SCCA Club Trials car classification - take 2!

[sperry]

Okay, there's a thread on this somewhere already, but I was just looking at the car classification chart for the TT classes and I think we've been doing it wrong.

Here are the charts:

Time Trials Production Classes by Displacement
TT-1 8.1 - Unlimited
TT-2 5.7 - 8.0
TT-3 4.3 - 5.6
TT-4 3.0 - 4.2
TT-5 2.1 - 2.9
TT-6 0.0 - 2.0

Displacement Multipliers Chart
Diesel                  x0.50
Rotary                  x2.00
Stock Turbo             x1.50
Other Turbo*            x1.75
4 valve/twin cam/VVT**  x1.25
Engine Swap***          x1.50
Front Drive             x0.90

*   Includes altered stock turbo (i.e. ECU, Boost Controller, 
    Wastegate, BOV), twin turbo and supercharged motors.

**  Variable Valve Timing (including but not limited to: 
    Honda's VTEC and Toyota's VVTi)

*** Does not include update/backdate among models covered by 
    the same OEM manual.

In the past we were doing things like this:

Scott's WRX:
2.0L (base displacement)
* 1.5 (stock turbo)
* 1.75 (altered stock turbo)
* 1.25 (4 valve, twin cam)
= 6.56L -> TT-2

However, I'm not so sure you can apply the "stock turbo" AND the "other turbo" modifiers. For example my car now has no stock turbo, it's just go an "other turbo". Somehow my displacement just went down!

I guess my question is: does the "stock turbo" multiplier get applied on any car that comes with a turbo? I'm inclined to say no, since a turbo'd 350Z shouldn't get a 400hp motor with less multipliers than an STi simply because the STi came with a turbo to begin with!

Another question: if you've got both DOHC and AVCS, do you have to apply the "4 valve/twin cam/VVT" multiplier twice? Hell, three times for that matter since it's a 4 valve motor too? I honestly don't think that the valvetrain in the STi is so advanced it's worth 1.75 times the motors displacement, but I could be wrong.

Let's take a look at some test cases.

Assuming the "best-case" rules interpretation:

Stock STi:
2.5L (base)
* 1.5 (stock turbo)
* 1.25 (4 valve, DOHC, AVCS)
= 4.69L -> TT-3

sperry's old car:
2.0L (base)
* 1.75 (altered stock turbo)
* 1.25 (4 valve, DOHC)
= 4.38L -> TT-3

sperry's current car:
2.5L (base)
* 1.75 (other turbo)
* 1.25 (4 valve, DOHC)
= 5.47 -> TT-3

Now let's assume the "worst-case":

Stock STi:
2.5L (base)
* 1.5 (stock turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
* 1.25 (AVCS)
= 7.33L -> TT-2

sperry's old car:
2.0L (base)
* 1.5 (stock turbo)
* 1.75 (altered stock turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
= 8.20L -> TT-1

sperry's current car:
2.5L (base)
* 1.5 (stock turbo)
* 1.75 (other turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
* 1.5 (engine swap)
= 15.38L -> TT-1

Okay, what the hell does a 15L motor drive like! That's so far above and beyond the 8.1L TT-1 minumum, I've gotta think we're over doing it.

Let's do a little deductive reasoning. First we need a car that actually is just straight displacement w/o any fancy multipliers. How about the ubiquitous Corvette. Most came with a Chevy 350 small block. That's 5.7L, 2 valve, pushrods, and that's it. A stock 350 Vette is a TT-2 car based purely on it's base displacement.

Now, MikeK has shown that a bone-stock STi can run down the stock Corvettes in our region at Club Trials. Our worst-case scenario places him in their class, making that a "fair fight". However, I'm inclined to think that a) Mike's car get help at altitude from the turbo over the N/A Vettes, and b) Mike's a better driver with larger than average balls. But I could be convinced that the STi should be classed with the Vettes, stock for stock, in Trials (just don't tell the Vette guys that!)

Now, if we look at my 2.0L car versus a stock STi, the "best-case" senario paints a pretty realistic picture. My tuned WRX really was just a little bit slower than the stock STis. Looking at the "worst-case" I think it's pretty obvious that something's awry. My 2.0 certainly didn't act like it was a liter up on a stock STi!

