Dyno question.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 9,926
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Dyno question.
I read an article in Vette/Corvette Fever? that did a test to show the significane of a lighter clutch/flywheel. They showe dthe importance of accelerating on the Dyno.
Now, is it another tool we can use to see how fast our cars accelerate to a point on the dyno? Toa certain speed etc?
For example: My car accelerates from 60mph to 130mph in 10 sec. Then I modifiy it the HP doesnt go up, but it accelerates 3 seconds faster in the same test.
Just curious as dynos are good tools to use, well how about a timied run on the dyno to see if the car is able to get a point quicker, showing that we have imporved the Vehicles performance.
Now, is it another tool we can use to see how fast our cars accelerate to a point on the dyno? Toa certain speed etc?
For example: My car accelerates from 60mph to 130mph in 10 sec. Then I modifiy it the HP doesnt go up, but it accelerates 3 seconds faster in the same test.
Just curious as dynos are good tools to use, well how about a timied run on the dyno to see if the car is able to get a point quicker, showing that we have imporved the Vehicles performance.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Most dynos already have a mode that you can run through the 1/4 mile on......isn't this the same thing your asking about?
How accurate it is or the tons of things its not taking into account are another story, but what your asking about I believe already exists. I am sure they could also time you with a simple stop watch to see how quick you can accelerate from 60mph-130mph. But as I alluded to before, its not going to be accurate since you don't have any forces like wind resistance acting on the car. Not trying to start a debate, just making sure you understand the measuring system your using is not modeled true to real life. You could I guess use it for a baseline to after tests, but again other factors need to be addressed to make sure its an apples to apples test, like DA measurements.
Let us know how you make out.
How accurate it is or the tons of things its not taking into account are another story, but what your asking about I believe already exists. I am sure they could also time you with a simple stop watch to see how quick you can accelerate from 60mph-130mph. But as I alluded to before, its not going to be accurate since you don't have any forces like wind resistance acting on the car. Not trying to start a debate, just making sure you understand the measuring system your using is not modeled true to real life. You could I guess use it for a baseline to after tests, but again other factors need to be addressed to make sure its an apples to apples test, like DA measurements.
Let us know how you make out.
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
I'm curious about this effect too since I'll be installing a much smaller and lighter converter than stock when I install my new shortblock.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 9,926
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Well, thsi test would get rid of all the other factors, which could show minimal if any change.Thsi acceleration test would show that potentially something postitive happened, ie quicker accelleration, means something is more efficient since the car accelerated quicker.
Racer
Joined: Sep 2005
Posts: 355
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From: minot nd
See the dyno doesn't have to be accurate in terms of drag and da etc. It only needs to show the same test twice with different results to prove the better performance. If he goes 60-130 in 10 secs on the dyno with a stock fw and then does another pull with a lighter one and does it in 7 secs well that won't be real world but he did make a gain performance wise. Now correct those figures for da and stuff and I think it would make a good test.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Corvette Kid, you should see some nice improvements with a smaller converter. Conversely, I think a lighter clutch and Flywheel on a manual car could be detramental to power. But let me explain. Depends on where you are looking for the gains at. A lgihtweight flywheel will not launch the car very efficiently, since a lightweight setup is going to loose lots of its momentum.
Overall though the ligher assembly should yield more power through the powerband, but again on shifts and stuff it might loose some of its performance and "carry-through" power.
One of those things you would just have to do A-B-A testing and see if it yields any results.
Overall though the ligher assembly should yield more power through the powerband, but again on shifts and stuff it might loose some of its performance and "carry-through" power.
One of those things you would just have to do A-B-A testing and see if it yields any results.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Originally Posted by ckd
See the dyno doesn't have to be accurate in terms of drag and da etc. It only needs to show the same test twice with different results to prove the better performance. If he goes 60-130 in 10 secs on the dyno with a stock fw and then does another pull with a lighter one and does it in 7 secs well that won't be real world but he did make a gain performance wise. Now correct those figures for da and stuff and I think it would make a good test.
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Le Mans Master
Joined: Jan 2003
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From: Portland Oregon
On my dyno which is a Mustang I can simulate acceleration times in any scenario. For instance, we can test 0 to 60, or 60 to 100 mph or any speed in between. I input the weight of your car and what they refer as hp@50mph which is in effect what Mustang uses for drag coefficient of a given car. With this information the dyno adds additional load to the car via its dual eddy current absorbers to simulate real time road load on your car just as if it was being driven on the street. I have tested this several times using the 1/4 mile drag strip simulation with several cars with actual time slips from the local strips. Typically my dyno is within a tenth to a tenth and a half of the actual time slip.
Using a lighter flywheel/clutch assembly in itself does not give you any more horsepower or torque. But doing so does free up hp/tq that your engine already has. It is just plain physics as it takes X amount of Hp/Tq to overcome the inertia of the extra weight and mass of the heavier flywheel. Lighten up the flywheel and you can use the power elsewhere and in this case the power is used to move the car.
Using a lighter flywheel/clutch assembly in itself does not give you any more horsepower or torque. But doing so does free up hp/tq that your engine already has. It is just plain physics as it takes X amount of Hp/Tq to overcome the inertia of the extra weight and mass of the heavier flywheel. Lighten up the flywheel and you can use the power elsewhere and in this case the power is used to move the car.
