ITB - what a bunch of crap

[Knestis]

Hay-soos Tap-dancing Cheeto.

YOU ALL ARE THE BEST ARGUMENT YET PRESENTED FOR *NOT* "USING WHAT WE KNOW" IN ANY FASHION WHATSOEVER IN THIS GAME. (EDIT - almost) ALL OF YOU.

Andy, based on his experience, is VERY confident about his understandings on the Miatae. He "knows" that things are certain ways.

The problem is, other people "know" other things that are potentially inconsistent with Andy's "knowns;" or based on what individuals "know," they think what others "know" is wrong.

This is precisely why I am going to do my damnedest to resist any of these "we know" things when they come to the ITAC. The gorilla in the room here is that a LOT of the inconsistencies that form the basis of the real concerns that started this goat rope of a thread are in our rule book because of what one person or another "knew" when the listing decision was made. At the end of the day, Giles' Civic spec weight is farked up because someone was just too smart by half - they "KNEW" something and applied it. The Golfs don't align within their brand, all with the same kind of technology, because each of the many decisions over time was influenced by well-intentioned (mostly) people, applying what they know. We they dicked because someone had it in for them? No - I am very confident that they were not. But our biases influence what we "know" even if we don't KNOW THAT THEY DO.

I am going to throw myself bodily in front of any suggestion that anything besides (a) the standard 1.25 multiplier, and (b) clear, yes/no attribute adders (e.g., FWD), until/unless I see with my own eyes a big-ass pile of actual data, with attribution.

K

[Andy Bettencourt]

All this discussion about Miatas is making my eyes roll up into my head. Why don't we just create ITM and they can all just go play by themselves. Seriously, my only gripe is that there are just so many of them and they are in about every class. And that is not really a gripe.........Getting back to what this thread strarted out about, does anyone know where on the internet one might access old Road Tests? I have tried to Google them without success. AS I was one of those who volunteered to do some of the ITACs leg work on running cars thru the process, I would like to get good data on those cars. Any Ideas?

Miatas: They handle like "Sports Cars". They make everything in the world for them and there is a world of knowlege out there about them. Even if they were slow (which they are not) they would be a good choice. Many of our cars are converted grocery getters that will never attain that level of handling. They are just easier to drive.

From a Motor Trend article that tested a stock 128hp Miata to a Peter Farrell turbo version: http://www.motortrend.com/roadtests/...ars_miata.html

Stock Miata
0-60 mph, sec: 9.7
Quarter mile, sec/mph:17.0/81.3
Braking, ft., 60-0 mph: 128
Slalom, 600-ft, mph: 66.8
Skidpad, 200-ft, lateral g: 0.86

[RSTPerformance]

wow.... a lot of pages to catch up on and try to read... I see Miatas in "B" in the future

ok lets talk ITB cars though (that is what this thread was about right?)...

Tell me if I am correct:

Audi Coupe GT:
110 stock hp * 1.25 engine potential multiplier = 137.5 hp * 17 target p/w ratio = 2337.5 lb base weight.

-50lbs for FWD = 2287.5 lbs

-50lbs Brakes (single piston calipers on tiny front brake rotors and rear drum brakes = 2237.5lbs

+50lbs A-Arms = 2287.5lbs

-50lbs Bad suspension design (solid rear beam axle and not so great geometry on the front despite the lower A-Arms = 2237.5

-50lbs for bad car layout (these cars were designed for AWD, not FWD) the engine is infront of the front axle putting 2/3 of the weight over the front wheels and less than 1/3 over the rear wheels.
= 2187.5

-50lbs for not having the capability to make any ECU mods (I added this because I truley feel it should be in the mix for most of the 80's cars) = 2137.5

= 2140 Final weight rounded to the nearest 5lbs

So the Audi Coupe GT (Most popular Audi raced in SCCA) is currently at 2540lbs which is 400lbs to heavy, then add in the potential 100lbs "close enough" rule and they are 500lbs underwight compaired to another car.

Raymond "Tim, your new Audi has a 495lbd disadvantage to your old Golf III" Blethen

[lateapex911]

Raymond, gotta hand it to you, that's some serious number wrangling there. Classic stuff, and you showed your colors, LOL. No ITAC invite for you!



You forgot the 50 pounds off for fuglyness.

[RSTPerformance]

Jake-

Fix it for me.... I guess you could argue the -50 for the ECU mods, the -50 for brakes, and -50 for bad layout, but I am not sure what car has worse brakes and a worse layout?? (oh and you can't mod Audi/VW CIS ECU).

With that we are still at 2290 as compaired to 2540 (current). That is 250lbs overweight and potentialy 350lbs overweight as compaired to another car (with current 100 +/- is ok rule).

Raymond

[924Guy]

wow.... a lot of pages to catch up on and try to read... I see Miatas in "B" in the future

ok lets talk ITB cars though (that is what this thread was about right?)...

Tell me if I am correct:

Audi Coupe GT:
110 stock hp * 1.25 engine potential multiplier = 137.5 hp * 17 target p/w ratio = 2337.5 lb base weight.

-50lbs for FWD = 2287.5 lbs

-50lbs Brakes (single piston calipers on tiny front brake rotors and rear drum brakes = 2237.5lbs

+50lbs A-Arms = 2287.5lbs

-50lbs Bad suspension design (solid rear beam axle and not so great geometry on the front despite the lower A-Arms = 2237.5

-50lbs for bad car layout (these cars were designed for AWD, not FWD) the engine is infront of the front axle putting 2/3 of the weight over the front wheels and less than 1/3 over the rear wheels.
= 2187.5

-50lbs for not having the capability to make any ECU mods (I added this because I truley feel it should be in the mix for most of the 80's cars) = 2137.5

= 2140 Final weight rounded to the nearest 5lbs

So the Audi Coupe GT (Most popular Audi raced in SCCA) is currently at 2540lbs which is 400lbs to heavy, then add in the potential 100lbs "close enough" rule and they are 500lbs underwight compaired to another car.

Raymond "Tim, your new Audi has a 495lbd disadvantage to your old Golf III" Blethen

LOL... OK, I'll bite... starting with your 2340 base weight (rounded to the nearest 5)...

-50lbs for FWD = 2290 lbs - yep

-50lbs Brakes (single piston calipers on tiny front brake rotors and rear drum brakes = 2237.5lbs - nope; this is a pretty common setup for ITB. From what I've seen, this is an adder only, for cars with significantly more brake than the class supports. So my car, the 924, gets the +50, but the same brakes on the 944 in ITS I don't believe incurs a penalty. Back to 2290.

+50lbs A-Arms = 2340 - yep

-50lbs Bad suspension design (solid rear beam axle and not so great geometry on the front despite the lower A-Arms = 2237.5 - no, sorry - not gonna be able to argue that in the land of struts and twist beams!!! Back to 2340.

-50lbs for bad car layout (these cars were designed for AWD, not FWD) the engine is infront of the front axle putting 2/3 of the weight over the front wheels and less than 1/3 over the rear wheels. - a FWD car with poor weight distribution... aaah, I'm not hearing that all the rest of the cars get a double-tap for this, so I bet you don't get it either. Still at 2340.

-50lbs for not having the capability to make any ECU mods (I added this because I truly feel it should be in the mix for most of the 80's cars) - this would only be appropriate if all the rest of the CIS cars get the same bene. Since we're trying to compare to the CURRENT situation, not a theoretical - I'm sure you want to understand why your car is behind the Golf 3's currently on-track, not theoretical ones - you need to not change the playing field just yet (though, as no surprise since I am also a CIS guy, there may be some merit to this idea).

So seems like you should be at least at 2340... Which would seem to put you 200# heavy... unless the 1.25 engine multiplier isn't appropriate? Maybe it's time for you to write a letter?

Did those cars REALLY make 110 stock?? That's awfully low... what's the run-down on them again? How big??

EDIT - OK, found some basic specs. Dang, that's a lot of torque. Perhaps something closer to 1.3 (engine multiplier) is appropriate, then...

[RSTPerformance]

Audi Coupe GT
Engine/Engine Design
Arrangement: Front mounted, longitudinal
Type: 5-cylinder,10 valve, in-line
Bore: 3.19 in. (81.0 mm)
Stroke: 3.40 in. (86.4 mm)
Displacement: 136.0 cu. in. (2226 cc)
Compression Ratio: 8.5:1
Horsepower (SAE Net): 110 @ 5500 RPM
Torque: 122 ft. lbs.@ 2500 RPM
Cylinder block: Cast Iron, tilted 27°
Crankshaft: Forged Steel, 6 main bearings
Cylinder head: Aluminum alloy
Valve Train: Belt-driven, overhead camshaft
Fuel System: CIS fuel injection w/ oxygen sensor
Drivetrain
Type: Front-wheel drive
Transmission: 5-speed manual
Gear Ratios: 1st 2.85:1 2nd1.52:1 3rd1.07:1 4th0.78:1 5th0.64:1 Reverse 3.17:1 Final Drive 4.90:1
Steering
Type: Rack & pinion, power assisted
Ratio: 16.8:1
Turns (lock-to-lock): 3.4
Turning circle (curb-to-curb): 32.5 ft.
Suspension
Front: Independent MacPherson struts with negative roll radius; 21 mm stabilizer bar, coil springs
Rear: Torsion crank axle, panhard rod, 18 mm stabilizer bar, coil spring struts
Brakes
Front, size and type: 10.1 in., Disc
Rear, size and type: Drum
Exterior Dimensions
Wheelbase: 99.8 in.
Front Track: 55.1 in.
Rear Track: 55.9 in.
Curb Weight: 2507 lbs.
Drag coefficient: 0.39


Remember this is a 10 valve motor that was very well built from the factory, I doubt that we are seeing anymore of performance gain than anyone else... Also, I am not an engine expert, however based on the prior posts, I think that many have agreed that torque is not a huge performance gain in ITB cars.

You say that the layout is not worth -50lbs.... however this was listed as a area that the ITAC considers in its current evaluation, what car has a worse layout??? Its not a "double tap." FWD is one thing, car balance is a completely different issue when it comes to car setup and handling.

I will settle on the brake setup being common, but I hope that all new classed cars that have better brakes are getting the adder.

The suspension is easy... The Golf III got the -50 for a solid rear axle and it has a 10+ year newer suspension design. tthe one in all of the Audi's 1980-1987 are the exact same A-Arm with 1 piece solid knuckle and strut housing design that was created back in the 70's. not to mention it has very small VW wheel bearings that can not handle the weight load created by racing.

The ECU -50 thing I think should be done with all CIS cars including yours.
__________________________________________________ ______________________

This is just one car, that I am familiar with. I am trying to see if I missed something or not? This would easily prove to me that cars in general need to go through the process and that things are not necessaraly equal. I know we have had success with our Audi's, but we are not suposed to be using on track performance, and we certainly get our but handed to us by a lot of competition depending on the track and who shows up.

Raymond

[Xian]

I will settle on the brake setup being common, but I hope that all new classed cars that have better brakes are getting the adder.

I don't have a ton to add other than that there are ITA cars with the same weight and front brake size/setup that are considered to have very good brakes. 10.1" and single piston really is quite good, imo.

[tnord]

I don't have a ton to add other than that there are ITA cars with the same weight and front brake size/setup that are considered to have very good brakes. 10.1" and single piston really is quite good, imo.

i think my miata had 9'' brakes for 2300lbs in SM trim, and even without ducting they worked great, lap after lap, and never ever faded on me even for a single lap.

[Xian]

True... but your car is waaaaay better balanced. The CRX's are notoriously tough on front brakes (9.2" fronts). Looong pedal toward the middle/end of a race is the norm, pads last a double weekend, etc, etc. I don't think Bowie really believed how quickly they went thru pads until I started talking with him about it in depth.

Sounds like the Audi has roughly the same weight distribution as most the Honda products... somewhere around 62/38-ish.

[tom91ita]

okay, i am getting dizzy scrolling through the pages looking for who to send the letter to.

is it the crb or itac? and if the itac, what is the email? i looked at scca.com and did not get any hits on the search for crb or itac....

thanks!

tom

[Xian]

I believe it was "[email protected]"

[RSTPerformance]

Volkswagen Scirocco II 8V
Ok, people seem to like my math...

Volkswagen Scirocco II...
90hp stock * 1.25 * 17 = 1913 lbs base weight
-50 for FWD = 1863
+50 for A-Arms = 1913
-50 for suspension (solid beam rear axle) = 1963
-50 for ECU (Again this is just my feelings, not part of current process) = 1813
Rounded to the nearest 5lbs would be 1815 as compaired to the current spec of 2130 means this car is 315lbs overweight and possibly 415 overweight compaired to a car that might be 100lbs underweight.

Raymond "These weights seem to be hard to reach, maybe the ideal ITB P/W ratio should be 18 or 19?" Blethen

[gran racing]

Dang, that's a lot of torque. Perhaps something closer to 1.3 (engine multiplier) is appropriate, then...

Same amount as the Golf III. I don't understand how anyone can say torque doesn't matter or matter much in ITB.

[924Guy]

I don't have a ton to add other than that there are ITA cars with the same weight and front brake size/setup that are considered to have very good brakes. 10.1" and single piston really is quite good, imo.

I can't speak for the ITAC, of course, but it would appear that the brake adder is judged relative to what is the norm for the class, not across all classes... otherwise no doubt all ITS and ITR cars would get the adder, and that's useless! In ITB/ITC, it seems that disc/drum setups are most common, so a 4-whl disc car like mine ought to (and does) get the adder... but going up to ITA/ITS, nearly all cars do have discs all around, so not such a big deal... now you've gotta have big discs before it's a concern.

But again, I don't speak for the ITAC - I'm just running numbers from what I see.

Ray - it may be that the more appropriate thing for the Scirocco II would be a re-class to ITC? In fact, that would appear to give it a weight of about 2120 - right where it's at (ITC specific weight factor multiplier is 18.84 IIRC)?

[924Guy]

Same amount as the Golf III. I don't understand how anyone can say torque doesn't matter or matter much in ITB.

BTW, I ran the back-calculation based on the numbers posted - at the current weight, seems like a multiplier of 1.35 is in use. Anyone able to get near 150hp out of them???

Torque is still a question, and not just for a few ITB drivers.

MAYBE - Big Proposal Time here - we should quit kicking the ITAC around for a few cars not EXACTLY where we want them, and instead ask that they spend their time and energy focusing on the next true Big Question - how to factor torque into the equation.

[lateapex911]

Vaughan gets full points for paying attention~! Gold stars for you!

Raymond, well he gets a for twisting the numbers to benefit his case.

But hey, no sweat Raymond. Nearly every request or initiative made here, or sent to the ITAC, has, somewhere deep down, self interests at it's core. It's the nature of the beast. Really.

A few other comments.
You say your engine is very well made, and won't make much more power. It's FIVE cylinders, and displaces 2.3 litres, yet is rated at 110 hp. That's LESS than 50hp per litre, a terrible specific output. Maybe OK for it's period, but, nothing to write home about. (While not from the same period, cars like the S2000 make 240 hp from 2.0 litres for a much higher 120 hp per litre.



Yes, that's a bit apples to oranges, but, if the Honda is classed with a multiplier of 15%, is it out of line that the Audi will gain a bit more? And lets not forget the torque.

(And, not that it should be brougth up, but, what's your trap speed at Road Atlanta? )

As for the other items, Vaughan explained them well. You've applied subtractors for things that suck, but in ITB, those things are the norm. So cars lacking those things get adders.

[RSTPerformance]

To that are added or subtracted a very limited number of incremental amounts for specific mechanical attributes - FWD gets a minus weight (50 or 100), brakes a plus or minus (50, but that's been applied pretty rarely), suspension (+50 for A-arms, the base presumes struts; -50 for "bad designs"), gear ratios (I don't think I've seen that in my time on the ITAC yet), and "other" - which as far as I know is mid-engine layout or good/lousy torque).

The engine power multiplier is typically 1.25. We have a tendency to make adjustments to that based on "type" (e.g., "smogged up '70s POS"). There ARE other multipliers that have been applied for special cases. I PERSONALLY think that some of them are not particularly well grounded in evidence but all were determined by people who were very confident in their numbers. Further (personally), I'd prefer that we (a) document and codify these "types," and add them only grudgingly; and (b) require a really huge standard of evidence to do anything "special."

Jake-

I am glad I posted numbers on a car that I understand. I would imagine that is how a lot of people might run numbers on a car they are interested in, and unfortunately (or fortunately) you and the rest of the ITAC may get flooded with inquiries like the one I posted and they may or may not make sense. I honestly posted mine because I wanted to understand this process better (before I put in a specific car request), and I want to run all the ITB cars that I feel are at the top through this process. I DO NOT think that the ITAC should automatically run every car through the process, we as members should know the process and run cars through ourselves. If we see something funky (like I have in the Audi and the VW Scirocco) we should then ask the ITAC to run that specific car.

I still have a few questions/clarifications though...

FWD: This is a subtractor, which is easy, got that!!! (About 50lbs in ITB and probably 100lbs in ITR)

Brakes: I think I understand the brakes now, In ITB you would likely only see an an adder for 4wheel disc brakes (+50lbs) rather than any subtractors, however in ITA or up you may see a subtractor for having rear drums (-50lbs).

Suspension is two parts:
A-Arms: I see on paper that is a +50lbs, but isn't that the norm???
Bad design: Is a -50 lbs for having a beam rear axle vs. independent rear suspension (probably mostly applies to “b” and “C” cars).

Gear Ratios: Not clear when this would apply….

“Other” is multi part: examples:
Car layout: I am guessing this is only a +50 for a mid engine car…
Lousy Torque: I am guessing this is only a -50lbs if your car lacks some… lol

So with this understanding I have rerun the Audi numbers (with the 1.25 multiplier) and I get 2290lbs (that takes into effect -50 FWD, +50 A-Arms, -50 Bad Design with the rear beam axle).

To reach the current spec we would need to use a 1.39 multiplier (get a 39% gain our motors, sorry not feasible)!!! This doesn’t make sense, these are motors that were not “smogged” up, simple, dependable, low power motors. With illegal mods (.60 pistons, cams, stroker kits, bigger valves, porting the intake/exhaust, etc.) you may be able to get that 39% gain, if you are a fantastic engine builder…

Raymond “Honestly, thanks for your time… not trying to be an @$$, and Jake you’re the abnormally tall ugly guy!!!” Belthen

[CRallo]

“Other” is multi part: examples:
Car layout: I am guessing this is only a +50 for a mid engine car…

so if there is an adder for an exceptional layout/balance, why not a subtractor for a poor layout/balcance??

these are used for many performance aspects that are not the class norm... makes sense to me.

[Andy Bettencourt]

It is very possible that the Audi's are a typical car that scares the process. 110hp and 5cyl. For two cars like this to qualify 1and 2 at the ARRC a couple years back - without extensive (ANY?) dyno tuning, it is obvious that they are some of the most powerful cars in ITB - especially if you are trying to sell us that they don't handle well.

It's hard to just plug cars like this into the process.