135i Performance Exhaust Dyno

[new2the3]

Would like some feedback on my Dyno. Does anyone know about what RPM my peak HP occured at? Also what happened to my A/F ratio on run 1?

For reference a stock 135i auto put down 267 and a 335i sedan auto put down 265 stock map, 330 with tune. An E90 M3 with exhaust put down 320hp.

[quattrosaint]

Every dyno is different, I'm assuming you did not get a baseline on your actual car. As far as the AF in run one, since your stock my guess that something was wrong with the sniffer also your HP numbers in run one did not change enough to reflect a problem with your AF. Also did they really do 140 MPH on the dyno with those numbers, that just cant be correct. This is a weird dyno sheet.

[new2the3]

Did not get a baseline unfortunately but 45 minutes prior a stock 135i (auto) did 267hp on the same dyno.

[yandy]

each car/dyno/condition is different, I did 284WHP completely stock about a year ago on a dynojet.

[quattrosaint]

Originally Posted by new2the3

Did not get a baseline unfortunately but 45 minutes prior a stock 135i (auto) did 267hp on the same dyno.

oh well, live and learn. Yeah every car is different (even the exact same car can get different numbers on the dyno). Where did you get this done? I grew up in the city called Parkland, its between Coral Springs and Boca. I used to know a couple performance shops around Boca/Palm Beach when I raced my 01 S4. (assuming that 561 is still that area)

[Sylon]

EuroTuner reported HP loss after installing the BMW Performance Exhaust on their project 135i.

[kirby135i]

bmw perf exhaust is just axleback right? so i wouldnt think u are going to see any real hp gain.

[TreDirtyFive]

There's something about how much our power plants love that minimal back pressure. Perhaps a factor in the European Car Testing power loss. I took off my Borla exhaust off my 335 to return my lease and I swear that my car feels faster. Esp. down low where it seems the back pressure is much more dialed in and the torque is more immediate. Up top at absolute speed may yield diff. results as an aftermarket piece usually flows better but I'm not 100% sold. I still think most axel backs for our cars are for sound only (maybe the most negligible of gains)...unless you get DPs.

[335xiRT1]

I think aftermarket axleback only adds like 6-8whp.

[HPFREAK]

The problem with the A/F is the sniffer. They suck at life. Very weird how they act from one run to another sometimes. when you have cats or even if you dont/ They only way to read A/F properly is with the sensor screwed into an bung before the cats and as close to the header as possible. Also you need to have a really good sensor like a Horiba meter which are not cheap. As for the numbers I cant say much since catback exhaust is not going to give you much with these cars on a stock tune.

[new2the3]

Originally Posted by Brad@PSI MOTORS

The problem with the A/F is the sniffer. They suck at life. Very weird how they act from one run to another sometimes. when you have cats or even if you dont/ They only way to read A/F properly is with the sensor screwed into an bung before the cats and as close to the header as possible. Also you need to have a really good sensor like a Horiba meter which are not cheap. As for the numbers I cant say much since catback exhaust is not going to give you much with these cars on a stock tune.

Well two other N54's put down 265 & 267 for their best runs. This was on the same dyno same day. Do you think I put down more because 6mt vs auto or because the exhaust helped? Maybe a mixture of both?