Building and tuning cars in FM3 (for beginners): E class

Posted: May 13, 2010 in Best Forza-ing

Ok, so you have a bunch of cars that you’ve built up from the career mode and now it’s time to venture online. Your cars have served you well over your career, winning many credits and cars but upon entering the arena known as Xbox live, they simply don’t stack up. What to do? Check the leaderboards and see what the fastest cars are and rock those? NO! That’s lame, be an individual Keep reading and you’ll have some rocking oddball cars to beat up on unsuspecting Audi’s in no time YMMV

I’m going to attempt to keep the cars in this guide in their original drivetrain, meaning that FWD, RWD and AWD cars will stay that way for the most part. In the beginning we’ll stay in the lower classes (E class to start, then C, ????, profit ) so we can learn to drive before we run the big cars. Smoothness is key in all forms of motorsport and virtual one’s are no different. Low class racing requires smooth inputs and accurate braking for good lap times, so it’s logical that we start there.

E275 class online tune

First we’re going to build a car for E class online use. Seeing that the E class hopper consists of mostly short tracks from 3 to 5 laps in length a lightweight car with decent power should be what we look for. We could choose something from F class and go wild with it, but if the build is wrong it’s going to get expensive to keep re-building it. So we’ll look for something in E class. Something relatively cheap and fairly low in PI relative to it’s class. Then we need to choose a “home” track, preferably one that’s in the hopper rotation for the class.

I have chosen the Honda CRX SiR as the car, and Suzuka East as it’s home track.

Now we need to see what we’re up against. You can’t (shouldn’t, really) simply throw a bunch of parts at a car and expect it to do what you wanted. The car’s not psychic you know, the lack of a sentient mind sort of supercedes that. So we need to know what the car needs to succeed. How do we do that? First, by driving it… stock, on it’s “home” track (to see if it’s any good), then, by checking out what’s possible in the upgrade shop (if it didn’t suck on the track that is).

To the Track!

Off to Suzuka we go! Since this post is about online cars, you probably have live. If this is the case, click GO RACE, then MULTIPLAYER, then PRIVATE RACE to test out the car. Remember to fill out the field with AI of the appropriate class (you can even choose their car manually if you like), turn on simulation damage, turn off collisions. Why here? First: you can race any car in the game without buying it first, second: just running 10 laps will net you about 11,000 credits (+ bonuses) which should cover the cost of the car you may or may not buy and also it’s upgrades (when we drive it later through testing). If you do not have live, then a similar career race should do the trick and allow for replays without saving them, plus you can still rewind if you mess up (you can’t in a private race, since it’s technically online).

Let’s take a look at the CRX in it’s stock configuration.

Honda CRX SiR
Class: E217, Power: 158hp / 112 ft/lb (1.6L), weight: 2161 lbs. (61% front)
SPD: 5.3, HND: 4.5, ACC: 3.9, LAU: 4.6, BRK: 4.2

Compared to other E class cars it’s not too bad, but nothing too special either. We can’t tell much from these numbers, how does a 3.9 acceleration stat differ from a 4.0? Who knows, so we’re going to use our “butt dyno” to tell us on the track…

Suzuka’s East section is a tight, twisty track with plenty of on-camber, part-throttle corners, mostly right-handers. On-camber corners are somewhat banked toward the apex, whereas an off-camber corner banks away from it, the former increasing grip, the latter, not. With most of the corners being right-handers, the left side tires are going to take a beating, especially on the last corner headed onto the straight.

Keeping this in mind, it’s time to take the REX to the pavement. Remember that the car is stock and will drive as such, be patient and above all: smooth. Remember to take mental notes as to what the car is doing and where: Corner entry / apex / corner exit, under brakes / coasting / acceleration.

CRX Stock notes:
– Understeer!! (everywhere)
– Lift throttle/brakes oversteer
– power on understeer
– body roll
+ Gearing is good (use 3rd for corners, 4/5th for straight)
+ bumps = no problem

Best lap: 59.042

So, let’s evaluate then:

Of our negative notes “Understeer!! (everywhere)” comes from it being FWD and prone to it, but turn-in is fine, it’s a matter of controlling the throttle, not a huge tuning issue per-se, but can be helped with some chassis stiffening. The lift throttle and lift braking oversteer is an issue though as controlling it costs us time. It can be tuned out with either damper tuning, differential tuning or both. The power on understeer is another FWD issue that can be tuned out easily with a differential upgrade. Excessive body roll is another issue that’s also easily tuned out with anti-roll bar upgrades.

