headers

[O-cha]

Originally Posted by Haretakis

O-Cha, I am not contesting you're knowledge, but I am running the headers without software and can tell you I have no problems. I do not have dyno sheets for proof, but I can tell you how I compare before and after next to my nephews tuned 335i. Before the headers, we were nearly dead even. Typically he pull a nose ahead, and rarely I would pull a nose ahead. The day after I picked my car up we did some pulls. This time I pulled at least half a car every time. Sometimes a car length or more (especially if we ran up past 130). This was all with my 115 pound GF in the car while he had no passenger. I definitely didn't lose power, but my gas mileage sucks ass and the car back fires like a motherf*cker. I know this doesn't help the OP directly, but I just want him to know that the car can run without software. Maybe recheck the O2s?

Car backfires like a mutherfucker because it's dumping fuel like crazy, which by the way makes you lose power. Optimal for power and efficiency is 14.7:1 these cars run at around 13-12.5:1 stock (have to go rich to suppress knock) and with headers the car will run even richer, so it's not possible for you to gain power.

If you managed to get the o2s out of the exhaust stream which will modify the reading and suppress the CEL it's possible, but still unlikely since as you said you're running rich and likely running out of the stock fuel map.

I have no idea how you're avoiding a CEL.


But running headers without the tune for it is one of the dumber things I have seen people do, and trust me I've seen some pretty dumb stuff.

[O-cha]

Also I read it again, go ahead and race him again now that it's been a while, it takes a while for the car to identify the inefficiency, it will do everything from pulling timing and cam to obviously richening the car to try and get the efficiency back up before throwing codes, all of this takes away power.

[mpower03]

this is a very common problem when installing the headers. i must have mixed up my precat 02 sensors, because i am misfiring. it should run normally after this (hopefully). you can run the headers without software or a tune. all the ses light is saying is that you have post cat sensor failure (when everything is wired up correctly), because the post cat sensors aren't reading the same as when you are stock. post cat sensors don't have anything to do with fuel trim. pre cat sensors measure a/f ratio. having the pre cat sensors in the correct location won't have any diffference on the car at all, because it is reading the same as it did stock. he would know if his car is dumping fuel because it wouldn't be running normally. his spark plugs would be going out, and he would eventually have a hard time turning over. maybe i am wrong, but tons of people run headers without a tune, and no post cat sensor plugged in.

[O-cha]

Originally Posted by mpower03

this is a very common problem when installing the headers. i must have mixed up my precat 02 sensors, because i am misfiring. it should run normally after this (hopefully). you can run the headers without software or a tune. all the ses light is saying is that you have post cat sensor failure (when everything is wired up correctly), because the post cat sensors aren't reading the same as when you are stock. post cat sensors don't have anything to do with fuel trim. pre cat sensors measure a/f ratio. having the pre cat sensors in the correct location won't have any diffference on the car at all, because it is reading the same as it did stock. he would know if his car is dumping fuel because it wouldn't be running normally. his spark plugs would be going out, and he would eventually have a hard time turning over. maybe i am wrong, but tons of people run headers without a tune, and no post cat sensor plugged in.

Wow, you can jump out of a plane without a parachute too, doesn't make it a good idea.

Have fun, don't listen to people who can actually view the cars engine parameters or anything. They know nothing.

[mpower03]

Originally Posted by O-cha

Wow, you can jump out of a plane without a parachute too, doesn't make it a good idea.

Have fun, don't listen to people who can actually view the cars engine parameters or anything. They know nothing.

csl headers only have two bungs, no cats, therfore no post cat sensors. you don't need them. Euro headers don't have cats, there fore no post cat sensors. there is two headers that are oem and that are compatible with our car that don't run post cat sensors. i don't know, but there is more than a dozen people on m3forum that have ebay headers, no software or tune, and no post cat sensors and their car is running fine. they have had the headers on the car for long periods of time, and drive hard and on the track. so it can be down. im not saying that you don't know what your are talking about, but it can be done.

edit: i should say that it has been done. i don't know if i am correct o-cha, but you seem to not accept the possibility of there being another answer except for yours.

[O-cha]

Originally Posted by mpower03

csl headers only have two bungs, no cats, therfore no post cat sensors. you don't need them. Euro headers don't have cats, there fore no post cat sensors. there is two headers that are oem and that are compatible with our car that don't run post cat sensors. i don't know, but there is more than a dozen people on m3forum that have ebay headers, no software or tune, and no post cat sensors and their car is running fine. they have had the headers on the car for long periods of time, and drive hard and on the track. so it can be down. im not saying that you don't know what your are talking about, but it can be done.

edit: i should say that it has been done. i don't know if i am correct o-cha, but you seem to not accept the possibility of there being another answer except for yours.

You're not right, and you're being a fool by not listening. Euro cars do have post cats, they are in the midpipes . Even if they did not it would be completely irrelevant since their coding is different, along with their tuning since they don't have close coupled cats.

Again, fucking listen cuz it's the last time I'm going to waste my time explaining this to you if you refuse to listen. The car will do EVERYTHING in it's power to try and get the cat efficiency back up. It will try pulling timing (kills power) retarding the exhaust cam (kills power) and running a point or more rich, kills power AND wastes gas as well as making it "backfire like a muther fucker" as the other guy not running a tune put it.

So just fucking listen and get as dam tune. Christ.

[mpower03]

i never said you weren't right because you very well could be, i was just pointing out situations in which people have done it without any problems. That might not be my case, and a tune might be my solution. I wasn't trying to prove you wrong i was trying to show you that it has been done before, because you can't seem to believe that. I am going to be working on my car in a little bit, and if i can't get it which i don't know if i will, then i will explore more options.

[O-cha]

I KNOW it's been done before, I have friends who have done it, customers, ETC. That's why I'm telling you, not guessing. This is how it is, period.

