June 2012 Fastrack

[lateapex911]

So the formula is based on a 25% hp improvement over Stock 1.8L hp or is that advertised 1.8L hp or dynoed 1.8L HP or crank HP or Wheel HP? I ask because I've never seen a 128-133HP stock, factory fresh Miata.... ever.

My original 92 miata 1.6 was listed at 116hp but on a dyno it peaked at 97hp.
I'll make the assumption that the 1.8's are the same. That car now has a 2001 VVt engine that is claimed to be in the 145hp range stock, but mine with I/H/E and ecu just barely makes 144 peak. So the claimed number and real numbers don't seem to be very accurate.

Some of us are new to this and weren't around when all the initial arguing was done.

I was pissed off about this initially because of the randomness of it. If changes are made to the weight of the car why not wait until the end of the year or prior to the beginning of a new season? You know during the off season when people are working on their cars anyway.

The basic Process takes stock crank hp and adds a 25% factor. So, in theory, the IT crank hp of the 1.8 should be 160 crank. Assumed IT RWHP (ITAC uses 18% as a deduct when discussing in RWHP, 15% for FWHP), would be 132.

Jeff says they have settled on it making 135 RWHP in IT trim based on their evidence.

So, thats three more HP than the Process predicts for the 1.8 at 128 stock crank. ITA is 14.5 lbs per hp, so 3 * 14.5 is 43.5 more pounds, based on Jeffs evidence. 2380 + 45 = 2425.

 

[preparedcivic]

I sort of knew that. Hence the something like 43% adder this car has.

I'm in the camp that doesn't see 80lbs slowing an ITA Miata down much, particularly at momentum/speed maintenance tracks.

And on edit, there are a bunch of cars that still have inconsistent power adders applied. Having been in the rules making business, that is the ITAC's and CRB's perogative. Those decisions just need to be defensible.

Hi Rob,

Not sure if this got answered already... the 2nd Gen CRX is an example of "backwards math" to arrive at the weight. During the Great Re-alignment, the Si was determined to be "the bogey" for ITA performance. The ITAC used "what we know" dyno examples of the car to determine how much the engine was under-rated from the factory and therefore bump the weight by 110#'s, IIRC.

All of this is by my best recollection and I wasn't heavily involved in the technical side of The Process at the time... anyone else can feel free to chime in with additions/corrections.

Christian

 

[JohnW8]

The basic Process takes stock crank hp and adds a 25% factor. So, in theory, the IT crank hp of the 1.8 should be 160 crank. Assumed IT RWHP (ITAC uses 18% as a deduct when discussing in RWHP, 15% for FWHP), would be 132.

Jeff says they have settled on it making 135 RWHP in IT trim based on their evidence.

So, thats three more HP than the Process predicts for the 1.8 at 128 stock crank. ITA is 14.5 lbs per hp, so 3 * 14.5 is 43.5 more pounds, based on Jeffs evidence. 2380 + 45 = 2425.

Thanks for the explanation Jake. Since this process comes up with 2425 where does 2460 come from?

 

[Greg Amy]

Non-sequitor from another thread...

Well, one change that will happen as a result of the ITA Miata weight gain is the loss of the SM crossover guys, as they will now be REALLY illegal for ITA if they don't bolt in enough weight to make the new 2460 number. I'd guess they'll all go to ST instead...So expect ITA numbers to drop further.

Maybe it's time to re-visit that whole "allow other categories into ours" thing.

I was personally opposed to Improved Touring allowing Spec Miata cars into IT under their own category specs, mostly because I saw that there were a number of mods allowed in SM that are decisively non-compliant in Improved Touring, and I saw with that a dilution of the "purity" of the class philosophy. However, even taken as a whole there's not really anything in there that would make an SM higher performance than a built ITA Miata.

Plus, my experience in Super Touring with that has generally been positive (noting, of course, that very little in SM is non-compliant in STL).

Granted, Speccers are fast, developed little rockets, and the top-flight versions will likely run at the pointy end of the ITA field (especially on Hoosiers now). But if they can resist the temptation to "cheat" in ITA (run the appropriate restrictors) it could be a ticket to getting ITA numbers back up (though little comfort to those non-Miata ITA guys that are going to get their tails whacked by a hoard of Spec Miatae...) I'd even consider supporting the '99+ crowd into ITA with appropriate SM weight and restrictors.

