Acceleration test AFTER weight reduction with some WEIRD results !!

[UnhuZ]

^ major relevant issue ... nice going Ross... i think that weight distribution would indeed play a crucial role in a steep accel like in 2nd from idle to 8000rpm.

Ross... i think you are right... don't know how much right, but right anyway...so, you are not wrong, but you can always give him the $100 discount anyways :tongue: :tongue: :tongue:

Nuno

 

[goldNSX]

I'm not with the weight distribution argument (other than selling products :tongue. It would count in turnes but MvM was driving straight. So less weight in the front would not hurt the excellent traction of the NSX in a way to see that much differences from the last samples.

 

[tbromley]

Now STIMPO just gave you a mouthful .....sounds like it may be a mouthful of cash - interesting. Me likey....this could get real good here!

 

[UnhuZ]

I'm not with the weight distribution argument (other than selling products :tongue. It would count in turnes but MvM was driving straight. So less weight in the front would not hurt the excellent traction of the NSX in a way to see that much differences from the last samples.

weight is not important only while cornering.

don't forget that the front being lighter, it will raise under hard accel, and the time the suspension is travelling up (front) and down (rear) due to weight unbalance, the car isn't moving forward...it's insignificant ammout of time, but probably enough to change is also expected tiny results :wink:

 

[goldNSX]

Nuno's point should be seen in the data. MvM: where does the NSX loose? Over the whole time or at the beginning? MvM could also mount his OEM set back on and retest again.

 

[greenberet]

Does anyone know just how much influence a difference in outside air temperature would make on engine performance?

You can calculate that using dyno correction factors. Assuming this webpage (http://www.csgnetwork.com/relhumhpcalc.html) applies the formulas correctly, a 3.5° C increase in ambient temperature should decrease horsepower by about 1%.

 

[StmpoRaceProducts]

I'm not with the weight distribution argument (other than selling products :tongue. It would count in turnes but MvM was driving straight. So less weight in the front would not hurt the excellent traction of the NSX in a way to see that much differences from the last samples.

Nuno's point should be seen in the data. MvM: where does the NSX loose? Over the whole time or at the beginning? MvM could also mount his OEM set back on and retest again.

Nuno is right... he is saying what I'm saying. this is math dude... super simple

ok... the hundred bucks was said because I am right...

Here is what will happen

take the stuff off the back without touching your suspension adjustments... I KNOW the numbers will fall in between the two averages... it's math...

spend the money to corner balance your car... you will beat all numbers!

Race teams make adjustments like this all the time.. f1 teams have even been caught and had points taken away for filling chassis tubes with water.

if water can change an f1 car... 50 lbs can chage the nsx

race teams also make adjustments using suspension adjustments... daily driver guys change ride hieght... when you changed your ride hieght... you screwed with every figure honda calculated... that 50 lbs could be more like 150 lbs because of it.

You bet your ass were trying to sell parts... all of our parts are functional.. and if your taking to time to remove the spare.. spend a couple hundred to loos the weight in the rear...

if your gonna tighten up your suspension... use a better part at a cheaper price.

also considered math...

Regards

 

[lowellhigh79]

Different day is the biggest variable. Just try another back to back run with and without the spare and +/- added weight in trunk. This should minimize differences in temp, humidity, wind, and tire. I bet you will be faster in the lighter car. Differences in aerodynamic drag from front lift is probably negligible in 20-100 kph (68 mph) acceleration runs. Besides, added lift from more air entering the front wheel well (after removal of the fog lights) probably created as much or more lift than weight distribution changes in a car that also had suspension changes (unpredictable new weight distribution could either exacerbate or reduce weight distribution changes from the weight reduction). Finally, keep in mind whatever the cause, rather than a faster time, we are talking slower, so the delta is more like double the weight loss amount, or 256 lbs.
Thanks for your efforts.

Danny

 

[StmpoRaceProducts]

Different day is the biggest variable. Just try another back to back run with and without the spare and +/- added weight in trunk. This should minimize differences in temp, humidity, wind, and tire. I bet you will be faster in the lighter car. Differences in aerodynamic drag from front lift is probably negligible in 20-100 kph (68 mph) acceleration runs. Besides, added lift from more air entering the front wheel well (after removal of the fog lights) probably created as much or more lift than weight distribution changes in a car that also had suspension changes (unpredictable new weight distribution could either exacerbate or reduce weight distribution changes from the weight reduction). Finally, keep in mind whatever the cause, rather than a faster time, we are talking slower, so the delta is more like double the weight loss amount, or 256 lbs.
Thanks for your efforts.

