Modded GTR owner in Japan gives report on his problems at high speed.

[dec55]

Originally Posted by tokyogtr

OK, so you've heard me mention how great the power is but the high speed handling needs tweaking. Well, it's getting worse. The car behaves so erratically when on fast highways with any bends that it's almost dangerous. On the circuit there's none of this but on a public highway above 180kph beware, it pitches like a SOAB. I've tried comfort, normal and R modes but it's always the same which means the springs are just not up to the job. When I spoke to mine's they said they had lots of complaints about this. Apparently the springs they supply will not fix the problem. This means either waiting for springs or going with a full suspension upgrade and therefore deleting the Comfort/Normal/R mode altogether and being stuck on R.

If the shocks really cannot be made to handle the weight of this car with any types of springs on highways then I will have to trump up the Yen1m to replace them. Or, wait to see if the Euro version is any better based on feedback from the JDM owners.

I'm going to have one last crack by speaking to the HPC and see if they will have any advice but JDM buyers beware, this car is NOT good on highways at high speeds. It's just too "bouncy".

This guy has the Japan version which I believe is set to go only up to 111 mph.

I was just wondering if the US version which is limited to close to 160 mph
will be more stable than the Japan version.

http://www.gtr.co.uk/forum/upload/98...dangerous.html

[UltimateGee27]

I doubt the US version suspension/spring rate/shocks will be any different than the models offered around the world. Besides the top speed the only two other things diff in the US spec is obviously left hand drive and the front seats are a bit wider for our fAT AMERICAN A$$'S


interesting article non the less...seems like they found a crack in the GT-R's armor....but just like every first MY car this will get corrected for 2010 and so on

[Sukairain]

....... I've known about this for months~ why did it take people this long to figure it out? The GT-R is not stable enough above 150mph. The rear end kicks out all too eagerly when throttle is lifted or even reduced on a sweeper. If you run over some bumps at high speed the car will shoot off sideways even though the VDC will get you back on track. Turning on the Steering assist and traction control helps a bit. The car can do straight line at high speed perfectly fine, but when it comes to high speed corners some work needs to be done.

[MC@MYGTR]

Originally Posted by dec55

I was just wondering if the US version which is limited to close to 160 mph

the US version is not limited but to top gear redline which is at around 193 MPH

[r0csfinest]

thats ok... ill just cruise around 140 mph lol

[UltimateGee27]

Originally Posted by Sukairain

....... I've known about this for months~ why did it take people this long to figure it out? .

maybe cuz 99% of the world hasnt driven it yet and the 1% that have driven it havent gone above 150mph

[jaspergtr]

Originally Posted by Sukairain

....... I've known about this for months~ why did it take people this long to figure it out? The GT-R is not stable enough above 150mph. The rear end kicks out all too eagerly when throttle is lifted or even reduced on a sweeper. If you run over some bumps at high speed the car will shoot off sideways even though the VDC will get you back on track. Turning on the Steering assist and traction control helps a bit. The car can do straight line at high speed perfectly fine, but when it comes to high speed corners some work needs to be done.

yeah, i'm not certain of this either, as i haven't driven the gt-r above 150mph yet.

that's awesome that you have, though, when did you get a chance to do this?

[tiguy99]

So...what does it feel like to drive the GTR above 130MPH??

[jaspergtr]

i saw dec55 over there. and i can't rule that out from my perspective.

if the unstable condition is caused by the 'cracking' of the ecu above 112mph, that would seriously explain why it happens at percisely that speed.

and also why no reviewer experienced this phenomenon.

the theory here is that the ecu was modified, and the ecu is no longer taking into account speed - and could even go as far as correcting for pitch at these higher speeds (because aero downforce is still being applied - but the car doesn't know it), and activating these controls to attempt to stabilize the vehicle for 112mph, and not 120mph.

basically - the chip was modified to go faster... were all of the other factors corrected at each speed/pitch and yaw degree? or just speed?

i think this is probable (and may explain why nissan doesn't think there is anything wrong). and this would explain why reviewers didn't see this, and why it's only being experienced by owners who bought vehicles that were governed at 112mph, and are traveling at speeds above that.

[anotherOAKg]

As always, 99% of the arguement against the OP was being done by those who don't own a GTR. No knocking anyone, just saying.

[jaspergtr]

the only reason i support the ecu being part of the problem (cracked but not solved), is that we've already heard from existing g/z owners that when on a dyno, the results aren't 100% true, because the conditions of a dyno are not realistic, and the ecu was not designed to have acceleration at those speeds in that gear. so the feedback to the ecu was false, and therefor the output for those given rpms (which cannot - in real world situations occur), cannot be computed accurately.

this mulitplied by how many calculations are needed to maintain the 'electonic nannies' (as someone put it) may not have been accounted for. and maybe tuners like mine's were only looking for acheiving speed results and not worrying about trying to solve for other factors that were not part of that equation...

[SwivelHips]

Okay, that's it. I'm not buying one.

[jaspergtr]

lol!

[Sukairain]

Originally Posted by jasperg35

yeah, i'm not certain of this either, as i haven't driven the gt-r above 150mph yet.

that's awesome that you have, though, when did you get a chance to do this?

I just did it again last night to reconfirm. Without electronic aids the GT-R is definitely not the most stable car around high speed bends. I did it on the stock GT-R on Gran Turismo Prologue around Fuji Speedway, same thing on Daytona.

[jaspergtr]

lol! that's awesome...

but that does lend itself to the suggestion (i'm not sure much credibility i'm going to offer sony) that the ecu, when not being used for stability would definitely make it less stable.

that's like saying when i remove the fuse for my brakes, my abs stops working... wtf?