Inspection and Testing

[GlennCMC70]

From the CMC rules:
3.10 Inspection and Testing
NASA tech inspectors and CMC Officials have the right to inspect anything in sight at any time the car is at the track. NASA tech inspectors and CMC Officials have the right to request disassembly or any other procedure required to verify car compliance with these rules including a dynamometer re-certification. CMC Officials may require that a CMC Official or designee be present for any dynamometer re-certification.

So a question was asked in another thread about concerns over placing a car on a dyno other than the one used to certify that car for the season. The above rules indicate that anyone can be checked at any point of the season. The tools used at the track are considered Official. You may be allowed to provide your tools to measure with if found out of compliance.
One thing to keep in mind. It is you who decides how close to the limit you will go. The published limits are not a required number, but rather a limit. Lots of folks will allow a little wiggle room, and other will not. The risk is yours.

[Suck fumes]

Ill just make sure to eat two cheeseburgers to put some weight on my ass before the race lol!

[GlennCMC70]

I know that w/ your SPEC Miata background that this is something you haven't had to deal w/ (in regards to dyno checks) since that class has no HP limits (F'ing stupid if you ask me - 99% the cause of that class being so $$$$). Normally you will see as much variance from the same dyno from pull to pull as you will from dyno to dyno. If you push the limits, you will at some point break out.
Here is a couple ways you can get into trouble....
1) You have your car set to make 267hp and 317tq (max allowed hp/tq numbers no matter the car's weight). If you make 268hp and 317tq, your DQ'ed. If you make 267hp and 318tq, your DQ'ed. You decided to max the numbers and you take the risk of breaking out. Safer numbers would be 260hp/310tq. This gives you max room in case you needit (as long as you havethe correct weight to go along w/ it.

2) You have your car set to 260hp and 310tq (for a LT1 4th gen). You have your car set-up to come off track right at 3250lbs (platform minimum weight). When checked you come off at 3249lbs. Yor DQ'ed. Even if your power numbers were 255hp/305tq, your still DQ'ed. Or you have the car at 260hp and 310tq and your post race weight is 3250lbs on the nose. But we pull you for a random dyno. On the dyno you make 1 more HP or TQ than your dyno sheet makes - your DQ'ed.

The leason in all this???? Push it as close as you want. How willing are you to get a DQ and end your chance at a season Championship is up to you. These type of DQ's are not droppable. They end a season points run.

If you ask me, 255hp and 305tq w/ a post race weight of 3260lbs (4th gen again) - is about as close as anyone needs to be. It gives you 5 hp and 5 tq wiggle room and 10lbs of margin. On our scales, even 10lbs is too close. In the past few years I was coming off the scales 50lbs over. That and my car was certed 5hp low. In our class, 5-10 hp ain't gonna hurt anything and 20-30lbs will go un-noticed. The cars are just to sloppy for it to matter that much. And the numbers are peak numbers. Over the average, this really doesn't matter too much.

And let this past weekend show how serious we are this year. We handed our more DQ's this past event then all of 2012.

[marshall_mosty]

On the dyno sheet, it dictates that the Dyno will correct to standard temp, humidity, and pressure. As long as you aren't in crazy elevation (which we aren't), each dyno should read the same.

Always give yourself a margin on being overweight. I was pulled at TWS a few years back and that dyno read a little high and my minimum weight ended up at 1/4 of 1 pound less than what I scaled... Yes, I was literally a fart away from being underweight, but just squeaked by.. :) I always like to come in 40-50 lbs heavy.

[kbrewmr2]

this "leave yourself a little wiggle room" applies to really ANY NASA class that uses dyno testing. GTS, ST, etc, etc, etc. Not many people really "get it" though...

[Crumpacker]

[I] pulled 260/287 after the races at Houston (sunny and mid-60's temp). I came off track 25 lbs. over minimum weight so technically I had room to pull 262 hp and still be legal.

This brings up a question.

