I had to read this twice and than it hit me..... ROPLMAO that is a good one ..... 2 thumbs up!!!!!!

It would worked very well Have done it but it is a trade off. The compressor is parasitic drag and also the extreme cool air going into your engine you would require to have a map adjusted for the ECU under thoer IAT operation caused by the AC into the intake .

First I NEVER said going heavier, stop wording things I did not say! As far as I am aware this was a conversation about a STREET DRIVIN DAILEY DRIVER and NOT A TRACK CAR!? lol
There is always those members that support arguments and debates with others information instead of there own real world testing ... LOL
You example has so many unmentioned and supportive values I wouldn't know where to start to explain but you go right ahead and buy your wheels and save 11 pounds off and feel the butt dyno kicking in on your daily driver!

If it makes you feel better on one of my street driven AC Cobras I ran true knock off (no lug nuts) Royal Epsilon wheels with Indy Blue Streaks
You can go do the research and see what that combo weight per wheel was.... LOL
Or my Super Gas Camaro with Centerlines, or my MCS with custom ordered magnesium Alexis wheels.....LOL
I could go on all day with examples.... but these were all cars with extremely modified suspension systems or for full Track use.
On the street car DAILEY DRIVER I prefer a little beefier wheel because of the varying road condition and don't want to be stuck on the side of the road with a broken lightweight wheel/tire combo saving 11bls per axle just to shave 4/10 of a second off my 0-60 times or less then .03 Gs on a 200 foot skid pad. . LOL



Btw before reducing weight on any vehicle track or street with the intent of increasing performance the first step is to get a certified weighing and if for track use or handling a 4 corner weighing. This should be done with a full tank of fuel.

 

But you did say it: "Odd I went with a heavier wheel than stock and it made no difference in my 0-60mph or 1/4 times...".

Of course you didn't say by how much, and I wasn't trying to say you said a lot of weight...just repeated that you said "heavier" and going heavier will hamper acceleration all other things being equal.

Now, you can poke holes in their test if you like (no test is "perfect"), but only God almighty can break the laws of physics man.

A lighter wheel/tire of the same radius (unless the weight distribution is absolutely crazy in how it is designed) will have lower polar moment of inertia than a heavy one, thus taking less force to accelerate. To put it into base terms, it takes less force to accelerate a lighter object about a given radius than it does a heavier one. Surely, you don't disagree with that.

Would a pound or two make much difference to a top fuel dragster? Probably not even measurable, but these vehicles don't make that kind of power. With a near 20% reduction in rotational mass (went from 60.8 to 49.8 lbs) on a vehicle that only makes what my Turbo does, like the test with the Miata showed, might very well be perceived.

All of this said, I hear you and I think I agree with the "spirit" of your reply!

The "butt dyno" is not very reliable. Far too many make claims without testing and I will test to verify.

 

^^^^^ in my world there is no such thing but also in my world is often used by many to argue there results. LOL
Most of the time the truth comes out with a simple Chassis Dyno run.

You would really need to be on a chassis DYNO do a short run remove the drive wheels replace with your "lighter tire/wheel combo repeat using a set established DELTA . Then look at the RPM vs HP and TQ , do not use ASE smoothing. Then post up those number based on the initial 11 lps per axle weight savings results!
Or by using an accelerometer and a known flat tarmac like a industrial parking lot, safety cone a 150-200 foot circumference and do a set MPG steady around that circle and note the delta. Then change to your tire/wheel combo and repeat . Note the results.
The 0-60 mph test like in the article has way to many uncontrollable influences and can not really be tested and related with DATA worthy of calling empirical.
I would suggest to stop using the laws of physics unless you really know all of them, that would apply for the conversation as your supportive argument because you are actually missing sever laws that apply.
Just so you know because yu are a new member I have engineered and developed suspension parts for performance on many platforms and must do extensive testing to make products claims that can be duplicated for results and also counted on for stated improvements or results.

But as I am pushing the limits of responding before the "dream team" starts in on me (small group of members that never seem to like my responses on forum's) the original OP question was how and what to get to improve performance related to engine output not suspension?

If you look in my signature below you should take a few minutes and go at least look at all the pictures?

 

I appreciate the reply!

You are absolutely correct in that specific testing criteria is needed to determine the amount of change. I've sold the old wheels so the best I can do is compare mine to published numbers and as you would point out, that's not very good data. I'm curious though and plan to do that.

As for the math (math minor with Comp Sci and Finance double major degrees), I understand it and there just cannot be any debate that lighter rotational mass will, all other things being equal, result in faster acceleration. Yes, other forces are applicable (note I said "all other things being equal) but for linear acceleration, we can focus there.

is a great overview of the math. He's a bit fast and loose with certain terms though (added horsepower comment....ugh).


You showed me some photos (very nice looking car BTW!)...here's something I built FWIW.

 

No one is arguing formulas but I am saying that the little benefits' for a street car are not worth all the talk and trouble. That video you posted has been debated and found while the theory is correct application with real world numbers goes back yo what I have been trying to convey that on a street car those small amount of weight are so little almost negligible.
BTW you can achieve a greater effect (in many circumstances) by simply going with a small diameter tire/wheel combo then struggling to save 11 lbs on the same size OEM wheel. If you were really sharp you may have caught that in a round about way by my responses and also my thread?
Your car is sharp looking for sure and I am surprised based on your saying you built that all this back and forth with me. You should know every thing I have been posted as accurate!
Interesting though I think we have talked on other forums. I now have a slight recollection of your picture and that vid posted somewhere else maybe a year or so ago?? IDK maybe not but it will come to me eventually/. hahahaha!

 

It could be we chatted elsewhere but probably not about that car as I sold it to a guy who races up north two years ago. Could be wrong though. I used to chat on 370Z forums (have had three of the beasties) so it could have been there. Also posted on several Coyote forums as the engine in that thing was BOSS/Coyote based.

I get what you are saying WRT what is, or isn't, applicable on the street, and agree in general. I'm just of the opinion that for the relatively weak output our cars have, the rotational mass is of greater importance....but it needs to be proven.

As for the smaller diameter part, agreed, but again, "all other things else being equal".

I think we are probably > 90% in alignment FWIW.

 

^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

Seriously, math videos
If you strap enough rockets on anything it'll go faster.
The Professor knows.

 

Ya I have had that video posted on a few forums I have participated on. It was posted a couple years ago on a PT Cruiser forum... LOL. While it was accurate in general theory the "kid" neglected to a few things that made it really a bad example to use regarding respirating parts on a vehicle... IMHPO I believe the reason he used car parts is the assumption that everyone knows how cars work. kind of like DIY on forums. Some are born knowing all about cars while others like myself had to go to schools to learn.
I prefer Nitous Oxide.....even on my daily driven Mazda 3 ......

 

Nitrous Oxide used to get me going after a long night back "way back" in the day.
Oh wait, you're talking about using it in a vehicle...
As for math, I was more of a grammar person, the videos were better.