So, IMO here's the way we should interpret the rules:

- "Stock turbo" and "Other turbo" are mutually exclusive.
- the "4 valve, twin cam, VVT" multiplier needs to be applied for *each* of the items on the car.

The only question left is specific to me: is a 2.5L STi short block considered an "update/backdate" in the context of Trials? We know they're not on the same line in the SCCA Solo2 rulebook. But this mentions the "OEM manual", not the Solo rulebook. IMO the "spirit" of the rule is to add a 1.5 multiplier for people that have dropped a chevy 350 into a Z and the like, whereas putting an STi shortblock into my car is the equivalent of just boring/stroking a 2.0L to 2.5L.

With all that said, here are some cars based on my interpretation of the rules:

Stock STi:
2.5L (base)
* 1.5 (stock turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
* 1.25 (AVCS)
= 7.33L -> TT-2

sperry's old car:
2.0L (base)
* 1.75 (altered stock turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
= 5.47L -> TT-3

sperry's new car (swap doesn't count):
2.5L (base)
* 1.75 (other turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
= 6.84L -> TT-2

sperry's new car (swap does count):
2.5L (base)
* 1.75 (other turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
* 1.50 (engine swap)
= 10.25L -> TT-1

MattR's car (for comparison's sake):
2.5L (base)
* 1.75 (altered stock turbo)
* 1.25 (4 valve)
* 1.25 (DOHC)
* 1.25 (AVCS)
= 8.55L -> TT-1

Finally, Matt and I were able to get an excemption for the AVCS on Subaru's in order to keep all of the Subarus in the same class. I didn't bother to assume that in these numbers, but that's one more thing to consider.

Thoughts everyone?

[MikeK]

On the course we had last time, there is no way in hell an STi should be able to beat a corvette. It was basically a 1/3 mile straight with a turn at each end.

The only reason Matt and I beat the corvette drivers is that we were flat to the floor all the way down the straight through the chicane, and were braking as late as possible. I was into the ABS at the end of the straight almost every run on the Sunday, and the only reason I felt confident enough to drive like that was because there was another 1/4 of a mile runoff down the taxiway if something went wrong. Meanwhile when I was working station 2 a lot of the corvette drivers were lifting for the chicane.

Lucas has signed up for the next event, so we will see what a corvette is really capable of. I predict he will beat us in raw times by at least 4 seconds.

Since there is no pax, I don't think it really makes much of a difference which class we run in. As long as we all end up in the same class it will be fun

[sperry]

So Mike, do you think the multiple 1.25 multipliers for 4 valve, DOHC and AVCS should apply, or would you consider a stock STi a TT-3 car?

[MikeK]

I think a stock STi should be one class less than Matt's car. Last time we were both in TT-2, but his extra power made a huge difference down the straight. Either stock is TT2 and Modified is TT1, or stock is TT3 and modified is TT2.

Also, I think that with equal drivers a corvette should beat an Sti at solo trials, so I don't think they should be in the same class. Watch Lucas this w/e, and we will know for sure.

[sperry]

Originally Posted by MikeK

I think a stock STi should be one class less than Matt's car. Last time we were both in TT-2, but his extra power made a huge difference down the straight. Either stock is TT2 and Modified is TT1, or stock is TT3 and modified is TT2.

Also, I think that with equal drivers a corvette should beat an Sti at solo trials, so I don't think they should be in the same class. Watch Lucas this w/e, and we will know for sure.

So basically, if we consider the "4 valve, twin cam, VVT" multiplier basically a "do you have an 'advanced' valvetrain" modifier and only apply it once, I think we're right where you'd like to be.

Let's try some examples:

Chevy 350 based Corvette
5.7L (base)
= 5.7L -> TT-2

Stock WRX:
2.0L (base)
* 1.50 (stock turbo)
* 1.25 (4 valve, DOHC)
= 3.75L -> TT-4

Stock STi:
2.5L (base)
* 1.50 (stock turbo)
* 1.25 (4 valve, DOHC, AVCS)
= 4.69L -> TT-3

Dean's car:
2.0L (base)
* 1.75 (modified boost on stock turbo)
* 1.25 (4 valve, DOHC)
= 4.38L -> TT-3

sperry's car:
2.5L (base)
* 1.75 (other turbo)
* 1.25 (4 valve, DOHC)
= 5.47L -> TT-3 (don't count swap)
* 1.50 (engine swap)
= 8.20 -> TT-1 (count swap)

MikeK & MattR's cars:
2.5L (base)
* 1.75 (modified boost on stock turbo)
* 1.25 (4 valve, DOHC, AVCS)
= 5.47L -> TT-3

That's it... I'm sold! That really seems to place the cars in classes relative to real-world results. As far as I'm concerned TT-3 should be the Subaru class. Those Vette owners should consider themselves lucky!

