Nissan GT-R LM Nismo bottoming out

Great to see this car offered. I’ve always been a fan of its out-of-the-box design philosophy, despite it’s stomach turning looks. Has anyone else noticed its propensity to bottom out? The “stock” tuning is a bit weird too, with the front rebound and damping being maxed out at 100%, but I can’t seem to get it to stop hammering it’s bottom-side in hard corners with reasonable spring height applies.

It’s a weird car so I’m sure the tuning will take a while to figure out, but has anyone else noticed this?

Nissan themselves have this same problem with the real car : )

Too much downforce, maybe? The stock tuning settings are crazy., and it’s really weird driving such a high-powered front-wheel drive car. It doesn’t seem to respond to the same driving style and lines I expect.

I’ve been trying to get this car set up for Nurburg (The Ring). I also struggled with the stock setting. At the moment I am having trouble with losing the rear when braking for slow corners. I’ve tried various tweaks on the braking and also on the gearing. But don’t seem to be able to keep the rear in check. On fast corners it handles brill, but on the slow corners it’s dreadful

I only tuned a handful of cars so far but Alfa 33 Stradale stock tune had woefully low spring rate. If it is bottoming out then the spring rate must to be increased.

The car is 63% (or 65%?!?) front so very unusual for a racing car = 35% rear weight.

In braking, front will see even more loading therefore the brake has to have usually high front bias; I’d start at about 65% brake bias. Also loosening up the rear rebound would also help.

FWD’s understeering tendency will be exaggerated on this car so low front accel diff may be needed. Car has 14" / 9" width wheels front / rear so it is very unusual. To accomodate such wide front tires it will need relatively low accel diff (less than 50%?!?)

Those are my guesses.

I think I’ll have a go at this tonight at LeMans; see if I can beat the RL pace (~3:35?). I like these wonky cars . . .

Just tried it out at LeMans; don’t know what you guys are talking about because I am not seeing ANYTHING wrong with this car.

Using stock car, made minor adjustments to tire pressures and aero only and got 3:35 at LeMans, good enough for top 500 times and #18 in hardcore (2nd fastest GT-R LM).

I have experienced no abnormalities during hard braking and virtually no understeer at corner exit. It is a great handling and easy car to drive.

One MAJOR problem with this car though; it’s a little thirsty. The fuel runs out about 2/3 way into lap 4. That’s lap 4. You would have to pit every 3rd lap. That does not seem right . . . So don’t try taking this car to an endurance race in FM.

You don’t see sparks flying out from under the front, or feel the car hit its bump stops and slide three feet wide?

I’ll admit it’s an odd car, and maybe my driving style doesn’t suit it. I’m usually heavy on braking, and use trail braking quite a bit, and on a car with this much front-end weight bias that might not be a good combination.

I saw no such thing . . . so sliding, no sparks, no oversteer, mild acceleration understeer, no drama . . .

3:35? You didn’t say LaSarthe or Classic. I got a 3:40 at LaSarthe completely stock and a 3:26 on the “Classic” (non-chicane) track and I clearly saw sparks.

I have a few screen shots but the Sparks don’t photograph well (instead of one or two sparks you get 10 times the amount you see live). I even saw sparks down the back straight so either you’re not seeing them, or your driving view isn’t showing them.

It’s not a big issue. There are always people who won’t see a tree when there’s plainly a tree there (or a Sasquatch in the bushes when there isn’t).

It’s a unique car, no doubt. How many S-Class cars and above have more than 50% of their weight on the front tires, OR FWD for that matter? It’s a fun car to try to figure out.

P.S. What exactly is “negative speech against CoC”?

It was at LaSarthe.

WTH? Negative speech against CoC!?! That must be a moderator moderating my signature which used to say, “There is a cure for XXXX, turn them off.” :frowning:

I got a 3:34, but only with the recommended upgrades to bring the PI up to around 993. But I saw sparks in Turns 4 and 5, along the back straight over the slight rise (it’s a bit more than slight when you’re going 220+). The bottoming out wasn’t as bad as it was on Bernese Alps. It would hit so hard I’d skate 10 feet wide in some corners. I know it’s a fictional track, but it was happening.

The lowest I could get it without bottoming out was
882.1/483.4 springs
2.6/4.5 ride height
Got 3:27 at Lemans classic

Thanks for backing me up, Schneeb. I knew I wasn’t seeing things.

Speaking of which did you see Sasquatch in the bushes behind turn 10?

Anyway, part of the issue with racing simulations is that even though there is most definitely a skill involved in racing a car in a video game it is not the same skilset involved with actually driving a car really fast. Part of that is from the lack of fear. You drive with zero fear for your life in a video game. Try that flying into a 210mph turn in a $960,000 car with your actual self strapped into the seat like a prettied-up bag of hamburger.

And in that same vein, there’s not a racer on the planet who would drive one of 4(?) multimillion dollar race cars around a track at 220mph with it bottoming out a dozen times a lap. His engineers and his owners would dope slap him into another garage. Maybe you’d put up with the car hitting its bump stops once a lap depending on the track (some tracks are extremely varied in their layout - like Lemans), but not 10 times a lap.

You’d be coming back to the pits with a car weighing 100 lbs lighter each time.

