[cwn23]

I have read the V3 suppose to control boost through the throttle position...I mean if you do a WOT with the throttle, shouldn't boost be at or near 14 psi from the get go....Right now in first gear and second i WOT, i only see about 10-11 psi at most near 5500 rpms...I am running the stage 2 with map 2....Basically if V3 controls boost with the throttle, WOT should be at or near 15 from the get go....I don't know if this statement is correct or maybe there is a boost leak on my car, but I would like some info on this if anyone can chime in....
I just want to know if my V3 is working right or there is something wrong with my car!!

[e90AW335i]

Originally Posted by cwn23

I have read the V3 suppose to control boost through the throttle position...I mean if you do a WOT with the throttle, shouldn't boost be at or near 14 psi from the get go....Right now in first gear and second i WOT, i only see about 10-11 psi at most near 5500 rpms...I am running the stage 2 with map 2....Basically if V3 controls boost with the throttle, WOT should be at or near 15 from the get go....I don't know if this statement is correct or maybe there is a boost leak on my car, but I would like some info on this if anyone can chime in....
I just want to know if my V3 is working right or there is something wrong with my car!!

On a non-doomsday high boost map with a WOT pull you should see 11-12 in the low end with a ramp up to 14psi around 4000rpm than drop back down a little and than a ramp up to ~15psi at 5000rpm-5800rpm and than it will drop down to ~10psi by redline....

[cwn23]

Originally Posted by e90AW335i

On a non-doomsday high boost map with a WOT pull you should see 11-12 in the low end with a ramp up to 14psi around 4000rpm than drop back down a little and than a ramp up to ~15psi at 5000rpm-5800rpm and than it will drop down to ~10psi by redline....

If thats the case, then my V3 is working correctly!!! I just thought that i would see 14 psi more earlier in the rpm band....I haven't really got on the car past third yet and I still haven't seen more than 12 psi with the stage 2 map 1..!!!!!!!!!

[e90AW335i]

Originally Posted by cwn23

If thats the case, then my V3 is working correctly!!! I just thought that i would see 14 psi more earlier in the rpm band....I haven't really got on the car past third yet and I still haven't seen more than 12 psi with the stage 2 map 1..!!!!!!!!!

You should cool down with the !!!!

It makes it hard to read. In order to see what V3 is really doing go out and down a 2nd thru 4th full rpm pull in DS mode letting the car shift. Do that and come back and tell us what boost you hit....

[Accel Junky]

I asked Shiv that question, as to why full boost wasn't hit earlier and he said it was (basically) to keep knock in check.

[rooster3.0]

The tps referenced boost control is the most noticable feature to me. Makes the initial take off with a 6mt much nicer.

[cwn23]

Originally Posted by Accel Junky

I asked Shiv that question, as to why full boost wasn't hit earlier and he said it was (basically) to keep knock in check.

Yeah i can understand that statement, but what puzzles me is that its not even close to 15 psi...Its about 3 to 4 psi...With V2 peak boost psi was reach as soon as you WOT and the car didn't seem to knock...

[Accel Junky]

Originally Posted by cwn23

Yeah i can understand that statement, but what puzzles me is that its not even close to 15 psi...Its about 3 to 4 psi...With V2 peak boost psi was reach as soon as you WOT and the car didn't seem to knock...

Yeah, I was kind of wondering why the car would knock at 15psi at earlier RPM and not later? I'm so used to the old school "spool it asap and hold it" philosophy. But these guys know the engine I would think.

I think he also mentioned this was to ensure better drivability (I guess tire spinning doesn't help the seat of the pants feeling). I can't remember where the thread is.

[StarrDlux]

these cars tend to run lean at peak torque (from dyno's i've seen) ,also at peak torque you have more time for detonation (or pre ignition) as the rpm's inc rease the time window for detonation derease.

I know the audi HPFP doesn't have enough flow at peak torque since it is partially mechanical (low pressure primary pump feeding a high pressure mechanical pump). does the bmw work the same way? a mechanical pump has a linear pump rate based on the rpm's.

anyone care to explain how the bmw HPFP works? is it high pressure electronic in rear? low pressure electronic (PWM? regulated?) in rear? secondary electric or mechanical HPFP in front?

inquiring minds would like to know

[Accel Junky]

Originally Posted by StarrDlux

a mechanical pump has a linear pump rate based on the rpm's.

Good call, I forgot about that. Maybe that does make sense then?

[e.n335]

Originally Posted by StarrDlux

these cars tend to run lean at peak torque (from dyno's i've seen) ,also at peak torque you have more time for detonation (or pre ignition) as the rpm's inc rease the time window for detonation derease.

I know the audi HPFP doesn't have enough flow at peak torque since it is partially mechanical (low pressure primary pump feeding a high pressure mechanical pump). does the bmw work the same way? a mechanical pump has a linear pump rate based on the rpm's.

anyone care to explain how the bmw HPFP works? is it high pressure electronic in rear? low pressure electronic (PWM? regulated?) in rear? secondary electric or mechanical HPFP in front?

inquiring minds would like to know

Mechanical, bolted on the engine feeding a rail to the injectors.

[scalbert]

Originally Posted by e.n335

Mechanical, bolted on the engine feeding a rail to the injectors.

But with an electrical controlled bypass solenoid valve. In other words, absolute fuel pressure is mechanically controlled but actual pressure is DME controlled.