[Kevin M]

I've been trying to calculate based on this equation:

Displacement + [(multipiler 1 * displacement) - displacement] + [(multipiler 2 * displacement) - displacement] and so on. Basically, adding together each multiplier instead of multiplying what you already multiplied. Right?

So a Miata is 1.8 * 1.25 for dohc/4 valve = 2.25 L. Adding a turbo to that will be 2.25 + (1.75 * 1.8 - 1. = 3.60. Or am I not following the rules?

[Kevin M]

Also, Scott you potentially could reduce your class under my interpretation by using 2.0 as your "base" displacement, since you technically still have a WRX motor (block architecture, heads) and add the 1.50 "motor swap" factor in for the EJ257.

I'm thinking very little analysis was done for applying these rules as they were written.

[sperry]

Originally Posted by BAN SUVS

I've been trying to calculate based on this equation:

Displacement + [(multipiler 1 * displacement) - displacement] + [(multipiler 2 * displacement) - displacement] and so on. Basically, adding together each multiplier instead of multiplying what you already multiplied. Right?

So a Miata is 1.8 * 1.25 for dohc/4 valve = 2.25 L. Adding a turbo to that will be 2.25 + (1.75 * 1.8 - 1. = 3.60. Or am I not following the rules?

That sounds *way* too complicated. I believe the multipliers are to be applied all at once. The idea is that if you've got DOHC and a turbo, they're going to make each other more helpful. i.e. adding a turbo should result in 75% more power no matter what you started with.

Take your miata example:
1.8L (base)
* 1.25 (4 valve, DOHC)
= 2.25L -> TT-5

Now add a turbo:
1.8L (base)
* 1.25 (4 valve, DOHC)
* 1.75 (other turbo)
= 4.94L -> TT-3

Originally Posted by BAN SUVS

Also, Scott you potentially could reduce your class under my interpretation by using 2.0 as your "base" displacement, since you technically still have a WRX motor (block architecture, heads) and add the 1.50 "motor swap" factor in for the EJ257.

I'm thinking very little analysis was done for applying these rules as they were written.

I think the "motor swap" multiplier is really designed to properly class cars that have complete swaps. Basically, if you take a little car like a Sprite or something and drop a small block chevy motor in it, you're going to have awesome power-to-weight. The "engine swap" multiplier factors in that most motor swaps result in far more power than the original car was intended to have.

In the case of my "swap", I really haven't swapped my motor. All I've done is effectively increased my base displacement. Hell, 90% of the parts on that motor *are* from the original, the only thing that's new is the short block. Which is why I'm planning on not applying the "engine swap" multiplier but bumping my base displacment and considering my car a TT-3 car, which is appropriate assuming all the tuned STi's are also TT-3. It's the same as if I pulled the 2.0L short block, and had it bored/stroked to 2.5L.

[MattR]

So? Am I in TT1 or TT2 or TT3??? Can someone decide for me. Perhaps print out you math so I can show it to the event chairs on Saturday.

[Kevin M]

My brain hurts. I think the only thing for sure about the TT classifications is that they need to be fixed by next year. Why don't we just carry over SP and ST and SM classes next year? I mean, under the current system Tyson's uppipe puts him in the same class as a WRX with a VF34, full turboback, injectors, etc. Potentially a 100 hp difference between otherwise identical cars. Not to mention the ridiculous disparity between completely different cars. So why are we bothering to care about how closely we adhere to such silly rules? I mean, the entire range of TT classes exists solely for Solo 2 cars/drivers to come out and get their feet wet in Track Trials. Why not just carry over from there?

By the way Matt, I vote for TT-2 for you and the rest of the STis. TT-3 for WRXs.

