ZPOST
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   ZPOST > BMW Z4 Technical Talk > Engine, Exhaust, Drivetrain Modifications
  TireRack

SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
Post Reply
 
Thread Tools Search this Thread
      04-14-2012, 12:11 PM   #529
Beedub
Major General
United Kingdom
423
Rep
5,327
Posts

Drives: 2007 Z4 M roadster vt2-500
Join Date: Sep 2007
Location: UK

iTrader: (0)

the prospect of an vt2 install going wrong is very scary, they never ever run right unless everything is right....

Ess has very wisely chosen to have this only available install a very limited dealers, i dont blame them.

im glad your still here OP, please post alittle more when work/family settles down :-) i miss your videos.
__________________
Z4MR VT2 - Clubsport build.
Multi award winning Detailing | Wrap | PPF specialists UK based - www.topwrapz.com
Appreciate 0
      04-14-2012, 07:36 PM   #530
iPhoneEngineer
Lieutenant
United_States
43
Rep
476
Posts

Drives: 2007 BMW Z4 M Coupe
Join Date: Jun 2010
Location: La Honda, CA

iTrader: (2)

Yeah, there are two major problems motivating me to send it in:

- When cold, the car is quite temperamental. I'm used to this as my '88 Supra Turbo was no better, but it's really annoying. The car will surge and misfire especially around 2.5-3k (never run a cold engine higher than that anyway, but 3k is usually desirable for a quicker warm-up, and that's not feasible until after the car has run for a few minutes).
- Even when completely warmed up, the engine will cut out entirely if given a large throttle input at or below 2,000RPM (even in 1st gear!). This invariably causes a violent lurching reaction in the power train as the motor is then restarted by the wheels, briefly produces power, and cuts out again, so I instead live in fear and try to avoid this.

I'm genuinely surprised that the car is so sensitive even at low RPM when there is very little boost that could possibly be leaking--and both smoke tests and my own analysis have indicated there is no leak until at least 4-5PSI. Of course, these problems exist even after ripping out the Active Autowerke Gen IV headers and swapping in OEM Euros.

I'm not really disappointed with the total power output since putting on the higher pressure pulley to compensate for the lost boost, but I'm hoping that the properly tuned setup will further impress.

As for videos, sadly I don't live up the hill anymore, but I'm not too far from the same route. I would like to take the car to a track soon (probably June or later due to other stuff) and will try some new AV stuff there.
Appreciate 0
      04-15-2012, 02:33 AM   #531
Beedub
Major General
United Kingdom
423
Rep
5,327
Posts

Drives: 2007 Z4 M roadster vt2-500
Join Date: Sep 2007
Location: UK

iTrader: (0)

iphone, i defo agree this car needs to go in for sure....

i can jam the throttle open at any rpm and get no hesistation or bucking... Now ther is one instance where i can cause a hesistation which is a known Ess s54 s/c tune blip.... If im in a low rev situation say 1500-2250, in a higer hear like 4th and open the throttle ill get a slightly hiccup, again AJ warned me he can tune this out but id loose some response as its due tot he agressive vanos timing... it NEVER happens because you literally never in a situation like this with the low Tq s54, so i choose to leave the aggressive tune in place....

1/2/3 however is jam the throttle down at any point and the car pulls cleanly and like a dog thats been bitten on the butt hole by gass snake.

iphone i stand back and look at my little z4m with its (admittedly) large amount of mods and i can help in thinking their really isnt much i could afford that id want over this.... the only car being a track spec GTR....

hows life with the Porsche and how are they run back to back.... the porsche forums are overun with grade A butt-holes.
__________________
Z4MR VT2 - Clubsport build.
Multi award winning Detailing | Wrap | PPF specialists UK based - www.topwrapz.com
Appreciate 0
      04-15-2012, 02:22 PM   #532
iPhoneEngineer
Lieutenant
United_States
43
Rep
476
Posts

Drives: 2007 BMW Z4 M Coupe
Join Date: Jun 2010
Location: La Honda, CA

iTrader: (2)

Definitely, I'd rather have the aggressive VANOS compared to higher gear, low end output as that's generally considered bad for the motor anyway and easily avoided. Hoping all remaining issues are sorted by the time I get the car back, but I won't be holding my breath.

The Turbo S has 900 miles on it now, though I'm still driving the M more than it. It totally demolished my friend's Lambo Gallardo in 3 different matchups (expected but fun). The driving character is obviously quite different with the very light front end on the Porsche, which can provide both a thrilling sense of agility and a disconcerting feeling depending on the situation. 0-60 in the Turbo S is completely unreal, but the boosted S54 never ceases to please, especially in sound (at least in person, the Porsche literally sounds more like a large turbine with lots of whooshing air induction--awesome in its own right, but not quite as satisfying as the mechanically vocal S54).

While the replies to my ~2 threads on 6speedonline (any other decent Porsche forums?) have been welcoming and helpful, in browsing the existing threads, I do notice the /average/ population is quite different from here in a very negative way. Fortunately there are still the domain experts with many thousands of posts that dedicate their time writing up DIY's and other helpful stuff.

Overall, it's a totally different machine. It's more or less perfect as-is so I don't plan to mod it, except perhaps an integrated radar detector. I'm going to treat the Porsche as a black box for at least a few years, and it's almost certainly for the better; it's really no fun to do work on personally, anyway. Amusingly complicated even just to change the spark plugs, which some find last only 15k miles: http://www.6speedonline.com/forums/9...ml#post2660804

That said, the traction and chassis stability is so dramatic that the car could easily handle a few hundred more HP as is commonly added via software tunes and/or larger VTG turbos. This wouldn't do much for 0-60 per say, but would be really killer in higher gears.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 08:51 AM.




zpost
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST