pmcrespo

Jas0nn. I think your package with good gear ratios, a decent power curve, and some aero to keep that nose planted when you need it could be a good e36 contender. But indeed, there are some well developed and driven GTS2 e36s out there.

With that said, there has been a lot of e36 GTS2/3 to e46 GTS3 migration action in the past two years and I feel GTS2 is really again a good class that can be competitively campaigned on the e36 platform as well as several Porsches such as yours, the 968, well prepped 944T, and developed (read aero) Boxsters.

fbirch

To be honest, I was disappointed with the last-minute decision to restrict the computation of the class HP to a smaller portion of the power band (20% vs the proposed 30%) AND average in the peak HP. The net result of those two changes is that your power curve has to be VERY non-flat to yield any kind of significant reduction in classing HP vs peak HP. However, I do understand the reason for it.

A few months back I picked up a nicely set up e36 that was too nice and too cheap to pass up. I just got a race license and figured I’d spend the first year learning the ropes, so having a max’ed out front runner wasn’t my first priority. GTS is the most popular class at my home track. I had hoped that the new rules might allow me to squeeze my car into GTS2 with minimal ballast, but that doesn’t appear to be the case.

My e36 has a lightly tweaked S52. Putting my numbers into the calculator, I come up with about 228 HP, which is only 2 HP lower than peak value. That means my minimum weight for GTS3 would be 2500 lbs (impossible to achieve, without seriously hacking apart the car and/or spending a fortune on carbon fiber) or 3,300 lbs for GTS2, which seems as if it would be a pig with only 228 HP. So the car is kind of stuck in no man’s land for GTS. Looks as if I’ll just play around at the back of the pack for 2015 and decide if I’d rather do an S54 swap or switch to a different car altogether for 2016.

magnetic1

Get a restrictor plate, cut it to like 210-215 HP and you'll be in the sweet spot for GTS2 for E36s.

mark kibort

If you remember, I was responsible for the group not making a grave error in fairness by using the "Hp+ torque/2" formula. the problem is that the the lower than hp, torque porsches would get a HUGE break, so it made no sense at all. when you realize that the formula's main goal was really to bring the average up a little when the torque was greater than HP. (an indication of a flat HP curve which can be an advantage), it helped bring those cars back in a fair range.. in some cases. however, with close ratio gear boxes, it would then become unfair for the broad hp curve cars.

(GT3 vs a Porsche 928)....... if both were 330rwhp, even though the torque was greater than hP on the 928, there is no reason for penalizing the 928, if the GT3 was able to keep engine RPM in the max HP range during its gear spacing.

I was a big proponent of HP averaging, as this is real answer here.
since acceleration at any vehicle speed is proportional to HP, it makes perfect sense. if you took a cars HP and averaged it over 4 data points ,that would be a fair way to asses HP. example, a turbo with 410rwhp might only have an average of 350rwhp with a peaky HP curve, while my car at 375rwhp might have the same average hp over its use range. averaging would make these two cars fair to compete, if they were the same weight.

Now, the other factor ive always fought for ,was an absolute weight concession, where handling and braking are huge advantages for more than 70% of a lap.

But, folks will continue to make complex algorithms and miss the most important weighted factors by a mile!

It seems that the averaging technique is now being used.... something I recommended many years ago.
I just hope that the absolute weight might fall into the factors too someday soon! (e.g. above 2200lbs to 2499lbs, 2500lbs to 2699lbs and maybe 2700lbs to 3000lbs all getting some type of weight concession or penalty)

mark kibort

folks shouldn't buck the laws of physics..... try and argue this:

acceleration = HP /(mass x velocity)...... problem is, not many are able to grasp the simple physics identity! they shouldn't cry about it, they should accept it and if they don't understand it, they should try and figure it out so in their mind they can grasp the concept!

Love it! this guy gets it!!

http://www.nasagts.com/index.php?opt...per&Itemid=258

mark kibort

Bingo!

sounds like a move in the right direction! close ratio gear boxes should be looked at too, because they can keep someone in the Peak HP range , to a greater level than someone with wide spaced gears.

flink

This. Restrictors are easy, and are trivially tunable. And they are non-linear in a good way: max power is reduced by a greater proportion than lower parts of the rev range, so you get a flatter power band.

fbirch

That was one of the reasons for only using 20% of the RPM band to compute the average power. In a typical car with 7000 RPM redline, 20% = a 1400 RPM slice of the power band, which helps account for cars with close ratios staying in a narrow band close to peak power.

fbirch

Flink and Magnetic: Thanks for the suggestion. I may give it a shot. My home track (NOLA) is fairly fast and I’m not sure how much fun it’ll be to drive something with even less power than I have now, but I suppose it’s all relative. GTS3 also has better field sizes than GTS2, but maybe the current trend of newer, detuned cars running in lower classes will push some of the current e36 GTS3 crowd down into GTS2.

Surfbum

Ok, I'll admit it, I an technically challenged. How do we get the "Raw Data" from dyno runs taken after Jan 15?
Do we get a thumb drive and submit it? Do we now need new software to read this data?

mark kibort

so where are the HP points averaged from? are you just using two points? one at max Hp and then one at 20% less RPM and averaging the two?
the problem there could be the higher reving cars could get a big break, becuause the lower reving cars could actually have to live with a 30% drop of RPM with some wider gears, and actually have a lower average hp utilization for the same Peak HP.

mikew968

I believe the top 20% (i.e. highest 20%) of the HP as per the dyno sheet will be used. Once that number is computed then it is averaged with the peak HP number. I am thinking once everyone sends in their dyno sheet electronically the program with do the computation automatically.

Reducing the range to 20% and then averaging was a way to get this "average hp" concept accepted vs a more progressive change which would have alienated a lot of people!!!

mark kibort

It something I was talking about 10 years ago... glad its being done now for fairness.... I hope the weight factor will be addressed soon too, as braking and cornering is a little bit of a factor too, right?

Good to see things moving in the right direction though.

911racer

The dyno operator would be able to output a table showing horsepower (and torque) at different RPM's. I have gotten this (sometimes) with my dynos. You just need to ask for it.

But, you can get the runs on a thumb drive and download the software and look at it yourself.

Thanks

Ed

mikew968

Mark:
While I agree the less weight is it's own advantage there are places like VIR and Road America where it seems like the heavier/more HP argument seems to do pretty good! I think that is a choice the driver will get to make for the foreseeable future!!!