At first lapping this car, I agree the stock tune and driving characteristics took a little getting use to. Leaving everything else on the car alone, I’ve spent 30 some laps at Indianapolis and Daytona and worked out a workable tune (for myself at least.) I’m thinking the base spring rates were maxed because with a car being front heavy, it helps to keep the front end from plowing into the tarmac while braking from 200mph. I started by taking half of the front spring rate as my start point and knocking just 100 off the rear. Increased front brake pressure to 63% and lowered my Rear Rebound to 4.0. The front end more stable but the rear still had a tendency to wander into sweepers; the front end still getting a shower of sparks. I increased the front ride height 3 clicks above the rear but now the rear end fishtailed going into a corner so I increased my LSD rear decel to 45 (hahahaha). it works. Anyway, collaborating with my bro (DaDoctor) I’ve came up with a decent tune which I feel makes the car fun to toss around tracks like Indy, Daytona road course, and Sonoma. Following is a quick tune to reign in this Nismo but remember, everything else was left alone so the car is not maxed out for any particular class. Try it out and feel free to give me a shout what works and what doesn’t.

Tire pressure: 28/28
Left gearing alone (might tinker with that next. Second gear at WOT is ‘deadly’. LOL)
Camber: 1.8/1.4
Toe: 0.0/-0.5
Caster: 5.6 (if it feels stiff, decrease it)
Roll Bars: 14/22 (the rear is stiffer because with my front ride height 3 clicks higher than rear, I personally feel it helps in rotation going into the corner. I tune/race with no assists so I can’t rely on STM to keep me in check).
Springs: 570/500.
Ride height: Front is 3 CLICKS higher than Rear which was left stock.
Dampers: Front Rebound: 8.0 Rear Rebound: 4.0 Front Bump: 4.5 Rear Bump: 2.5. (If the rear end feels unstable accelerating OUT of a corner, increase the Front Bump 2-3 clicks and try again. )
Brake balance: 63% Front (My pressure is at 98% but tailor this setting to what you feel comfortable with).
LSD settings: 50% Accel/45% Decel.
Happy lapping guys/gals!

63% front brake bias is higher than on any other car I’ve tuned, but this is a very different animal.

What times and what tracks are you getting (I need a benchmark to either aim for or gauge myself on)

I’ll give it a go after I get some work done (I’m self-enslaved, not self-employed).

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This also brings up another “issue”, specifically with brake balance. The way the brake balance is shown in the tuning field the percentage sign you see indicates how much brake balance is ON the rear of the car. Correct. Me if I’m wrong here, but I’ve read in numerous posts how confusing this is.

If your brake balance setting is at 63% you’re shifting the brake balance OFF the front and towards the rear brakes. You can’t use the position of the slider to gauge where you’re sending the braking power. If you look at the slider and take the mid-point to be the middle of the car and you slide the brake bias to the left (towards the “front” of the car) you’re actually tuning the brake balance to shift more on the rear wheels.

It’s definitely confusing, but like i said I’ve read this in numerous places. So what you want, if you really want 63% of the braking power on the front wheels, is for the percentage to be at 37% (with the balance point in the visual slider to be going to the right).

Anyone else find this confusing?

I’ve tested at Indianapolis GP Alternate and ran a best of 1.33:984. Consistent mid- 1.30’s. On the Oval, I can hit 40 second laps. Daytona Road Course (First Tier) I’ve done a 1.48 but there is a zone somewhere which dirties your lap because my time comes with the ‘!’ icon. I’ve not ran any ‘Rivals’ or Time-Attack events with it so I don’t have a top-score established. Just been messing around with it and learning what works for me. In launching. . I’m shifting thru 1st thru 3 gears in 4-6k RPM’s to try and minimalize wheel spin. At Indy, the last tight hairpin before sweeping thru the front straight, I drop to second just before turning and then just as it feels she’s losing grip in accelerating, i throw it in 3rd. I use a controller, manual w/ clutch (no room or the time to set up a racing wheel - haha). Have fun.

I just popped in a 1:33 at the first Daytona Track (the familiar track where they run the Daytona 200 for Superbikes), but I’ve got the car upgraded to 993 PI. I’m finding your tuning a little difficult to handle, specifically the brake balance. I have mine turned “down” to 45%, which, if I’m reading the tuning tool correctly means only 45% of the braking power is on the rears. I use trail braking a lot and use the front to scrub speed into corner entry so if I have too much brake bias on the fronts the rear likes to come around too easily for my tastes.

I’m still scraping the front end all along the banking but not enough to upset the suspension. I’m not sure how anyone can say otherwise, but it’s definitely bottoming out.

I can’t come close to the Mazda 787 times - that car is a frigin monster.

I was understanding that the brake bias has been corrected in FM6. If I slide the balance the all the way to the front (100%) and then slam on the brakes while viewing in 3rd person view, my front tires are locking up first. Just for giggles, I took my balance down to 45% and I feel it’s difficult for me. At the Indy sweeper, I’m washing out the rear end as I’m braking. I’m not at a 993PI myself so I expect my tune would yield different lap times than what you are seeing. I’ll go take a look at it again and see what could a tweak.

That 787 is Frankenstein. :smiley:

They should just re-name the Brake Balance slider to be “over steer adjust” LoL