Brick on Wheels - R3 #2 BMW M3

[Spiny Anteater]

That random number site of Serial's is certainly thowing me a lot of high numbers at the moment - I'm in R3 again, this time with the BMW.

First impressions were that it is one hell of a handful. I took it to my usual test track (Mugello Short) and this time I tried out Skiskev's method of tuning with minimal d/f then adding the d/f later. I have to say that it's a great way of really highlighting the characteristics of a car - which in this case seemed to be terminal oversteer. It took quite a bit more time to find the tune on this one. I played around with the springs, dampers, tyre pressure, diffs and camber before deciding to have a go at changing the caster from my usual 5.4 setting. Once I'd put that up to 5.6 the car settled down and I was able to run much more consistently. I've never really played around with caster before, mainly because a small change in setting can have a huge change on the car's behaviour. But, judging by this it will be a useful took for seriously out-of-sorts cars.

As for how it runs, the first port of call was the Speedway. Now I would have expected this to be slower than the NSX around here as it has the same bhp and is more brick-like than pointy (the Porsche has fewer bhp, but seems to be more slippery than the NSX). I was therefore very surprised to set a ghost with this. Granted it's not up there with the Vipers, but it is much faster than I expected topping out at 184mph down the start/finish straight. I'm now in the process of running the QR to see where, if anywhere, it has the edge on the other two.

[Spiny Anteater]

Well, this is what I ended up with. This tune is for Mugello Short, but to be honest the only thing which changes for all tracks (except Ovals and Sunset Short) is the gearing:

Still, the tune:

Tyres: 28/28
FD: 4.20
1-6: 2.17, 1.69, 1.40, 1.19, 1.04, 0.93
Camber: -0.8/-0.7
Toe: 0/-0.2
Caster: 5.6
ARBs: 21.34/17.74
Springs: 447.8/280.3
Rebound: 7.7/7.9
Bump: 3.9/3.6
Aero: 198/463 (max)
Brakes: 48% Front/100% pressure
Diff: 40/25

Benchmarks:
0-60: 3.074s
0-100: 6.844s
Top Speed: 170.8 mph
60-0: 86.2ft
100-0: 224.1 ft
g's @60: 1.40
g's@100: 1.54

It's better than the benchmarks suggest

[Snyder005]

I love this car    My 2nd favorite R3 car, and my first top 100 on the Time Trials leaderboard with the car.  It seems on level with the Xanavi Skyline, but the Xanavi has much more torque.  Interesting to see how this car holds up.  I predict it will be faster than the other two R3 cars you have tried.

[bimmerlovere39]

I love it too, but that's not much of a surprise, now is it? 

[Spiny Anteater]

I love it too, but that's not much of a surprise, now is it? 

No.

The thing which has surprised me on this is that the stats are rubbish. It has the same stats as the 911 apart from accel (BMW=7.0, Porsche = 7.4) while the NSX beats it all ends up on the stats screen. Yet this thing is competitive, but not obviously faster like Snyder predicted. It revs higher than the Skylines and I suspect that is why it's less torquey than those two.

I haven't finished the QR or PR yet, but it has the fastest Twisty Rank (2:10.054 vs. 2:10.152 for the 911) but the slowest Flowing Rank (2:10.868 vs. 2:10.788 for the NSX and 2:10.642 for the NSX). So there's not a lot in Forza world performance across all 3 cars. Looks like R3 is pretty evenly matched once you take out the Vipers and Ferrari.

I'll be taking my tuning sheet downstairs to the box tonight, so should get the tune for this and the Challenger in this weeks challenge uploaded soon. But, I'll probably only run the Twisty tracks and Speedways for now, with the Power tracks to also be included if it sets a new best Power Rank.

[Spiny Anteater]

Tune added....

[bimmerlovere39]

Hm.  I'm looking at this tune next to my own... noticed a few things:

1) You're running a tighter gearset than me, but with a much taller FD.  Interesting.

2) You're running .1 more negative camber than I am on the front, but -.2 more rear toe - I'm guessing the camber was to get some turnin that the toe took away in the name of stability, or was it a heating issue?

