Reduce unsprung weight or add power/tq?
 

I'm considering one of these 2 options:

1. Enkei RPF1 wheels in stock size = 4 lbs. per corner weight reduction

2. Cobb AccessPort = 10 whp / 10 wtq

The price difference is not an issue, but I want to know what will better help accleration.

Thanks.

I think the wheels would help alittle bit more to get better accleration

My reason behind this power to weight ratio. Lets say the car weighs 3400 lbs and makes 200hp. Wioth the Cobb AccessPort you make 210. 3400/210=16.19.
Now with the new wheels the weight of the car is now 3384. And 3384/200=16.92. I know there isnt a big difference between the two products.

lets not forget he is talking about acceleration. the wheels are unsprung weight. just their pure physical weight reduction is not only noticed. its more than that. since the rotational mass of the wheels is reduced it takes a lot less effort to turn the wheels.

+1 for wheels.

wheels are rotational weight, just like a lightweight flywheel or pullies.

Order of performance gain

rotational weight(wheels, pullies, flywheel, light clutch, brake rotors)>unsprung weight(brake calipers, suspension parts)>sprung weight (everything else in the car)

The wheels work great! Saving brake weight= good. Saving exhaust system weight= good. Clutch and flywheels saving weight= good. Do you sense a trend?

except reducing sprung weight is free. :D just remove it.

also, the curb weight of the rx8 is 3053lbs.

Get the RPF1.
The wheels will help in multiple categories:
acceleration
steering
handling
looks
...
:dubs:

Very true!

I've been debating in my head what road to take. The light 17's, or nice looking 19's...

Keep in mind my version of nice looking 19's are some clean 5-spoke's powder coated dark gun metal. The only wheel I like for looks (in my opinion) on an 8 are some TSW Vortex. 19x9.5 all around, if it could fit would look nice...

I dunno, getting 17's would make it quicker, but looking good happens even when your parked.... You don't need to drive to prove what you payed for on 19's... And is 3 pounds the best there is? The lightest best looking wheel I've found are some Velox Pg-Rev10's but those things are not produced anymore, to bad because it weighed 12-13 pounds...

If I found a leightweight style wheel with the design I like than I'd be a buyer, just seen RPF-1's too many, everywhere...

Depends on the model. A fully loaded GT with nav comes in at 3060. Considering a base lacks the HIDs, DSC, TCS, moonroof, power and heated seats, Bose audio with 6 disc CD changer, navigation, keyless start, and satellite radio, I'm pretty sure a base will come in under 3000 pounds.

get the access port...6% horsepower gain throughout the hp curve and like 100 other very useful tools
the wheels imo would help very little with accel, try going to subway instead of micky d's for weight loss, hold the cheese...

Get the wheels, acceleration as well as cosmetic appeal.

Enkei 17x9 RPF1 45mm offest 15lbs - 1 inch wider perfect for 245/45/17" tires - 6 lbs per wheel - 24 lbs off rotational weight, plus same 24lbs off unsprung weight, plus same 24 lbs off total weight.

win - win - win

better acceleration, faster braking, lighter car - why do you care what people think your car looks like? For most people, even forgeting the wheels, it looks hellof a lot better than what they own anyway.

What about a set of wheels, running at between 8-9lbs per corner?

http://www.racelinewheels.com/p-224-magnesium.aspx

Too bad they only come in 17x7.5 .... I know that will pretty much put everyone off.

A wheel that light can even get damaged running off track or over the aprons.

Definately not for the street.

Besides they are7.5" wide.

I vote .. go for the wheels over Cobb

I did a little research, and I could be wrong about it, but car manufactures, etc have been using Magnesium for quite a while & it is supposed to be pretty strong.. Again, I could be wrong.. Also, yea.. It blows they only come in 17x7.5 .. It is the only size they are offering & I edited my post..

losing weight off your car IS equivalent to gaining hp...
actually, rather increasing ur power-to-weight ratio. plus the fact like all mentioned, better accel, braking, cornering, gas saving, and your pads lasts longer... whats to lose?

Saving weight is much better than simply upping the hp. It will effect braking, accelerating and handling in general. Lotus has used this strrategy for a while. +1 for the wheels

however, by the time your done getting a lightweight set of wheels and some good rubber, your looking at over a $2k bill... you better be gaining a shitload of performance for $2,ooo :eyetwitch

My 19x8.5 wheels weigh 2lbs less than OE wheels. In addition my tires also weigh 2lbs less than what came with the car so that is 4lbs less per wheel. Of course this is not the same savings you would get with RPF1 wheels but it is still a decent weight savings.

There's no shortcut to meaningful improvements, whether it be acceleration, braking improvement, steering response, better lateral Gs, improved ride, taughter suspension response, or improved mileage, for example using weight loss in specific components.

If you think losing pounds is troublesome and and expensive, Mazda (and other manufactures) often work on a "by the gram" weight loss improvement effort to reach their performance design goals. And here we are attempting to 'guild the lilly' so to speak, as Mazda is already done with their effort pretty much on our version of the 8!

But it all adds up - just like Karma :lol2:

Honestly if you just want improved acceleration, the Accessport might be the way to go. While wheels help in all dynamic situations and the Accessport doesn't, for acceleration purposes 10 hp might do more than a few pounds off the wheels.