Silvia S15 C Class Grip (+a) build & Discussion

[Blooze]

This will be a discussion of my Silvia S15 grip build and how the Tooning Sheet and various principles are used to come up with it, the Toon.

The attached Workbook contains two spreadsheets, the first is my operational Toon sheet for the C Class Grip version of the car.  This sheet contains the Registration or Title (if you will) for the car and maintains the car's Forza History numbers (in case you get to looking over the financial part of the sheet and start to wonder wtf...)

A helpful little ditty about the size.  I imagine that when you load this that it conforms to whatever window size you have your Excel set to.  However if you were to resize your Excel to the following...

• The Spreadsheet should be expanded to be the only window inside the Excel fram - the spreadsheets should not be tiled.
• Move the bottom frame untill Row 41 is displayed in its entirety.
• Move the right frame until Column U is displayed (part of the racing stripe).

Doing this will affect 'pages' for the sheet.  Now if you were to hit Ctrl-Home, the following will be true...

• What you see in front of you - cells A1 to U41 is the whole tuning section of the sheet.
• If you hit the PgDn key, you will presented with the parts selection area (on the left) and the Damper Agents on the right.
• Hitting PgDn again will bring you to the financial portion of the sheet.
• Scrolling the width of the sheet from home will put you in the Transmission Designer
• Page Down from there will land you in the Dyno Graph in case you have filled in the numbers.

Having my Excell Window sized this way makes moving around on the car sheet much easier and less confusing looking.
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Also included is the worksheet "Adjuster" that I used to develop the "Tonka" functions that are used in the sheet.  These are essentially quadratic types of equations that define the slope and curve of the graph created by the SWR tables.  Note: the set of functions that were used finally are the ones developed by Silvo 1981, who was a significant contributor to the "Redux" thread.

I won't go into the justification for the SWR and its importance to the suspension relationships here. - that is already explained to the hilt in both of the Bias Tooning Threads.

The primary reason for adding this sheet is to show which SWR was selected and why.

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[Blooze]

Here is a text version of the build...

2000 Nissan Silvia Spec-R

• Hp: 300
• Tq: 243
• Wt: 2839

Parts

• AWD conversion.
• Engine: [Street] Oil Cooler, flywheel; [Sport] air filter, exhaust, valves, and intercooler
• Handling: [Street] Weight Reduction; [Race] Brakes, Springs, R&L ARB
• Drivetrain All Race.
• Tires: Stock Compound; 225mm; 17"; Holeshot Holestar
• Body: Forza front and rear wings; rear bumper, side skirts, and hood

Gears

• FD = 3.76
• 1-6= 3.12   2.18   1.66   1.30   1.06   0.90

Setup

Wt Bias - SWR	50.00%	46.50%
Parameter	Front	Rear
Tires	28.0	29.0
Camber	-1.1	-0.9
Toe	0.2	0.1
Caster	5.0
ARB +40%	12.3	13.1
Springs	660	660
Height	5.7	5.8
Rebound	8.2	8.1
Bump	4.2	4.5
Aero	75	137
Brakes	48	102
Front Diff	26	0
Rear Diff	32	26
Torque	54

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[Blooze]

And now we'll start with some explanations...

Weight Bias = 50.00%:
Due to my belief that when we set the Spring Bias, we are actually setting the Weight Bias - in affect moving stuff around on the car until it is balanced the way we want.  Getting the car to rotate is the whole deal for me as far as push and loose (under and over steer) are concerned.  It is much easier to spin something when the angle of momentum on both sides of the fulcrum is equal (think of spinning a baton).  Almost all of my builds are at 50%, and very seldom do I move off of that.

SWR = 46.50%:
The stock values produced an SWR of 51.32%.  Checking the "Adjuster" sheet shows us that that is a stronger set of springs than one would find on an R4 race car, or an Enzo Ferrari.  My setting of 46.5%  is another increment in my slow move down.  I expect to eventually end up about halfway between an Enzo and a Stock car...  say 41% or there abouts.

The Values for a 2839 # car with a 46.5 SWR and 50% Bias are...
Springs = 660 F&R
ARB = 9.1 F&R
Dampers = 8 and 4 F&R

I will discuss modifications to those values in the next installment.

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[barumba]

Hey, Blooze, I'm jumping right in, as usual. You might want to start the OP with, Upgrade the Drivetrain to AWD.
I did not own the Silvia, so purchased one. Built her up as in your outline. Got to the differentials and my only choice to adjust was Accel and Deccel. Also, my curb weight was off. Upon closer look, I saw that you advised for the diff Front/Rear/Torque. Well, knowing a wee bit, I figured out I needed an AWD to accommodate those adjustments. So, I went and upgraded the drive to AWD. Well that required a new trans and diff, not to mention retuning those new parts. Not a big deal, but cost a few extra shekels for the second race upgrade trans and diff.
I haven't had a chance to run the tune, thought this might be more important for now.
Cheers!

