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borgiaz
Alias Luana
Regione: Estero
Cittą: Bikini Bottom
5137 Messaggi |
 Inserito il - 27 gen 2009 : 23:30:31
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Aggiornamenti:
This is a dead issue. I've pounded through this with the XP car since the inception. It is not related to ABS. This is related to lack of vacuum in the brake booster after a period of acceleration. With no vaccum in the brake booster, you will have essentially zero power brakes until the vacuum recovers. Replacing the check valve that is just off the motor will help. However, we solved it with a supplemental vacuum canister and an additional check valve. This supplements the vacuum available to the master cylinder. We do not have "ICE mode" anymore. The lotus OEM valve is a super-cheap plastic piece of crap and should be the first thing replaced. BTW, currently our tires are BIGGER diameter in the front vs. rear. This solution cured the braking problem when we had properly sized tires and it has not come back with the current configuration.
The check valve is a connection between the vacuum hose that runs off of the intake manifold/throttle body. Follow the hose to a fitting that connects to another hose. The check valve is two barbs, one on either side of quarter-sized circle.
http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2DG1464&N=700+4294922533+115&autoview=sku
http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2D230606&N=700+400304+115&autoview=sku
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Gran Direttore del Collegio dei Probi Viri di Derapados ad Honorem
L'avvocato č un galantuomo che salva i vostri beni dai vostri nemici tenendoli per sč (Heinrich Heine)
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Modificato da - borgiaz in data 28 gen 2009 12:05:27 |
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ale.cigo
Derapados Ignorant Member
Regione: Piemonte
Cittą: verbania
2195 Messaggi |
Inserito il - 28 gen 2009 : 21:19:13
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| ...........brutti pensieri........ quanto pesa tutto l' "affare" dell abs?? non credo che mi ucciderei senza..bho |
http://www.workshoplife.net/ |
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borgiaz
Alias Luana
Regione: Estero
Cittą: Bikini Bottom
5137 Messaggi |
Inserito il - 28 gen 2009 : 21:41:24
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| Su strada basta che intervenga una volta nella vita per ripagarsi del peso in piu. Per un utilizzo esclusivo in pista, toglierlo sarebbe una buona scusa per eliminare anche il servofreno, che e“ indispensabile per il funzionamento dell“abs. |
Gran Direttore del Collegio dei Probi Viri di Derapados ad Honorem
L'avvocato č un galantuomo che salva i vostri beni dai vostri nemici tenendoli per sč (Heinrich Heine)
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Andytpks
Membro sottosterzante
Regione: Lombardia
Cittą: Sondrio
85 Messaggi |
Inserito il - 29 gen 2009 : 23:52:16
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ne approfitto per farti gli auguri di buon compleanno, borgiaz!  |
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borgiaz
Alias Luana
Regione: Estero
Cittą: Bikini Bottom
5137 Messaggi |
Inserito il - 30 gen 2009 : 09:42:08
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THANKZ!! |
Gran Direttore del Collegio dei Probi Viri di Derapados ad Honorem
L'avvocato č un galantuomo che salva i vostri beni dai vostri nemici tenendoli per sč (Heinrich Heine)
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borgiaz
Alias Luana
Regione: Estero
Cittą: Bikini Bottom
5137 Messaggi |
Inserito il - 30 gen 2009 : 16:20:23
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Giusto per essere completi (Wire, mettiamo tutto nelle FAQ una volta per tutte?)
Dear Mr Cross,
Re: Vauxhall VX220
I write further to my previous letter dated 14 July. I welcome this opportunity to offer technical feedback provided by our Senior Product Evaluation Engineers.
Following receipt of comments made on behalf of 60 VX220 customers regarding braking performance with ABS activated, a ride session was conducted at Palmer Sport Bedford. In attendance were representatives of General Motors International Technical Development Centre, Lotus Cars, General Motors Europe Customer Care and Palmer Sport instructors.
