[Acap14]

i was racing a camaro SS last nite, from a dig i killed him, but from a 30 roll he pulled a car and a half. I probably could have caught him but when shifting from 2nd to 3rd my car hesitated before accelerating, and the same thing with 3rd to 4th. Why does this happen and how do i fix it?

[533ogetnom]

Originally Posted by Acap14

i was racing a camaro SS last nite, from a dig i killed him, but from a 30 roll he pulled a car and a half. I probably could have caught him but when shifting from 2nd to 3rd my car hesitated before accelerating, and the same thing with 3rd to 4th. Why does this happen and how do i fix it?

it could have either been boost lag or the CDV/way you shift

was it a kind of bouncing thing when you went into gear and hit the gas, or did it just slowly ramp up the power?

[Acap14]

i did the cdv delete and it wasnt bouncing or anything it just wouldnt go for a sec.

[533ogetnom]

Originally Posted by Acap14

i did the cdv delete and it wasnt bouncing or anything it just wouldnt go for a sec.

right.. so was it like no accel at all, then it acceled all of a sudden, or was it an acell, then a quickly raising increase in accel?

the prior would be due to the way you shifted, the latter is boost lag (its more noticeable in higher gears)

[Acap14]

accel then quickly raising, how do i get rid of that.

[533ogetnom]

Originally Posted by Acap14

accel then quickly raising, how do i get rid of that.

take off the turbos?

[Acap14]

my boy told me a bov will help, but idk how true that is, no exhaust mod will help this?

[533ogetnom]

Originally Posted by Acap14

my boy told me a bov will help, but idk how true that is, no exhaust mod will help this?

your boy is a complete fool

exhausts mods will help, in fact thats pretty much the only thing that will if its turbo lag, anything that lowers the back pressure on the turbo (DPs exhaust) will help them spool fatser

how long of a delay? <2 seconds or more

get a boost gauge, that will tell you for sure

[Acap14]

nah def not longer than a sec. i think im gonna order Dps this week. maybe im shifting wrong, but what am i doin wrong?

[turbotko]

I've felt it before, normally on the 2-3 shift though. If I bang a hard ass shift (close to powershifting) when the clutch re-engages the engine does not supply power for just a breif second. It's almost like the throttle body didn't open back up again immediately when I backed off the throttle then re-applied it very quickly. I have the CDV deleted and it's not the clutch slipping........I can feel the clutch re-engage in my ass, but the engine just does not supply ANY power for a split second.

I am willing to bet money it's in the drive by wire system on the car not opening up the TB immediately.......oddly it doesn't do it every time. Anybody ever notice when running to redline in a couple of gears then quickly backing off the throttle at high rpm (close to redline), the car continues to accelerate for a split second........almost like I didn't take my foot off of the gas? More drive by wire crap. I miss the feel of a cable operated TB.

I've chocked it up as normal.......most the newer manual trans beemers I drive do it when shifted brutally fast.

[Clem]

I know exactly what you mean. You fall totally off boost for a second and then spool up. It happens to me occasionally when I shift really fast. My remedy is to slow my shifts just a little bit and I don't have the loss of boost. One thing's for sure, it sucks when engaged in a friendly speed contest. It happen to me while having a go with a new Acura TL Type S. I dusted him by two cars in first and then lost boost when I hit second. He didn't gain on me, but he did fall back like he should have.

[A418t81]

Yep, it happens when you shift fast. Its not a transient boost problem, its DBW crap, whether programmed or not, I'm not sure.

[Acap14]

i remember reading something about it on here but when i searched it nothing came up, i was soo pissed that nite thinking my car was Fed up. bimmers are weird in order to go faster i have to slow my shift. sweet. thanks for the feedback.

[533ogetnom]

i dont think its dbw stuff (least related to throttle), i know what your talking about, it seems like the clutch is either slipping (cdv or not) or like boost isnt being generated, maybe its the waste gates not acting fast enough

[Acap14]

maybe its the wastegate being open too long?

[achien]

Is this because of Procede? I never had this "hesitation" on my MT, even going past +6,000 RPM.

Originally Posted by Acap14

i was racing a camaro SS last nite, from a dig i killed him, but from a 30 roll he pulled a car and a half. I probably could have caught him but when shifting from 2nd to 3rd my car hesitated before accelerating, and the same thing with 3rd to 4th. Why does this happen and how do i fix it?

[Cookiemonster]

Don't go to redline. Shift maybe 500 to 700 rpm short of red line and you will not get the hesitation.

[M3EST]

Correct.When i try to shift a litle earlyer it doesnt happen.It can happen with or without procede.

[Acap14]

i redline 2nd but not 3rd and it happens both times.

[Sniz]

ive had this happen too....not cool!

I wish someone knew for sure what is causing it? Its like the car is bogging for a half second right after aggressive shifting. Strange. Never had this before in any of my other cars. I had it on the 3 to 4 shift.

[turbotko]

I swear it's not boost response........the engine doesn't produce ANY power for a split second. If it was boost response you would at least get some power then feel the boost come back on. It's gotta be DBW not getting the TB closed and back open again fast enough.

It feels like I lifted off the throttle briefly to shift (just short of a power shift) and then forgot to re-apply the throttle again after the shift. I also have noticed that on a slightly slower shift it's fine. I did a few full bore power shifts last night (I know I know) without taking my foot off the gas at all and the car pulled just fine as soon as the clutch was back out.

It's DBW..........it's gotta be. It could be something as simple as the motor in the TB can't go from WOT to completely closed and back to WOT as fast as my foot can.

[Sniz]

Originally Posted by turbotko

I swear it's not boost response........the engine doesn't produce ANY power for a split second. If it was boost response you would at least get some power then feel the boost come back on. It's gotta be DBW not getting the TB closed and back open again fast enough.

It feels like I lifted off the throttle briefly to shift (just short of a power shift) and then forgot to re-apply the throttle again after the shift. I also have noticed that on a slightly slower shift it's fine. I did a few full bore power shifts last night (I know I know) without taking my foot off the gas at all and the car pulled just fine as soon as the clutch was back out.

It's DBW..........it's gotta be. It could be something as simple as the motor in the TB can't go from WOT to completely closed and back to WOT as fast as my foot can.

maybe the best technique would be to not fully let off the gas during the aggressive shift. Its a VERY fast movement and maybe the DBW cant react that fast. The idea of Powershifting w/ gas FULLY depressed at 6500k is just asking to break something, so maybe going 1/2 throttle for that split second will help. The DBW simply wont have to adjust as much.