GTR Forum banner
1 - 20 of 32 Posts

·
Registered
Joined
·
1,095 Posts
Discussion Starter · #1 ·
Replacing the seats and exhaust on my GTR with carbon and titanium items has lightened the car by over 100kg, this seems to have affected the handling adversely. The Car seems to ride high, understeers and lacks high speed stability.

The car is already running a GTC custom map so before I go modifying the turbos for even more power I really want to sort the handling out.

It would be nice to keep the incar adjustability although Im looking for complete stability and progressive slide rather than grip grip grip O shit! as the car feels currently.

Question: Whats the ultimate tried and tested suspension set up for track/fast road?

Spring kit? Antiroll bars? Coilovers? KW? Geometry? Ride Height? Other?
 

·
Registered
Joined
·
17 Posts
For Nissan suspension geometry calculations, the height of the vehicle at curb weight is used as the zero point. Because you have lightened your vehicle significantly you have changed the relative position of your body to chassis (the ride height) and you have also changed the zero point for your suspension geometry. That means that right now your car's alignment specifications are different than when you had the extra 100kgs, and this is the reason for the understeer and high speed stability issues.

The best solution is not an aftermarket suspension. Instead you should install the GT-R Spec-V springs. As they are designed for a lighter vehicle (but have the same rates as normal GT-R springs) the ride height will be reduced and the vehicle handling will be as Nissan intended. This way you will also be able to keep the adjustable Bilstein shock absorbers.

I don't think the Spec-V springs are available yet, though, so in the mean time if you have your vehicle realigned, the understeer and stability issues will be fixed. Then when the springs are available have them installed and have the vehicle alignment set again (of course).
 

·
Registered
Joined
·
1,095 Posts
Discussion Starter · #3 ·
That seems like sound advice thanks. :bowdown1:

Does anyone from the aftermarket world have a view on this?
 

·
Registered
Joined
·
288 Posts
I would start with the basic stuff first. If your car is 100kg lighter it will naturally sit a little higher, although I'm not sure if it will be noticable directly as it's only around 25kg less per spring when there is around 375kg instead of 400kg on each spring (6% reduction).

What could be noticable though is that the tracking will have changed slightly. Then again, you could argue the same when carrying 1, 2, 3 or 4 people, as in each case the toe settings will alter a little - it has the same effect as bump steer by carrying different weight.

I'd get the car re-aligned with its new weight (half a tank of fuel) and then go from there.
 

·
Registered
Joined
·
3,574 Posts
Buy a KW Clubsport + a rear ARB.....this will make your car handle a lot better then stock....:chuckle:

I´ve got a KW 3way competition,allso around 80kg less then stock,handles awesome.

PS:Spec-V Springs in standard GTR dampers will for sure not improve handling....total BS imo :rolleyes:
 

·
Registered
Joined
·
300 Posts
nissan ask a full tank for the alignement.

Go to your HPC with the tank full and ask for and alignement. This will cost you less than 200 and should improve things a bit.
 

·
Registered
Joined
·
17 Posts
Question: Whats the ultimate tried and tested suspension set up for track/fast road?

Spring kit? Antiroll bars? Coilovers? KW? Geometry? Ride Height? Other?
Buy a KW Clubsport + a rear ARB.....this will make your car handle a lot better then stock....:chuckle:

I´ve got a KW 3way competition,allso around 80kg less then stock,handles awesome.

PS:Spec-V Springs in standard GTR dampers will for sure not improve handling....total BS imo :rolleyes:
GT-R stock suspension at full race damping and alignment settings is the ultimate "tried and tested" package for track/fast road. Nobody has data, or times, to prove otherwise, regardless of the opinions out there.
 

·
Registered
Joined
·
1,537 Posts
GT-R stock suspension at full race damping and alignment settings is the ultimate "tried and tested" package for track/fast road. Nobody has data, or times, to prove otherwise, regardless of the opinions out there.
But putting in mismatched shock/spring combo of Vspec springs with standard shocks is the better alternative?
Considering any data is based on standard springs/shocks or vspec spring/shock combos, the no data/time argument is invalid.
 

·
Registered
Joined
·
3,574 Posts
GT-R stock suspension at full race damping and alignment settings is the ultimate "tried and tested" package for track/fast road. Nobody has data, or times, to prove otherwise, regardless of the opinions out there.
Says who.......:nervous:

I can go a lot faster on track with my setup then i can with the stock setup....but if you have tested yourself.....we all believe you:chuckle:
 

·
Registered
Joined
·
17 Posts
But putting in mismatched shock/spring combo of Vspec springs with standard shocks is the better alternative?
Considering any data is based on standard springs/shocks or vspec spring/shock combos, the no data/time argument is invalid.
The idea is to get the vehicle as close to factory spec as possible. As for the components being mismatched, the damping forces and spring rates are the same, as well as the spring and spring seat shape. The only guess is about the set load. It will be close...

Says who.......:nervous:

I can go a lot faster on track with my setup then i can with the stock setup....but if you have tested yourself.....we all believe you:chuckle:
Of course you can....we all believe you. :blahblah:
 

·
Registered
Joined
·
3,574 Posts
The idea is to get the vehicle as close to factory spec as possible. As for the components being mismatched, the damping forces and spring rates are the same, as well as the spring and spring seat shape. The only guess is about the set load. It will be close...



Of course you can....we all believe you. :blahblah:
13 posts and all just useless bs.....do you actually own a GTR or do you work for Nissan....have you ever driven one:nervous:
 

·
Registered
Joined
·
2,061 Posts
As has been posted by Evo6, the best will be an aftermarket complete kit that has adjustable ride-height. Then get the cars ride-height set and corner-weighted by a suspension professional (not an HPC).

The KW kit has been tested as faster and is what I would get, I had KW V3 kits on my 911 GT2 and M3 CSL and both worked well.
 

·
Registered
Joined
·
3,574 Posts
Correct,a good rideheight adjustable suspension,damper in rebound and compression adjustable,cornerweighting and a good agressive alignment will help a lot...my car doesn´t have understeer,it handles much more predictable and is a lot more fun then stock.....

A suspension in a "normal car" is allways a compromise from the manufacturer,as they can´t go as low as they want,they can´t go as hard as they want..they have to make compromises....in case of the GTR they have done a lot....i´d say.


Get a KW suspension,get a rear ARB and have someone to set it up properly,it will be more comfortable,more grip and less understeer....:bowdown1:

GTR´s with raised power don´t work with the stock suspension,you feel that the limit is reached....time to upgrade
 

·
Registered
Joined
·
288 Posts
I think the standard setup is an excellent road/track compromise. For track work there is always room for improvement though.

Anyone interested in proper aftermarket suspension for their GT-R would be best waiting a month or so. EXE-TC will be releasing their suspension kit for the car very soon, and based on their previous efforts, it will almost certainly blow everything else into the weeds once they have finished testing.

I'm very keen to see the finished product.
 

·
Registered
Joined
·
381 Posts
Alignment settings are the way of maximizing the stock suspension/handling potentials.

on my daily/road track car 240sx/sileighty (F/R)

+.5mm toe in front / rear toe (0)
camber F/R -1.5 all around
Locked 1.5 cusco rear - teeth shattering nose but works great.


as for the R35 with Front engine rear trans axle set up i dont know what would be the best set up with a car like this.
 

·
Registered
Joined
·
1,095 Posts
Discussion Starter · #18 ·
GTR´s with raised power don´t work with the stock suspension,you feel that the limit is reached....time to upgrade
Youre absolutely right, since my power hike the car feels unsteady in the bends, its crying out to have the suspention upgraded , I ordered the KW V1 Spring Coilover Kit KW Coilover Kit - Variant 1 Inox for Nissan - larkspeed.com which seemed like a good compromise, however, now Im wondering if the V1's will be good enough, should I change the order to the V3s? I had v3's on the FGT and they were superb, no body roll whatsoever, also what ARB do you recommend?
 

·
Registered
Joined
·
98 Posts
Simple, your car needs the geometry reset before you start firing more mods at it.

Considering that an average male is about 90kg, your 100kg cant make that much difference.

I would be VERY surprised if it didnt drive fine after that.
 

·
Registered
Joined
·
1,095 Posts
Discussion Starter · #20 ·
KW V3 Clubsport Coilovers

Ive had the KW V3 Clubsport Coilovers installed for a while now and have been very happy with the ride comfort although I cant help but feel the handling is being compromised as a result.

The ride can feel almost too comfortable at times and the car slow to react to large undulations in the road. The car also tends to bounce, a bit like what you can imagine a big heavy American car would do on a British B road.

Are these characteristics common with big heavy cars? or are our roads the problem? I cant seem to remember the car doing this before the mods. Dont get me wrong, the car handles much better but the mods seem to have highlighted the more difficult roads.

The shocks are currently set to full hard compression front and rear with a rebound setting about 3 clicks from max on the front, 5 clicks on the rear. Clubsport spring rates are Front: 970lbs/inch Rear: 515lbs/inch. The car has been properly set up and I have increased the tyre pressures which helped to a point but past 38PSI the car begins to bob.

Is the weight of the car the issue here? is it the fact that the spring rates are too high for British B roads?? Or could it be the Michelin PS2 tyres, they are not run flat but do have a fairly high load rating Front 105 Rear 104.

The new Michelin PS3 tyres in 345 & 315 widths have an even higher load rating Front 110 Rear 106, will this help? Someone has even suggested fitting a softer spring and re-valving the KWs to stiffen them up but I thought the rule is the lighter the car higher the spring rate so I cant see how this would work?

What do you handling moguls suggest? :bowdown1:
 
1 - 20 of 32 Posts
Top