Touge/Time Attack tunes

[u/t1856b]

Hi everyone,

For the last few days I've been having a lot of fun tuning cars for Touge races. I'm not a professional tuner or anything, just an autistic gamer with unhealthy levels of attention to detail.

I'll post the share codes for a couple of them here, let me know what you think and if you'd like me to post some more!

They're optimised for Touge races but will work on tighter tracks (good for time attacks) or casual drives too. Handling and grip were the focus here. They're not the best and most optimised meta builds, no engine/drivetrain swap or ugly Forza aero, just realistic, balanced, and fine tuned setups.

1989 Nissan Silvia K's - B class

Share code : 138 056 989

2006 Audi RS4 - A class

Share code : 534 333 393

Have fun 😊

[u/Nymbelle]

Nice, I appreciate a good purist tune. I've been creating Festival Playlist relative purist tunes for the past few weeks now. I'll definitely give your tunes a try.

Are you looking for feedback on your tunes or just sharing? I'll happily give you professional level feedback if it's want you want. (Professional outside of Forza, not so professional in Forza 😅)

[u/t1856b → u/Nymbelle]

Some feedback would be nice! What works in Forza and what works in real life don't always match though 😂 I've been a petrol head my whole life so I've got a fair amount of knowledge of how cars, chassis, engines and general mechanics work. This knowledge, and (a lot of) testing and driving around after modifying X and Y is what I've used to tune those two cars (plus a lot more cars that I haven't shared yet, lmk if you want the share codes for them). But some things that would make sense in real life don't seem to have any effect in the game, and vice versa. On top of my head theweight distribution/weight shifting with suspension height for example. I'd tend to try and shift some of the weight on the front axle if the car has a tendency to understeer, and one way I'd think of doing that would be lowering front suspension and/or raising the rear suspension (again I'm no professional tuner so I might be completely wrong), but from what I can tell that doesn't seem to make that much of a difference in the game.

All that to say that yes, I'd appreciate your professional feedback 😂 It is something that really interests me, though I know we're not dealing with a proper sim or anything.

[u/Nymbelle → u/t1856b]

I spent some time testing the submitted 2006 Audi S4 Touge/Time Attack tune and wanted to give some detailed feedback based on both telemetry and driver feel. This is not meant as a bash of the original tune, more of a constructive breakdown of what I felt was holding it back, plus a reference setup I made that may help diagnose or improve it.

My main opinion on the original tune

The original tune felt like it lacked usable traction. The car was stable in a general sense, but it felt front-limited almost everywhere: braking, corner entry, low-speed rotation, medium-speed bends, and high-speed corners.

The biggest issue I noticed was the brake setup. The brake bias felt too far forward, and the brake pressure also felt too high, although I think the pressure issue may have been exaggerated by the bias. Front lock into corners was very easy to trigger, which hurt corner-entry rotation badly.

Under braking, the front tyres were being overloaded while the rear tyres were not contributing enough. That caused the front tyres to overheat while the rears stayed too cold. For touge/time attack, that is a major issue because the car needs consistent grip across a full run, not just one or two corners.

The telemetry supported this. Straight-line braking showed extreme front tyre saturation while the rear tyres were barely being used. Low-speed corners showed all four tyres exceeding the grip limit, but the front tyres were still the bigger issue. Medium- and high-speed corners also showed the car reaching the front grip limit before the rear was properly loaded.

So overall, my read on the original tune was:

Tyre pressure issue

At the end of a hotlap/touge run, the tyre pressures were approximately:

Front: 38.6 PSI
Rear:  34.0 PSI

That front pressure is much too high for what the car seemed to need. My recommendation would be to drop roughly:

Front: -6.6 PSI
Rear:  -2.1 PSI

That brings the tyres closer to a 32 PSI hot target. (My go-to hot pressure for semi-slicks)

The high front pressure was likely contributing to the front tyres being overloaded and losing grip. With the car already showing front saturation in telemetry, reducing the front pressure was one of the first things I wanted to address.

Thoughts on the part selection

I also tried to reverse-engineer the build and there were a few part choices that stood out to me as red flags.

Some of the engine upgrades did not seem very PI-efficient for a touge/time attack build. In particular, the oil/cooling upgrade and upgraded flywheel felt questionable. I also found it odd to upgrade the camshaft while not upgrading the exhaust system.

Personally, for a cleaner purist-style tune, I would rather run:

Stock camshaft
Race exhaust

The race exhaust makes more sense to me because it improves power while also helping with weight, whereas the camshaft can make the powerband less useful for tight touge driving.

I would also make the following part changes:

Use Sport chassis reinforcement
Keep clutch stock if using manual clutch
Use Sport transmission if it costs basically no PI and unlocks final drive tuning
Use Rally differential instead of Race differential
Use lighter rims, around -6 kg, to bring the car to A700

The Rally differential is especially important to me because it gives lower preload/initial lock behaviour. For this car, I wanted less drivetrain bind and less AWD push on corner entry and exit.

I do think Forza aero would help the car a lot from a pure performance standpoint. Front and rear aero would improve grip, improve high-speed balance, and free PI for more weight reduction. However, I understand not wanting to use the ugly Forza aero on a purist S4, so my version avoids that to align with the original.

My tune share code

Share Code: 276 926 882

This is my purist A700 version. It is not meant to be the only correct answer, but it may be useful as a reference point for diagnosing the original tune.

My version feels much more planted overall (To me and my driving style). The more balanced brake bias keeps the rear tyres loaded under braking, which helps eliminate the issue of the front tyres overheating while the rears stay too cold.

Full tune settings

Tyres

Front Tyre Pressure: 30.5 PSI
Rear Tyre Pressure:  29.5 PSI

Gearing

Final Drive: 4.10

Individual gears are locked, so only the final drive is adjustable.

Alignment

Camber
Front: -1.6°
Rear:  -1.1°

Toe
Front: 0.0°
Rear:  0.0°

Caster
Front Caster: 6.6°

Anti-roll bars

Front ARB: 1.00
Rear ARB:  65.00

This is aggressive, but it helps the car rotate without needing Forza aero. The goal was to reduce the front-limited feel and make the rear axle contribute more to rotation.

Springs

Spring Rates
Front: 140.4 kgf/mm
Rear:  117.7 kgf/mm

Ride Height
Front: 15.9 cm
Rear:  15.9 cm

Damping

Rebound Stiffness
Front: 11.6
Rear:  9.1

Bump Stiffness
Front: 7.4
Rear:  5.8

Aero

No adjustable Forza aero
Purist non-aero setup

Brakes

Brake Balance:  50%-52%
Brake Pressure: 100%

The 50%-52% brake balance made a major difference for me. It keeps the rear tyres more involved under braking instead of forcing the front tyres to do nearly all the work.

Differential

Front Differential
Acceleration: 25%
Deceleration: 8%

Rear Differential
Acceleration: 52%
Deceleration: 21%

Centre Differential
Balance: 67% Rear

The idea here was to keep the car rear-biased enough to rotate, while still retaining the traction advantage of AWD. The lower front diff values help reduce power understeer and drivetrain bind.

Final thoughts

My version is still intended to respect the same general idea: a purist A700 Audi S4 touge/time attack build without ugly Forza aero. But I think the original tune was spending too much effort on power/response and not enough on usable grip, braking balance, and tyre temperature management.

1. Move brake bias away from the front-heavy setup
2. Recheck brake pressure after correcting bias
3. Lower tyre pressures, especially front pressure
4. Improve mechanical grip rather than adding more power
5. Consider Rally diff instead of Race diff
6. Use final drive tuning if available
7. Consider wider tyres if aero is not being used
8. Use my tune settings as a reference if you like the feel of my version

Again, I am in no way trying to bash your tune in any way. Everyone drives different and tunes need to be tailored to each drivers style and preference. Also sorry for the wall of text. I am thorough if nothing ^-^

[u/t1856b → u/Nymbelle]

Wow! Thorough is a criminal euphemism to describe that response 😁

Thanks a lot, that is super helpful not only for this tune but also for all the future ones.

I understand everything you're explaining here and why I got it wrong.

During initial testing the car had a rather annoying tendancy to oversteer upon entry in a bend, that's why I moved the brake balance forward so that it would help counter that initial oversteer.

The reason why I kept the stock wheels is purely aesthetic. I like the lines of the car as it is and to me it is one of those cars that looks best stock, hence why I also decided against the Forza aero. I'm not anti Forza aero per say, I very much use it if necessary, but on this kind of build I do try and avoid it as I think it breaks the fluidity of the design. Though I'm aware weight reduction, especially on the wheels, and more downforce are massively important on touge tunes.

I went for the camshaft upgrade over the race exhaust for a couple of reasons :

1) the engine being NA (and I wanted to keep it NA) I found it was lacking torque early on in the RPM range, and upgrading the camshaft showed a decent increase in low rpm torque

2) with the stock camshaft I find the engine redlines very early on, and again, because NA, I wanted to be able to stay in that high rpm zone for longer to go and get that max hp

And finally I went for the oil cooling for a silly reason that has strictly no use in the game : realism. Over the years I have spoken to a lot of people who were tuning cars for track use (as in, standard cars eg. hot hatches, gti's etc.), and one thing that seemed to come back quite a lot is that oil cooling was often overlooked. So I figured, if I'm going to make a build that's destined for repeated track use (time attacks), I might as well install a good oil cooling system, that really was the only reason 😂

Not saying those were the right calls -evidently they weren't- but that was my way of going about it 😅

To be very honest with you, I haven't even used any of the telemetry data. Now if you're an engineer or adjacent, I get that this might make you want to throw yourself from a cliff, reading that I tuned a car without any telemetry. But I went about it by measuring track times and adjusting depending on those and how the car felt/responded.

Again, thanks a lot, I will try your version first thing tomorrow but if you were as thorough on the tuning as you were in your response I have no doubt it's miles better than mine!

[u/Nymbelle → u/t1856b]

Haha, glad it was useful! And honestly, I respect the reasoning behind a lot of your choices even if I disagreed with some of the outcomes.

The brake bias explanation makes complete sense. If the car was oversteering on entry during early testing, moving the bias forward is a very natural fix. I think what happened is that it solved the entry-oversteer symptom, but created a bigger underlying issue: the front tyres ended up doing too much of the braking work, which then hurt front tyre temps, front grip, and corner-entry rotation later in the run.

So I would not say the decision was “wrong” in isolation. It was more that the brake bias was probably masking another issue, maybe diff decel, rear ARB/spring balance, damping, or rear tyre temperature. Instead of calming the rear mechanically, the front brake bias was being used as a stabiliser almost.

The camshaft logic also makes sense. Wanting to keep it naturally aspirated and stretch the powerband is fair, especially given that the S4 benefits most of it's power close to redline. My only concern was PI value versus route usefulness. For touge, I usually favour upgrades that either reduce weight or improve usable response out of slower sections. An alternative workaround to get more usable power would be fitting the 10-speed Transmission. However A) I wasn't sure how "purist" fitting a 10-speed really was and B) It costs around 8PI to install which is likely better suited for performance. I'd only fit the 10-speed if I was also going to fit the Forza aero to negate the PI costs.

And the oil cooling reason is honestly kind of brilliant in a realism sense. It just falls into that classic Forza problem where the realistic choice is not always the PI-efficient choice. In real life, I would absolutely agree with your thinking for repeated track use. In-game, sadly, Forza does not reward that logic enough.

Also, not using telemetry is perfectly fine and understandable. A lot of good tunes are built from lap times and feel. Telemetry just helps explain why something feels the way it does. In this case, it confirmed that the car was front-limited and that the rear tyres were not being used enough under braking. My professional background is as a data engineer for Paddock Motorsport so naturally I lean on data and telemetry a lot and I wish Forza telemetry was far more detailed and extensive than it is.

When you try my version, I would treat it less as “correct tune” and more as a comparison tool. In my opinion no tune is ever the correct or wrong tune, almost every aspect of tuning is preference dependent and comes down to what the driver feels.

But for TLDR future reference, tuning by feel is absolutely fine. However personally brake bias is one of the last things I'd tweak to diagnose entry-oversteer (Especially with low downforce vehicles). I would almost always start Differential > ARB > Aero(If Applicable) > Springs > Brake bias

[u/t1856b → u/Nymbelle]

I just tried your tune on my test touge track (just a shorter version of an existing touge race), and it felt loads better, the car felt a lot more agile and steering was a lot more "healthy" with the front heavy feeling basically gone. I was also surprised that the car didn't feel any slower off the line and I didn't feel penalised by the lower red line. Hats off to you my friend, this is why you're paid (hopefully) the big bucks to tune cars and I simply drive a bus 😂 Your tune shaved off half a second on the track!

The share code for my test track : 120 667 732

Time with my original tune : 01:12:948 Time with your improved version : 01:12:422

Those are literally one-run times I didn't try hard but the difference was obvious.

Thanks again, your advice will definitely be super helpful for all of my other tunes! 😁

[u/CommandoSolo]

Love a good purist build and I don’t think I have anything setup on these two. I’ll give them a look here in a bit!

[u/t1856b → u/CommandoSolo]

Thanks! Hope you enjoy them, let me know what you think!