3) Caster - you're running a bit more, probably just a personal preference for stability vs responsiveness.

4) Springs/ARBs - Wow.  BIG differences here.  You're running more ARB all around, and a significant front ARB bias, whereas I have a slight rear ARB bias.  You've got about 20lbs more front spring than me, but you're running a whopping 110lbs less on the rear.  At least on paper, this sounds like it SHOULD be understeer city.  Are you using a lot of throttle to rotate the car?

5) Downforce - Again, you have a little more than me on the front, and a HUGE amount more on the rear.  On the Ring especially, and also some other fast tracks, were you having issues with the rear end bottoming out at speed?  This seems like a lot of downforce for 280lb springs to resist.

6) Dampers - As is par for the course with shocks, mine are stiffer.  It also looks like you were using them to help you put the power down?

7) Differential - You're 40/25, I'm 75/75.  Are you able to keep the inside rear wheel from burning up when getting on the power?  I admit that mine's a little on the extreme side, but I pulled ti from a RL unit, and it seems to work pretty well.

Benchmarks - You've got me beat to 60, probably due to your softer rear and longer first gear.  I barely eek out the win to 100, which I would put to gearing.  I've got you beat by 7mph on the top end; I'd say this is probably a combination of aero and gearing (I think my top speed is gear limited).  You beat me on the brake, which I'm going to say is probably downforce related.  Strangely enough, we pull the EXACT same G's at both speeds, despite the big difference in aero numbers.

For reference/comparison, my tune can be found here: http://forza-tuning.net/index.php/topic,753.0.html

PS: If any of this post came across as aggressive, it was not intentional, I assure you.

[Spiny Anteater]

Don't worry, it didn't come across as at all aggressive, and I always like to see how other people have reacted to the same challenge - it's amazing to think that there are almost as many solutions as there are tuning choices I've added my comments below in red

Hm.  I'm looking at this tune next to my own... noticed a few things:

1) You're running a tighter gearset than me, but with a much taller FD.  Interesting. That FD is the stock FD - to be honest I very rarely change it about nowadays preferring to play with the individual gears. So for this, 1st is set to give a clean start without having to worry too much about wheelspin, 6th was so I was just above peak power (@8000rpm) at the end of the Mugello Short straight. This is a car which seems much happier above 6500 rpm hence the quite closely spaced gears. I've also noticed that I have a habit of often running an extra gear compared to most people on this site.

2) You're running .1 more negative camber than I am on the front, but -.2 more rear toe - I'm guessing the camber was to get some turnin that the toe took away in the name of stability, or was it a heating issue? The toe was to try and give me a bit more stability accelerating out of corners. For me, -0.2 works for the vast majority of RWD cars. I tried reducing it when I was trying to stabilise the car but ended up doing pirouttes The camber is purely to make the heating across the tyres more even.

3) Caster - you're running a bit more, probably just a personal preference for stability vs responsiveness.This was the final tweak which stabilised the car on turn in - I don't usually run this much.

4) Springs/ARBs - Wow.  BIG differences here.  You're running more ARB all around, and a significant front ARB bias, whereas I have a slight rear ARB bias.  You've got about 20lbs more front spring than me, but you're running a whopping 110lbs less on the rear.  At least on paper, this sounds like it SHOULD be understeer city.  Are you using a lot of throttle to rotate the car? You're right I do tend to use the throttle to rotate my RWD cars on corner exit. This one is no exception. If it goes right you get a good run onto the following straight. If you get on the power too early though, it can give you a nice view of the nearest barrier. Again though, the bias was partly to counteract the initial oversteer I was experiencing.

5) Downforce - Again, you have a little more than me on the front, and a HUGE amount more on the rear.  On the Ring especially, and also some other fast tracks, were you having issues with the rear end bottoming out at speed?  This seems like a lot of downforce for 280lb springs to resist. I've not run it at the 'Ring yet, but on that one if I can control the car with lower downforce I often reduce the values to 75% or even 50% of the maximum value. With the caster increase to 5.6, this car has become something of a pussycat, and I suspect it is a prime candidate for reducing the downforce. The reason I run maximum downforce on most tracks stems from when I ran the R2 Ferrari at Sebring Short. To me that was the archetypal power track, yet I gained over half a second just by banging the d/f up to maximum. I suspect that Forza doesn't add enough drag to really even up the added grip from big wings. As for bottoming out, the only place I've noticed this is at Sebring through the last corner. That lost me a couple of 10ths on the 911, but the losses were greater on the rest of the track when I tried to adjust the suspension (which must have thrown the balance somewhat). I didn't think of reducing the d/f after the Ferrari episode.

6) Dampers - As is par for the course with shocks, mine are stiffer.  It also looks like you were using them to help you put the power down? You're right, this was one of the tweaks I tried to get the power down - in fact I think it's the biggest adjustment to damper tuning I've ever made! It didn't really work so I moved onto other settings, but as it didn't make things worse I retained the setting and it seemed to work pretty well once the caster was adjusted.

7) Differential - You're 40/25, I'm 75/75.  Are you able to keep the inside rear wheel from burning up when getting on the power?  I admit that mine's a little on the extreme side, but I pulled ti from a RL unit, and it seems to work pretty well. I very rarely get that problem in my RWD tunes (sometimes I see in in the FWD ones). Maybe driving the Cobra has it's advantages

Benchmarks - You've got me beat to 60, probably due to your softer rear and longer first gear.  I barely eek out the win to 100, which I would put to gearing.  I've got you beat by 7mph on the top end; I'd say this is probably a combination of aero and gearing (I think my top speed is gear limited).  You beat me on the brake, which I'm going to say is probably downforce related.  Strangely enough, we pull the EXACT same G's at both speeds, despite the big difference in aero numbers. I'm very surprised at that, because the brakes on mine are weaker than on the NSX and 911. I also noticed that I have more of a front bias than you - I suspect I use the brakes to assist turn in and counteract the more stable tune. As for the top speed, I think that must be due to the d/f which slows mine down by about 13mph. The equal g's are surprising and suggests that your tune gives you better mechanical grip - probably partly due to mine being relatively unbalanced.

For reference/comparison, my tune can be found here: http://forza-tuning.net/index.php/topic,753.0.html

PS: If any of this post came across as aggressive, it was not intentional, I assure you.

[sk15kev]

Ran both your setups the other night after burning out on Laguna in the Challenge.  Took it around RAS.

Bimmer - Had trouble with this one to start with before the tyres warmed up.  To be honest and don't take it personally, but I have had trouble get used to a couple of your setups your setup that was posted in the past for the E30 and E36.  Different styles I guess.  I owuld probably use this setup for hotlapping as oppose to a race, as I would have problems keeping on the track.  Not because of a bad setup, just how light it feels.

Spiny - This was planted to the road. Although a bit slower getting out of corners, I was going into and through them really fast.  Also noticed the need for throtle to counter what seemed to be exit understeer.  On this track this setup was a lot quicker, but I dare say on something more open Bimmers should be faster.

thanks for posting them up.

[Spiny Anteater]

No it's interesting you should say that, because I have the ranking times in now:

QR = 168.335s (almost equidistant between the other NSX and 911)
Power Rank = 171.608s (marginally slower than the 911,much faster than the NSX - it would have been fastest but for the aforementioned issues on the last corner of Sebring Short)
Flowing Rank = 130.868s (the slowest of the 3)
Twisty Rank = 130.054s (the fastest of the 3)

Now what's interesting is that you found it good at Road Atlanta Short when the flowing tracks are what this car seems to be worse at. Having said that though, it did just edge out the NSX here (911=50.297s, M3=50.403s, NSX=50.486s). If you're still in the mood for trying it out I would say the figures suggest that it will be happiest on the short tracks. But I'm glad that you like it - it's always nice to know that your tune has been read and appreciated

[BarbecuePete]

Hey Spiny...

I'm thinking of attacking R3 as its where I have the most time to make up along with R2, out of the 3 cars and tunes you've run recently, this, the Porsche and the NSX, which would you recommend to give a run out to set some times with?