Let's say my sn95 mustang has 260/290 on the sticker, which means my min weight is 3150 (also listed on the sticker). The tech official checks my weight based on a 3150 minimum and I pass by a few pounds in each of the first 3 races. After R4, I'm selected for random dyno and pull a 263 - but I happen to be 40lbs over weight for that race (which is okay for 263hp)... I'm still legal?

I haven't looked at the rulebook, but I was under the impression you could only dyno up to 260 if your sticker showed anything under that because your min weight is being checked against a 260hp car.

[ShadowBolt]

This brings up a question.

Let's say my sn95 mustang has 260/290 on the sticker, which means my min weight is 3150 (also listed on the sticker). The tech official checks my weight based on a 3150 minimum and I pass by a few pounds in each of the first 3 races. After R4, I'm selected for random dyno and pull a 263 - but I happen to be 40lbs over weight for that race (which is okay for 263hp)... I'm still legal?

I haven't looked at the rulebook, but I was under the impression you could only dyno up to 260 if your sticker showed anything under that because your min weight is being checked against a 260hp car.

If I understand it correctly if you pulled 263 and had the extra weight to cover the extra 3 HP you would be okay. Yes/NO?


JJ

[Suck fumes]

Here's my concern, whether it be NASA or SCCA, their scales are never consistent! I remember last year I weighed before a race and was 30 Pds overweight then after the race I weighed only 5 pds lighter. Now I know I burned 4 gallons of gas which is roughly 25pds! Plus I've also noticed that scales fluctuate based on temp change as well so I just don't see how this whole Dyno/weight thing could be that accurate with so many variables.

[Rob Liebbe]

Here's my concern, whether it be NASA or SCCA, their scales are never consistent! I remember last year I weighed before a race and was 30 Pds overweight then after the race I weighed only 5 pds lighter. Now I know I burned 4 gallons of gas which is roughly 25pds! Plus I've also noticed that scales fluctuate based on temp change as well so I just don't see how this whole Dyno/weight thing could be that accurate with so many variables.

That is why you don't cut weight and power too close. Also, at least with NASA, you can re-weigh if there is a question about your results. I've seen cars be pushed off the scales and back on so long as it doesn't leave sight of the tech inspectors.

[GlennCMC70]

If I understand it correctly if you pulled 263 and had the extra weight to cover the extra 3 HP you would be okay. Yes/NO?


JJ

Yes - legal. And it would be the weight recorded at the time of dyno selection.

[GlennCMC70]

Here's my concern, whether it be NASA or SCCA, their scales are never consistent! I remember last year I weighed before a race and was 30 Pds overweight then after the race I weighed only 5 pds lighter. Now I know I burned 4 gallons of gas which is roughly 25pds! Plus I've also noticed that scales fluctuate based on temp change as well so I just don't see how this whole Dyno/weight thing could be that accurate with so many variables.

And this is why we tell you not to push the limits. Give yourself some wiggle room. Also remember, all the other racers are playing w/ the same lack of accuarcy that you are. We are all being measured w/ the same jacked up ruler. So we are all at the same risk.
Since you come into this w/ racing experiance and former knowlege of the problem, we shouldn't expect any issues from you, should we?

[Suck fumes]

No I'm not an idiot haha.

[Dulaney]

Re: HP wiggle room from an AI perspective
We run 60-100 HP more than CMC. (Last year I was 320, this year 340), yet our laptimes aren't vastly different. Slow AI cars are often slower that fast CMC guys. Thru most of the track, following a CMC car, I don't feel the power advantage. Only on longer straights do I notice the gap decrease.
I've been trying to explain this to my spec piniata buddy that 3 HP doesn't matter. 10-15, maybe. It'd matter at TWS, but I'm not sure where else.
Just my opinion/observation. YMMV

[Rob Liebbe]

Re: HP wiggle room from an AI perspective
We run 60-100 HP more than CMC. (Last year I was 320, this year 340), yet our laptimes aren't vastly different. Slow AI cars are often slower that fast CMC guys. Thru most of the track, following a CMC car, I don't feel the power advantage. Only on longer straights do I notice the gap decrease.
I've been trying to explain this to my spec piniata buddy that 3 HP doesn't matter. 10-15, maybe. It'd matter at TWS, but I'm not sure where else.
Just my opinion/observation. YMMV

To make you feel even better about horsepower, compare Spec Miata times to CMC times, even at TWS, and you will find they are nearly the same. Then go think about horsepower "advantage". Everyone gets around the track differently.

