Unlinked dyno dangerous 4WD?
06-08-2016, 11:46 AM
#1
Unlinked dyno dangerous 4WD?
Have arranged a group of 12 guys to go get our cars dyno´ed at a long time "specialist". Two of the cars are 4WD, namely my 964 and a 996.
Now 3 days before the workshop tells me that they won't take responsibility for the 4Wd´s because the 4WD dyno consist of 2 separate dyno, that is not linked together and that could cause serious damage to the differential on the car.
Anyone know if that is true?
He tells me that they have no issue in dynoing Audi´s but can't do newer porsches
Now 3 days before the workshop tells me that they won't take responsibility for the 4Wd´s because the 4WD dyno consist of 2 separate dyno, that is not linked together and that could cause serious damage to the differential on the car.
Anyone know if that is true?
He tells me that they have no issue in dynoing Audi´s but can't do newer porsches
06-08-2016, 12:57 PM
#3
This is from technical overview so I belive you are right :
WARNING —
The all wheel drive system is permanently engaged and can-not be switched off. Do not allow a Carrera 4 to be tested on
a 2-wheel dynamometer. This applies equally to an officially sanctioned emission inspection station or a performance
shop.
WARNING —
The all wheel drive system is permanently engaged and can-not be switched off. Do not allow a Carrera 4 to be tested on
a 2-wheel dynamometer. This applies equally to an officially sanctioned emission inspection station or a performance
shop.
06-08-2016, 06:58 PM
#4
Rennlist Member
Join Date: Jun 2010
Location: Detroit (Rock City); 1990 C4
Posts: 1,710
Likes: 0
Received 4 Likes
on
4 Posts
Must respectfully disagree, provided we can come to terms.
I think that what fluxdon is really describing in the first post is an awd dyno where there is no mechanical connection between the front and rear axle rollers; this would allow them to spin at different speeds depending on how the transmission in the car works.
The quote from the manual specifically refers to a 2-wheel dyno, which would force one set of wheels to remain motionless while the other spun at over 110mph. That would be bad, as there is a solid mechanical connection between the front and rear axle sets in the 964 C4 (vs. a completely open center diff). This same reason (I believe) would allow the car to work fine on an unlocked awd dyno. I'd go carefully, knowing that PDAS will step in to try and level things out if it detects too much speed difference front to rear, but it shouldn't hurt the car.
I dunno what the 996 AWD setup is like, but it should be OK too; the thing that will jack up an AWD car with a locking center differential is holding one set absolutely motionless while the other is free to spin.
I think that what fluxdon is really describing in the first post is an awd dyno where there is no mechanical connection between the front and rear axle rollers; this would allow them to spin at different speeds depending on how the transmission in the car works.
The quote from the manual specifically refers to a 2-wheel dyno, which would force one set of wheels to remain motionless while the other spun at over 110mph. That would be bad, as there is a solid mechanical connection between the front and rear axle sets in the 964 C4 (vs. a completely open center diff). This same reason (I believe) would allow the car to work fine on an unlocked awd dyno. I'd go carefully, knowing that PDAS will step in to try and level things out if it detects too much speed difference front to rear, but it shouldn't hurt the car.
I dunno what the 996 AWD setup is like, but it should be OK too; the thing that will jack up an AWD car with a locking center differential is holding one set absolutely motionless while the other is free to spin.
06-09-2016, 03:23 AM
#7
Trending Topics
10-03-2016, 11:22 PM
#10
Intermediate
Join Date: Dec 2011
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Are there any others that have used an unlinked Dynojet and had no issues? I am about to get my 964 c4 tuned next week on one of these dynos and do not want a broken drivetrain. Thanks in advance.