What's new
Porsche 911 UK Enthusiasts Online Community Discussion Forum GB

Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.

Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.

Welcome to Hartech, the UK's leading Independent Porsche engine specialists, located in Bolton, UK

Why wouldn't you put a 4x4 on RR?

P

plynchy

Suzuka
Joined
13 Aug 2004
Messages
1,017
Sure I've read on here before that the C4, C4S and Turbo shouldn't be ran on a rolling road?

What are the reasons behind it? :?:
 
cos it will just drive off it?

Unless its a 4wd rolling road. And then your 4wd system is through a viscous coupling so will be unpredictable / might overheat and trash the coupling depending on the dyno.

AFAIK people disconnect the front propshaft on c4/s when on the dyno.

Best ask the operator of the dyno, they should know.
 
who told you that? nonsense

unless its a 2wd RR and you forget that and the front wheels get traction. ha ha :lol: :lol:

there are loads of good 4wd RRs around from Powerstation to Surrey RR who would take into account the car, power, toruqe vectoring and movement of power to get an accurate reading

Abbey Motorsport have a dynopack RR which you have to remove the wheels for and you then raise the car to run on the axles which the RR bolts onto.

this gives a reading at the wheels more accurately.
 
I thought the bigger issue for running 911's (specifically turbos) on a rolling road was the amount of fans needed to push air with the intakes on the side and the engine intake in the boot and the rads up front.
 
chriscoates81 said:
I thought the bigger issue for running 911's (specifically turbos) on a rolling road was the amount of fans needed to push air with the intakes on the side and the engine intake in the boot and the rads up front.
Click to expand...

That would definately need to be considered!!!
Given that the 4wd system only diverts torque to the front if needed, if the RR has front and rear rollers which are effectively independant then a much larger percentage of torque would go to the front. I don't know if this could cause temperature issues in the viscous coupling, but I bet somebody else will....

MC
 
MisterCorn said:
chriscoates81 said:
I thought the bigger issue for running 911's (specifically turbos) on a rolling road was the amount of fans needed to push air with the intakes on the side and the engine intake in the boot and the rads up front.
Click to expand...

That would definately need to be considered!!!
Given that the 4wd system only diverts torque to the front if needed, if the RR has front and rear rollers which are effectively independant then a much larger percentage of torque would go to the front. I don't know if this could cause temperature issues in the viscous coupling, but I bet somebody else will....

MC
Click to expand...

That's along the lines of what I've read before...
 
chriscoates81 said:
I thought the bigger issue for running 911's (specifically turbos) on a rolling road was the amount of fans needed to push air with the intakes on the side and the engine intake in the boot and the rads up front.
Click to expand...

Can't see it, I watched my friends 800hp Skyline in the Dyno and they had no issue cooling it.
 
most RR now seem to have this sorted and they know where to put the fans for cooling to mirror the wind in and over the car if its was out driving.
 
Some porsche specialists have custom RR for rear engine cars eg 9M in warrington.

With a 993 the 4 wheel drive can be decoupled in 15 min to allow them to be tuned on a 2wd RR, not sure if its as easy on a 996, all those water pipes may get in the way :grin:
 
I think you need a proper 4 wheel rolling dyno if you want to be competitive in the tuning world these days, as so many performance cars are all wheel drive ... in fact, I'd be rather put off if the dyno was only one set of rollers.

That being said, a full hub dyno would better, even if it is a bitch to set the car up. It's not like, drive on, strap down, fans on, wind up the power, adjust the parameters, print graph.)
 
A bit OT, bit I am setting up my turbo for more data logging, looking at different temperatures and pressures to measure turbocharger efficieenct as well as intercooler efficiency, effect of meth injection, etc. From some earlier track testing I saw a 20 degree change in inlet temperatures and over 100 degrees in front brake temperature just from changing direction of driving from headwind to tailwind. It shows the importance of a controlled environment for performance calibration and testing. All interesting stuff.

MC
 
jonttt said:
Some porsche specialists have custom RR for rear engine cars eg 9M in warrington.

With a 993 the 4 wheel drive can be decoupled in 15 min to allow them to be tuned on a 2wd RR, not sure if its as easy on a 996, all those water pipes may get in the way :grin:
Click to expand...