Racer
Joined: Dec 2003
Posts: 454
Likes: 0
From: Double Oak TX
Originally Posted by tjwong
On my dyno which is a Mustang I can simulate acceleration times in any scenario. For instance, we can test 0 to 60, or 60 to 100 mph or any speed in between. I input the weight of your car and what they refer as hp@50mph which is in effect what Mustang uses for drag coefficient of a given car. With this information the dyno adds additional load to the car via its dual eddy current absorbers to simulate real time road load on your car just as if it was being driven on the street. I have tested this several times using the 1/4 mile drag strip simulation with several cars with actual time slips from the local strips. Typically my dyno is within a tenth to a tenth and a half of the actual time slip.
Using a lighter flywheel/clutch assembly in itself does not give you any more horsepower or torque. But doing so does free up hp/tq that your engine already has. It is just plain physics as it takes X amount of Hp/Tq to overcome the inertia of the extra weight and mass of the heavier flywheel. Lighten up the flywheel and you can use the power elsewhere and in this case the power is used to move the car.
Using a lighter flywheel/clutch assembly in itself does not give you any more horsepower or torque. But doing so does free up hp/tq that your engine already has. It is just plain physics as it takes X amount of Hp/Tq to overcome the inertia of the extra weight and mass of the heavier flywheel. Lighten up the flywheel and you can use the power elsewhere and in this case the power is used to move the car.
Got a lightweight setup just sitting in my garage and running the stock dualmass as it is easier to drive on the street, it's for sure quieter and honestly don't see any dyno difference.
Sounds like more Aftermarket hype BS to get ya to buy their stuff to me.
Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
Guys,
A inertia dyno works w/ newtons laws.. nothing more nothing less.
F=ma
FxD (torque and work) = Ibar x Alpha (moment of inertia times angular accleration)
Work X Time = power.
A inertia dyno works w/ newtons laws.. nothing more nothing less.
F=ma
FxD (torque and work) = Ibar x Alpha (moment of inertia times angular accleration)
Work X Time = power.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 9,926
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Originally Posted by d48mclain
I've dynoed several combinations from stock dualmass, dual disk w/billet to single disk with lightened billet and found no real difference in any of them. At the drag strip the lighter flywheels seem to be a bit harder to find the sweat spot during launching.
Got a lightweight setup just sitting in my garage and running the stock dualmass as it is easier to drive on the street, it's for sure quieter and honestly don't see any dyno difference.
Sounds like more Aftermarket hype BS to get ya to buy their stuff to me.
Got a lightweight setup just sitting in my garage and running the stock dualmass as it is easier to drive on the street, it's for sure quieter and honestly don't see any dyno difference.
Sounds like more Aftermarket hype BS to get ya to buy their stuff to me.
Burning Brakes
Joined: Nov 2004
Posts: 1,057
Likes: 0
From: Warren Ohio
Originally Posted by Alvin
Guys,
A inertia dyno works w/ newtons laws.. nothing more nothing less.
F=ma
FxD (torque and work) = Ibar x Alpha (moment of inertia times angular accleration)
Work X Time = power.
A inertia dyno works w/ newtons laws.. nothing more nothing less.
F=ma
FxD (torque and work) = Ibar x Alpha (moment of inertia times angular accleration)
Work X Time = power.
Exactly.
As mass (m) is reduced, the rate of acceleration produced by a given force (F) is increased.
Since the rate of acceleration is higher, the amount of work done over a given time period is increased...appearing as more power on an inertia dyno.
If this is the article ( http://vetteweb.com/tech/0407vet_flywheel/ ), they released about 10hp, and 10 ft. lbs. of torque by using a Fidanza flywheel on a stock Z06, and more on a modded Z.
Because the gain here is a delta between rates of acceleration, transmission gearing plays a significant role. A lighter flywheel will have a greater effect in the lower gears.
Somewhere in the archives, there's a post on the math involved to estimate the effects of changes in drivetrain mass on rwhp output. (I did a quick search, but couldn't find it.) As I recall, a 3300lb. car with the ZF6's gearing and a stock 3.45 rear end would gain about the same increase in performance from a 25lb. F/W mass reduction as it would by adding 27rwhp...in first gear only. It tapered down to something like 18hp in 2nd, 12hp in 3rd, etc.
So, yes...lighter is better.
Burning Brakes
Joined: Jun 2003
Posts: 937
Likes: 0
From: Bedford Tx
How does a inertia dyno,
handle unknown driveline inertia?
I kinda assume they make a guess, then
put the numbers into some
secret {read BS} fomula
to produce a RWHP number.
Do any of them --> REALLY <-- report
power delivered to the drum?
handle unknown driveline inertia?
I kinda assume they make a guess, then
put the numbers into some
secret {read BS} fomula
to produce a RWHP number.
Do any of them --> REALLY <-- report
power delivered to the drum?
Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
Originally Posted by silver84
How does a inertia dyno,
handle unknown driveline inertia?
I kinda assume they make a guess, then
put the numbers into some
secret {read BS} fomula
to produce a RWHP number.
Do any of them --> REALLY <-- report
power delivered to the drum?
handle unknown driveline inertia?
I kinda assume they make a guess, then
put the numbers into some
secret {read BS} fomula
to produce a RWHP number.
Do any of them --> REALLY <-- report
power delivered to the drum?
It doesn't need to, it measures raw force and power at the drum. If the car has a lighter flywheel it will put more force and power at the drum.
By secret BS formula I guess your referring to newtons laws.. the same stuff we used to put man on the moon.