Standardized dyno testing procedure.

[Vinny]

Something I was curious on and I'm sure others are as well, some other race classes such as American iron have a rule set dedicated to dyno testing procedures. http://www.nasaproracing.com/rules/american_iron_rules.pdf see pages 14-15. Is there also a chance we could get some clarification/rules on what the procedure should be for compliance testing.

 

Mainly:

fan or no fan?

Hood open or closed?

cars should be dyno'd at full operating temp etc.

 

This would be nice information to have for shops (such as the one i work at) to make sure we are setting up racers who come here for tunes correctly.

[kbrew8991]

I too would like to see something a bit more structured as well. One thing we'll have to think about though is that we've got a wide variety of different cars with engines, radiators (hell some don't even have this!), air intakes, hoods/engine lids, etc located all over the place on the car - CMC and AI have it easy since all of their cars are relatively close to configured the same in comparison. It'll be a challenge but it would be worth it to have this I feel.

[Markus]

cars should be dyno'd at full operating temp etc.

 

How do you define this? Does operating temp = something like first couple of laps on track?

 

Reason I'm asking - think about a turbo car on a kind of cool September day at MidOhio. When the car is cool and first goes out on track, the engine/turbo could be making full power. As the car heats up the power level could drop. If you test a turbo car right after a hard 15min track session, could the power be measurably lower than it was for the first couple of laps? This makes a difference now that we have strict weight/power ratios to adhere to.

 

Say someone protests a competitor and asks for a dyno, do they get to specify when it is done? (IE - not right after hot session)

 

- Mark

[Vinny]

cars should be dyno'd at full operating temp etc.

 

How do you define this? Does operating temp = something like first couple of laps on track?

 

Reason I'm asking - think about a turbo car on a kind of cool September day at MidOhio. When the car is cool and first goes out on track, the engine/turbo could be making full power. As the car heats up the power level could drop. If you test a turbo car right after a hard 15min track session, could the power be measurably lower than it was for the first couple of laps? This makes a difference now that we have strict weight/power ratios to adhere to.

 

Say someone protests a competitor and asks for a dyno, do they get to specify when it is done? (IE - not right after hot session)

 

- Mark

 

Could be seen both ways. Some cars with enough timing pulled out of them cold won't make as much power as when they are hot and combustion chamber temps are up to par(However you'll be able to usually tell by a choppy graph). The procedure im sure wont be perfect, but IMO there needs to be some kind of guidelines. I would assume most peoples car's are warmed up to safe oil temp/water temp levels after the warmup lap(VIR)...mine is even if its cold in paddock.

[nasa ser]

My understanding is from talking with Greg, who can correct me if i am wrong , is that NASA reserves the right to dyno at any time under any condition (ie, with our without fans, while the car is hot, or when the car has cooled down, right when you come off track or two hours later...........I assume NASA is not going to dyno in such a fashion as to damage someones car but they may be the only limitation...

 

I know in the mid atlantic in PT, i plan to dyno once cars have cooled down (ie, not when they are hot right off the track), with a fan on the car and the hood open and I believe Felton intends to follow the same procedure for TT (he can correct me if I am wrong as well).............

[Vinny]

Well at least you have a game plan Stephen. I just think since PT/TT is national then we should all be following the same guidelines. Make for less of a headache at nationals, or for when members from other regions run in our region and vice versa.

 

The dynoing of the cars once they are cool is something to be discussed, they are raced hot. Also i imagine even cool there needs to be some sort of mandate on when pulls are made, I wouldn't want my car to be pulled to rev limiter under 150 degree oil temps. Scattering a motor all over the dyno isn't on my to do list, and i imagine anyone elses

[hustler]

The dyno should be done on a cool car, at target water temp and I'm not sure what to do about a fan.

a) Requiring a car to run around the track before a dyno is a bit challenging from the logistics side.

b) Fan placement is a moving target with variables like fan type, distance from the intercooler, time spent on the intercooler prior to the run. A large box fan means I dyno at roughly 232whp (140*f intake air temp, a carpet fan means I dyno at 245whp(70*f air temp).

[kbrew8991]

what if you don't have an intercooler? (or boost)?

If you point the fan at the front of some cars its also pointed at the intake and can boost it a whp or two - what do you do for a mid or rear engine car that has its intake far away from the fan?

etc

etc.

 

Gotta think about a whole lot more than just your own car.