[Burt Reynolds]

O-Cha do you like the ESS tune with 02 sensor turned off for running headers? If not, what tune would you go with?

[O-cha]

Originally Posted by Burt Reynolds

O-Cha do you like the ESS tune with 02 sensor turned off for running headers? If not, what tune would you go with?

That's about your only option as far as I know.

You could always do a set of O2 sims to kill the cat inefficiency issues, but then you'd still have to deal with the car not being tuned optimally for the headers. Still miles ahead of just throwing them on though.

[Haretakis]

Look o-cha, you're not god and don't know everything. My car makes More power then it did. Plain and simple. Just to see what'd happen with no passenger, I ran my nephew again last night. Pulled more then a car length on several runs. Before headers thay never happened. I know for a fact the car would be healthier with some software, but are you gonna lose power? Maybe, but I certainly didn't. You haven't seen, dyno'd, or driven my car, how would you know what's going on? Have you really installed that many eBay headers on z4ms?

[fatmatt0116]

Originally Posted by O-cha

That's about your only option as far as I know.

You could always do a set of O2 sims to kill the cat inefficiency issues, but then you'd still have to deal with the car not being tuned optimally for the headers. Still miles ahead of just throwing them on though.

O-Cha, it sounds like you have a lot of experience so I would like your opinion on some planned upgrades. I'm getting the ESS ECU upgrade this month and then plan on getting the supersprint step headers after that over the summer. Is this a good sequence for the upgrade?

[mpower03]

well after looking some more at the headers i had the correct pre cat sensors in the correct headers i just didn't put it in the right bung. the rear header was fine, i moved the pre cat sensor on the front header out of the pre cat bung into the post cat bung. That did the trick. I guess it wasn't getting an accurate reading in the pre cat bung because the precat bung is sitting in the collector. My car runs great so far. I put 60 miled on it. I let the car sit a couple of times turned off. I did several hard launches. so hopefully it stay this way. it is definetly smoother, but it barely i mean barelys gurgles on deceleration. it doesn't backfire like a motherf'er like haretakis is describing. i do think that a tune will be necessary though. it is running slighlty retard or advance. i will be getting a tune shortly.

[mpower03]

Originally Posted by Burt Reynolds

thanks for the update...good luck. Be sure to post a sound clip. Also, what section 1 are you running?

i am running all stock exhaust except for headers now.

[Haretakis]

Maybe saying it backfires like a mofo was an exaggeration. Glad to hear your car is running well though! I've put around 450 miles since the headers and it is still running fine, just took a 55 mile drive actually.

[O-cha]

Originally Posted by Haretakis

Look o-cha, you're not god and don't know everything. My car makes More power then it did. Plain and simple. Just to see what'd happen with no passenger, I ran my nephew again last night. Pulled more then a car length on several runs. Before headers thay never happened. I know for a fact the car would be healthier with some software, but are you gonna lose power? Maybe, but I certainly didn't. You haven't seen, dyno'd, or driven my car, how would you know what's going on? Have you really installed that many eBay headers on z4ms?

Haha, you're right, I'm not a god, but you're arguing against fact. I have no intention of continuing to argue fact against you who choose not to accept it. And I have only put headers on my own coupe, M3s are a different story. Even so everything I have said is true, while it is minutely possible you're not down on power by some serious stretch of perfect conditions (which is VERY doubtful since by you're admission you are running very rich) everything else applies and you're ecu is wigging out.

You said you had no CEL, so either you're FOS or somehow you have managed to evade the ECU. There is a mechanical way of fooling the ECU by pulling the secondary sensor out of the exhaust stream which modifies the readings and I have seen some headers like this, but if you put them in that way the o2s are probably millimeters from touching the tranny and the other header.

Enjoy you're car but anyway you cut it you guys are making a very unwise decision.

Originally Posted by fatmatt0116

O-Cha, it sounds like you have a lot of experience so I would like your opinion on some planned upgrades. I'm getting the ESS ECU upgrade this month and then plan on getting the supersprint step headers after that over the summer. Is this a good sequence for the upgrade?

Sounds like a plan to me, I would have done similar had I not put in the supercharger.

[$upreme]

Wonder which seller did you get the eBay header from? Can you please send me the link?

[mpower03]

i ordered from racedesignimport.

here is a link
http://cgi.ebay.com/ebaymotors/BMW-E...1%7C240%3A1318

[Burt Reynolds]

Those flanges are actually pretty thick compared to other e-bay headrs. How would you rate overall fit?

[mpower03]

the rears were perfect they slipped right on. the fronts went on in about 15 min. the fitment on the fronts weren't that good, but we got it on after hitting them in with a 2x4. i would reccomend longer studs though because the flanges like you said are really thick. i would do this again in a heartbeat, and i reccomend this.

[silversprint]

Originally Posted by mpower03

the rears were perfect they slipped right on. the fronts went on in about 15 min. the fitment on the fronts weren't that good, but we got it on after hitting them in with a 2x4. i would reccomend longer studs though because the flanges like you said are really thick. i would do this again in a heartbeat, and i reccomend this.

Do you have a SES light on??

I doubt the engine uses the O2 sensors at WOT, most cars don't. That's why on a dyno it will show you are making more power.

However cruising and idle will run rich.

Let me know if the SES light doesn't come on. That would make things much easier.

[Z4MCJJ]

Originally Posted by mpower03

the rears were perfect they slipped right on. the fronts went on in about 15 min. the fitment on the fronts weren't that good, but we got it on after hitting them in with a 2x4. i would reccomend longer studs though because the flanges like you said are really thick. i would do this again in a heartbeat, and i reccomend this.

mpower03,

What benefits have you noticed with the new headers? -->Performance, sound, etc?