Danny

I hope that one day we can agree on things instead of making outragous opinions differently.. I said weight was responsible factor bacause his spring rates are wrong causing an exponetional amount of weight loss up front.. 50 lbs of actual solid componets and another couple hundred based on the spring not pushing enough of the front of the car down...

we both know what is happening... but you mentioned fog lights and used the word exacerbate...

Danny... you have to be an intellegent guy in order to incorporate the word exacerbate into any sentance from your mental usable vocabulary... intelegent people can agree on things...

the day my car is faster because I add 128lbs to it and fog lights... I'm going to buy 128 lbs of fog lights and bolt them on my car like it was some hum-v from the movie total recall

100 bucks off if Im wrong... i'll give you the rear bumper for free if your car is faster on a fog light swap only.

I'm not trying be a dick here bro... but continuing to try to let the community think I dont know what i'm talking about will only hurt that community in the long run.

You have 1000 hp NSX... you should consider stiffing your chassis... our products do work... they actualy work well... and they work even better on higher modded cars than they do un-modded cars.

Regards

 

[MvM]

Well guys, thanks you all for your input.

Unfortunately, as you will understand, it is very hard to quantify each opinion without doing more extensive testing. And having taken all the trouble to take the soft OEM suspension out and put the TEIN-RA with 10/10kg springs in I am not going to do all that again just to do these tests again.

GoldNSX,
As always, thanks for thinking with me.
I am a little busy at the moment but I will see if I can post the actual test-results for some of the runs. The differences seem to be throughout the run.
G-Forces during the tests usually start at around 0.30 G at the start to a max of about 0.41 G.

Greenberet,
Thanks for the link for the influence of temperature. I will have to buy a thermometer to measure outside temperatures for the next tests.

Danny,
Considering the link from Greenberet stating that 3.5 degrees makes 1% difference in HP, I will start using a thermomenter in the future.

STMPO:Thanks for your input on the influence of spring rates and front/rear balance on the acceleration of a car. Actually, I had no idea that changing out shocks and springs could make that much of a difference.

I am planning to do some more modifications on the car.
First, the OEM exhaust will be replaced with a Taitec GTLW. This of course will have influence on the power delivery of the car, which is why I had postponed it so far.

It would be easy to redo these tests in the future with some weight added in the passenger seat and/or trunk.
@STMPO: I assume you will agree that putting weight in the passenger seat should not change the balance of the car much if at all if I keep all other variables the same?

 

[StmpoRaceProducts]

Well guys, thanks you all for your input.

Unfortunately, as you will understand, it is very hard to quantify each opinion without doing more extensive testing. And having taken all the trouble to take the soft OEM suspension out and put the TEIN-RA with 10/10kg springs in I am not going to do all that again just to do these tests again.

GoldNSX,
As always, thanks for thinking with me.
I am a little busy at the moment but I will see if I can post the actual test-results for some of the runs. The differences seem to be throughout the run.
G-Forces during the tests usually start at around 0.30 G at the start to a max of about 0.41 G.

Greenberet,
Thanks for the link for the influence of temperature. I will have to buy a thermometer to measure outside temperatures for the next tests.

Danny,
Considering the link from Greenberet stating that 3.5 degrees makes 1% difference in HP, I will start using a thermomenter in the future.

STMPO:Thanks for your input on the influence of spring rates and front/rear balance on the acceleration of a car. Actually, I had no idea that changing out shocks and springs could make that much of a difference.

I am planning to do some more modifications on the car.
First, the OEM exhaust will be replaced with a Taitec GTLW. This of course will have influence on the power delivery of the car, which is why I had postponed it so far.

It would be easy to redo these tests in the future with some weight added in the passenger seat and/or trunk.
@STMPO: I assume you will agree that putting weight in the passenger seat should not change the balance of the car much if at all if I keep all other variables the same?

Weight added from left to right effect turns more than anything... a passenger is closer to the middle of the car so it would have a smaller impact on the change you made...

you need to adjust your spring rates to recieve the gains of what you did.

Regards

 

[Hapa88]

I think an easier way to test this would be to do a few runs with a 250+lb (110+ kg) passanger in the passanger seat. You can take him out and put him back in as many times as you want. . .

Do one run with him in the seat, do the next run without him. . Repeat and average the values.

 

[DB92]

Can anyone compare the torque curve within the test rpm range and a graph of the aerodynamic drag in the speed range of test? If you have a spike in drag at a lower torque range weight in some cases could be an advantage since it can carry momentum from a higher torque range. This may not be the case with your test, Im just saying this is a possible senario. Its called aero "dynamics" for a reason, right? It is not a constant at all speeds, and neither is our torque. Then again I could be completely wrong.

