A bit of tuning frustration.

[timothy_gammey]

I like to consider myself pretty adept at tuning cars. I've been a mechanic for 30yrs, And during that period I have built and raced (drag, road racing) some pretty serious machinery. I have been playing Forza since the first one, and have come to know the idiosyncrasies of their tuning pretty well, and, while not being the best driver, I can usually put my tuned touring cars in the top half of the field, and have taken a few wins, too. I am no rookie, and have won in every one of the touring cars- EXCEPT THE ASTRA.

I am not sure if it's bugged, or if I'm stupid, but that dang thing REFUSES to steer under any sort of throttle- you become locked in to it's chosen trajectory, which is usually the wall. Diff fully locked, fully open, it doesn't seem to do anything other than dictate how much wheelspin you'll get while the car takes up landscaping, Any other car, I can enter the outer loop at Watkin's Glen short at about 98-99, touch the brake to knock it down to about 94, and with the controller pinned right, use the throttle to choose my line through the corner. The Astra simply refuses to allow this to happen. You seemingly can't even reduce rear grip and get it hold a line- It's like they programmed a base level of understeer into the damned thing that cannot be dialed out. You get the choice between understeering off the track with the rear tires hooked up, or understeering off into the wild blue yonder sideways- simply going where the front tires are pointed seems to beyond the capability of the car.

I even tried downloading someone else's tune, but in true Forza fashion, I got "too many saves" error, followed by "network connection error" any time I try to download any tunes (or install my own saved ones), so I'm stuck, and frustrated with it. It is literally the only car I have not gotten a handle on.

So if any of yall have a setup that works, and wouldn't mind typing out the settings, I'd appreciate it.

[clairvoyantwolf]

I’ll look at it when I get some time

[clairvoyantwolf]

Well I'm never driven the Astra till now, interesting little car.

Anyway to be completely honest it kind of handles like any average FWD car to me. I was entering the outer loop at about 102-105mph with a mid corner speed of 92mph and then exiting at around 107 (if I remember correctly).

I also drove the Ford touring car as point of comparison and compared to that car the Astra seemed to actually rotate MORE off throttle but less on throttle, going from one to the other required a driving style adjustment, with the Forza being more traditional slow in fast out, but the Astra being fast in, use the aggressive rotation to your advantage and then pin the throttle when you're pointing the right way (that technique gives up mid corner speed).

At a granular level the understeer appeared to be the worse at initial turn in. I had some promising results tuning that tendency out by using dampers. Also the stock camber settings are quite aggressive (the the rear having more than the front), optimizing that might also yield some gains.

Hope that helps.

(I know you were looking for specific tuning settings but I don't have the time or interest in perfecting a car I'll never use...sorry)

[timothy_gammey]

That's cool. What I have figured out so far is that it seems to want more rear spring rate than any of the other cars, and next to no rebound damping in the rear seems to help with rotation. Ultimate front grip is still lacking, but at least it's drivable in "racing trim"- which for me is 17% fuel. hard tires.

I will try to post what I came up with when I can get a dry race at the Glen and have an apples-to-apples comparison. My goal is never to be the fastest car on track, but be within a half second on hard tires. That strat has gotten me the best results in races (IE having more tire left in the final few laps to make up ground)- but doesn't work out so well when you have an understeering pig on your hands.

[timothy_gammey]

I found some settings that work fairly well. Doesn't magically transform t into something that will rival the MG's and Audis, but it isn't super far off their pace, and with a better driver, could probably hang with them. I was running low 1:17;s at the Glen with this setup on hard tires, 7 laps fuel during practice- so it still a touch off the pace of the MG.

Setup:
Tire pressures: Front 31.5, Rear 28.5
Alignment: Camber -1.6 front, -1.1 rear
Toe: 0/0
Caster: 7.0
anti roll bars: F 7.0 R 11.0
Springs F 510, R 490 Ride height as low as it will go
Dampers F 7 compression, 7 rebound R- 3 compression, 1.5 rebound
Geometry roll centers 0/0, antidive 9.8 antisquat -2.3
Aero F-all the way up (276) R all the way down (might need to add a touch for tracks like Hakone)
Brakes 60% front, 120% pressure (adjust to your taste)
Diff Accel 95% decel 0%

I am not going to say it is the best tune, probably far from it, but it does make the car steer under throttle with hard tires in most scenarios. There are some obvious "band-aids" like the the damper settings but i could.t get the car to rotate on turn in without either losing most of the rear damping or increasing the rear antiroll bar (but the bar adjustment would cause high speed instability, necessitating increased aero- which slowed it down), and the front settings and anti-dive were an attempt to prevent what I call "weight jacking"- where the front end will rise and push the car wide when transitioning back to throttle coming out of a corner. I had to decrease anti-dive to tone this down, but in doing so it also led to more wheelspin in lower speed corners, so the shock valving is an attempt to keep the bad behavior cause bt that change in check, without it being so stiff it "skips" across the track.

[clairvoyantwolf]

You really want some aggressive rotation. Question, why did you want the ride height so low?

[timothy_gammey]

lower cg means higher ultimate cornering speed and the ability to run less spring and sway bar for a given cornering load. And Yes lol, as aggressive as I can get without spinning on entry- it also helps with mid corner corrections, allowing the rear to step out when you breathe off the throttle to tighten the line (which, with my lackluster driving skill, comes in handy).

[clairvoyantwolf]

Unless I missed my guess. I was under the impression that a lowered car required more spring to stop bottoming out? But ultimately whatever works. I might play around with your tune for fun. Second question, is the car stock or does it have upgrades?

[timothy_gammey]

Completely stock. The way I see it, bottoming out may effect the car on a corner or two, and unless it's severe, you'll likely never notice- but being too high will effect every corner. There are some cars i tend to run higher and very soft, Porsche 911's I find "work" better with additional weight transfer (being as you really don't ever corner with a 911, you slide them until the nose is generally in the intended direction of travel and accelerate until another slide is required lol).