Has anyone out there dyno their x/b, then switched to a set of lighter wheels and then hit the dyno again did you pick up any hp or tq ? My new Weedssports TC-005 are 12 pounds lighter per wheel than stock alloy scion wheel. My box will find out this friday when I get my act clutch street kit installed and will get two dyno runs. Does anyone think I will or won't pick up any hp your thoughts and your reasoning behind your answers.

Freddy

 

it doesnt add hp but it allows the engine to work easier to get up to speed and turn the wheels in essence freeing up a bit of lost hp.

 

Yes, cause they weigh less.

 

Well, they won't "add more power" like the title asks, but they may free up some power that heavier wheels are requiring. The biggest gain, IMO, is the savings in unsprung weight. It should help your handling and ride.

Many people think of the shocks and springs as holding the car up. IMO, they are there to hold the wheels down. Ever see a hooptie with a blown shock that has one wheel bouncing like mad. That corner of the car doesn't bounce up and down, the wheel bounces to the top of the suspension travel and the shock pushes it back to the ground, or at least it should. The less unsprung weight, the less the suspension has to fight to keep the wheels on the ground.

BTW, I generally think of my wheels as a performance mod. The looks are just gravy...

 

Great, thanks for shooting down my smartass comment.

 

I'm running oz wheels on my box just feels more responsive steering brakes and when you step on the gas. Unsprung weight thing.

 

Well I dynoed my car bone stock with 16x7 5Zigen FN01R-C Wrapped in Nitto Neo Gen 205/50VR16 (13lbs. Aluminum rims,) and 91 Octane and I pulled 97.7 Hp and 101.2 ft.lbs.

 

If you saved 48 lbs.total for the 4 wheels, you get a better power to weight ratio for the car which means the power you have will be more efficient for the lower overall weight. However I don't know if you'll notice the difference much since you only removed around 1/40th of the cars weight. Although if you were a drag racer that would be a significant amount.

All of the other things mentioned above about unsprung weight, etc are also true.

johncal

 

Im just GuessinG, I think the light wheels will make for a better power to weight ratio, that and reducing rotational mass, that stuff will translate to slightly better acceleration getting your rpms higher faster, but I don't think that will show up on the dyno cuz it measures power to rpms.
you can dyno using speed but thats weird.

 

I just talked to my dyno guy he said it might show up as 1-2 hp but it might not show up at all. Once the wheels are up to speed it really doesn't matter on the weight of the wheel. I will see an inprovment at the track because less weight will make the box go down the track quicker. Two ways to go faster either more hp or make your x/b lighter.

Since the weight came off a moving part it should rev quicker + and help the box accelerate down the quarter mile. Iam curious to see if my box picks up any hp or tq so I will fork over 80.00 bucks for 3 pulls or is it 2 I dont remember. Just to see if anything happens. I will post the results on saturday when I get my box back with my new act clutch. Then I have to baby it for 500 miles so not to glaze the organic clutch face. I can't wait to feel that heavy duty pessure plate under my left foot.

Only thing left to do once the clutch is broken in tear it up at the drag strip. With my drag radials and my hd pessure plate and clutch I will first try to get out of the hole around 3000 rpm and keep increasing my rpm higher untill my 60 footer slows done then go back to the last runs rpm . Hopefully I can leave at 3500- 4000 rpm that would be sweet since it's all about the 60 foot times and your r/t times in drag racing. I will set the drag radialsat 12-15 psi will give me enough bite and a little spin so not to break any parts.


Freddy

 

Yes, wheels will add power. Just don't interfere with the magic invisible wheel/engine connection.

 

I hear you can double you 'light wheel horse power' by adding an oil catch can...

 

there should be no question here Freddy... there is no way that wheels will add power to your car. Power comes from the engine, not your wheels. You could put tank treads or rollerskate wheels on your car... it won't matter, the horsepower will remain the same. This is like a 7 year old thinking he can run faster because he just got new sneakers. ( I was so guilty of this when I was 7 )

 

how much do the stock wheels weigh anyway?

 

I thought stock was only like 17 lbs or so... cant remember correctly off the top of my head... wouldn't that make your new wheels insanely light? 5 lbs per wheel?

I could be wrong about the stock wheel weight though... I 'll look that up later

 

Chimmy3;

My new wheels are 10 pounds each not 5lbs, the alloy EM-7 wheel with a 185 60 15 goodyear Ls tire was 37 lbs. The tire weight is 16lbs so the wheel weight is 21 lbs.

Freddy

 

lighter wheels= less rotating mass. "For every action, there's an equal and opposite reaction". While ur motor's trying to turn say 25lb 18s in ---> this direction, keep in mind that that 25lb rim is also exerting that weight back in this direction <----. Lighter rims have less momentumal resistance.