 

I agree on aiming to measure a cooler car - you can get a fast lap in with warm fluids but pretty cool everything else and we should be measuring horsepower assuming that I feel (at least in TT).

[TurboShortBus]

Once we establish a pretty close relationship of dyno-sourced rwhp (after track sessions) and GPS-sourced rwhp (during track sessions), the need for a dyno at the track might go away. I'm looking forward to having an easy system in place that can erase all doubt when somebody is turning quick lap times.

 

Mark

[MSP608]

Whynot everyone do whatever they think will make the best numbers at their shop? That way fan placement, or engine temp won't matter at the track. Worst they could do is replicate what you've done before.

[nasa ser]

We have a winner!

 

Exactly, quit worrying about how we are going to test cars at the track.......get the highest # you can at the shop, cool car, open hood, optimum fan placement etc.........use that number to get your dyno re-class from greg and, give yourself another 5 hp of leeway and never worry about it again..............

 

quit cutting it so close people and you won't have as much to worry about.......

 

 

 

Whynot everyone do whatever they think will make the best numbers at their shop? That way fan placement, or engine temp won't matter at the track. Worst they could do is replicate what you've done before.

[nasa ser]

its a great idea, but i don't think its going to happen where the GPS sourced HP will re-place the dyno, to many variables for it to be a replacement.

its a great concept, it would make life a lot easier when dyno isn't available or is broken......

 

 

Once we establish a pretty close relationship of dyno-sourced rwhp (after track sessions) and GPS-sourced rwhp (during track sessions), the need for a dyno at the track might go away. I'm looking forward to having an easy system in place that can erase all doubt when somebody is turning quick lap times.

 

Mark

[kbrew8991]

quit cutting it so close people and you won't have as much to worry about........

 

maybe this is why you PTE guys run 2-3 seconds slower than your TTE counterparts

 

Standardize how it will be measured and let me worry about how close or not close to cut it.

[TurboShortBus]

its a great idea, but i don't think its going to happen where the GPS sourced HP will re-place the dyno, to many variables for it to be a replacement.

its a great concept, it would make life a lot easier when dyno isn't available or is broken......

For a region such as ours where a dyno is not available at an event, the GPS will be extremely helpful.

 

DQing a car for a 2% rwhp variation won't be necessary, but if the GPS shows a 10% variation, then it's safe to assume that a DQ is in order. But first, we have to order the GPS units...

 

Mark

[drivinhardz06]

DQing a car for a 2% rwhp variation won't be necessary, but if the GPS shows a 10% variation, then it's safe to assume that a DQ is in order.

 

how about 20%

 

mark "468 rwhp" nunnally and still slower than jason down the backstraight

[Vinny]

We have a winner!

 

Exactly, quit worrying about how we are going to test cars at the track.......get the highest # you can at the shop, cool car, open hood, optimum fan placement etc.........use that number to get your dyno re-class from greg and, give yourself another 5 hp of leeway and never worry about it again..............

 

quit cutting it so close people and you won't have as much to worry about.......

 

 

 

Whynot everyone do whatever they think will make the best numbers at their shop? That way fan placement, or engine temp won't matter at the track. Worst they could do is replicate what you've done before.

 

 

Or we could simply have a standard way of dynoing the cars. Doesn't seem like that big of a deal, i don't want to take a 10hp hit on a 133whp car because we don't have a system in place while other classes do. Just as last year some car's got DQ'd on power, yet another race in the same year other cars got to run on the dyno a different way.

[Greg G.]

When we Dyno test a car, we are looking for its maximum hp. If we have a large cooling fan available, we will use it. Hoods are open. We don't test heat-soaked cars. They generally have to wait for testing after coming off the track anyway. Cars are brought up to safe operating temperature, and then tested--as many times as we want to get the Max hp. We test in the gear closest to 1:1, which on most vehicles is 4th gear. We test the cars with the same amount of air in the tires as they had when on the track. There is a slight benefit that the tires may be cooler and lower pressure than when on the track, but on the other hand, the engine may be cooler and producing more Hp than on the track initially. I won 5 National Championships running my car with at least a 3-7% buffer on my best measured vs. max limit of Dyno hp. If you guys don't want to use a buffer, then do so at your own peril. Dyno's have variability. Car engines have variability--especially those with ECU's that try and correct for environmental conditions. If you test at 150 rwhp at the shop, and expect that you could never test at 152 rwhp at the track, you are not being very realistic or cautious. However, surprisingly, I get dyno requests all the time for drivers wanting to have the number listed on their Dyno sheets as their max. They are the first ones that I test when it comes time for compliance testing.

