sonu_e55

About to build some headers for my E55 and had a few questions. Current mods include the basics, 83mm pulley, EC tune and upgraded cooling. Planning on installing water/meth and 77mm FSP/Tune along with the headers.

What is the ideal OD for the tubing for the primaries? Has there been any testing b/w 1.75", 1.87" or 2"? Will be using SS304 16ga tubing.

Also, every car I have modified in the past has been a Turbocharged vehicle and I usually run Tru-Dual exhaust. Is there any data on benefits of running a X-Pipe on a supercharged setup (particularly the E55). I have found that on turbocharged cars there is not any real benefit (gain) from running an x-pipe and prefer the sound of the tru duals, does the hold true on the E55?

Hulk

1 7/8 for primaries, more than that and you will run fitment issues, H pipe or X pipe your choice, you will need it for scavenging

Sir-Boost-a-Lot

iTrader: (1)

On a turbo car there's not much point since the exhaust pulses are all run through the turbines. However on an NA or blower car they really sound like **** with no balance pipe. Some of the Ferraris with 180' crankshafts sound neat without one though.

BC928

How long were you thinking? Collector length seems to be more important than length of primaries in certain cases.

The very conservative cam can also tell you what you want to do with primary diameter.

kponti

1 7/8, one of the reasons MBH makes so much more power than the rest.

sonu_e55

I guess I will go with an X-pipe. Or perhaps make both (X and tru-dual) and compare.

Do you mean the collector angle (angle of the merge)?

Current plan is to use 2" primaries (since I have a lot of 2" material sitting around) and having the merge right before the bend towards the back of the car, at around where the stock primary cats would be.

Not sure if I want to remove the stock resonators or not.

DVC

LOL, MBH are 1.75"

BC928

I was gonna say. With the mid range on those, they aren't *that* big. Maybe they step to that?

1 7/8 and 2 is for very large engines or after a step.

DVC

Yes, 1.75 all the way down to a very long merge collector - necked down, and then back out to 3", with an internal velocity spike.