[sperry]

Originally Posted by BAN SUVS

My brain hurts. I think the only thing for sure about the TT classifications is that they need to be fixed by next year. Why don't we just carry over SP and ST and SM classes next year? I mean, under the current system Tyson's uppipe puts him in the same class as a WRX with a VF34, full turboback, injectors, etc. Potentially a 100 hp difference between otherwise identical cars. Not to mention the ridiculous disparity between completely different cars. So why are we bothering to care about how closely we adhere to such silly rules? I mean, the entire range of TT classes exists solely for Solo 2 cars/drivers to come out and get their feet wet in Track Trials. Why not just carry over from there?

By the way Matt, I vote for TT-2 for you and the rest of the STis. TT-3 for WRXs.

Welcome to road race. Classes are usually defined by a displacement and a minimum weight. You want to keep up with the competition that's got an extra 100 hp? Get an extra 100 hp in your car. Part of being fast at this level is building a fast car.

Solo2 make consessions to try to keep costs down and allow fair competition between un- or low- modified cars and puts the emphasis on driver ability. And look how complicated the rules are to try to meet those goals. In fact, this may be the very 1st time I've ever seen someone suggest "hey lets just use the Solo2 classes, they're so much easier!" Solo2 rules suck, and at this level they'll be all screwed up because they're designed to keep cars equal at 65 mph. How well do you think a national champion quality STX Honda Si (that can hand us our asses at Solo2) would do in Club Trials vs. Dean's WRX?

One more thing to note about Trials. The laps are long, and fast. There's a lot of time to make mistakes, and those mistakes are multiplied by the length of the straights. What this means is that driver error is measured in seconds, not thousandths as they are in Solo2. Car's don't need to be classed so rigorously because they're not going to make that big of a difference, relative to the driver's error. Think of it this way: two fully tuned STi's, exactly the same, but one's got an ALK. In Solo2, that might be the difference between a National Champ, and being ouside of the trophies. In Trials, the ALK's advantage would be disguised by one of the drivers getting the car onto the longest straight at just 1 mph faster, or by one driver having just a little bit more balls and going deeper into a braking zone. My point is, as long as your car is in the ballpark, all you have to do is drive better to win. All those little nit-pick style mods don't get you a huge advantage.

Now I'll agree that the TT rules are a bit vague, and we need to get some clarification on how to apply them, but I certainly wouldn't just toss 'em out. They're a nice bridge between the Stock classes and having to crack open the GCR and pick a road race class.

Back to the topic, here's the preamble to the TT classes:

Time Trials Production Classes - Reno TT Regional Classes only

A Time Trials Production class is defined as commonly available produced automobiles intended for street use, modified for Time Trials or Solo II competition (original frame or unibody). Cars will be classified by the engine displacement (liters) of the vehicle they are racing and shall compete in their applicable Time Trials (TT) Production class listed below. A vehicles displacement is determined by the current (factory or modified) displacement and then modified by the displacement multipliers chart to determine final car classification. Please note that more than one multiplier can apply to one car.

Reading that carefully, we see why I wouldn't call my car 2.0L *1.5 for the engine swap. You have to use the current, actual displacement.

We also can get some insight into the way we're supposed to apply the multipliers. The "more than one multiplier can apply to one car" of course means that we don't just pick one multiplier. But it also implys by omission that we should only apply each multiplier once. If we were supposed to apply the x1.25 for the 4 valve, and again for the twin cam, and again for the VVT, the rule propably would have explicitly said "multipliers may be applied more than once", or more obviously, there would have been a seperate multiplier each for 4 valve, twin cam, and VVT.

[sperry]

Okay, I took a stab at writing some clearer rules for Time Trials classes. Take a look, they should mean exactly the same thing as the current rules (assuming I'm interpreting them correctly), but now there's less room for misunderstanding (I hope).

Grab a copy of the .DOC and let me know what you think.

[Kevin M]

All good points Scott, but there's one thing that makes me disagree with much of it. It's the fact that the TT classes aren't supposed to be the primary classing system for Track Trials- SCCA Road Race classes are. So anyone dumping cubic dollars into a car should be doing it with a Road Race series in mind, not a Time Trials class. It seems to me TT classes exist as a way to get Solo 2 cars and drivers out to the track Trials to get involved in that stuff too. Since everyone's bringing a Solo 2 car out to play in a non-Solo 2 sandbox, I think it makes sense to bring the silly and arcane Solo 2 rules with them.

There's also a glaring omission from the TT classes- minimum weights. It seems that if you wish to win your TT class, you can't have a car that weighs more than 2000 pounds or so, regardless of what it's powered by. So yeah, I suppose I could build a TT-3 competitive Miata, but there's no chance of building a winning TT-3 WRX or TT-4 RS.

[Kevin M]

However, as I said, TT classes are intended for people who aren't yet serious about Club Trials to give it a shot in something more organized than RNP. So maybe nailing down competitive balance is just not that important for them.

[sperry]

Originally Posted by BAN SUVS

All good points Scott, but there's one thing that makes me disagree with much of it. It's the fact that the TT classes aren't supposed to be the primary classing system for Track Trials- SCCA Road Race classes are. So anyone dumping cubic dollars into a car should be doing it with a Road Race series in mind, not a Time Trials class. It seems to me TT classes exist as a way to get Solo 2 cars and drivers out to the track Trials to get involved in that stuff too. Since everyone's bringing a Solo 2 car out to play in a non-Solo 2 sandbox, I think it makes sense to bring the silly and arcane Solo 2 rules with them.

There's also a glaring omission from the TT classes- minimum weights. It seems that if you wish to win your TT class, you can't have a car that weighs more than 2000 pounds or so, regardless of what it's powered by. So yeah, I suppose I could build a TT-3 competitive Miata, but there's no chance of building a winning TT-3 WRX or TT-4 RS.

I'm confused as to why it's better to migrate a complicated, long winded, and ultimately non-applicable rule set to Trials, when you can specify adequate rules in about a page of text.

As far as dumping money into a TT car... you're right they're only a regional classes. I wouldn't suggest that anyone specifically build a car to those rules. My point however, was that anyone that's competing in Trials is (or should be) already "into" the sport and would have a car that's well tuned for motorsports competition. Trials is not Solo2, and as such, isn't intended for the casual competitor. Solo2 is where you should start, and once you get the inkling for something faster, the TT classes are there to allow you to move up without having to worry about having to deal with a new set of rediculous rules.

See if you can follow my logic: Solo2 classes are inadequate for Time Trials because they're designed to classify cars based on their performance on slow, tight courses. In addition, there are so many Solo2 classes that using them for Time Trials would usually result in an event with 30 entrants in 25 different classes. Road race classes are fairly specific, and building a car for those specs will almost always result in a car that's either Prepared or Modified if you were to continue to run the car in Solo2.

The TT rules allow people to compete with like-cars without having to give up their Solo2 classes... and that's because they're intentionally vague. You're absolutely right that someone could build a class killer by simply putting a powerful motor in a very light car. Hell, look at the TVR that comes out to play... it's techinically a TT-4 car IIRC and he was gunning for the Bensons' SPO times! But, also as you mentioned, the TT classes aren't designed for long-term competition, they're just there to generate classes so part-timers will have someone else to race against instead of being the only ESP car or something.

I think the TT classes do a very good job at their intended function: class generally similar cars together without becoming so specialized that a competitor has to build to the letter of the rules to remain competative, and allow backwards compatability with Solo2 rules. My only beef with them is the language of the rules that made it confusing to apply the modifiers... something I hope we've cleared up already.

[MattR]

Okay, I still am unclear as to what my proper classing should be...Scott, can you clear this up for me please...

My Sti
Stock Turbo
Ecutek
2.5L.

[sperry]

Originally Posted by MattR

Okay, I still am unclear as to what my proper classing should be...Scott, can you clear this up for me please...

My Sti
Stock Turbo
Ecutek
2.5L.

Okay, lemme give it a go....

2.5L base
*1.25 (AVCS/4 valves/DOHC)
*1.75 (modified boost on stock turbo)
= 5.46875 = TT-3

And just for my own reference, here's my car:
2.5L base (engine swap does not apply, just the new base displacement)
*1.25 (4 valves/DOHC)
*1.75 (new turbo)
= 5.46875 = TT-3
...so, same class just a different way to get there!

[MattR]

Sweet. Sounds good.