[Al Fernandez]

I agree with Glenn regarding weight and dyno timing.

[Rsmith350]

I agree with Glenn regarding weight and dyno timing.

Me too!!!.......oh wait.......sorry, I just enforce......

[edrock96GT]

Re: HP wiggle room from an AI perspective
We run 60-100 HP more than CMC. (Last year I was 320, this year 340), yet our laptimes aren't vastly different. Slow AI cars are often slower that fast CMC guys. Thru most of the track, following a CMC car, I don't feel the power advantage. Only on longer straights do I notice the gap decrease.
I've been trying to explain this to my spec piniata buddy that 3 HP doesn't matter. 10-15, maybe. It'd matter at TWS, but I'm not sure where else.
Just my opinion/observation. YMMV

It's all relative. A 3hp increase on our cars could come from changing your oil or cleaning your air filter. 3hp on a 23hp motorcycle is a huge performance gain usually achieved by full exhaust and tuning. I can see where your pinata buddy is coming from, but he may not quite understand our point of view. I've been on the losing end of a power advantage, but felt what a braking and handling advantage can do to tip the scales.

I too don't like the idea of leaving wiggle room. We all know how the discrepancies from one dyno (and operator) to the next can affect readings and therefore your legality. Why take the time to tune your engine to an exact hp/tq rating to match your car's weight if you have to add 20 or so pounds of weight as a safety net?

It makes you wonder what the point of a pre season dyno certification is if you may get pulled some time during the season to validate it. If that is in place to keep us honest and make sure we actually dyno'd properly, then the readings need to be taken with a grain of salt that the dyno and operator working for NASA that particular weekend are not the be-all end-all of dyno expertise and essentially saying "you went over by 1hp, you clearly didn't dyno your car properly at the beginning of the year...here's your DQ".

[Suck fumes]

Well said. I second the opinion of getting a Dyno certification at the beginning of the year pointless due to cooler weather and to many variables. But whatever, I'll just follow the policies that are put in place and hope someday that some of the rules will change over time and make more sense.

[marshall_mosty]

Well said. I second the opinion of getting a Dyno certification at the beginning of the year pointless due to cooler weather and to many variables. But whatever, I'll just follow the policies that are put in place and hope someday that some of the rules will change over time and make more sense.

The dynojet software will adjust to standard temp and pressure. Michael's first Dyno was 52 degrees and raining. The MSR-H Dyno was 77 degrees and dry. His Dyno runs were within a few HP/TQ of the first Dyno...

As said above, Dyno validation a can be random, first 2 cars in each class, etc...

[Suck fumes]

You just proved my point with this quote: " His Dyno runs were within a few HP/TQ of the first Dyno..."

[GlennCMC70]

You just proved my point with this quote: " His Dyno runs were within a few HP/TQ of the first Dyno..."

And you would get the same result on the same dyno on a different day. The error rate is w/in 1%. That is w/in Dyno Jet's specs on thier site.

[michaelmosty]

And you would get the same result on the same dyno on a different day. The error rate is w/in 1%. That is w/in Dyno Jet's specs on thier site.
I completely agree!!
Just for an interesting numbers standpoint: Since the beginning of last year I have dyno'd 4 times and have not touched a single thing on the car. Below are the results:

Date Location Results
Beginning of 2012 - Dallas Mustang 261/295
Before ECR, 2012 - Dallas Mustang 266/299 - I was wanting to pick up hp to 264 since ECR is a horsepower track. Dallas Mustang put in a new dyno and rumor was it was tuned to show more hp so their customers felt great b/c their cars made more hp after the work their shop did for them. After this finding I will never dyno there again as I feel their numbers are completely inaccurate.
Beginning of 2013 - HPP 257/287
MSRH, after Round 1 - MSRH 260/287

Again, not a single change was made to the car b/w dyno 1 and dyno 4 yet there is a pretty large variance.

