Looking at the rules I am curious about the logic, or lack of, in regards to fly wheel weights. The Zetec is 8 lb and the Pinto is 10.5 lb This seems odd. Any thoughts.
Thanks
pinto ztec flywheel/clutch?
Looking at the rules I am curious about the logic, or lack of, in regards to fly wheel weights. The Zetec is 8 lb and the Pinto is 10.5 lb This seems odd. Any thoughts.
Thanks
You want logic? That makes no sense.
Since the Z produces more torq at lower rpm you need less rotating mass to make it more equal.
Seriously? The logic is it's probably the flywheel they had on the engine when they tested and declared the Z equal to the Pinto.
Flywheel weight and rotational moment of inertia (think wheel with most of it's weight at the outside being harder to spin up when accelerating) are the keys.
A 10# wheel can have less moment of inertia than an 8# wheel.
Many moons ago there was an SVO wheel for the Pinto, before the lighter wheels were allowed and it was thick near the center and skeletal near the rim. Same weight but less difficult to spin up.
the point of all this is that weight is not the only thing that matters.
It was based on significant dyno testing in order to try to reach parity between the Pinto and Zetec. Several years ago there was a new flywheel/cam package allowed for the Pinto. There is more to the inertia equation than just the flywheel; crank, rods, pistons, geometry, etc. My guess would be the flywheel was the cheapest and easiest place to remove the weight on the Pinto to try to get the speed that the two rev up more equal.
Originally Posted by Steve Demeter
So, the OP's point is that they should be equal. If the engines are on parity then whatever attaches to the crank on back (flywheel/clutch/gearbox) should be the same. But it isn't.
If any logic was applied they should be switched. Since the Zetec makes better low rev torque, the lighter flywheel furthers it's advantage to spin up faster and get out of the corners faster.
As I stated in my letter to the CRB the peak HP is irrelevant if the power curve gives a low end advantage.
You need to understand how where the weight is relative to the center affects inertia to understand how flywheels of 2 different weights can have the same inertia.
Whether or not they do actually have the same inertia, I do not know, but looking at weight only will not give you the answer to that.
i race at a start stop track and the low end pull the ztecs have is enough to make you cry
Carbs v. Fuel Injection.
Like I said, the flywheel is only one part in the rotating assembly. Let's say Engine A has a 40lbs crank, and Engine B has a 20lbs crank, should they both have a 10lbs flywheel so they are equal? No.
The speed at which they rev up is not solely based on the static weight of a flywheel. It's one part of many factors.
And, like Richard said, I'll take a 15lbs flywheel with 90% of the weight in the center, over a 10lbs flywheel with 90% of the weight on the circumference.
I see a lot of reasons thrown out for why “it could be” but no answers to the original question. I’m curious as to why, too. Anyone got an explanation specific to these two motors?
One of the reasons, yep. But they won't let us have FI.
As Richard and Reid point out, inertia. Sure but that doesn't answer the question as to why they aren't the same.
I don't believe for a second that the zetec flywheel carries it's weight on the outer limits.
I have Pinto flywheels and they certainly do.
So if you're saying the zetec fly has a higher moment to equalize the torque, it ain't working.
So either they all cheat and move the moment or it's not effective.
my understanding is that less flywheel weight =better drive off acceleration and that is where the pinto falls on its face
Possible answer to the OPs question:
Both engines have to use the original flywheel to start (though the pinto does have an alternative), and what can be done with them to reduce weight will be dependent on the original design and material. I can't comment on the Zetec flywheel since I haven't seen one for a couple decades, and it's also been about that long since I last looked at a Pinto flywheel, but I'd bet that you cannot take off much more from the Pinto without it becoming dangerous.
I believe the answer is simple without being concerned about black helicopters.
There are two ways to get light pinto flywheels. Buy one from a supplier. Or, cut a stock one down.
The lightest pinto flywheel on the open market has historically been 10.5 lbs. That being a custom part that a person can buy from an engine builder, etc. It is a purpose built engineered unit. There is not enough market for anybody to now go out and engineer, test, and market a lighter one. There would not be enough return on investment.