PS, have you chosen a track or two for comparison's sake?

[barumba]

OK, got a few laps in the Blooze Silvia, Cat GP. After about 4-5 laps, 124.936. About 2 secs off Blooze's time.
Virtually no OS/US, breaks (no ABS)-no lock-up. Corner entry and exit, diffs very well balanced, no traction loss, only when I over cooked a corner (in test drive and first hot lap). For me, that was easy to do. This tune handled so well I found I had an uncontrollable urge to push harder each lap. Then I calmed down. I test drove the car in tune, got a 124.958. Went into Leader-board with lots of confidence. Only deserted on the first lap (DF). The restart and subsequent 3-4 laps were righteous.
I could go on, but there is little else to say. The balance, in all aspects; braking, accel, deccel, turn in and out, both tight and sweepers was impeccable.
I just might race a few laps with this little darling.
Cheers!
 

[Blooze]

...You might want to start the OP with, Upgrade the Drivetrain to AWD

Heavens!  What a grievious omission!!  Good Catch!

My appologies to all who may have run into this like Barumba here.  I'm not sure, but I think that if you will remove the AWD - don't sell it - just remove it, then you will be able to return to the Drivetrains section and sell any parts that you bought before making the AWD conversion and thereby recouping at least half the money wasted on my faux-pas.

Not to try to excuse this in any fashion, but perhaps to explain it a little.  Whenever I make a change such as this - AWD Conversion or an Engine Swap - I add them at the very front of the build and then treat the Converted vehicle as the Base Automobile.  The end result is that the fact that the car is the product of a major upgrade can be moved to the back of my mind relatively quickly.

For comparative tracks...  I don't know.  The car is built with a general or universal Toon so the tracks involved with the QR2 and the Targa Forza should proove as a pretty good test bed.  At minimum, the straight QR tracks should work as well.  The Silvia currently holds the top in all three tracks in my C Class garage.

Once again, sorry for the inconvienience...

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Barumba - it is gratifying for me to read that the Toon is working well for you.  Thanks for the report!!

[barumba]

"Once again, sorry for the inconvienience..."
No need for that, Blooze. For cryin' out Pete's sake.
God only knows you have earned a whole slew of get-out-of-gaol free passes. Consider this one cashed in. 
Cheers!

[ORG63]

I tried your S15 setup and I can't add any thing more than what barumba said so I will just say Big Thumbs Up to you on this car.  The only thing I changed was the Braking set up to what I like. I looked over your  setup before starting on the car and spotted the awd diff settings. Again Great setup thanks.

Don

[Blooze]

@ Barumba - heh, not to worry - I'm not going slit my wrists or anything.  But I do pride myself in accuracy and I hate when my lack of it costs someone else time.

@Don - thanks for the report!  I'm glad it is working for you!

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[Blooze]

Previously...

The Values for a 2839 # car with a 46.5 SWR and 50% Bias are...

• Springs = 660 F&R
• ARB = 9.1 F&R
• Dampers = 8 and 4 F&R

I could say that once the base numbers are reached that tweakage begins, but that really isn't the case.  A good part of most of my setups are fixed using functions upstream from the SWR calculations, and the SWR numbers are merely input for those functions.  Except for the Spring Rates, these functions alter the numbers to the point that one can hardly recognize the other values as part of 50% biased build.

All of the following with no requard to order...

ARB = 12.3/13.1 - most of the modifications to the SWR values are to facilitate what I refer to as "Rotating Thru the Turn"..   Turn 10 really threw me for a loop with their ARB settings with this version.  And, as we discovered, all the squirreliness seems to be confined to "production" cars.  After a bit of testing I returned to the "Inverse" Bias form of determining initial ARB values rather than the fixed 55% they are using now.  As for the numbers themselves - I have no idea...  the total ARB value for the Silvia is 51.46 - the total ARB for an R1 LMP1 car is 25.33.   For the life of me I can find no justification for this other than to make drifting easier for noobies...  but I have been reticent to discount the higher values all together so I have been sneaking up on the numbers.  The SWR calc says 9.1 and I am currently increasing that by 40%  (I started out at 80% and have been gradually lowering it.)  This produces an ARB Value of 12.7.  The final values are the result of changing the ARB bias from 50% to 48.5%.  As stated, this is to help the car rotate through the turn.

Alignment = -1.1,-0.9; 0.2,0.1; 5.0 My default settings for the alignment is -1 and -.8 for the camber and everything else as it comes from the Forza.  The Positive Toe settings 0.2 for the front, and 0.1 for the rear, are provided to help with the car's rotation, especially at lower speeds where momentum isn't helping much.

The next thing to discuss is the Damping Agents...  I think I will save that for the next installment.

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