[MikeP99Z]

My perspective (and some rambling):

1 hp over = DQ, 1 lb. light = DQ, 1/8" too much track width or too low = DQ, shall we continue? Build and tune your car to the rules that are in place knowing that variances exist in the real world, and then cover your ass for those variances.

The dyno is a tool and does have some variance between 224 and 248 models, shop to shop, weather to a certain extent, and altitude. Yes, the weather stations are supposed to correct for weather and altitude, but sometimes that doesn't quite work out. Dyno computers having the latest software updates is also important. Are the brakes in the dyno set correctly for no drag? Insert other unknowns here... The tool is not perfect, but does provide a benchmark to put us all in the same range. Who's dyno is right? Who knows. Account for the variance.

I've had the luxury of free dyno time since 1993 (thank you Brice, my sponsor, at Alamo). I dyno all the time. Hundreds and hundreds of runs on various motors, different engine and exhaust parts, different tunes, different restrictor plates, different fluids, different tires, various wheels, etc. Also I've tested between 224 and 248 models, different shops in the area, and track-specific dynos or portables. I think Dynojet actually indicated that a variance can be up to 2% between models. The difference between Alamo's 224 and 248 is 1.3% (the 224 reads slightly lower than the 248 - or 5hp for my car). I do all of my testing on the same dyno (Dynojet 248, Serial Number 003) for the historical consistency and for comparisons. I've found this dyno to be the middle of the road, not reading to high, not reading to low..

Again, who's dyno is right? If you are at the track, then the dyno at the track is right. NASA has no other alternative. If you're that close and scared...then pay to put it on the track dyno, or add some weight. If you get sealed and requested to dyno (since a track might not have an on-site dyno), then I would choose the dyno that you use all the time.

I run my car very close to the edge of the hp/tq ratios for my class. But, I add about 40 lbs. of ballast to account for the unknown. The unknown being another dyno, or a different set of scales. This only gives me a window of 4 hp (or 1%) - is that too close??. Maybe, but that's my choice, and if I came up low on weight, or high on hp I'm willing to accept the DQ even though I know I prepared my car to be within the legal limits using my tools - full well knowing that shit can happen or factors can be different on other peoples tools.

The Brass Monkey dyno (a 224) gave me a result that was 2.4% lower than Alamo's 248 (or 1% lower than Alamo's 224). The Modular Mustangs portable dynojet at Miller in 2010 gave me a result that was 2% higher than Alamo's 248 (was it the dyno, or the weather station, or the fuel, or the altitude?? dunno) I paid for the dynojet time at Miller during the practice day to find out what the "official" event dyno had to say - and then I adjusted for it (I had to detune the car by 10hp, and I added some extra weight just in case...). I plan on re-dynoing on Alamo's 248 and 224, and HPP's dyno in the next few weeks to do a back-comparison to the Brass Monkey dyno result. (And yeah, I'll pony up the $85 for the HPP runs just for the sake of knowledge.)

My scales happen to be fairly close to what the NASA scales read. Every weekend I go to the track, I roll it across the scales on Friday night or Saturday morning, just to see if the NASA scales are reading low. If so, I add some more ballast. It's free, why not.

[Suck fumes]

I do the same with my scales. I compare both mine and theirs. I just add gas if need be. Just defeats the point of having a minimum weight in the class cause you could be right on point over the scales then have the Dyno screw you cause it wants to read higher that day. Like I said I'll live with it, just sucks having to have a 50 pd cushion in the car every time. 40-50 pds DOES make a difference in performance especially braking. I have all the data to back it up.

[MikeP99Z]

For Michael Mosty:

I will be happy to arrange for your car to be put on the Alamo 248 and 224 for free to do the same comparison for the sake of knowledge.

[MikeP99Z]

just sucks having to have a 50 pd cushion in the car every time. 40-50 pds DOES make a difference in performance especially braking. I have all the data to back it up.