Someone want to list the items allowed in Spec Miata that are non-compliant in Improved Touring? - GA

 

[JohnW8]

Someone want to list the items allowed in Spec Miata that are non-compliant in Improved Touring? - GA

1. De-powered racks

 

[lateapex911]

Non-sequitor from another thread...


Maybe it's time to re-visit that whole "allow other categories into ours" thing.

I was personally opposed to Improved Touring allowing Spec Miata cars into IT under their own category specs, mostly because I saw that there were a number of mods allowed in SM that are decisively non-compliant in Improved Touring, and I saw with that a dilution of the "purity" of the class philosophy. However, even taken as a whole there's not really anything in there that would make an SM higher performance than a built ITA Miata.

Pl - GA

Actually IT does not allow SMs into the category. There's no provision that they may run. Many are, in fact entering and running illegally, and nobody is saying anything, or protesting.
Key is, of course, that in our area, no SM has been able to knock off the top dogs, and the mid packers haven't felt displaced.

 

[Greg Amy]

Actually IT does not allow SMs into the category.

I understand that; that's why I'm suggesting it could be revisited... - GA

 

[JIgou]

1. De-powered racks

2. Allowance of Torsen diff (and the associated larger carrier) in the 1.6L SMs

3 - maybe? Mechanism of changing the timing on 99+ Miatas

 

[Chip42]

just to clear up the math:

current ITCS classification: 2380
standard process math using stock hp
128 (low number): 2370 (128*1.25*14.5+50)
133 (high number): 2460 (133*1.25*14.5+50)

"known horsepower method", assuming 135RWHP: 2440 (135/0.82*14.5+50)

jake's math is off on 2 counts, the ITCS weight doesn't match process math at any level, and the change of 3 whp is closer to 4 crank, assuming an 18% driveline loss. IT weights are calculated using crank or assumed crank HP (using a 15% or 18% loss from WHP - 18% has a prop shaft, 15% is transverse)

so the new classification is 20 lbs heavier than the "known" whp, which is 70 lbs heavier than the process math for the 128 chp number. some ITAC members didn't have confidencce in the dyno data enough to fall back that 20 lbs, so we went ahead and ran it at the higher OEM published number. for those of you keeping score, that assumes a 136whp, 1 more than the known. well within dyno noise and NOT worth an argument. in reality, this is the process working, it's just a fucking lightning rod car so it gets all the cloak and dagger paranoia.

IF we had followed the known hp route (which was the minimum we would consider) AND voted to add the 50lb rear SLA ("double wishbone") suspension adder Andy asked for a while back, then we would have had a new weight of 2490 lb. I think in the long run this is just a lot of noise and wont amount to any measurable, on-track changes.

The REAL issue getting people worked up here the casuation of the change, not the change. the cause was a lot of interest from a lot of people both in and outside of the SCCA's rulemaking hierarchy. letters came and letters went. we all know who wrote the letter that finally got the nod for a weight change. we all know who his friends and customers are. we all know who recently (re)joined the CRB. Connections LOOK obvious so everyone WANTS to make a mountain out of this. in reality there was some attention from on high, but NOT a lot of pressure, that led us to reconsider this listing. we did NOT "cave" or "fold" though we did allow that interest to push us to revisit this when we historically had simply dismissed the requests. I can tell you for damn sure the car was not going to come out of that discussion at less than 2440 (known hp).

you want black helicopters and stuff? look at ITB accords and MR2s. the miata was pretty cut and dry.

 

[lateapex911]

just to clear up the math:

current ITCS classification: 2380
standard process math using stock hp
128 (low number): 2370 (128*1.25*14.5+50)
133 (high number): 2460 (133*1.25*14.5+50)

"known horsepower method", assuming 135RWHP: 2440 (135/0.82*14.5+50)

jake's math is off on 2 counts, the ITCS weight doesn't match process math at any level,
.

Uh, yea, good point. I forgot the 2380 number came at a time when there were built cars to be considered and cage rules had a weight break that we needed to consider. The cage rules have since changed, freeing up weight changes.

 

[Xian]

I sort of knew that. Hence the something like 43% adder this car has.

I'm in the camp that doesn't see 80lbs slowing an ITA Miata down much, particularly at momentum/speed maintenance tracks.

