[Steve335i]

I've got a 335i sedan on order and have been reading as much as possible about the vehicle. Frankly I'm suprised at the approach to modding some people take. Maybe it's just an experience thing. After owning and modding a few forced-induction vehicles I've come to believe that real-time information gathering is the place to begin. Most OE forced-induction motors have compression ratios between 8 and 9:1. At 10:1 cylinder pressure and temperatures are going to need careful management when boost and timing are increased. Any ecu mod product I contemplate must have data-logging abilities. I'm really suprised at the lean AF ratios on some of the dyno sheets I've seen posted here. Traditionally target AF ratios for forced-induction engines have been in the high 11's to low 12's.

My initial mod plan is to pick-up a set of catless downpipes and have a bung put in each for the FAST dual wideband gauge. I'll also be looking for an electric fuel pressure gauge. From this point I'll be able to communicate with a tuner / dyno operator, establish a baseline and judge the benefits of each mod.

Looking forward to joining the community and learning more.

[WilyB]

Please keep sharing your experiences!

[e90AW335i]

Welcome.....

[BoostedBMW]

Welcome to the fourms! Sounds like you are experienced with turbo cars, and I look forward to seeing your results once you start modding your car.

As far as the lean AFR's go, just keep in mind that this is a direct injection engine and they typically run a little leaner than most other fuel injected FI cars.

[!Xoible]

ur missing the first picture too

[Former_Boosted_IS]

Originally Posted by Steve335i

I've got a 335i sedan on order and have been reading as much as possible about the vehicle. Frankly I'm suprised at the approach to modding some people take. Maybe it's just an experience thing. After owning and modding a few forced-induction vehicles I've come to believe that real-time information gathering is the place to begin. Most OE forced-induction motors have compression ratios between 8 and 9:1. At 10:1 cylinder pressure and temperatures are going to need careful management when boost and timing are increased. Any ecu mod product I contemplate must have data-logging abilities. I'm really suprised at the lean AF ratios on some of the dyno sheets I've seen posted here. Traditionally target AF ratios for forced-induction engines have been in the high 11's to low 12's.

My initial mod plan is to pick-up a set of catless downpipes and have a bung put in each for the FAST dual wideband gauge. I'll also be looking for an electric fuel pressure gauge. From this point I'll be able to communicate with a tuner / dyno operator, establish a baseline and judge the benefits of each mod.

Looking forward to joining the community and learning more.

I am in the same boat as you. I came off a big single turbo IS300 with a lowered compression of 9.0:1. I was surprised as well about the relatively higher compression ratio. As some of the tuners have stated the injectors on this car atomize the fuel differently allowing higher a/f ratios.

IATs are amazing low on the car even with boost up to a bar on the car. If you search around a bit, I think you can find some of the info I found as well on the design of the motor/fuel system.

[Riss Racing]

Welcome!

[Kiemyster]

welcome to the forum, keep us posted on your car

[Year's_End]

Nice first post! Welcome to teh forums.

[sambonator]

Be sure to get a high-pressure fuel-pressure gauge. I'm not sure if any other cars run such a high pressure fuel system (200 bar or something).

[Steve335i]

Good point! After further study it doesn't look like there is anywhere for a FP gauge on the high pressure side, unless the signal could be robbed from the high pressure sensor.

So much to learn. Thanks for the welcomes.

[Former_Boosted_IS]

Originally Posted by Steve335i

Good point! After further study it doesn't look like there is anywhere for a FP gauge on the high pressure side, unless the signal could be robbed from the high pressure sensor.

So much to learn. Thanks for the welcomes.

I am sorry, but why would you put a FP gauge on the car? I understand the fuel pump failures, but that is BMW's problem if it fails. The wideband O2 seems like a better investment.

[Steve335i]

Once you start modding you can't necessarily rely on your warranty if something goes wrong. Going lean on a highly stressed forced-induction motor will cause damage. Monitoring AF and FP is cheap compared to valvetrain and or piston damage. Like I said, the wideband will be my first mod with the DP's.

Finding a 3,000 psi FP gauge is going to be a challenge!

[Sleepr335]

Direct injection allows you to safely run higher compression and a more lean AFR. Its the same approach that VW/Audi took. The old 1.8T was not direct injection, had about 9.0 to 1 compression and safely run 20psi on pump. The new 2.0T FSI motor is direct injection, has 10.0 to 1 compression and still can run 20psi on pump gas. I could be wrong but I think Mitsubishi has also started using direct injection.

[Former_Boosted_IS]

Originally Posted by Steve335i

Once you start modding you can't necessarily rely on your warranty if something goes wrong. Going lean on a highly stressed forced-induction motor will cause damage. Monitoring AF and FP is cheap compared to valvetrain and or piston damage. Like I said, the wideband will be my first mod with the DP's.

Finding a 3,000 psi FP gauge is going to be a challenge!

I am not sure why you state it is a highly stressed engine? F/I doesn't imply highly stressed if the internals are built correctly.

FP and wideband are clearly the best choices if that is the direction you choose. On a side note, the stock car tunes about 13.5:1 under full boost. The tuners I have seen are tuning about 12.5:1 on full boost. The fact that BMW is tuning to 13.5:1 shows this engine is not like our old boosted cars.