I don't disagree. But, I've noted that an extra 40 pounds in a 3400 pound car has never caused me a race-winning critical difference in lap times. Where you place the ballast also counts...

[Rsmith350]

"Every weekend I go to the track, I roll it across the scales on Friday night or Saturday morning, just to see if the NASA scales are reading low. If so, I add some more ballast. It's free, why not."

Like clock work......so does Mike Mosty, so does Dan Alford, so does James Proctor ( notice a trend). I get tickled at the people that roll over the scales after qualifying for the first time and we get a "but, but, but, that can't be right!!!" Is anyone here suggesting that weight/ horsepower tables are not part of the "game"? No one here is driving a turn key race car, there's adjustment and strategy involved. I think it's part of the fun of it!

[BryanL]

Well said. I second the opinion of getting a Dyno certification at the beginning of the year pointless due to cooler weather and to many variables. But whatever, I'll just follow the policies that are put in place and hope someday that some of the rules will change over time and make more sense.

Yet again you just don't get it.

[BryanL]

Just defeats the point of having a minimum weight in the class cause you could be right on point over the scales then have the Dyno screw you cause it wants to read higher that day. Like I said I'll live with it, just sucks having to have a 50 pd cushion in the car every time. 40-50 pds DOES make a difference in performance especially braking. I have all the data to back it up.
How do you have the data to back it up in your cmc car that has never seen the track? You have a lot to learn if you don't understand why there is a minimum weight. I suggest you asking for explanations if you don't understand the point instead of making statements.

[Suck fumes]

CMC cars are not the only reference I have for on track performance. Like I said I'll learn to live with it!

[GlennCMC70]

Alright guys. Starting to get personal. Lets give him the benifit of the doubt and allow him to adjust to a differnt perspective of racing. As he said, he was willing to live w/ it and adjust.

50lbs in a SPEC Miata, sure, it factors. What is the minimum in that class? What % is 50lbs of that compaired to 3100-3300lbs?

[rleng1]

"Every weekend I go to the track, I roll it across the scales on Friday night or Saturday morning, just to see if the NASA scales are reading low. If so, I add some more ballast. It's free, why not."

Like clock work......so does Mike Mosty, so does Dan Alford, so does James Proctor ( notice a trend). I get tickled at the people that roll over the scales after qualifying for the first time and we get a "but, but, but, that can't be right!!!" Is anyone here suggesting that weight/ horsepower tables are not part of the "game"? No one here is driving a turn key race car, there's adjustment and strategy involved. I think it's part of the fun of it!

Those are the trophy girls. They have something to lose.
Pretty soon you'll have Jordan and Al weighing their cars on Friday.......does this mean we have to come up with another name besides Trophy Girls?
Fwiw, Brass Monkey seems to dyno about 3hp lower on my car.

[AllZWay]

I dislike the dyno as THE tool since it has such wide variability in results.....but on the other hand I think it is the best tool we currently have available.

I would like to see us explore more of the gps based tools and only require a dyno once a year and that dyno be valid until you have made changes to the car. My yearly dyno is expensive....not the actual dyno time... Alamo has been aweseome, but the two hour drive time and fuel costs to haul to just get the yearly dyno.

BTW....I don't think 50lbs make a huge difference in times in our cars, but it does make a difference in tire life and brake life and braking ability....especially with stock brakes.

[Suck fumes]

I think you just expressed my thoughts in a much better worded post. Thanks!

[Rsmith350]

I think you just expressed my thoughts in a much better worded post. Thanks!

That was pretty good....

[kbrewmr2]

I would like to see us explore more of the gps based tools
we're playing with the gps based stuff in TT as a "hmm, we should probably seal that car and measure it for real on the dyno" type test. And even then, it's still getting there but not ready for prime time / as the sole means of measurement yet. If you think there are too many variables with the dyno...

So that really leaves you (royal "you", not picking on James) two options:
1.) Here's the engine & mod list, and we can tear the engine down and check all your parts ie - you bring your motor home in a box if they check things...
2.) The dyno, and slight ~1% variances between models, locations, etc...

I'd pick 2... but that's just me.