I have turned many stock pinto wheels down on a lathe. I'm joining in on Richard's chorus. I don't believe you can safely cut a stock pinto flywheel down to 8.5 lb. IMHO it would be a bomb ready to explode.
Then come on down to Spokane for a race where it's just straightaways as far as the eye can see!
9.7lb steel - less than $500 delivered
http://www.burtonpower.com/steel-fly...ft250ulrg.html
6.5lbs steel - less than $450 delivered
https://www.turbosport.net/product/f...et-flywheel-2/
This is a spec fly for a series - so it is probably reliable
Even lighter:
https://www.turbosport.net/product/f...llet-flywheel/
None of them are currently legal, though, are they.
If people think that a lighter, less inertia flywheel is something the Pinto needs, do the dyno work to get the data, submit it to the CRB, and ask for a change in the rules.
I do not race in the SCCA, but my current flywheel is 5.5 lbs, is bolted to a 200 hp Pinto with quite a bit more torque than SCCA trim. Has 11 race weekends on it. Still going strong. Ready for another season.
(I had to purchase it from Europe).
Regards,
Aaron
The one below is the one I have been running.
Even lighter:
https://www.turbosport.net/product/f...llet-flywheel/[/QUOTE]
11 race weekends on it. Works just fine.
Aaron
No, but they can be done safely.
Pinto owners are mostly budget racers.
As I explained to the CRB, the method for rule changes is too expensive for the Pinto population.
Why in the world would I want to spend $5k on parts and dyno testing for a hope and a prayer?
That's money I could spend racing at the back of the pack
The more I talk to people the more I find that owners have taken it upon themselves to level the field.
And that doesn't apply to Pintos only. And that tells me the process is broken. Am I'm the only one being vocal about it?
SCCA and Vara have basically the same rules - so I have no other series options.
That is how the Club has worked for the last 50 years - it isn't up to the Club management to make your formula car competitive - it is the members who drive most changes.
You'd have trouble seeing anything on a normal dyno, since the only change due to a lighter flywheel is in inertia, i.e., acceleration. You'd need a dyno capable of (accurately) measuring that for both engines. Those are not very common.
However, since Pinto's are by most accounts suffering mainly in low-end response and torque, it is, IMO, common sense to allow as light a flywheel as safe and practical.
Also, a ~4-to-5-lb lighter flywheel will allow overweight cars to get that much closer to minimum.
Last edited by DaveW; 03.02.18 at 7:21 PM.
Dave Weitzenhof
Note that those flywheels are all steel, not cast iron. Big difference in strengths and how it handles tension stresses compared to cast iron.
Keeping members - and active members - are in the best interest of the clubs existence.
Times have changed. Costs have changed over those 50 years.
There are more ways now (GPS/g-meters) to determine on track performance which is more readily available AND cheaper than a dyno. On track is what counts.
Maybe the club needs to adapt.
There are more ways now (GPS/g-meters) to determine on track performance which is more readily available AND cheaper than a dyno. On track is what counts.
Let's be careful here GPS and or accelerometers meeting traceable ANSI requirements are not the garden variety used in motorsports nor were they designed to take the long term abuse from a race car. Calibration of same is a laborious process I have done many times when testing high speed spindles and dynamic (not static) cutter frequencies for the aerospace industry. To obtain the accuracy required to quantify results lets say .1 will require three individual accelerometers, not a triaxial accelerometer (X,Y,Z) with traceable accuracy to .01 to get the cumulative error to an acceptable tolerance. Cheaper than a dyno no and also you are talking modal (dynamic) analysis, whole different ball game with considerable variances. Three years of my life and thousands of calculations what I learned about bearing technology during this stint fills dang near a petabyte in my head somewhere when I can remember how to access it. http://www.ni.com/pdf/csma/us/ronaldyanos.pdf
what I am talking about is apples to apples a couple of my competitors switched from pinto to ztec and gained 1 or 2 sec a lap with the same prep same guys and same track I'm am just wondering why there is a difference in the weights when the pintos are already handicapped
You ask a great question but one that is hard to quantify, I would ask you this to understand the parameters of your question better.
