[Tommy420]

I feel like my turbos don't kick in until I hit about 3000rpms for every gear except first, which seems to come in a bit earlier. Is this more or less normal?

[335xi2k8]

Not exactly sure but since peak torque starts at 1900rpm..i assume they start kicking in before that.

[Taittinger]

Originally Posted by 335xi2k8

Not exactly sure but since peak torque starts at 1900rpm..i assume they start kicking in before that.

Peak torque is at 1400 rpm, or 1500.

[cooldude]

The turbos are always on.
otherwise there is no way they can get that torque.
the air compression varies by throttle response though.

[335xi2k8]

Originally Posted by Taittinger

Peak torque is at 1400 rpm, or 1500.

Yeah it is 1400rpm...sorry

[Accel Junky]

^^ What they said about the peak torque. On my test drive the powerband was very linear. Never felt a kick. Power from the get-go.

[achien]

the second my right foot gets on the pedal...

Originally Posted by Tommy420

I feel like my turbos don't kick in until I hit about 3000rpms for every gear except first, which seems to come in a bit earlier. Is this more or less normal?

[delman27]

With a tune you may feel a bit more lag and more "kick". In stock form it should feel pretty linear. If you crawl in first or second between 2000 and 2500 rpms with the windows down you should be able to hear them. At 1500 rpms they are already spooled.

[ZheHbKa]

Originally Posted by 335xi2k8

Yeah it is 1400rpm...sorry

+1, so as soon as you start moving they are on

[Tommy420]

I guess I might have worded my question wrong then. Usually, when I hit 2500-3000rpms, my car really picks up speed. Not that it's not fast before then, but the 2500-3000rpm area is where I really feel a pick-up. Is this normal?

[david @ eas]

Originally Posted by cooldude

The turbos are always on.
otherwise there is no way they can get that torque.
the air compression varies by throttle response though.

[Bimmerista]

Yes it is normal.

That's when the double VANOS kicks in.

[Taittinger]

Originally Posted by smokeya1

I.ve been trying to figure this out as well. When i floor it from a standstill, acceleration seems week between 0-10 MPH, after this a huge surge of power develops. Im not sure if this was caused by the reprogramming of the car, or if thats just how it is, but its rather annoying. My accelleration is NOT linear like everyone on here says.

Do you have DSC turned off? It will intervene until wheelspin is negligible.

[cooldude]

Originally Posted by jurrian @ eas

what's your point ?

[Xiaofeng]

As others have stated, the turbos have spooled up by ~1400 RPM. For what it's worth, on my car it feels like it really kicks in closer to ~1900 RPM, but that is probably due in part to xDrive and slightly higher parasitic losses. Beyond that, the power delivery is pretty linear.

Originally Posted by cooldude

what's your point ?

I think Jurrian was just agreeing with you....

[GhostyM]

Lol. Torque is there, but the actually HP aspect of it is at its max at around 3K-4K rpm... thats why you probably think that way, whats better? 300TQ and 200HP or 300TQ and 300HP lol.

[GeauxChadE90]

the turbos are small, and turbos "spool up" from the exhaust exiting the headers. smaller turbos=faster spool up time. the higher the RPM's, the more frequently combustion occurs in the cylinder, and the more exhaust must flow out of the headers, powering the turbo faster. The 335 has a near flat line torque curve from 1900 RPM to just shy of redline, because the turbos spool quickly and produce the extra "umph" from the get go. There should be lag.

However, you don't recognize the lag in the higher gears because the turbos are already spooled up and the short amount of time that exists between shifting gears is not long enough to let the turbos spool down. In addition, when you switch gears, your engine enters the next gear at a higher RPM than at rest (about 600 rpm), where there is already more power.

This all breaks down to lag is normal when accelerating from a stop. Less noticeable in higher gears for 2 reasons: higher starting RPM when hitting next gear and turbos already compressing air into the cylinders (they don't need to spool up).

If you really want a difference, go buy a BIG after-market turbo (K04...add's 250 horsies), and watch that big bast*rd take off at about 5500 RPM...

On the other hand, superchargers are powered by a belt connected to the actual engine, instead of utilizing the byproduct of combustion like turbos, so the engine constantly powers the supercharger, and the supercharger constantly provides the same amount of power (more or less), thus no lag.

[The Other Tom]

Originally Posted by Chipped B6

Lol. Torque is there, but the actually HP aspect of it is at its max at around 3K-4K rpm... thats why you probably think that way, whats better? 300TQ and 200HP or 300TQ and 300HP lol.

Not sure what you mean by that, but it's the torque that gives the seat of the pants kick. HP gives top end speed.

[mwahlert]

Originally Posted by GeauxChadE90

the turbos are small, and turbos "spool up" from the exhaust exiting the headers. smaller turbos=faster spool up time. the higher the RPM's, the more frequently combustion occurs in the cylinder, and the more exhaust must flow out of the headers, powering the turbo faster. The 335 has a near flat line torque curve from 1900 RPM to just shy of redline, because the turbos spool quickly and produce the extra "umph" from the get go. There should be lag.

However, you don't recognize the lag in the higher gears because the turbos are already spooled up and the short amount of time that exists between shifting gears is not long enough to let the turbos spool down. In addition, when you switch gears, your engine enters the next gear at a higher RPM than at rest (about 600 rpm), where there is already more power.

This all breaks down to lag is normal when accelerating from a stop. Less noticeable in higher gears for 2 reasons: higher starting RPM when hitting next gear and turbos already compressing air into the cylinders (they don't need to spool up).

If you really want a difference, go buy a BIG after-market turbo (K04...add's 250 horsies), and watch that big bast*rd take off at about 5500 RPM...

On the other hand, superchargers are powered by a belt connected to the actual engine, instead of utilizing the byproduct of combustion like turbos, so the engine constantly powers the supercharger, and the supercharger constantly provides the same amount of power (more or less), thus no lag.

a K04 is NOT a large turbo....

and it depends on what type of supercharger.... centrifugal superchargers provide more boost as RPM increases, where "roots" or "positive displacement" superchargers ARE capable of providing X boost basically across the entire RPM range.

[Heat00]

I guess the old saying is actually true... there is no substitute for cubic inches

maybe you should have bought a vette or something... lol

My twins seem to be just right....

[av8thor]

But I just can't resist.


I know

I don't care.

[GeauxChadE90]

sorry, i misspoke about HP....should, and meant to, have said torque when referencing pickup....

K04 is not an exceptionally large turbo, but about as large as I would go on a turbo upgrade for a 335i before making it sound like a rice rocket, which would in turn require strapping a fart tube on the back and a 4 gallon bucket of hair gel in the back seat...

and, as there are 2 types of superchargers, anyone that would use a centrifugal over +displacement is moronic, and need not know the difference anyways...