Weight, Torque curve, drag dynamic. From A to B within your test distance, there must be a ideal formula.
Also wouldnt stiff suspension in some cases slow a car very very incrementally? Im ready to be laughed at..lol

 

[goldNSX]

I think an easier way to test this would be to do a few runs with a 250+lb (110+ kg) passanger in the passanger seat. You can take him out and put him back in as many times as you want. . .

...depends on the passanger how long he/she's willing to take a seat in the NSX or how fast he/she'll get sick.

 

[gdae]

...depends on the passanger how long he/she's willing to take a seat in the NSX or how fast he/she'll get sick.

250lbs of bricks won't get sick.:wink:

 

[1BADNSX]

I am not familiar with the AP22, but I know the AX22 has GPS speed built into the system. Based on your description of the AP22, it sounds like your unit is like many of the Vericomm systems that don’t actually measure speed, they integrate the acceleration profile to calculate speed. Your “calibration” is just measuring the static angle of the instrument and you have to start from a dead stop to begin the calculation. After you start driving, road grade, and vehicle pitch effects the acceleration measurement due to gravity, and this effects the calculated speed. The bottom line, is they don’t measure speed, they calculate it, and the calculation has many areas that can induce error. Just my guess.

Bob

 

[StmpoRaceProducts]

I think an easier way to test this would be to do a few runs with a 250+lb (110+ kg) passanger in the passanger seat. You can take him out and put him back in as many times as you want. . .

Do one run with him in the seat, do the next run without him. . Repeat and average the values.

Can anyone compare the torque curve within the test rpm range and a graph of the aerodynamic drag in the speed range of test? If you have a spike in drag at a lower torque range weight in some cases could be an advantage since it can carry momentum from a higher torque range. This may not be the case with your test, Im just saying this is a possible senario. Its called aero "dynamics" for a reason, right? It is not a constant at all speeds, and neither is our torque. Then again I could be completly wrong.

Weight, Torque curve, drag dynamic. From A to B within your test distance, there must be a ideal formula. Since our engines power is not linear and there is dynamic resistance I thing you have to factor weight as having positive or negative influence on time.

Also wouldnt stiff suspension in some cases slow a car very very incrementally? Im ready to be laughed at..lol

OMG... I just realized I told myself a long time ago to stop posting on threads...

Suspensions are used to adjust weight distribution...

last time I say this... 97% of what happens on a track is suspension adjustments... 3% is aero

how would the weight distribution change if you added 250 lbs to the center of this..

how would it change the aero too

Regards

 

[goldNSX]

250lbs of bricks won't get sick.:wink:

True.

If Stmpo's argument should be right why not going a step further. Fill the trunk with water and measure again. :tongue:

 

[StmpoRaceProducts]

True.

If Stmpo's argument should be right why not going a step further. Fill the trunk with water and measure again. :tongue:

because Im saying to remove weight from the rear to equalize the front... adding weight to the rear will increase the problem

like adding weight to the left side of this very simple picture

im saying to take weight away from the left side

I'm trying to get people to understand their car more.. thats it man.

Regards

 

[goldNSX]

... adding weight to the rear will increase the problem

Indeed, it will. I was not serious with water in trunk, honestly.

The best thing would be to go back to the OEM wheels with their tires and test again. Then you see if the new tires on the OZ wheel count for the larger difference. I'm pretty sure you'll find it there (my argument) and not in the weight distribution (STMPO's argument) or suspension.

On thing about the AP-22. I've one too and you can set the tilt value of the car. Soft suspensions have a large value, stiffer ones a lower one. It's hard to tell the correct value. The AP-22's manual gives some recommendations on this but I personally didn't find any differences. I still believe the new tyres to be the cause. I bet a virtual beer with you.

 

[1BADNSX]

On thing about the AP-22. I've one too and you can set the tilt value of the car.

Well that answers it. The AP-22 does not measure speed, it integrates and calculates. Your vehicle is faster with less weight, but your measurement error is greater than the difference in speed.

Bob

 

[lowellhigh79]

I hope that one day we can agree on things instead of making outragous opinions differently.. I said weight was responsible factor bacause his spring rates are wrong causing an exponetional amount of weight loss up front.. 50 lbs of actual solid componets and another couple hundred based on the spring not pushing enough of the front of the car down...

we both know what is happening... but you mentioned fog lights and used the word exacerbate...

