9 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHIs it safe to put a 996tt on a RR?
Leading reported evidence
Run c4s a couple of years ago in 4wd mode
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I ran my C4S a couple of years ago in 4wd mode on a Dyno Dynamics dyno, this had a 400bhp 4wd limit and the car's ABS/PSM and viscous coupling had the car bucking endangering the car and the dyno.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
The correct way to RR a C4S/Turbo is to disconnect the propshaft and run it in 2wd, in 4wd the viscous coupling will constantly divert power front to rear to front, the Turbo will possibly try and throw itself off the rolling road.
Leading evidence: 'Run c4s a couple of years ago in 4wd mode' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Disconnect propshaft' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
The correct way to RR a C4S/Turbo is to disconnect the propshaft and run it in 2wd, in 4wd the viscous coupling will constantly divert power front to rear to front, the Turbo will possibly try and throw itself off the rolling road.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
WRC's at Silverstone has run many 993 Turbos although that's only with the massive fans Allan has put in place to replace the missing airflow.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I thought there were some places where you could run 4WD cars now?
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
WRC's at Silverstone has run many 993 Turbos although that's only with the massive fans Allan has put in place to replace the missing airflow.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Disconnect propshaft
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
The correct way to RR a C4S/Turbo is to disconnect the propshaft and run it in 2wd, in 4wd the viscous coupling will constantly divert power front to rear to front, the Turbo will possibly try and throw itself off the rolling road.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I ran my C4S a couple of years ago in 4wd mode on a Dyno Dynamics dyno, this had a 400bhp 4wd limit and the car's ABS/PSM and viscous coupling had the car bucking endangering the car and the dyno.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I may be wrong, but I believe 4WD rolling roads assume an 'open' centre diff/coupling and calculate bhp by a formula using the figure at the measured axle?
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
9 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
911uk: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T051247Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Got my 996tt booked in for a power run on a local rolling road tomorrow but just wanted to check it's ok? It's a 4wd rolling road so no issues there, and I guess since the 996 is water-cooled with rads at the front, it should be fine?
Also, anyone any idea what transmission losses are expected on the 996tt?
Cheers,
Boon
Migration info. Legacy thread was 138743
The correct way to RR a C4S/Turbo is to disconnect the propshaft and run it in 2wd, in 4wd the viscous coupling will constantly divert power front to rear to front, the Turbo will possibly try and throw itself off the rolling road.
I ran my C4S a couple of years ago in 4wd mode on a Dyno Dynamics dyno, this had a 400bhp 4wd limit and the car's ABS/PSM and viscous coupling had the car bucking endangering the car and the dyno.
I'd take care! But do your research and make your own mind up.
Migration info. Legacy thread was 138746
Cheers, I'll give it a miss then.
I haven't had the car a week yet and am using the first month to build a snag list to go back to dealer with under OPC warranty.
I don't fancy having the prop disconnected etc.
Migration info. Legacy thread was 138752
You can run Subarus, Mitsubishis etc on a 4wd RR it's that Porsches have a little more intelligence in their drivetrains to run successfully.
Migration info. Legacy thread was 138825
Porsche use an uneven split viscous coupling - 95% rear unless traction is lost, then up to 40% front as required: Unless the resistance from front and rear rollers is absolutely identical the electronics will assume the car is out of control and keep transferring drive between front and rear and could 'rock' the car out of the rollers I suspect?
Even if you turn PSM off (which you should anyway incidentally, as high powered cars will shift side-to-side slightly and could trigger PSM activity) this has no effect on the viscous coupling.
I may be wrong, but I believe 4WD rolling roads assume an 'open' centre diff/coupling and calculate bhp by a formula using the figure at the measured axle?
Migration info. Legacy thread was 138912
I was told not to take my 993TT on a RR by JZM. I a little hazzey why steve said it was a bad idea but something like engine can detonate and you wont know till long after
Migration info. Legacy thread was 138970
Not enough airflow on most dynos. WRC's at Silverstone has run many 993 Turbos although that's only with the massive fans Allan has put in place to replace the missing airflow.
Migration info. Legacy thread was 139003
This is a source reference. Confirm exact model applicability in the original material.
