Si Factory Accessories / Performance Parts Released!

[Tonezorz]

19" HFP Wheels

http://www.collegehillshonda.com/product/08W19-TEA-100.html

I quite like the look, but I do worry these will hamper the ride quality with reduced sidewall. Si would be my DD and California highways are junk.

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[TheRealWizzy]

I'm very much looking forward to adding the Si with my preferred options to my list of definite buys.

Same, I've been looking for a different (more fun) car since I bought my first car at 16. After thousands of hours searching over that the internet for a different car, I finally decided I am getting a blue Si coupe whenever a local dealership gets one. Was hoping to have it before my 20th birthday but it doesn't look like that is going to happen.

 

[Leetcivx]

19" HFP Wheels

http://www.collegehillshonda.com/product/08W19-TEA-100.html

i would have preferred lighter weight 17" instead of 19"

 

[ikbenben]

Then buy some OZ Ultraleggera's ??

 

[Design]

i would have preferred lighter weight 17" instead of 19"

Honda almost never offers significantly lighter or heavier wheels due to their spring/damper configurations. Net weight including tires is usually within 15% of the factory package.

 

[dmitri]

So do you guys know if losing as little as 2 or 3 lbs per wheel would actually make any sort of tangible difference in handling? (I.e. "tangible" to the point of it being worth investing $1000 or more into lighter wheels?)

 

[Metfanant]

So do you guys know if losing as little as 2 or 3 lbs per wheel would actually make any sort of tangible difference in handling? (I.e. "tangible" to the point of it being worth investing $1000 or more into lighter wheels?)

for the VAST majority of Si owners, who will never do more than the occasional dash between stop lights? Nope...of course it will objectively make your car faster...but noticeable on the street? Nah...

 

[Design]

So do you guys know if losing as little as 2 or 3 lbs per wheel would actually make any sort of tangible difference in handling? (I.e. "tangible" to the point of it being worth investing $1000 or more into lighter wheels?)

There are better areas to invest your money IMHO. Namely tires. You may see a small improvement in acceleration and braking. But those are usually overshadowed by a significant increase in road noise.

 

[joe007]

2 to 3 lbs per wheel (unsprung weight) will be a huge difference on the strip and on the track. You can get a decent set of lightweight wheels w/ tires (eg. RPF1) for cheaper than the HFP upgrade. Basically the HFP upgrade is stupid bling, like many of the Si features, unfortunately.

 

[dmitri]

2 to 3 lbs per wheel (unsprung weight) will be a huge difference on the strip and on the track.

So let me rephrase my original question a little, to clarify what I was asking (and make sure @Metfanant and @Design considered this when answering [which they probably did, but just in case]): is there any qualitative difference between getting/making 4 wheels each 2 lbs lighter, vs just removing those same 8 lbs from elsewhere, say from the cabin? I.e. reducing wheel weight specifically, vs just reducing overall weight by the same amount?
Quick online research seems to suggest there is a difference, but I was wondering if it will actually be noticeable when driving on the street. (Given the same tires and everything else)

You can get a decent set of lightweight wheels w/ tires (eg. RPF1) for cheaper than the HFP upgrade. Basically the HFP upgrade is stupid bling, like many of the Si features, unfortunately.

Yeah i know... I was looking at tirerack.com - but it's still a lot of money... Although I've no idea what the HFP ones will cost (or weigh, for that matter)...

 

[Metfanant]

So let me rephrase my original question a little, to clarify what I was asking (and make sure @Metfanant and @Design considered this when answering [which they probably did, but just in case]): is there any qualitative difference between getting/making 4 wheels each 2 lbs lighter, vs just removing those same 8 lbs from elsewhere, say from the cabin? I.e. reducing wheel weight specifically, vs just reducing overall weight by the same amount?
Quick online research seems to suggest there is a difference, but I was wondering if it will actually be noticeable when driving on the street. (Given the same tires and everything else)


Yeah i know... I was looking at tirerack.com - but it's still a lot of money... Although I've no idea what the HFP ones will cost (or weigh, for that matter)...

Yes, there is a difference, quite a big difference when you're dealing with unsprung vs spring weight...and even more so when you're dealing with rotational mass (wheels/tires)...

Removing 8lbs from your wheels/tires would be equivalent to removing a lot more weight from somewhere else on the car (like exhaust, seats, creature comforts, etc...)

If you have 2 cars with the same weight and power...the one with less unsprung weight will be faster...

That being said...I still don't think 8lbs is going to offer you a noticeable upgrade on the old butt dyno... we're talking fractions of a second in performance gains here

 

[ikbenben]

Losing unsprung weight gives more power at the wheels, less drivetrain loss.
1lbs unsprung weight has an equivalent of 4lbs spring weight. So losing 8lbs from your wheels gives the same result as losing 32lbs from elsewhere in your car.

 

[Browncoat3000]

Any prices showing yet?

 

[JYR]

I don't think there's going to be a lot of difference in straight line acceleration when comparing an Si to a non Si 1.5l Turbo civic w Hondata tune.

I recall reading the difference between the Si was just a factory tune. You may just as well be splitting hairs by comparing the two.

Be interesting to see how well the Si handles w it's suspension and lsd. On paper it looks good if not great, but who knows unless there's a test of the two.

Different turbo, and significantly different transmission. There will be differences.

Your assessment of a non-Si with Hondata tune is likely going to be apples to oranges. A tune is great, but not great without the supporting transmission. Honda offers fantastic grearboxes.

 

[zroger73]

Jason Fenske (Engineering Explained) does a good job explaining things in terms that are easier to understand. Here is his explanation on rotational inertia and why you want a flywheel and other components with a lower amount of it.

Part 1 of 2
Part 2 of 2

Here is an good article on unsprung weight and rotational inertia.

Part 1 of 2 http://hondaswap.com/threads/unsprung-weight-part-1.29057/
Part 2 of 2 http://hondaswap.com/threads/unsprung-weight-part-2.29058/

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