Of our positive points, the gearing is sufficient for our needs at Suzuka East, we simply have to watch our power output to make sure we don’t exceed our gearing capacity. The fact that the CRX corners just fine aside from some differential inadequacies and the fact that it swallows up rumble strips and bumps with ease means we don’t really need any suspension upgrades, but maybe some tires should be on the agenda.

Upgrade notes:
– Anti-roll bars
– Chassis stiffening (roll cage?)
– Differential
– Tires
– Power

Oh! And we should probably buy the car now…

To the Garage!

Here we are in the upgrade garage, this is where the magic happens!  Seriously though, lets take a look around and see what can be done with this car. A lot can be learned from simply looking at the upgrade selections available. For instance, we can note that the CRX has a total of 3 engine swap options (aside from stock of course ), 1 drivetrain swap option (RWD) and 3 aspiration swaps (single turbo, twin-screw s/c and a centrifugal s/c) in the conversion section. We can safely ignore these as any engine swap jumps us up a class or 2 and the aspiration swaps do the same. In trying to keep this guide as simple as possible I’m going to keep the car in it’s original drivetrain configuration so we can ignore that swap too. You can notice how the car is set up stock from the upgrades available too, such as the differential. If a Street diff is available to buy, the stock car has an open differential, if the first option is Sport the car comes with a Street diff stock. The same is true with tires, if a car has Sport tires available for purchase then it comes with Street tires stock. This comes in handy when you’re looking for parts to buy for your car, if the car has Street tires stock, then they’re pretty good and you can probably put your credits and PI elsewhere for better performance. This is not always the case but you’ll rarely build the best car on the first try, so things will get shuffled around.

Now back to our upgrade list. Here are the upgrades to bring us up to E275:

-RACE Anti-roll bars (f&r)
The race ARB’s basically cost 0PI as their weight offsets their performance benefit. I just want something adjustable that I actually need.

-RACE roll cage
Even though it adds quite a bit of weight and PI it helps make the suspension do it’s job, instead of the chassis flexing like a wet noodle ruining our handling. We may reduce this in another build in favour of something else.

-STREET tires
Even though we can fit better tires and stay in class, I didn’t feel that the car needed a ton of grip. This should be sufficient for now, the tune will probably be tweaked again down the road.

-STREET Air Filter
-STREET exhaust
-STREET valves
With engine parts it’s best to stay with those that reduce weight. On the CRX, lighter engine parts also reduce the front weight of the car, helping to improve handling too. win-win

-STREET driveline
I use the flywheel, driveline and wheels to round out a build’s PI for the most part. Driveline can change you PI in 1 (or slightly less than 1) PI increments, while flywheel upgrades are a bit more than that. They improve driveline response, but I just use them to round out PI

And that does it for Build 1. Let’s take a look…

Honda CRX SiR
Class: E275, Power: 173hp / 122 ft/lb (1.6L), weight: 2253 lbs. (60% front)
SPD: 5.5, HND: 4.8, ACC: 4.1, LAU: 4.8, BRK: 4.6

Now to test it out. Go back to a private race, or an E class career race and hit the bricks with the stock tune (I recommend a career race or even free-run to have an easier time getting the replay). Remember to take mental notes about how the car is handling and where, both good and bad things. Also record your best lap time to see if your tinkering is having an effect.

CRX build 1 notes:
-lift oversteer worse
-throttle understeer worse
+lots more grip
+carries more speed through corners
+decent speed on straight
+gearing still holding up (3rd still good for esses)

best time: 57.162 (#546)

Once finished it’s time to watch the replay. Pay close attention to the “traction”, “tire misc” and “heat” tabs. Use the “traction” tab to see if you’re pushing the car too hard. Try and keep all the lines in the circles (keeping them green). If the line pushes out the top of the circle, you’re giving it too much gas, out the sides: too much steering and the bottom: you locked up the brakes. This tab is for tuning the one thing that matters: the loose nut behind the wheel (ie: whoever is driving). Unfortunately you can’t really tune that out with the sliders, you actually have to get better for that. The “tire misc” tab shows all of the suspension parameters for each corner of the car, it’s not the biggest deal here, as we don’t have an adjustable suspension, but it’s important to note anyway. The “heat” tab shows how hot each tire is at the inside/middle/outside of the tire. This is used to tune camber, caster and toe, which we’re not doing here, but it’s still good to see how our tires are doing anyway.

Watching the telemetry, specifially “heat” and “tire misc” I notice that the left front tire is getting up to some high pressures around lap 5. It’s spiking up to 34 psi and getting pretty hot too. time to tweak the tune now.

Let’s take a look at the stock tune as set by default (all notations by me are always in a “front / rear” configuration)…

CRX build 1 default tune:
Tire pressures: 30/30
Anti-roll bars: 28.00/22.78

Notes:
-front tires hitting 34 psi on lap 5 = pressure too high
-Arb’s too stiff, not letting suspension work
-I forgot to add the differential

So we see that our tires are getting up to too high of a pressure, and the rears are fine. We want 32 psi at all 4 tires and from 180*f – 200*f in temperature for optimum grip at peak. So our front tires are about 2 psi too high.

We bought anti-roll bars for a reason, to limit body roll, but since our suspension is stock (and soft), we still want some roll, otherwise we’ll end up on our roof after a run-in with a rumble strip. Seeing that the roll bars are set at a really stiff 28/23 setup, lets just about half that and see what it does?

Let’s see if this helps, even without the diff

CRX build 1 tweak
Tire pressures: 28/30
ARBs: 12.50/12.50

best time: 56.927

Notes:
+Much better, feels more compliant over bumps and there’s much more front grip.
– still push on accel
– still lift oversteer
– needs diff

Since the understeer on acceleration and lift-throttle oversteer is driving me insane it’s time to go back to the upgrade garage for a differential.

Moar upgradez!

-RACE differential
Since the STREET, SPORT and RACE diffs are all the same weight (+4 lbs) and thus all the same PI increase (ie: zero) go with the RACE diff as it’s tunable.

-SPORT driveline
Since the diff added 4 lbs to our car, we can now remove it with a higher spec driveline. It removes a little more weight than the diff put on, so we’re back where we started, only now with a much more tunable car.

On teh road again…

So now we head back to Suzuka East for some more test running. Our tune is now as follows:

CRX Build 1.5
pressures: 28/30
ARB: 12.50/12.50
Differential: 50%/0% (untuned)

Run it for at least 10 laps and remember to take your mental notes on the car’s handling…

notes:
+Much less push on accel
-still horrible lift-oversteer

best time: 56.889

With the differential I can now get on the gas much earlier than before, power comes on very controlled. Unless I miss an apex, accelerating through it is not an issue. the lift-throttle oversteer on the other hand…

Since the only tunable thing left on the car is the diff, let’s get to it. If the car accelerates fine then it must be the deceleration rating that’s causing our trouble, and it’s set to 0%. The only way you can go is up so head there. I reccomend setting the decel in a FWD car to half the accel rating (there are times where this won’t work, but that’s why we test right?) this should cure any lift-throttle issues we may have.

Now to tweak it and drive it again…

CRX build 1.5 tweak:
pressures: 28/30
ARB: 12.50/12.50
Diff: 50%/25%

Best time: 56.395 (#159)

notes:
+lift oversteer much better
+push on accel much better
-left front tire overheating lap 7+ (230+*f )

So, there we have it. A two-wheel drive car that competes on at least 1 track in E class. Now, we can keep it here and test/tune for a multitude of tracks for a good all-round tune, or we can revisit the upgrade garage to see if another parts combo would work better. We could look into why the left front tire is overheating, or, since this car is for online use: not worry about it as no race is longer than 5 laps online anyway. What I’m going to do with it is try for a decent all-round tune for the handling tracks found in the E class hoppers. I’ll let you know how that goes in another post.

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Comments
  1. […] case you missed it, here’s Part 1 in my building and tuning in FM3 series to get you up to […]

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