PedalFaster

Recapping briefly: Honda's marketing department is not the definitive authority on autocross setup. While the S2000's engine resides between its axles, making it technically mid-engined by a very literal interpretation of the term, industry convention has for ages been that "mid-engine" referred to cars with the engine behind the passenger compartment but in front of the rear axle.

50/50 weight distribution is great for handling balance, but it's not optimal for putting down power. That's why all purpose-built race cars have mid engines and rear-biased weight distributions unless expressly forbidden by the rules. One of the main reasons the 911 continues to be a potent force in motorsports despite its antiquated rear-engine configuration is because that antiquated configuration puts a lot of weight over the rear wheels. The 911 carries over sixty percent of its weight over its rear wheels; can you think of a single front-engined car with more than sixty percent of its weight over its *front* wheels that's successful in motorsports without huge help from the rules?

Have you ever autocrossed an S2000 on street tires? If not, you should -- it will change your perspective on the Boxster versus S2000 comparison. This coming from a guy who's owned five Porsches, used to campaign a Boxster nationally, and now campaigns an S2000 nationally on street tires.

P.S. - I wrote Letter 8962.

MechanicalEng

So what is SCCAs argument for not letting a 2.5-2.7 Boxster compete in STR???

PedalFaster

I once read this really good advice in a really good article:

To that point -- from the first two pages of this thread alone:

https://rennlist.com/forums/8622951-post6.html
https://rennlist.com/forums/8632586-post10.html
https://rennlist.com/forums/8780028-post12.html
https://rennlist.com/forums/8849571-post17.html
https://rennlist.com/forums/8851478-post23.html
https://rennlist.com/forums/8852333-post25.html
https://rennlist.com/forums/8857883-post29.html

ToSi

986 weight distribution is 47f / 53r. Won't change dramatically due to allowances - lighter exhaust offsets light battery & removal of spare tire.

Hail national competitor, please enlighten those of us who don't drive an S2000.

& what did it say? Wasn't published..


The fear is that it'll be too fast for the class. The founding premise for STR is that either an S2000 or Miata needs to be 'the car to have'. Others are allowed but only if they don't upset the pecking order.

PedalFaster

Sounds like we're agreeing that the Boxster has a more rearward weight distribution than either of the current class-leading cars, the MX-5 and the S2000.

It can be a challenge putting the power down in an S2000 on street tires, especially in STR trim. That makes the Boxster's traction advantage very relevant to any discussion of its potential competitiveness.

It was me requesting that the 986 be classed in STU. It was rolled into the request for comment for 9146.

MechanicalEng

I dont see any reason why the Base 986 (2.5 & 2.7) would NOT be allowed in STR, I run a fully prepared S2000 in STR and have driven 986s and the only advantages the 986 has is better TQ and better brakes, the S2K is way faster and lighter. My S2K weights 2690 and puts down about 215RWHP. Also both cars cost the same, I have seen 986s going for $8k...
As PedalF said the S2K is very tricky on Street tires, but as on any car with the engine between the axles the weight distribution can be "virtually altered" by corner balancing the car, we can easily shift a few # to any corner we want by adjusting the CoilOver and try to compensate with alignment and sway bar settings...

ToSi

Hypothetically, if one were to drive an s2000 w/ power reduced by ~20% to 201hp (coincidentally the same output of the 2.5L Boxster), would the car still have the same difficulty with traction?

sjfehr

SEB is actively soliciting comments on letting 986 into STR or STU, so write those letters!

Q. What would the potential weight reduction be for Boxsters be in STR? Anyone run the #s?

DOUGLAP1

Thanks for the head's up. I found it in the latest SCCA FastTrack:

The SEB is seeking member comment regarding possible classing for the 1997-2004 Porsche Boxster (986 chassis, non-S) in the Street Touring Category. Input is specifically requested regarding potential interest in and/or suitability of these cars for either STU or STR. The SEB is also interested in member feedback regarding the possibility of preparation adjustments (for example, tire width limitations for mid-engine RWD cars), in order to address possible competition imbalances.

The 986 non S certainly belongs in STR on the same tire sizes as the S2000 and Miata, but I believe the weight to tire width /Hp ratio will not really let it be competitive. I don't get the STU thing - by definition STU is for sporty grocery getters with a back seat like my M3 (that was another one the SCCA was paranoid about classing).

It's too bad they are not considering any classing for the 986S, but I guess it's a start...

sjfehr

The STU suggestion was because SEB repeatedly denied addition of Boxster to STR for fear it would become an overdog. Someone here suggested that SEB might be more conducive to allowing into STU, even though it appears on the surface to be a poor fit for STU, and Pedalfaster and I wrote letters to SEB to that effect.

I still need to write my letter on this, too!

DOUGLAP1

Well, good luck to you guys on that. I sincerely hope you prevail.

I hate to be jaded, but I have personally given up on letters to the SCCA. I have already presented my best arguments in a previous letter, and never had a decent response.

kjchristopher

Well, so far only four people feel strongly enough about it to have responded to the SEB request.

PedalFaster

KJ, since you're still monitoring the thread:

I don't think it'll change any minds in this discussion, but I'm still curious: can you share what specific metrics caused the the Boxster to be an outlier in the models? There's already been a lot of discussion about the fact that it's mid-engined on this thread (which people seem to either believe is an advantage or not) -- were there any other notable distinguishing factors?

kjchristopher

We use a few formulas to compute a "grip factor", which is a representation of the tire to weight ratio of the cars in a select data set, and a "thrust factor", which is a representation of the wheel torque to weight ratio in a select data set. One can take various combinations of these two factors to predict competitiveness of the vehicles in the data set. For example, on a course made up of nothing but sweepers, the thrust factor will have less influence than the grip factor.

It isn't one metric that the Boxster is an outlier in. The 2.5/2.7 Boxster happen to have a ton of potential and would likely be immediate top of the class cars.

On top of that, we use subjective data to supplement what these factors tell us. Such as acknowledge the existence of SLA vs strut, etc, on the various models we review.

Personally, I think the 2.5/2.7 would be ok in STR (and would build the 2.5 over a 2.7). But I completely understand the reluctance of leadership to upset a very well subscribed/popular class by sticking a car in there that has the potential to be an overdog because four people in the entire country wrote a letter to ask for it.

kjchristopher

Will you be in San Diego for the Tour?