- Are the cars the same say 98 VD Pinto to 98 VD Zetec?
- If so then there still are multiple variables in place.
- Fuel injection vs Carb
- Does FI provide better low end torque?
- How does the Zetec torque curve compare to the Pinto
- Acceleration is the rate of change of velocity per unit of time, so eliminate the variables to get closer to your answer. I'm just not sure the flywheel is the root cause factor. Just my opinion worth about .02cents
The weight of the flywheel, all by itself, is not the controlling factor - the inertia created by where that weight is located from the centerline of the crank is what we have been trying to explain - and what little difference there may be between the Zetec and Pinto flywheels is not going to make a 2 second lap difference.
Let's not get too crazy about ANSI requirements. SCCA can have their own rules. Couple of points.
SCCA currently randomly mounts AIM Solo devices on cars of certain classes to check them. So they already think it's good enough.
Because they are faster out of the corner. Track dependent for sure. The more corners (and slow corners), the bigger the difference.
No it's not the root factor, but we all know the Zetec has more low RPM torque.You ask a great question but one that is hard to quantify, I would ask you this to understand the parameters of your question better.
...
I'm just not sure the flywheel is the root cause factor. Just my opinion worth about .02cents
Richard - totally understand but you don't seem to understand my point.
The meat on a lighter flywheel has to be in the middle at the clutch. (shorter from center, less inertia). That's why all the aftermarket light flywheels have spokes.
And, as I said above the time difference is track dependent. The more slow corners, the greater the difference.
There have been discussions about the Pinto having a top speed advantage. No question. True. But you have to be able to get there and very few straights are long enough. On a track like Laguna Seca, the Zetec gets the advantage out of 4 corners, one being turn 11 (slowest on the track) onto the front straight (longest and uphill). The straight would need to be at least 4x longer for the Pinto to gain any advantage.
So, as the OP said, the rule doesn't make much sense. The physics proves the rule make no sense.
What I'm trying to explain is simply this:Let's not get too crazy about ANSI requirements. SCCA can have their own rules. Couple of points.
- You want to quantify the information I assume relative information won't hold up that is why the same dyno is used to seal engines. It the dyno that is will hold up as relative data that is just that relative and comparable same testing unit.
- You would have to have a traceable means same make and model is irrelevant the Ansi standard is look at any gas pump and see the state seal for commerce purposes.
- I'm not trying to be a smart ass just the facts and understand the parameters of what you are testing to get results you can truly compare other than that you are comparing pears to apples this is simple engineering 101.
- I bet if you test your car you expect results you can make reliable decisions on n'est -ce Pas?
Rick,
1. I get that regarding sealed engines I get that actual numbers make no difference when they're all run on the same dyno, but the CRB isn't asking for dyno results from a specific dyno. And to correctly analyze this they would have to compare my Pinto, my modified Pinto, and a 'zetec per the rules' all on the same dyno and probably should be on the same day - but they don't ask for that. So it's not relative and comparable. I can make a graph on billy-bob's dyno.
2. Okay, who's putting the seal on the dynos? Are specific methods being adhered too (same fuel, etc). I can put ethanol in race gas and run a stock motor, then tank the modified with pump gas.
3. That's my point. The parameters/methods are loose. The results treated as fact. Dyno results aren't worth the paper they are printed on. That's why I suggest on-track data for comparison.
4. No decisions to make - stuck with the rules.
- Hmm actually I would hope the sampling size would encompass more engines than that to properly obtain enough data to establish the parameters.
- This is actually interesting as I bought AW engine dyno's f
or our electric motor shop at Boeinghttp://www.awdyno.com/products/engin...ne-dynamometer
- Calibrating these were a nightmare because the units didn't have proportional control systems. Calibration once the system is properly retrofitted wasn't bad and competent measurement house can seal the unit ours required calibration check every 90's days to maintain compliance.
