
car alarms b/c of the low vibrations =]
enjoy!

[Jon K]

yeah it'll benefit from a larger than stock one, but i gotta wonder if the triflo
will be enough...

60 millimeters = 2.36220472 inches

so i guess if the triflo is like 2.5?
good lucks =]

i was talking to jason about it and he said it'd set off
car alarms b/c of the low vibrations =]
enjoy!


In case you forget, i was running open catalytics... im pretty familiar with car alarms ;)

It will flow WAY more than enough. Barely any resonators, plus M50 piping is like 2.0"... going to a 2.5" exhaust is more than enough.