Did they have 4wd on 911s in the 60s?
 
Running one set of wheels for a period of time on a awd 996 mashes the dilatant fluid in the coupling, thus making it useless. Same goes for when they're brake testing on the MOT. No doubt some numpty somewhere has left the front wheels rolling on the rollers whilst testing the brakes and knackered someone's awd system without even knowing it. :nooo:
 
What prompted the question was a post I saw today on FB from a tuning company I use for my Cosworth, with an action pic of what appeared to be a 4x4 997 on their RR.

They have a solid reputation which is why I was surprised to see it.
 
Was it a Gen II? They have an electro magnetic coupling that can be disengaged.
 
You must log in or register to reply here.

Similar threads

P
Cooling fans cheat.
Replies
1
Views
648
sja360
S
T
An ode to the 996 c2022, aircooled evangelists find a safe space
Replies
5
Views
237
jerzybondov
J
T
997.1 gt3...usability?
2
Replies
22
Views
2K
Tom-89
T
N
997.1 turbo Vs 981 GT4
Replies
9
Views
1K
Clanky
C
Paul_S
997 Heated Seat Retrofit Wiring
Replies
3
Views
822
KarlRS
K
B
Hopefully 911 Newbie - Advice on purchase
Replies
8
Views
1K
Bedrock bill
B
L
PCA eVALUation vid
Replies
0
Views
492
Luddite
L
Porsche Insurance

Latest posts

New Threads

Porsche Model Range

Porsche 911

Porsche 992: 2018- Porsche 992: 2018- Porsche 991: 2011-2019 Porsche 991: 2011-2019 Porsche 997: 2004-2012 Porsche 997: 2004-2012 Porsche 996: 1997-2005 Porsche 996: 1997-2005 Porsche 993: 1993-1998 Porsche 993: 1993-1998 Porsche 964: 1989-1993 Porsche 964: 1989-1993 Porsche Carrera 3.2: 1983-1989 Porsche Carrera 3.2: 1983-1989 Porsche Carrera SC: 1977-1983 Porsche Carrera SC: 1977-1983 Porsche 930 Turbo: 1975-1989 Porsche 930 Turbo: 1975-1989 Porsche Early 911: 1964-1977 Porsche Early 911: 1964-1977

Porsche Hypercars

Porsche 918 Spyder Porsche 918 Spyder Porsche Carrera GT Porsche Carrera GT Porsche GT1 Porsche GT1 Porsche 959 Porsche 959

Other Current Porsche Model

Porsche Taycan : (2019-0%) Porsche Taycan : (2019-0%) Porsche Macan : 2013- Porsche Macan : 2013- Porsche Panamera : 2009- Porsche Panamera : 2009- Porsche Cayman: 2005- Porsche Cayman: 2005- Porsche Cayenne: 2003- Porsche Cayenne: 2003- Porsche Boxster: 1997- Porsche Boxster: 1997-

Porsche Legacy Models

Porsche 928 Porsche 928 Porsche 968 Porsche 968 Porsche 944 Porsche 944 Porsche 924 Porsche 924 Porsche 914 Porsche 914 Porsche 912 Porsche 912 Porsche 904 Porsche 904 Porsche 550 Porsche 550 Porsche 356 Speedster Porsche 356 Speedster Porsche 356 Porsche 356

Forum statistics

Threads
124,551
Messages
1,441,447
Members
48,965
Latest member
renn27

porsche insurance porsche parts porsche sales porsche car sales porsche for sale
porsche classic sales porsche tuning porsche sold porsche specialist porsche engine rebuilds porsche driver training porsche car sales porsche exhausts

Community platform by XenForo® © 2010-2024 XenForo Ltd. XenForo theme by xenfocus

www.911uk.com @Porsche911UK THE DEFINITIVE PORSCHE FORUM Copyright © 911UK 2002-2024 All rights reserved.

911uk.com is not associated and is wholly independent of Porsche Automobil Holdings SE, Dr. Ing.h.c.F.Porsche AG, Porsche Cars GB, its subsidiaries and offical Porsche centres. Any word, phrase or graphic that in any way resembles anything to do with the Porsche name or organisation are registered trademarks of Porsche Automobil Holdings SE and Dr. Ing.h.c.F. Porsche AG.

Back
Top