GTR tune up on a 2WD dyno

[writeoff]

Hi Everyone,

I'm about to get my GTR tuned up and was wondering what the differences are b/w using a 2WD vs a 4WD dyno.

I rang Shaun from Boost Worx (2WD) and he said the power figures would be slightly different but the rest would make no difference. Michael from Turbo Tune (4WD) stated their would be a difference but didn't elaborate and the chick (she didn't give a name) from Tillbrooks (4WD) said that I'd want to do it on a 4WD dyno.

Interestingly Shaun quoted $145, Michael $250, and Tillbrooks up to $500 depending on the computer.

Thanks

[mr_rbman]

well naturally the power figures are going to be different. i guess if u only want a tune then 2wd will be fine but u will get a higher rwkw reading than on a 4wd dyno!

[Sneaker]

You should really do it on a 4WD dyno as the car acts differently between 2 and 4 wheel drive. The stresses are different in AWD against the engine. I am about to jump on the dyna-pac at Speedworks. A full retune of the standard computer along with dyno time should be about the $500 mark.

[GTS4dood]

?? the 4WD only works when theres traction loss..... so wouldnt a 4WD dyno be useless. as the front wheels wouldnt engage. correct me if im wrong...and if i am then wouldnt a 2WD dyno be totally wrong to test on as it would launch the car off the dyno once the front wheels engage. ???

[Sneaker]

?? the 4WD only works when theres traction loss..... so wouldnt a 4WD dyno be useless. as the front wheels wouldnt engage. correct me if im wrong...and if i am then wouldnt a 2WD dyno be totally wrong to test on as it would launch the car off the dyno once the front wheels engage. ???

Actually the front wheels engage not so much under traction loss but at high g-forces. When you put your foot down hard it kicks the front in to assist in traction - not letting it get to the stage of slip in the first place. If there is traction loss it assists depending on other factors of the car (lateral forces, steering position, throttle position, etc...)

You can disengage the front wheel drive by removing the fuse to the attesa, making it a purely RWD car - required for 2WD dynos.

[GTS4dood]

yeah i knew about the fuse as i have a switch on my R32 GTS4. i think it different on the R33's. isnt it run through the cars computer instead and not a fuse?

[targa]

Actually the front wheels engage not so much under traction loss but at high g-forces. When you put your foot down hard it kicks the front in to assist in traction - not letting it get to the stage of slip in the first place. If there is traction loss it assists depending on other factors of the car (lateral forces, steering position, throttle position, etc...)

You can disengage the front wheel drive by removing the fuse to the attesa, making it a purely RWD car - required for 2WD dynos.

you car only "pull the fuse " on R 32

R 33,R 34 have 10% drive to the front all time

The trick is to lift the coin tray, undo a nut at the front of the G senser

and lift it up to about 30 degrees to make 4 wheel drive work all the time

jeff

[Cubes]

2wd or 4wd..

Unless its a super high powered GTR that does not get traction in rwd on a rwd dyno then there should be no difference on the load that is put on the motor. If it aint spinning on the dyno in rwd then 4wd won't put any more load on the motor that is going to affect the tune. If load affected the tune that much then all cars would be tuned in 5th.

On the R32 you can either remove the fuse or drop the front shaft, R33 you have to drop the front shaft.

I would lean towards Boostworx and Tilbrooks. I've had experience with all 3 work shops.

Tilbrooks are excellent and have the PowerFC software, Shaun simply does his wizard thing with the hand controller.

I currently use Shaun @ Boostworx.

[ALL GTR]

A 4wd dyno is the true way to tune a GTR.

There is no point doing it on a 2wd dyno its pointless.

[Cubes]

Explain from a technical point of view why it is pointless?

or do you not know why?

So what your saying is a Rb26DETT in a RWD GTST should first be tuned in a GTR or GTS4 then dropped in to the RWD as its pointless tuning it in rwd?!?

[Leewah]

My car is tuned on a 2wd dyno all the time as is the RacePace GTR.

The only real difference you'll see b/w the 2wd and the 4wd dyno is the power reading. A 2wd dyno will give a higher reading due to drive train losses through the 4wd system.

Last year at AutoSalon, my car ran 593awkw whereas in 2WD it ran 617rwkw. This time round we made 604awkw and 608rwkw. The 608rwkw was not indicative of the power simply due to wheelspin. After 3 tries and 500kgs ballast, we still couldn't get traction on the rollers so we gave up.

The tuning of a GTR whether it be on a 2wd or 4wd is irrelevant as all your changing is the mapping of the engine itself.

33 and 34 GTRs always have power going to the front wheels. The front shaft should be dropped out from the transfer case when tuning. It's a simple 5 min job involving 4 bolts.

[WazR32GTSt]

Explain from a technical point of view why it is pointless?

or do you not know why?

So what your saying is a Rb26DETT in a RWD GTST should first be tuned in a GTR or GTS4 then dropped in to the RWD as its pointless tuning it in rwd?!?

i think he's an "armchair tuner"...

[ferni]

My car is tuned on a 2wd dyno all the time as is the RacePace GTR.

The only real difference you'll see b/w the 2wd and the 4wd dyno is the power reading.  A 2wd dyno will give a higher reading due to drive train losses through the 4wd system.

Last year at AutoSalon, my car ran 593awkw whereas in 2WD it ran 617rwkw.  This time round we made 604awkw and 608rwkw.  The 608rwkw was not indicative of the power simply due to wheelspin.  After 3 tries and 500kgs ballast, we still couldn't get traction on the rollers so we gave up.

The tuning of a GTR whether it be on a 2wd or 4wd is irrelevant as all your changing is the mapping of the engine itself.

33 and 34 GTRs always have power going to the front wheels.  The front shaft should be dropped out from the transfer case when tuning.  It's a simple 5 min job involving 4 bolts.

Finally someone who knows what they are talking about

[writeoff]

Okay, so after reading all this it seems that there is no real difference in the mapping etc of a GTR on a 2WD dyno vs a 4WD dyno but the rwkW figures will be slightly higher.

Have I got this right?

Cubes, any reason why you wouldn't recommend Turbo Tune?

[Leewah]

Okay, so after reading all this it seems that there is no real difference in the mapping etc of a GTR on a 2WD dyno vs a 4WD dyno but the rwkW figures will be slightly higher.

Have I got this right?

Cubes, any reason why you wouldn't recommend Turbo Tune?

True and correct. Lock it in Eddie.

[maverick]

My car is tuned on a 2wd dyno all the time as is the RacePace GTR.

The only real difference you'll see b/w the 2wd and the 4wd dyno is the power reading.  A 2wd dyno will give a higher reading due to drive train losses through the 4wd system.

Last year at AutoSalon, my car ran 593awkw whereas in 2WD it ran 617rwkw.  This time round we made 604awkw and 608rwkw.  The 608rwkw was not indicative of the power simply due to wheelspin.  After 3 tries and 500kgs ballast, we still couldn't get traction on the rollers so we gave up.

The tuning of a GTR whether it be on a 2wd or 4wd is irrelevant as all your changing is the mapping of the engine itself.

33 and 34 GTRs always have power going to the front wheels.  The front shaft should be dropped out from the transfer case when tuning.  It's a simple 5 min job involving 4 bolts.

I love your car...it looks hot...did you happen to be driving on Princes Highway towards Dandenong on Tuesday night? I was in a R32 GTR

I tell you...midnight purple looks hot at night.

[Leewah]

I love your car...it looks hot...did you happen to be driving on Princes Highway towards Dandenong on Tuesday night?  I was in a R32 GTR

I tell you...midnight purple looks hot at night.

Nah, wasn't me.