Z-BOX revisited

[DanE]

Ok, now I have finally got some sets in behind the PP Z-Box in our club boat (99 SN Gt-40 422 ACME)

Early sets of the season it felt promising, I ran it at weight setting Normal and C2 (C2 is what I use at tourneys).

Weighing 190 and running in to 38 off 34 mph made my ball three times slow with the usual cathing up for a perfect 16.95 end course time.

At first it looked like an easy fix as the speed entering the course seemed ok and ball 1 times were spot on (1.77) all I did was increase the ball three value (background settings for balancing the segment times) to 60 (factory default was 50).

Now the split times got as good as they can get with ball 1 times mostly 1.77 ball 3 alot of 7.13 and 7.14 and an occasional 7.15 (7.15 is were I feel the boat racing after ball 3 to play catch up) but since the 7.15 were very rare I considered tweaking was done.

Well after some more skiing and driving I think allthough the split times are good the response out of the system is best described as weird- I would say It does not throttle enough through the gates and out of #1 and therefore starting a catch up game coming in to #2 to get good times to #3.

One can hear the boat continously increasing rpm´s up until 3 ball were it finally settles in for the rest of the course.

So, I tried the weight setting X-Large and got good times right away with one ball more often 1.76 than 1.77 but the rest of the pass dead on.

Well, this also caused a weird acting from the system similar to what I described above but maybe even worse.

At X-Large the boat comes in a little fast through the gates so I cannot hear any gassing through the gates or out of #1 wich causes the boat to be slow between #1 and #2 and the revving starts again to increase until it gets a perfect 7.13 and settles in.

I swear I have seen Youtube vids showing PP Z-Box sounding very similar to Zero off with a noticable rpm increase for every pull the skier make including the cut through the entrance gates, my system does not sound like that-it´s more of an increasing rpm all the way from gate to ball 3 then nothing spectacular from 3 to exit. Just weird, needless to say #2 and #3 are difficult to get through as I´m dealing with a boat that runs away.

 

Does anyone recognize this and have a fix (I´m mailing PP also but am greatful for all input I can get)

 

p.s sorry for the long post

[nate93]

A guy I ski with has a 98 Nautique and has the exact same issue. I skied it one time and had to take a week off so my back could recover! The stargazer does the same thing.

[gjohnson]

@DanE - We've been struggling with ZBOX all season and the run away boat has been an on going problem. Recently we made a change to the zbx setting. I believe the default setting is 11 and we changed it to 7. That seemed to taper it a bit. But I've only got a few passes under my belt so I'm not sure if it's the answer or not yet. You may benefit from that if you haven't already tried it.

[jackski]

@ Dan, are you putting in the crew weight ? On short setups it makes a difference on mine for sure.

 

What is your entance speed outside of the course around the 55's ? For me to get actuals on most segments and I need to be right around 55. 4.

[DanE]

@jackski Yes I´m entering crew weight, we ski on a big lake so the setup is as long as we choose.

Speed at the greens is 55 kph.

I skied a set just now and tweaked away just for kicks.

I have not really felt the ZO zoom yet (wich I actually like as the boat accelerates me through the wakes when in a strong position and leaves me alone when in the turn) so I thought that PPs own KX value might be too strong so the Z-box doesn´t need to give that much input.

Lowered KX to - and added 5 to the ball 1 setting.

This felt better allthough I didn´t drive a skier my weight so I cannot confirm what the boat sounds like, but it did feel as I was more free of the boat in the turns.

Now the ball 1 and 3 times were both on the slow side so I upped them to 18 for ball 1 and 60 for ball 3, ( started the set with ball 1 at 13 and ball 3 at 50) and now the times for 1 and 3 was constantly good (head and tailwind still most 6.77s and 7.13s) but ball 2 was always +.02 on the slow side and ball 4,5 and 6 all were all around -3 on the fast side and still perfect 16.95 at the end.

Seems to me that I pull the boat down out of #1 so its slow to #2 and therefore races to # 3 in order to get a 7.13 then overshoots the speed so it´s fast to #4.

Next step was to lower the 4to EXIT value but by then the chop had turned too big and I was tired so I didn´t get to try that.

 

[danbirch]

I've heard this from several other people as well. Sounds like a "software update" would be appropriate.

[Razorskier1]

Check with PP. My boat is a 2005 and DBW, but I did just install a software update. Seems to help. Also running zbx at 7.

[DanE]

I have been in contact with PP and they say that the few hundreds I´m looking to correct is neglibigle (of wich I agree).

It´s not the times I´m dissapointed with, it´s the feel of the system and knowing the boat is always slow to ball 2 and catching up to ball 3.

Being a lefty I don´t need 2 ball to be any more difficult than it already is.

[Marco]

I've got an '01 Malibu and I'm lovin the Z box. I'll take one set behind my boat, and the next behind a ZO CC, and the pull feels remarkably similar. I've been skiing C1 lately, and can hardly tell the difference between the two systems.

[usaski1]

Agreed Marco, skiied behind a 2012 malibu with ZO on B2 last night, and it was great, and my B2 on my z-box, I can't tell a differnce. So if you don't look at the numbers, can you tell a difference? .01-.02 is splitting hairs.

[kurt]

Dan I have an 01 malibu and I am loving the z box ,the trouble comes when I have a new driver that drives it like ZO and over accelerates then it slows down too much between the gates and 1 ball then accelerates between 2 & 3 . If you throttle up right to the needed rpm it is perfect.

It takes a little to get used to but it is great when dialed in.I also have lowered my setting to a 7 and it feels just like my buddy's '12 TXI

[Marco]

Agreed... Driving Stargazer is not as brainless as driving ZO. A little driver training goes a long way!

[nate93]

Have you guys seen the times go from +3 to -5 in on gate? That is making up .08 in on bouy. Yea they are in tolerance but you can't ski that! We've tried everything as far as settings go to eliminate it.

[DanE]

@nate93 Exactly! This is what I´m talking about, mine goes from +.02 to - .03 from ball 2 to ball 4 (a .05 pickup in two buoys) even that is too much not to be felt.

And I feel as the gassing occurs in the preturn and through the turn at #2.

From the comments here it appears that 1:1 trannies seem to work better with SG/Z-box.

I do believe I saw a video in some older thread that showed a Malibu that sounded exactly like a ZO boat.

Fwiw, I have told the drivers to just move the throttle up until engagement and no further, we have a setup that is ridiculously long so the system has plenty of time to settle in before the greens.