GTR Forum banner
1 - 20 of 24 Posts

·
Registered
Joined
·
211 Posts
Discussion Starter · #1 ·
Hi folks, I have a quick one.

If i fit a funky 2wd switch which I will be doing this weekend...... Can I run the car on a 2wd dyno ?

I have been wondering this for a while but have not managed to find anything saying if its possible ?

The reason I ask is that although we have a few 4wd dynos up here there is one particular guy id like to take the car to for a power run, however he only has a 2wd dyno.

Thoughts ??
 

·
Registered
Joined
·
211 Posts
Discussion Starter · #7 ·
Or like I said, use the switch ill be fitting ??

I just ask because I wondered if it were safe to dyno it in 2wd mode i.e theres no chance of it getting upset and throwing power to the front at 8000 rpm in 4th on the rollers ! LOL

Id imagine it would make a right mess ! LOL

Has anyone actually dyno'd their R32 gtr on a 2wd dyno ?
 

·
Registered
Joined
·
4,821 Posts
Or like I said, use the switch ill be fitting ??
I misread that LOL. Thought you were paying big money for a fancy dan controller. Grid dancer etc.

Yes, the switch will do they fuse trick more cleanly :)

Give it a test on the road first (watch the torque spilt gauge).... bear in mind it'll be bloody wild in RWD! Then i'd do some slow tests on the dyno to double check.
 

·
Registered
Joined
·
3,585 Posts
Or like I said, use the switch ill be fitting ??

I just ask because I wondered if it were safe to dyno it in 2wd mode i.e theres no chance of it getting upset and throwing power to the front at 8000 rpm in 4th on the rollers ! LOL

Id imagine it would make a right mess ! LOL

Has anyone actually dyno'd their R32 gtr on a 2wd dyno ?
mine has been 2wd dynoed, 8000 rpm 460 rwhp no problem with fuse removed.
 

·
Registered
Joined
·
8,804 Posts
I've only done 2WD dynos. Partly because 4WD dynos are a bit hard to find, but mostly because I believe engine power SHOULD be measured in 2WD only, unless the car runs full-time AWD.

R32s merely require pulling the fuse by the knee. R33s and R34s are trickier to 2WD dyno and can leak a bit of power to the front propshaft, so removing that is a must on those cars.
 

·
Registered
Joined
·
1,329 Posts
it is perfectly safe to 2wd dyno a 32 with the fuse removed. as said, check on the road to be sure you have removed the right fuse.

kev
 

·
Registered
Joined
·
3,585 Posts
a quick question .

when removing the front shaft, does the car not just waste power by still sending power through the transfer box and spin the end of where the prop should be connected?
 

·
Registered
Joined
·
1,329 Posts
a quick question .

when removing the front shaft, does the car not just waste power by still sending power through the transfer box and spin the end of where the prop should be connected?
yes i would imagine it would, the torque would still be divided although im not sure what would happen to the potential energy it cant just be lost.

basically, a r32 needs a switch or the fuse removed
 

·
Registered
Joined
·
8,804 Posts
actually, it wouldn't, not much IMHO. Even with the transfer box fully locked up, the only load you've added to the drivetrain is a spinning transfer clutch.

Power is never "divided" with the Skyline (Porsche 959-derived) drivetrain; the rear wheels are always engaged, and when 4WD is engaged, the fronts start borrowing power from the rear, more or less. The amount is determined by how much the transfer box clutchplates engage. So by taking out the propshaft, even if the computer tries to go for maximum 50:50 torque split, mechanically, it's not happening without that front propshaft, and therefore the rears are all that are left spinning, minus the added weight of some very small clutchplates.
 

·
Registered
Joined
·
1,329 Posts
actually, it wouldn't, not much IMHO. Even with the transfer box fully locked up, the only load you've added to the drivetrain is a spinning transfer clutch.

Power is never "divided" with the Skyline (Porsche 959-derived) drivetrain; the rear wheels are always engaged, and when 4WD is engaged, the fronts start borrowing power from the rear, more or less. The amount is determined by how much the transfer box clutchplates engage. So by taking out the propshaft, even if the computer tries to go for maximum 50:50 torque split, mechanically, it's not happening without that front propshaft, and therefore the rears are all that are left spinning, minus the added weight of some very small clutchplates.
this is very interesting and something ive never really understood. ive only really had experiance with sierras 4wd with which the power is aways divided!

kev
 

·
Registered
Joined
·
211 Posts
Discussion Starter · #18 ·
Awesome :0 well thats cleared up my question :) Makes sense to do the runs in 2wd as its also usually cheaper too !!!

Ill be fitting my drifty switch at the weekend :) Should be fun with the power im running ! LOL 400bhp in the RX7 was great so god knows what the GTR will be like, currently it will light up all 4 wheels fairly easily so in 2wd mode it will indeed be wild !
 

·
Registered
Joined
·
9,657 Posts
it is perfectly safe to 2wd dyno a 32 with the fuse removed.
NOCTURNAL did this at an I.A.MOTORSPORT Rolling Road day a few years back on his R32 GTR & it worked fine :thumbsup:
 

·
Registered
Joined
·
3,585 Posts
i think if it doesnt spin on the rollers once in the gear to do the run then 2wd will give a perfectly accurate power figure imo.
 
1 - 20 of 24 Posts
Top