Its mainly the Original and Reverse tracks I haven't done...

[Spiny Anteater]

Of the 3 the first one I would discount is the NSX - it's the slowest in a straight line and is only fastest on a few tracks. The Porsche has the best QR, but the BMW has the best Twisty Rank (Boomslang, Tsukuba and Mugello Short). However, that is mainly because the Porsche struggled at Tsukuba - as I'm running the BMW though the snakes it's definitely showing signs of struggling to keep pace with the other two on quite a few of the tracks. Then again, if it's the snakes which you're planning on running, these are the tracks where the NSX seems to be pretty close to the other two cars - it's the more open tracks where it struggles more (despite having a better Flowing Rank than the BMW, the Porsche walloped it on the flowing tracks over all).

To summarise:

If you're running all tracks in the same car, go for the Porsche, although the BMW isn't far behind.

If you're just planning on running the original and reverse tracks, you could pretty well try any of them. The BMW is fastest in a straight line, but on the snakes the cars are generally pretty close overall, although the BMW is particularly variable between tracks. So run your favourite if you just plan on running these.

Or,  if you want to aim high on the leaderboard, the leaderboard cars in this class seem to be the Ferrari and the Vipers.

I'll be interested to see what you get out of these.

[BarbecuePete]

Thanks Spiny, I think I might just give the NSX a go as its mainly the snakes I think i'll be running, I took a quick run out last night on a few tracks in the only R3 car I have tuned in my garage, the #35 Yellow Hat Supra.

Im going to run it on a few more tracks and then give the NSX a run to compare, The only place i'm faster so far is at the Motegi Speedway... I may also give the Porsche a try as I need one for the 911 Ring Enduro...

I'll let you know how I get on and post some times up here, the only changes I may make are to the brakes as without ABS I find a 50/50 split to work to best..

[Spiny Anteater]

Im going to run it on a few more tracks and then give the NSX a run to compare, The only place i'm faster so far is at the Motegi Speedway... I may also give the Porsche a try as I need one for the 911 Ring Enduro...

Initially that surprised me as the NSX is definetly down on acceleration and top speed compared to the other two, but when I checked my times it was faster here than the 911 too (NSX: 33.475s, 911: 33.544s). I've not run the BMW here yet but I have a feeling it could be the fastest.

[EDIT: I ran it last night, and it wasn't fastest, instead it neatly bisected the other two finishing with a time of 33.506s. I suppose if nothing else it's more evidence of how closely matched the rank and file R3 cars are once you've removed the leaderboard cars ]

As for the Supra, it is a very quick car - I would say it is the quickest of the Japanese cars in R3. I still have a couple of ghosts remaining from last year when i went through Career, even after running all the tracks in free run in the NSX and 911.

As a note on the brake bias, I suspect it's not all to do with the ABS. I definitely like to drive my cars in a way that gets the back end coming out a bit under braking - without ABS I would probably move the bias a little to the front but I doubt that 50-50 would suit my driving style.

[Spiny Anteater]

In the end I was a little disappointed with this car on the snakes. I decided I would only run it on the full complement for the twisty tracks as the other two cars had it beat on the PR and FR tracks. However, it didn't prove to be as good as the other two cars on a number of tracks. In many cases, it would be fastest on the either the forward or reverse track, yet slowest on the other one.

Consider Death Adder. These are the times I set with the 2 cars (green=fastest, red slowest).

Death Adder Forwards:
BMW: 36.868
911: 36.976
NSX: 37.028

Death Adder Reverse:
BMW: 36.797
911: 36.704
NSX: 36.566

The order of the cars is reversed betweeen the two directions. I can't really say why that is. Certainly one aspect may be that a certain type of corner suits this car going through it one way, but really unsettles it the other. That could explain the difference, although as the times on many tracks are only separated by a couple of tenths it is likely that driver factors had a significant part to play too.

I was really expecting this car to beat the other two after the first couple of hotlapping tracks. Unfortunately, I have to say that it has failed to live up to that early promised and instead seems as if it would fall about halfway between the 911 and NSX in terms of overall time if I ran all the tracks.