[Markus]

Whynot everyone do whatever they think will make the best numbers at their shop? That way fan placement, or engine temp won't matter at the track. Worst they could do is replicate what you've done before.

 

Or we could simply have a standard way of dynoing the cars. Doesn't seem like that big of a deal, i don't want to take a 10hp hit on a 133whp car because we don't have a system in place while other classes do. Just as last year some car's got DQ'd on power, yet another race in the same year other cars got to run on the dyno a different way.

 

A) So you're basically saying "how about everyone just follow the rules and not cheat"? If it were that easy, we wouldn't need to have Tech. And Greg could save alot of time reviewing car classification forms.

 

B) An NA car might be off 5-10hp, but even a lower horsepower 200hp turbo car could be off 20hp depending on temp. Like if they are running a stock intercooler or whatever. So yeah it can be a big deal.

 

FYI, I like what Greg posted above! Sounds like he has a good handle on it. I also am intrigued by the expanded use of GPS for backup, will be interesting to see how that plays out.

 

- Mark

[Vinny]

Greg,

 

When you say "we" is this at nationals? Who determines the procedures regionally? If a car gets DQ'd on being 1hp over...fan on, hood open....yet a few events later people are able to request hood down no fan..who decides this? Car owner? Dyno operator? officials? Anyone seeing where im coming from? Being uniform goes far in enforcing rules, and gives people much less to question.

 

 

 

Markus,

 

You're missing what I'm saying...we don't have rules to follow for dynoing...that's my point.

 

I'm well aware of temperature differences causing different readings as the shop i work at has a dynojet in house. Greg does have a good handle on how he handles things, but its not followed everywhere. It should be handled the same way regionally as it is nationally in my opinion.

[Greg G.]

Section 6.5.2:

For compliance testing, the dynamometer operator and the Time Trial Director or NASA Official

will determine the dynamometer testing procedures and how many test runs will be performed

for any given car being tested in order to obtain accurate test data. Prior to the dynamometer

inspection the competitor may top off any fluids needed to ensure the engine and drivetrain are

not damaged during testing. The fluids must be added with a NASA Official present. No other

modifications or adjustments may be made to the car. To ensure fairness, a NASA Official, or

an individual appointed by a NASA Official, will operate any cars being inspected on the

dynamometer. SAE correction with a smoothing factor of five (5) will be used. Any run that

results in an erratic or non-reproducible result may be dismissed by Time Trial officials.

 

I am not going to lock us in to any procedures that may not be possible. If the procedure says there must

be a certain size fan, and the fan breaks, then the test is no longer valid and we shut down the Dyno operation for

the day? If we find that a particular car has the ECU adjusted to run max power at 150 degree water temps, but the

procedure says we test at 160 degrees, the test is not valid if we want to check the car at 150? NO. We are testing

for the maximum power possible on the Dyno. This will be the number most likely to correlate with the actual max HP

on the track once you take tire temps/pressures, ram air intakes, and the extra cooling of running at 100+ mph into account.

TT Officials are looking for those numbers if we are testing cars, whether at the National Championships or at regional events.

Drivers are advised to do the same. If a driver tests the car at the shop with low tire pressures, hood closed, no fan, and

heat-soaked just to get low Dyno numbers, then he/she is a cheater, plain and simple. And, when he/she gets caught, they will

appropriately be disqualified and possibly ejected from TT altogether or from all classes except TTR depending on the results.

[Joshua]

I think this is a valuable discussion as my car is one of those cars classed by Greg based on W/P. It is true that dyno tests are variable, and conditions will never be the same at the track as they are at the dyno shop. That's why Greg suggests allowing for some buffer. In a recent event, two cars in TTD that were dyno re-classed by Greg finished 0.012 and 0.091 seconds apart over the weekend. It was some fun and exciting competition, and provides evidence that the formula works pretty well.

 

http://www.nasa-tt.com/Florida_Regional_Results/p2044_articleid/141

http://www.nasa-tt.com/Florida_Regional_Results/p2044_articleid/142

 

In a related topic, I'm starting a thread to discuss the on-track procedures using Traqmate data loggers.

I invite comment and clarification: viewtopic.php?f=2&t=38813