The main concerns addressed were:
* Lack of deceleration after activation of ABS in general
* Lack of deceleration after passing a friction transition from low (wet surface) to high (dry surface)
* Premature intervention of ABS on bumpy surfaces resulting in reduced deceleration and vehicle understeer
It is believed that some of the above comments had resulted from a decision by Palmer Sport instructors to run the track cars with the ABS permanently de-activated. A series of tests was carried out to show the Palmer Sport instructors that the vehicle deceleration with ABS is much better compared to the deceleration without. They personally tested the vehicles and were surprised by the results.
Service Request No. : ************
Concerning transition, the test procedure on ice to asphalt transitions in North Sweden was explained and also the requirements behind it (maximum deceleration on high friction surfaces reached within 0.7 second of passing the transition, which will be more demanding than wet to dry asphalt).
It was also explained that the subjective feeling of early intervention on bumpy roads or solid bumps are not symptomatic of an efficiency problem. This behaviour is driven by the low front axle load of the car. Specifically, braking in a turn can cause early interventionon the inside front wheel. However, ABS allows application of a much higher brake pressure on the outside front wheel than would be possible without ABS. The result without ABS is a locked inside front wheel. This was agreed by all participants.
On their test tracks, he instructors show customers how to race a VX220. In view of this, the ABS is de-activated and, in this instance, they are able to steer the car in difficult situations using the brakes, if there is too much understeer. The car oversteers in these situations and thus allows optimisation of the handling. However, under these conditions, the car is only controllable by an expert driver.
With ABS and DRP (Dynamic Rear Proportioning module) is activated and this prevents oversteer by controlling the braking to the rear axle. Therefore, a VX220 driver is not able to control the car as demonstrated by the Palmer Sport instructors. However, the car performs exactly to the design intent and this ensures maximum stability in normal driving conditions. It is a deliberate policy that the handling performance on open roads will never be reduced to the level of shutdown of the DRP function.
Conclusions
1. No safety problem on the VX220/Speedsteer was evident
2. TRW have checked the difference between the Lotus Elise and VX220/Speedster. A statement from TRW shows no major deviations between the production software of the two cars. Only phsyical items, such as dynamic tyre circumference, are different; the rest seems identical.
There are small differences in slip values on the rear wheels, but everything is the same at the fronts, which is important for the ABS intervention on bumpy roads. TRW have also stated that system tuning has been set to reach the same vehicle behaviour.
3. Deceleration after ABS intervention caused by bumps or pot holes.
In all cases (straight ahead and bends), the deceleration is 8-10% higher with ABS operational compared to the shut off version. This confirms initial results concerning deceleration potential of the ABS system, obtained during a previous visit to Palmer Sport.
4. All engineers performance targets concerning friction transitions are achieved with this ABS system.
Target: After a transition from low friction (below 0.15) to high friction (above 0.8), the maximum deceleration on a high friction surface must be reached after 1 second. ABS will be activated at least 1.5 seconds before the transition. Maximum pedal force is 500 Newtons.
The VX220/Speedster reaches the maximum deceleration after 700-800 milliseconds, which is state of the art.
I hope all of the above information is of use to you.
Thank you for allowing me to comment.
Your sincerely
Executive Support Manager |
Gran Direttore del Collegio dei Probi Viri di Derapados ad Honorem
L'avvocato č un galantuomo che salva i vostri beni dai vostri nemici tenendoli per sč (Heinrich Heine)
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DreamingNeonBlack
il Dreaming
Regione: Piemonte
Cittą: Torino
1957 Messaggi |
Inserito il - 31 gen 2009 : 14:47:08
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| Insomma... va tutto alla grande. |
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borgiaz
Alias Luana
Regione: Estero
Cittą: Bikini Bottom
5137 Messaggi |
Inserito il - 31 gen 2009 : 15:46:59
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| Ovvio. |
Gran Direttore del Collegio dei Probi Viri di Derapados ad Honorem
L'avvocato č un galantuomo che salva i vostri beni dai vostri nemici tenendoli per sč (Heinrich Heine)
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Problemi ABS? Pedale duro?
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