And on edit, there are a bunch of cars that still have inconsistent power adders applied. Having been in the rules making business, that is the ITAC's and CRB's perogative. Those decisions just need to be defensible.

Heck, 110#'s didn't slow down the CRX's... they went through front brakes, bearings, and hubs faster but they didn't really get any slower. [popcorn]

 

[lateapex911]

Heck, 110#'s didn't slow down the CRX's... they went through front brakes, bearings, and hubs faster but they didn't really get any slower. [popcorn]

Do we really know that? Were there back to back sessions run with, without and with the weight to confirm?
I remember getting a scathing letter from Robert Moser who was not happy and felt the cars were worthless after the weight addition. And calls from his crew chief. (Ear is still ringing, LOL) But, King built new engines, intakes were changed, ignitions were changed, and I think they clawed back lap time.

But, I think it was bit by bit. I suspect, if they were allowed to remove the weight, and they developed for that setup, they'd be faster over the course of a race.

 

[Andy Bettencourt]

just to clear up the math:

current ITCS classification: 2380
standard process math using stock hp
128 (low number): 2370 (128*1.25*14.5+50)
133 (high number): 2460 (133*1.25*14.5+50)

"known horsepower method", assuming 135RWHP: 2440 (135/0.82*14.5+50)

jake's math is off on 2 counts, the ITCS weight doesn't match process math at any level, and the change of 3 whp is closer to 4 crank, assuming an 18% driveline loss. IT weights are calculated using crank or assumed crank HP (using a 15% or 18% loss from WHP - 18% has a prop shaft, 15% is transverse)

.

The 2380 comes from 2370 + an attempt at the time to add 50lbs for 'more than the sum of it's parts'. Since SM conversions at the time could only be 2380, only 10lbs was added - thankfully. It would have been a bad decision on our part. Thank god for the documentation work over the past few years.

And no, it's not the causation of the change, its the WAY you changed it. Against Ops manual and the result sets a weight that no dyno sheet supports. It's bogus on two counts, no matter how 'close' you argue it is based on dyno data. The issue is not with the Miata weight, it's with the method. For a car that gets 'updated' like this in the future, the precedent has been set to screw up the classification.

 

[Chip42]

If 20lbs and 1whp is a "screwed up" classification, then what the hell do you call the half of the ITCS that has far greater divergence from actual HP (above or below) and gets NO attention and NO noise???

this is not a big deal. we did not overturn years of hard work and let the CRB decide what we do and how we do it. you only want to think that. let go, it's OK. everything is working pretty damned well. thank you for a good process and system. Thank you for beating a hole into the CRB/ITAC paradigm barrier thorugh which we can comunicate. it's still working.

 

[JeffYoung]

Ahh, I see your question. We never really codified an answer to that question, and so I don't know the answer.

My personal take is that (ack!) I agree with Mark Andy. At this point, the Miata is a perfect example of a car where we know a lot and we could credibly just go ahead and use the "known horsepower method", regardless of the difference from the existing classification. Remember that the use of that method requires the commitee's confidence in the dyno data to be quite high. If there's enough confidence in the dyno numbers, why not use it?

Which is basically what I did personally in justifying my vote, to me, so I could live with it.

From the dyno sheets I've seen, and we have more than on any car other than the MR2, we see "very good" builds in the low 130s and "top notch" builds in the 135 range.

135/.82 x 14.5 = 2390 + 50 = 2440, or 20 lbs below where it is. Jake, you did the math a bit wrong (it's bad if you can't out math a lawyer! lol....). Andy, saying this car is set higher than what the dyno data shows is kinda sorta correct. It's 20 lbs higher, and on top of that given that the submitted sheets show 135, I'm pretty sure somewhere somone has one 1.5 hp higher.

THIS - the above -- is why I'm not too worked over this. The car is very close to what the process spits out on a known horsepower calculation. I don't like the instability issues with dicking with this again after having beat it to death before, but if we were going to make a change this one is not only in the ballpark, it's very close to what the process provides.

 

[Kyle Freiheit]

just to clear up the math:

current ITCS classification: 2380
standard process math using stock hp
128 (low number): 2370 (128*1.25*14.5+50)
133 (high number): 2460 (133*1.25*14.5+50)
QUOTE]

Huh, Didn't know that 5hp was worth 90lbs in ITA. Interesting.

Kyle

 

[lateapex911]

Which is basically what I did personally in justifying my vote, to me, so I could live with it.

From the dyno sheets I've seen, and we have more than on any car other than the MR2, we see "very good" builds in the low 130s and "top notch" builds in the 135 range.

135/.82 x 14.5 = 2390 + 50 = 2440, or 20 lbs below where it is. Jake, you did the math a bit wrong (it's bad if you can't out math a lawyer! lol....). .

I didnt do the math, which was the issue, LOL. I did the post math, then added it to the existing weight. Errr except the existing weight isn't the pure process weight.
I design. Others add,

 

[Andy Bettencourt]

If 20lbs and 1whp is a "screwed up" classification, then what the hell do you call the half of the ITCS that has far greater divergence from actual HP (above or below) and gets NO attention and NO noise???

this is not a big deal. we did not overturn years of hard work and let the CRB decide gwhat we do and how we do it. you only want to think that. let go, it's OK. everything is working pretty damned well. thank you for a good process and system. Thank you for beating a hole into the CRB/ITAC paradigm barrier thorugh which we can comunicate. it's still working.

So the issue is that your end is justifying the means.

There are issues here. First, the Ops manual was ignored for this re-weight. That is a warning sign for us all. Second, some are trying to justify the weight as 'correct-enough' based on dyno data. Another huge warning sign. Why? Because it's ridiculous to re-weigh something if you don't have data outside the area of statistical noise. If you want to hang your hat on the dyno numbers, then you would have to say that you would vote yes for a correction on any car that you had confidence made just 3whp more than the process estimated it could. Holy crap.

There has to be a threshold that you have to hit before you make a change. It's just common sense. What is yours Chip? 1whp? 2? 3? If a cars process weight is based on 140whp and you get sheets that nail it to 142whp, are you saying you would recommend a 20lbs increase (using ITA)? Sounds like you are.

Let's stop trying to justify this reprocess and just admit where it came from. Going around the Ops manual and then saying 'well it would be within 40 lbs if we used dyno data' is just a load of manure. If you think it's the right thing to do to recommend a change to a cars weight based on 3whp over it's target, I think you are nuts.

I'll start collecting dyno sheets for you guys for some other cars so you can really do some work.

It's not about the weight on this car guys. It's about 2 totally flawed arguments trying to justify an action that was pushed on you from above, based largely on a video. Miata now, anyone could be next. Ops manual means nothing. Sorry if that offends people who I consider friends with high integrity like Jeff and Chip but the facts are the facts.

I left the ITAC because the CRB bought into what we were doing, then snapped. They let us design and administer a process. Once we wanted to write it down so that it could be transparent and pass it on to future committees, they got cranky and started using factors never considered to shoot down recommendations. Liesons never communicated with the other CRB members what we were doing, how and why. When they heard it for the first time, they were skeptical because it was so foreign from what they do in all the other classes. That was their right to do but I certainly wasn't going to hang around while they took shots in the dark and I took the heat. It's come full circle IMHO.

 

[Andy Bettencourt]

I'm pretty sure somewhere somone has one 1.5 hp higher.

THIS - the above -- is why I'm not too worked over this. The car is very close to what the process spits out on a known horsepower calculation. I don't like the instability issues with dicking with this again after having beat it to death before, but if we were going to make a change this one is not only in the ballpark, it's very close to what the process provides.

I bet there are some 1.5 lower too. Saying that you have a high level of confidence in 135whp is just fine. I would agree. I could have that extra 1whp if I wanted to start eating away at my gorgeous torque curve.

I would be MUCH happier if we would have just said, the Miata is winning a ton of races, we have dyno data that suggests 135whp is very accurate so we are resetting the weight to 2440 because 1, its more accurate than the 25% and 2, it's a good political move for the class because many feel the car is the only car that can win. Still pissy mind you, but only from an owners standpoint, not from a process standpoint. If the ITAC wanted to codify those small increments as triggers for change, I would say you are crazy but as long as it was written down and repeatable...go for it.

Dicking with the Ops manual and using an incorrect hp number to re-run just doesn't pass the smell test because it has no evidenciary standard.

 

[Knestis]

Again, Andy has explained my concerns really well while I was off doing other things.

If it's a "what we know" dyno sheet adjustment, just say it, but we'd better be ready to do exactly the same thing with other dyno sheet evidence (see also, MR2). To do one but not the other is institutionalizing a lie.

K