- The testing parameters have to be predetermined and you have to adhere to them for the unit under test so no substitution of any kind this will invalidate the test
- After reviewing the GCR 2016 the only flywheel listed is the QM which I find odd however your suggestion of on track data is still fraught with accuracy issues. Standard garden variety GPS accuracy is approximately a 16 foot radius in the areas where we generally race cars you can obtain near real time accuracy with dual frequency receivers and get this down to fractions of an inch so you are correct just not sure our devices are that good maybe you already know but I don't. for the rest of the ontrack data point a to point b test points can easily be established but my suspicion is this has very little to do with flywheel weight. Flywheel design has gotten way better thanks to the use of computers and the selection and evaluation of correct algorithms for design.
- Can you help me understand why the flywheel is garnering this attention for the acceleration? Is it purely the weight difference? Out of curiosity has anyone asked an engine builder I'm sure they could offer up the answer. I'm due to see Arnie Loyning in a month I'm more than happy to ask him. Arnie has been good to me over the years he even let me build fuel injection units for Toyota Atlantic engines one day and select and build up mine for my Reynard in 2001 because I'm naturally curious including asking a lot of questions which he doesn't seem to mind
Basic explanation in layman's terms:
Linear acceleration is force divided by mass. In the case of rotational acceleration, it is torque divided by rotational inertia.
Since the Zetec has more low-RPM torque and responds quicker to throttle application, most agree that the Pinto needs an increase in low RPM acceleration to at least partially counteract that.
While the lower-rotational-inertia (i.e., lightweight) flywheels do not specifically affect only low RPM acceleration, they will definitely increase engine rotational acceleration at all RPM's. And since the Pinto acceleration deficit is most apparent coming off the corners, and lower engine rotational inertia is more important in lower gears due to the quicker rotational engine acceleration, a lower rotational inertia will most noticeably benefit acceleration under those conditions.
In higher gears, acceleration is much less affected by car mass or engine rotational inertia since acceleration is much lower due to gearing and aero drag. So top speed will be pretty much unaffected by flywheel mass/inertia.
Dave Weitzenhof
Ok I understand torque is rotational acceleration and thanks for not calling it twisting motion. So is the problem simply variables aside an increase in the torque curve matching or closer to the Zetec. So if this relatively simple flywheel weight could be the equivalency cure has this been explored and/or proposed? Seems to be one of the logical steps to the Pinto/Zetec performance equalization. I’ve read the drawn out debate on this site but up until this year I’ve only driven a Pinto engines car as the last time my body accelerometer sat in a FC only Pinto engines were available.
Last edited by Rick Brannon; 03.03.18 at 12:17 PM. Reason: Fat fingered
A low rotational inertia FW (LFW) will for sure help the Pinto. Will it make them all equal to the Zetec and even more importantly, to each other? That is extremely unlikely. You still have the obvious overriding issue that Pintos themselves vary greatly in HP and torque. For a world-beater Pinto like what Niki used to have, maybe a LFW would make it as good as or better than a Zetec at most tracks. For the average Pinto, probably not.
So as with any performance upgrade other than a new spec optimized cylinder head, there would still be large differences Pinto-to-Pinto.
Dave Weitzenhof
Thanks Dave. I saw somewhere on the site you explained iirc an oil/water oil cooler instead of the regular air/oil cooler. Can I assume this to control the oil temperature to the crankshaft sleeve bearings? I’m curious of the range of temperature?
Oil-water heat exchanger
I used the oil-water cooler on the Pinto because I had enough water cooling capacity, and the OWC heated the oil faster early in a session and cooled it later to ~20F more than the water temperature. So it resulted in more consistent oil temperatures and I didn't need an air-oil cooler, which would not have been as neat an installation. The object was just to more closely control oil temperature than an air-oil cooler would even though I never had any type of bearing issues. I had used a "donut" VW OWC since very early in my FF days.
On the Zetec, I use both types. OWC after the pressure oil pump, and a small air-oil cooler for a bit more oil cooling and de-aeration of oil scavenged from the crankcase.
See this thread: http://www.apexspeed.com/forums/show...ght=oil+cooler
Last edited by DaveW; 03.03.18 at 7:56 PM. Reason: added link
Dave Weitzenhof
How come these guys don’t make a 10.5lbs one? Has no one asked, or should I email them about it? I don’t want to shave mine down, since I want to remove the weight from the outer most part of the f/w.
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