new v8 header question

[topaz540i]

being that m62 headers are rediculiously expensive.... has anyone tried seeing if the manifolds fit off of the newer larger engines like the 4.6 or 4.8 found in the x5?

are the n62b48 engine made from the same block as the m62?

im obviously trying to find low cost drop in solutions that havent been explored before that i know of.

[croat]

I read that you can use E38 740i ones with small modification. I guess these are supposed to be relatively cheap

[Justin517]

They do not use anything special on the 4.6 and 4.8 in the E53. Plus if you think about it, they didnt really ahve a reason to, the M5 makes more power than both and they used essentially pre-vanos "headers" on it, but with less restrictive piping after the headers (larger diameter and no "pinch" where the 02 sensor goes in like pre-vanos). Plus an SUV is geared more towards low-mid range torque, not screaming top end power.

Pre-vanos:


vanos:


4.6 E53:


4.8 E53 N62:


I do not think that any OEM replacement is worth the cost and definitely not worth the time/energy to install them.

But... if you were able to get used OEM stuff for cheap... I would probably look into pre-vanos manifolds and M5 cat section. it seems to be the best of what is available. BUT... new manifolds and cats (not even OEM) will run you close to $2k... at that point I'd just get evolve headers.

[topaz540i]

im eventually going to do prevanos headers as they appear to have far superior flow paths. that vanos bank 2 is so bad i have no doubt the banks make unequal power explaining unequal fuel trims.

Im mostly likely going to get a two year inspection sticker and then do a custom mid section to connect it all without cats.

btw- how much louder does a cat delete make your car?

[TriniSpeC]

I dont think the cat delete should make a sound difference, just a difference in smell.

[topaz540i]

im going for the "who farted" rotten eggs smell mod.

[BMWPlanetDude]

Cats are here for a good reason. If you want noise get the aftermarket headers, muffler (delete if you want), resonator.
A car without cat(s) is even more dangerous, I think we are eating enough chemicals as it is in the food/water supplies...

[Bricas45]

the cats are very restrictive...they do indeed reduce the sound. I wouldn't do a full cat delete however. When I did headers and high flow cats on my mine (with nothing else changed) the sound was much much much louder.

im going for the "who farted" rotten eggs smell mod.

Mine is a bit stinky when I stop at a light I can occasionally smell it. Otherwise I don't notice it at all when moving

[edjack]

Bricas45, I would welcome a before/after dyno run for your ride. I don't believe that the cats are "very restrictive." The OEM cats include a muffler in the same can. Perhaps you saw more noise removing them as a result. The Butt Dyno equates noise with power.

Did anyone ever notice that the cats have a much larger cross-section than the pipes by a factor of about 3?

To all: the M62 is a low-revving engine (readline 6100 RPM). The stock headers are fine, thank you very much.

topaz540, I welcome the same b/a dyno run on your beast.

[topaz540i]

i know you dont believe its possible to improve anything bmw has ever done but i will get a dyno. Unfortuneatly it will be months apart and people will say its inconsistant or not apples to apples due to weather or something else. The only real test of power seems to be measuring 0-60 time improvement unless i can make it to the 1/4 mile drag someday.
Problem is, in theory its easy to prove this stuff but in the real world who owns a dyno and can get tested day in and day out? you have to admit that just looking at the pre and post vanos designs the pre are much smoother like a tubular header where the post are more cast iron mainfold style.

[Bricas45]

Bricas45, I would welcome a before/after dyno run for your ride. I don't believe that the cats are "very restrictive." The OEM cats include a muffler in the same can. Perhaps you saw more noise removing them as a result. The Butt Dyno equates noise with power.

Did anyone ever notice that the cats have a much larger cross-section than the pipes by a factor of about 3?

To all: the M62 is a low-revving engine (readline 6100 RPM). The stock headers are fine, thank you very much.

topaz540, I welcome the same b/a dyno run on your beast.

https://www.bimmerfest.com/forums/at...4&d=1343698752

Hopefully that works I have posted my before and after dyno results several times.

268 to 289 rwHP. Gain is 21rwhp or about 25bhp

285 to 302 ft-lbs. gain is 17 ft-lb at wheels or 20at the crank.

The only change between these is the headers and high flow cats. So almost a 10% increase I would certainly say the vanos exhaust manifolds and cats are very restrictive... The non-vanos aren't as bad but still not great. The M5 guys see about the same gains percentage wise.

i know you dont believe its possible to improve anything bmw has ever done but i will get a dyno. Unfortuneatly it will be months apart and people will say its inconsistant or not apples to apples due to weather or something else. The only real test of power seems to be measuring 0-60 time improvement unless i can make it to the 1/4 mile drag someday.
Problem is, in theory its easy to prove this stuff but in the real world who owns a dyno and can get tested day in and day out? you have to admit that just looking at the pre and post vanos designs the pre are much smoother like a tubular header where the post are more cast iron mainfold style.

Keep in mind it is a huge job! I don't really know the gains from vanos to non-vanos are worth the effort though. Also, the dyno computer does a pretty good job of calibrating out environmental changes.

[dovlet]

Any news?