chope97
Well-Known Member
I noticed this on the 75 30si that sold last week on BAT. I have seen balance pipes like this on performance v8 exhaust systems. I wonder what is the benefit of putting it on a exhaust like this one?
Exhaust balance pipe
- Thread starter chope97
- Start date
The intended effect of a balance pipe cuts harmonic resonance in half. Depending how the mid-resonator is plumbed, and the muffler or other resonator after it, this can have a notice-able effect on exhaust tone. But in general it won't do much if you have a 2-into-one connection somewhere downstream
I know from experience that it can cut down on resonance and exhaust noise. I would say it’s not optimal, and as you can see from the picture, he has no support from the exhaust to the transmission, which would probably do a lot more to cut down vibration and exhaust noise then connecting them. that little U bracket connected from the exhaust to the transmission, makes a big difference. Especially if you have headers.
Belgiumbarry
Well-Known Member
a balance pipe helps torque on low end , a X pipe favors HP at top .
Should be placed as short as possible after the headers.
Just made one for my Chevy V8 , as we "think" i have "reversion leanout" which gives shocking pulses accelerating from 1000 to 1500 rpm.
Seen dyno results without & with it , no more lean condition and torque comes better in . Once above 1500 rpm all stays the same.
As i have headers going outboard to side pipes , it was a bit more complex to build ....
Should be placed as short as possible after the headers.
Just made one for my Chevy V8 , as we "think" i have "reversion leanout" which gives shocking pulses accelerating from 1000 to 1500 rpm.
Seen dyno results without & with it , no more lean condition and torque comes better in . Once above 1500 rpm all stays the same.
As i have headers going outboard to side pipes , it was a bit more complex to build ....
gwittman
Well-Known Member
It is my opinion that cross pipes and X-pipes work well on a V8 because of the uneven exhaust pulses. I think the BMW in line 6 has very even exhaust pulses and do not benefit with the addition of a cross pipe. I am pretty sure BMW split the exhaust manifold to help keep the exhaust flowing smoothly. My bet is, it is not just to make it look cool. I have no hard information to back up my thoughts on this, just using a little common sense and experience of racing and building race engines for over 30 years. The uneven V8 exhaust pulse is well known and is part of what makes it sound unique.
Hi Barry
That is a very nice piece of fabrication.
I am wondering why you curved it back on itself on the left with approximately 16 cuts , before coming back out and running across to the other side .
And then the long straight length is oval not round, was all that for gas flow or were you trying to avoid some components under there like the steering rack.
It’s very nicely done. !
Belgiumbarry
Well-Known Member
yes, the middle part is oval 73 x 45 ( same section as the 2.5" round part ) to stay away from the R&P as far as possible.
I also could do it because the pan dept difference is more then 73 mm , so no ground clearance lost .
The bend ( welded with oval 15° pie cuts and at 45° a little straight pipe to get our exact dimensions ) was needed to pass the R&P support on the passenger side.
On drivers side i only needed to weld a "dent" in it.
And a compensator , it is stainless and 1 m long. So it wants to expand 1.8 mm per 100°C.... 300°C is already more then 5 mm....500°C would be 9 mm !
I also could do it because the pan dept difference is more then 73 mm , so no ground clearance lost .
The bend ( welded with oval 15° pie cuts and at 45° a little straight pipe to get our exact dimensions ) was needed to pass the R&P support on the passenger side.
On drivers side i only needed to weld a "dent" in it.
And a compensator , it is stainless and 1 m long. So it wants to expand 1.8 mm per 100°C.... 300°C is already more then 5 mm....500°C would be 9 mm !
Oh Okay
I hadn’t thought about expansion rates, that does make a lot of sense now that you say it.
Are the joints you used a metal seal type or is there a gasket in there also ?
Belgiumbarry
Well-Known Member
no gasket in those , just male/female metal joint.
the collar is V shaped , so the more torque on the bolt , the more they are compressed together.
Of course the compensator also allows us being a little bit out of level with the two. ( nozzles not easy to weld at that spot )
the collar is V shaped , so the more torque on the bolt , the more they are compressed together.
Of course the compensator also allows us being a little bit out of level with the two. ( nozzles not easy to weld at that spot )