Danny... you have to be an intellegent guy in order to incorporate the word exacerbate into any sentance from your mental usable vocabulary... intelegent people can agree on things...

the day my car is faster because I add 128lbs to it and fog lights... I'm going to buy 128 lbs of fog lights and bolt them on my car like it was some hum-v from the movie total recall

100 bucks off if Im wrong... i'll give you the rear bumper for free if your car is faster on a fog light swap only.

I'm not trying be a dick here bro... but continuing to try to let the community think I dont know what i'm talking about will only hurt that community in the long run.

You have 1000 hp NSX... you should consider stiffing your chassis... our products do work... they actualy work well... and they work even better on higher modded cars than they do un-modded cars.

Regards

STMPO: Your aversion to anything beyond grade school English is both stunning and sad. You have no idea what the new weight distribution is after the suspension changes and simply presumed that the front became relatively stiffer thereby producing an "exponential amount of weight loss up front". Your continued lack of critical thinking and comprehension is excusable except when you attempt to sell your product as a remedy to an incorrect answer. As for your products, I will defer to others as to their quality (good) and application (beneficial). I have no need for your products as I have been through that path 5-15 years before: 3" Al square tube bumper replacements for front and back (2000), integrated front IC radiator bracket/subframe made of 3/16" Al channel mounted in the exact same location as your front chassis brace (2002), 4 point Al rear strut bar (2005), integrated twin turbo mounting sub-frame (2002), Seat belt harness bar mounted to B pillars (1996). Also, no need for the FSTB if none of the body structure in between the strut tower has been modified (cut).

GoldNSX and 1BADNSX, you may be on to something.

MVM, simply make another series of runs w/ and w/o the spare/engine cover and additional 60-70 lbs however you want to distribute them and let us know how it turns out.

Regards,

Danny

 

[StmpoRaceProducts]

STMPO: Your aversion to anything beyond grade school English is both stunning and sad. You have no idea what the new weight distribution is after the suspension changes and simply presumed that the front became relatively stiffer thereby producing an "exponential amount of weight loss up front". Your continued lack of critical thinking and comprehension is excusable except when you attempt to sell your product as a remedy to an incorrect answer. As for your products, I will defer to others as to their quality (good) and application (beneficial). I have no need for your products as I have been through that path 5-15 years before: 3" Al square tube bumper replacements for front and back (2000), integrated front IC radiator bracket/subframe made of 3/16" Al channel mounted in the exact same location as your front chassis brace (2002), 4 point Al rear strut bar (2005), integrated twin turbo mounting sub-frame (2002), Seat belt harness bar mounted to B pillars (1996). Also, no need for the FSTB if none of the body structure in between the strut tower has been modified (cut).

GoldNSX and 1BADNSX, you may be on to something.

MVM, simply make another series of runs w/ and w/o the spare/engine cover and additional 60-70 lbs however you want to distribute them and let us know how it turns out.

Regards,

Danny

Do as the Dr with long words says... and make sure you turn the fog lights on.

Regards

 

[goldNSX]

Do as the Dr with long words says... and make sure you turn the fog lights on.

Common, please chill out and take a ride on the thing in the picture you've posted.
Nice catch on trying to sell parts which will have a slight effect on the acceleration-numbers but NOT the effect we're trying to understand and discuss. :wink:

 

[MvM]

@1BADNSX
You are absolutely right, the AP-22 measures time and acceleration and from that will calculate speed.
The accuracy is 0.01 G and 0.01 seconds, meaning that is error in measurement as very much smaller than the differences in speed.
Actually, the only way to measure speed with an accuray greater than that of the AP22 would be by connecting calibrated external wheeled devices to your car.
The way I mount the AP22 to the dash has always the same since I've owned it.

@StmpoRaceProducts & All Others

Originally, the idea was to test my car as it was in stock conditon and later on when all changes had been made and total weighted reduced as much as possible.
This all to measure the effect of the reduced weight on the performance of the NSX. Something I think many owners might be interested in.

Now, it turns out than at least some of the changes have introduced factors into the test which cannot be truly quantified, meaning than these new variables have an unknown effect with adds or substracts from the effects of the changed weight.

So, I will continue with the planned changes to my car and AFTER I am more or less finished I will redo these test with the car as it is compared to the same car with enough added weights to get it back to its original weight of 1420 kg.

And since that last part should not be difficult, I might even do these tests with the weight place in front (battery hold), passenger seat and in the trunk.
Then we will also now the effect upon the acceleration times of the car of the same weight added to the car in different places.
Might turn out pretty interesting :smile: :smile: