[335pm]

I have jb4 and e85. When launching the car hard on first and second gear change i feel a knock from the back sometimes.it feels like maybe diff. Im not sure if its normal. It only hapends sometimes when the car launches really hardd

[harms]

Never had this myself. But symptoms you describe sound like diff. Perhaps check all bushes though.

[fo55il]

Sounds like dtc/dsc.

Does it happen with it off?

[DR-JEKL]

wheel hop/axle tramp?

That's relatively normal if it's always been there, if its only just started to occur it could be your diff dying...

[335pm]

It only hapends when boost hits realy high. I think it might be either dtc or the gearbox switching gears so fast. Does jb4 alter gear changes any way?

[Scotty89]

Originally Posted by 335pm

It only hapends when boost hits realy high. I think it might be either dtc or the gearbox switching gears so fast. Does jb4 alter gear changes any way?

No I don't believe so, however I have seen a "boost reduction on shift" setting in the JB4 desktop program.

Can you get a video of it by any chance?

Might be worth getting a Pedders 28 point check, they will put your car up on the lift and check suspension and bushing components and tell you if there are any problems.

The check used to be like $15 or something, and free for RACV members (and no obligations). I'm not sure if they still do it.

[fo55il]

Try wkth traction control off first before u do anything else

[335pm]

Felt it again last night.out of about 30 WOT it happend once. Only when i changed from first to second on a very hard launch i felt a knock from diff area. My dtc and dsc were off. Im not sure if its the tranny coz it hapends only on gear change or maybe diff but i dont have any other simptoms and it hapends once every 20 hard launches

[harms]

Originally Posted by 335pm

it hapends once every 20 hard launches

Jeez, how many hard launches each day do you do?

[335pm]

Originally Posted by harms

Jeez, how many hard launches each day do you do?

Lol hahah was on hwy last night so did a lot of racing. Soo hard to drive it normal.

[BMJ]

LOL i can count the number of times i go in to DS in a month on my hand. jeeze i have to start flogging my car more.

[harms]

Originally Posted by 335pm

Lol hahah was on hwy last night so did a lot of racing. Soo hard to drive it normal.

What do you call a hard launch... stalling up the auto first, or just flooring it from the lights?

[335pm]

Originally Posted by harms

What do you call a hard launch... stalling up the auto first, or just flooring it from the lights?

Stalling up to 1500 rpm and launch. So hard cruising in D with alpina trans flash. Its soo slow in D. Feel like miss daisy

[lemonpark]

HAHAHA naaaiiiiiiice, someone that drives the car hard too!! I'm the opposite, I think I can count on one hand how many times I've left the car in D for more than 5seconds when I drive

[Testercles]

Stupid question: Stalling-up first. Does that mean revving in N then going into D?
Also with the Alpina trans flash I imagine that you get way better economy in D?

[harms]

Originally Posted by Testercles

Stupid question: Stalling-up first. Does that mean revving in N then going into D?
Also with the Alpina trans flash I imagine that you get way better economy in D?

Its holding the brake and accelerator at the same time. Let go of brake and off you go like a rocket.

I do 80% of my driving in D with with alpina, mostly inner city and cbd. Didn't really notice improved economy. I don't really like the flash - D is not sensitive enough, S holds the gears too long, and I have an odd shift in M sometimes when pushing along and i short shift. I'm thinking of reverting back.

[Scotty89]

Originally Posted by Testercles

Stupid question: Stalling-up first. Does that mean revving in N then going into D?
Also with the Alpina trans flash I imagine that you get way better economy in D?

No no no... don't shift it from N into D unless you are off the accelerator.

Stalling up means to prep the stall converter in the auto by holding the brake pedal with the left foot (hard) and then light pressing the accelerator to raise rpm to about 1500 - 2000 or so.

Then when you want to launch, release the brake and press the accelerator to the floor.

Don't try it in traffic, as the first time you ever try left foot on the brake is always awkward and will result in tragedy when you don't have a clear path ahead of you.

[Socket]

Originally Posted by harms

Its holding the brake and accelerator at the same time. Let go of brake and off you go like a rocket.

I do 80% of my driving in D with with alpina, mostly inner city and cbd. Didn't really notice improved economy. I don't really like the flash - D is not sensitive enough, S holds the gears too long, and I have an odd shift in M sometimes when pushing along and i short shift. I'm thinking of reverting back.

I have alpina flash too.... I use D for bumper to bumper traffic only, drive mostly in S, don't notice the long gear hold in S, changes up around the 3500 mark
M downshift rev matching is much better than stock. Got mine installed in Oct latest version and no problems here

[harms]

Originally Posted by Socket

I have alpina flash too.... I use D for bumper to bumper traffic only, drive mostly in S, don't notice the long gear hold in S, changes up around the 3500 mark
M downshift rev matching is much better than stock. Got mine installed in Oct latest version and no problems here

Off topic here, but yeah D is fine for most bumper to bumper driving, but its a pain if you need a quick squirt to get through an amber light or something like that. Throttle sensitivity is really low. S does change at 3.5 ish which is fine, but i find when i give it the boot up to 6-ish and then back off (usually to stay within the speed limit) it just annoyingly holds the gear and doesn't upshift. But i really like the throttle sensitivity in S.

M downshift is better than stock most of the time, but i find it sometimes ever so slightly over-revs in the rev matching, creating a run-on effect. I had the flash done just last month so assume its the latest version.

I wonder if the flash would be better if my car had more power to work with... (i just have jb4). Perhaps i'm just looking for an excuse to get downpipes...

[Socket]

Originally Posted by harms

Off topic here, but yeah D is fine for most bumper to bumper driving, but its a pain if you need a quick squirt to get through an amber light or something like that. Throttle sensitivity is really low. S does change at 3.5 ish which is fine, but i find when i give it the boot up to 6-ish and then back off (usually to stay within the speed limit) it just annoyingly holds the gear and doesn't upshift. But i really like the throttle sensitivity in S.

M downshift is better than stock most of the time, but i find it sometimes ever so slightly over-revs in the rev matching, creating a run-on effect. I had the flash done just last month so assume its the latest version.

I wonder if the flash would be better if my car had more power to work with... (i just have jb4). Perhaps i'm just looking for an excuse to get downpipes...

Running JB4 only here too, sounds like our experience with the AF is the same... maybe you're more ricer then me Harmsy